自动适应TextView for Android

Question

背景

我们需要多次将TextView的字体自动调整到给定的边界。

问题

可悲的是，即使有很多主题和帖子（以及建议的解决方案）都在谈论这个问题（例如here，here和here），但它们都没有真正奏效。

这就是为什么，我决定测试每一个，直到我找到真正的交易。

我认为来自这样一个textView的要求应该是：

1. 应允许使用任何字体，字体，样式和字符集。

2. 应同时处理宽度和高度

3. 没有截断，除非文字由于限制而无法适应，我们已经 给它（例如：文本太长，可用尺寸太小）。但是，如果我们愿意，我们可以请求水平/垂直滚动条，仅适用于那些情况。

4. 应允许多行或单行。如果是多线，请允许max＆amp; min lines。

5. 计算不应该慢。使用循环找到最佳尺寸？至少要优化它，不要每次增加1个样本。

6. 如果是多行，应该允许更喜欢调整大小或使用更多行，和/或允许使用“\ n”字符自行选择行。

我尝试了什么

我已经尝试过这么多样本（包括链接的那些，我已经写过了），而且我也尝试修改它们来处理这些情况，我已经谈过了，但没有一个真正有效。< / p>

我做了一个示例项目，让我可以直观地看到TextView是否自动适合。

目前，我的示例项目只是随机化文本（英文字母加上数字）和textView的大小，并让它保持单行，但即使这样也不适用于我的任何样本试过。

这是代码（也可用here）：

档案res/layout/activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
  android:layout_height="match_parent" tools:context=".MainActivity">
  <Button android:id="@+id/button1" android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true" android:text="Button" />
  <FrameLayout android:layout_width="match_parent"
    android:layout_height="wrap_content" android:layout_above="@+id/button1"
    android:layout_alignParentLeft="true" android:background="#ffff0000"
    android:layout_alignParentRight="true" android:id="@+id/container"
    android:layout_alignParentTop="true" />

</RelativeLayout>

档案src/.../MainActivity.java

public class MainActivity extends Activity
  {
  private final Random        _random            =new Random();
  private static final String ALLOWED_CHARACTERS ="qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM1234567890";

  @Override
  protected void onCreate(final Bundle savedInstanceState)
    {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    final ViewGroup container=(ViewGroup)findViewById(R.id.container);
    findViewById(R.id.button1).setOnClickListener(new OnClickListener()
      {
        @Override
        public void onClick(final View v)
          {
          container.removeAllViews();
          final int maxWidth=container.getWidth();
          final int maxHeight=container.getHeight();
          final FontFitTextView fontFitTextView=new FontFitTextView(MainActivity.this);
          final int width=_random.nextInt(maxWidth)+1;
          final int height=_random.nextInt(maxHeight)+1;
          fontFitTextView.setLayoutParams(new LayoutParams(width,height));
          fontFitTextView.setSingleLine();
          fontFitTextView.setBackgroundColor(0xff00ff00);
          final String text=getRandomText();
          fontFitTextView.setText(text);
          container.addView(fontFitTextView);
          Log.d("DEBUG","width:"+width+" height:"+height+" text:"+text);
          }
      });
    }

  private String getRandomText()
    {
    final int textLength=_random.nextInt(20)+1;
    final StringBuilder builder=new StringBuilder();
    for(int i=0;i<textLength;++i)
      builder.append(ALLOWED_CHARACTERS.charAt(_random.nextInt(ALLOWED_CHARACTERS.length())));
    return builder.toString();
    }
  }

问题

有人知道这个常见问题的解决方案吗？

即使是一个解决方案，其功能要少得多，我所写的内容，例如只有一定数量的文本行，并根据其大小调整字体，但从来没有出现过奇怪的故障，并且与可用空间相比，文本变得太大/太小。

---

GitHub项目

由于这是一个非常重要的TextView，我决定发布一个库，以便每个人都可以轻松地使用它，并为此做出贡献，here。

Answer 1

感谢MartinH的简单修复here，此代码还会处理android:drawableLeft，android:drawableRight，android:drawableTop和android:drawableBottom标记。

---

我的回答应该让你开心Auto Scale TextView Text to Fit within Bounds

我修改了你的测试用例：

@Override
protected void onCreate(final Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    final ViewGroup container = (ViewGroup) findViewById(R.id.container);
    findViewById(R.id.button1).setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(final View v) {
            container.removeAllViews();
            final int maxWidth = container.getWidth();
            final int maxHeight = container.getHeight();
            final AutoResizeTextView fontFitTextView = new AutoResizeTextView(MainActivity.this);
            final int width = _random.nextInt(maxWidth) + 1;
            final int height = _random.nextInt(maxHeight) + 1;
            fontFitTextView.setLayoutParams(new FrameLayout.LayoutParams(
                    width, height));
            int maxLines = _random.nextInt(4) + 1;
            fontFitTextView.setMaxLines(maxLines);
            fontFitTextView.setTextSize(500);// max size
            fontFitTextView.enableSizeCache(false);
            fontFitTextView.setBackgroundColor(0xff00ff00);
            final String text = getRandomText();
            fontFitTextView.setText(text);
            container.addView(fontFitTextView);
            Log.d("DEBUG", "width:" + width + " height:" + height
                    + " text:" + text + " maxLines:" + maxLines);
        }
    });
}

我在每个 android开发者的请求中发布代码：

最终效果：

示例布局文件：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="16dp" >

<com.vj.widgets.AutoResizeTextView
    android:layout_width="match_parent"
    android:layout_height="100dp"
    android:ellipsize="none"
    android:maxLines="2"
    android:text="Auto Resized Text, max 2 lines"
    android:textSize="100sp" /> <!-- maximum size -->

<com.vj.widgets.AutoResizeTextView
    android:layout_width="match_parent"
    android:layout_height="100dp"
    android:ellipsize="none"
    android:gravity="center"
    android:maxLines="1"
    android:text="Auto Resized Text, max 1 line"
    android:textSize="100sp" /> <!-- maximum size -->

<com.vj.widgets.AutoResizeTextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="Auto Resized Text"
    android:textSize="500sp" /> <!-- maximum size -->

</LinearLayout>

和Java代码：

import android.annotation.TargetApi;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.RectF;
import android.os.Build;
import android.text.Layout.Alignment;
import android.text.StaticLayout;
import android.text.TextPaint;
import android.util.AttributeSet;
import android.util.SparseIntArray;
import android.util.TypedValue;
import android.widget.TextView;

public class AutoResizeTextView extends TextView {
    private interface SizeTester {
        /**
         *
         * @param suggestedSize
         *            Size of text to be tested
         * @param availableSpace
         *            available space in which text must fit
         * @return an integer < 0 if after applying {@code suggestedSize} to
         *         text, it takes less space than {@code availableSpace}, > 0
         *         otherwise
         */
        public int onTestSize(int suggestedSize, RectF availableSpace);
    }

    private RectF mTextRect = new RectF();

    private RectF mAvailableSpaceRect;

    private SparseIntArray mTextCachedSizes;

    private TextPaint mPaint;

    private float mMaxTextSize;

    private float mSpacingMult = 1.0f;

    private float mSpacingAdd = 0.0f;

    private float mMinTextSize = 20;

    private int mWidthLimit;

    private static final int NO_LINE_LIMIT = -1;
    private int mMaxLines;

    private boolean mEnableSizeCache = true;
    private boolean mInitializedDimens;

    public AutoResizeTextView(Context context) {
        super(context);
        initialize();
    }

    public AutoResizeTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
        initialize();
    }

    public AutoResizeTextView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        initialize();
    }

    private void initialize() {
        mPaint = new TextPaint(getPaint());
        mMaxTextSize = getTextSize();
        mAvailableSpaceRect = new RectF();
        mTextCachedSizes = new SparseIntArray();
        if (mMaxLines == 0) {
            // no value was assigned during construction
            mMaxLines = NO_LINE_LIMIT;
        }
    }

    @Override
    public void setTextSize(float size) {
        mMaxTextSize = size;
        mTextCachedSizes.clear();
        adjustTextSize();
    }

    @Override
    public void setMaxLines(int maxlines) {
        super.setMaxLines(maxlines);
        mMaxLines = maxlines;
        adjustTextSize();
    }

    public int getMaxLines() {
        return mMaxLines;
    }

    @Override
    public void setSingleLine() {
        super.setSingleLine();
        mMaxLines = 1;
        adjustTextSize();
    }

    @Override
    public void setSingleLine(boolean singleLine) {
        super.setSingleLine(singleLine);
        if (singleLine) {
            mMaxLines = 1;
        } else {
            mMaxLines = NO_LINE_LIMIT;
        }
        adjustTextSize();
    }

    @Override
    public void setLines(int lines) {
        super.setLines(lines);
        mMaxLines = lines;
        adjustTextSize();
    }

    @Override
    public void setTextSize(int unit, float size) {
        Context c = getContext();
        Resources r;

        if (c == null)
            r = Resources.getSystem();
        else
            r = c.getResources();
        mMaxTextSize = TypedValue.applyDimension(unit, size,
                r.getDisplayMetrics());
        mTextCachedSizes.clear();
        adjustTextSize();
    }

    @Override
    public void setLineSpacing(float add, float mult) {
        super.setLineSpacing(add, mult);
        mSpacingMult = mult;
        mSpacingAdd = add;
    }

    /**
     * Set the lower text size limit and invalidate the view
     *
     * @param minTextSize
     */
    public void setMinTextSize(float minTextSize) {
        mMinTextSize = minTextSize;
        adjustTextSize();
    }

    private void adjustTextSize() {
        if (!mInitializedDimens) {
            return;
        }
        int startSize = (int) mMinTextSize;
        int heightLimit = getMeasuredHeight() - getCompoundPaddingBottom()
                - getCompoundPaddingTop();
        mWidthLimit = getMeasuredWidth() - getCompoundPaddingLeft()
                - getCompoundPaddingRight();
        mAvailableSpaceRect.right = mWidthLimit;
        mAvailableSpaceRect.bottom = heightLimit;
        super.setTextSize(
                TypedValue.COMPLEX_UNIT_PX,
                efficientTextSizeSearch(startSize, (int) mMaxTextSize,
                        mSizeTester, mAvailableSpaceRect));
    }

    private final SizeTester mSizeTester = new SizeTester() {
        @TargetApi(Build.VERSION_CODES.JELLY_BEAN)
        @Override
        public int onTestSize(int suggestedSize, RectF availableSPace) {
            mPaint.setTextSize(suggestedSize);
            String text = getText().toString();
            boolean singleline = getMaxLines() == 1;
            if (singleline) {
                mTextRect.bottom = mPaint.getFontSpacing();
                mTextRect.right = mPaint.measureText(text);
            } else {
                StaticLayout layout = new StaticLayout(text, mPaint,
                        mWidthLimit, Alignment.ALIGN_NORMAL, mSpacingMult,
                        mSpacingAdd, true);

                // Return early if we have more lines
                if (getMaxLines() != NO_LINE_LIMIT
                        && layout.getLineCount() > getMaxLines()) {
                    return 1;
                }
                mTextRect.bottom = layout.getHeight();
                int maxWidth = -1;
                for (int i = 0; i < layout.getLineCount(); i++) {
                    if (maxWidth < layout.getLineWidth(i)) {
                        maxWidth = (int) layout.getLineWidth(i);
                    }
                }
                mTextRect.right = maxWidth;
            }

            mTextRect.offsetTo(0, 0);
            if (availableSPace.contains(mTextRect)) {

                // May be too small, don't worry we will find the best match
                return -1;
            } else {
                // too big
                return 1;
            }
        }
    };

    /**
     * Enables or disables size caching, enabling it will improve performance
     * where you are animating a value inside TextView. This stores the font
     * size against getText().length() Be careful though while enabling it as 0
     * takes more space than 1 on some fonts and so on.
     *
     * @param enable
     *            Enable font size caching
     */
    public void enableSizeCache(boolean enable) {
        mEnableSizeCache = enable;
        mTextCachedSizes.clear();
        adjustTextSize(getText().toString());
    }

    private int efficientTextSizeSearch(int start, int end,
            SizeTester sizeTester, RectF availableSpace) {
        if (!mEnableSizeCache) {
            return binarySearch(start, end, sizeTester, availableSpace);
        }
        int key = getText().toString().length();
        int size = mTextCachedSizes.get(key);
        if (size != 0) {
            return size;
        }
        size = binarySearch(start, end, sizeTester, availableSpace);
        mTextCachedSizes.put(key, size);
        return size;
    }

    private static int binarySearch(int start, int end, SizeTester sizeTester,
            RectF availableSpace) {
        int lastBest = start;
        int lo = start;
        int hi = end - 1;
        int mid = 0;
        while (lo <= hi) {
            mid = (lo + hi) >>> 1;
            int midValCmp = sizeTester.onTestSize(mid, availableSpace);
            if (midValCmp < 0) {
                lastBest = lo;
                lo = mid + 1;
            } else if (midValCmp > 0) {
                hi = mid - 1;
                lastBest = hi;
            } else {
                return mid;
            }
        }
        // Make sure to return the last best.
        // This is what should always be returned.
        return lastBest;

    }

    @Override
    protected void onTextChanged(final CharSequence text, final int start,
            final int before, final int after) {
        super.onTextChanged(text, start, before, after);
        adjustTextSize();
    }

    @Override
    protected void onSizeChanged(int width, int height, int oldwidth,
            int oldheight) {
        mInitializedDimens = true;
        mTextCachedSizes.clear();
        super.onSizeChanged(width, height, oldwidth, oldheight);
        if (width != oldwidth || height != oldheight) {
            adjustTextSize();
        }
    }
}

警告：

请注意Android 3.1（Honeycomb）中的resolved bug。

Answer 2

我已经修改了M-WaJeEh的答案，以考虑侧面的复合画面。

getCompoundPaddingXXXX()方法返回padding of the view + drawable space。例如，请参阅：TextView.getCompoundPaddingLeft()

<强>问题： 这样可以修复文本可用TextView空间的宽度和高度。如果我们不考虑可绘制的大小，它将被忽略，文本将最终与drawable重叠。

---

更新了细分受众群adjustTextSize(String)：

private void adjustTextSize(final String text) {
  if (!mInitialized) {
    return;
  }
  int heightLimit = getMeasuredHeight() - getCompoundPaddingBottom() - getCompoundPaddingTop();
  mWidthLimit = getMeasuredWidth() - getCompoundPaddingLeft() - getCompoundPaddingRight();

  mAvailableSpaceRect.right = mWidthLimit;
  mAvailableSpaceRect.bottom = heightLimit;

  int maxTextSplits = text.split(" ").length;
  AutoResizeTextView.super.setMaxLines(Math.min(maxTextSplits, mMaxLines));

  super.setTextSize(
      TypedValue.COMPLEX_UNIT_PX,
      binarySearch((int) mMinTextSize, (int) mMaxTextSize,
                   mSizeTester, mAvailableSpaceRect));
}

Answer 3

好的，我上周使用了大量重写我的代码，以精确适合您的测试。您现在可以复制1：1，它将立即起作用 - 包括setSingleLine()。如果您想要获得极端值，请务必调整MIN_TEXT_SIZE和MAX_TEXT_SIZE。

融合算法如下所示：

for (float testSize; (upperTextSize - lowerTextSize) > mThreshold;) {

    // Go to the mean value...
    testSize = (upperTextSize + lowerTextSize) / 2;

    // ... inflate the dummy TextView by setting a scaled textSize and the text...
    mTestView.setTextSize(TypedValue.COMPLEX_UNIT_SP, testSize / mScaledDensityFactor);
    mTestView.setText(text);

    // ... call measure to find the current values that the text WANTS to occupy
    mTestView.measure(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED);
    int tempHeight = mTestView.getMeasuredHeight();

    // ... decide whether those values are appropriate.
    if (tempHeight >= targetFieldHeight) {
        upperTextSize = testSize; // Font is too big, decrease upperSize
    }
    else {
        lowerTextSize = testSize; // Font is too small, increase lowerSize
    }
}

全班可以be found here.

现在结果非常灵活。这与xml中声明的相同，如下所示：

<com.example.myProject.AutoFitText
    android:id="@+id/textView"
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="4"
    android:text="@string/LoremIpsum" />

...以及在测试中以编程方式构建。

我真的希望你现在可以使用它。您现在可以立即致电setText(CharSequence text)来使用它。该课程处理极少数的例外，应该是坚如磐石的。该算法唯一支持不的是：

• 致电setMaxLines(x) x >= 2

但是如果你愿意，我已经添加了大量的评论来帮助你建立这个！

---

请注意：

如果您只是正常使用它而不将其限制在一行，那么可能会出现您之前提到的断字。这是 Android功能，不 AutoFitText的错误。 Android总是会破坏TextView太长的单词，这实际上非常方便。如果你想在这里进行干预，请从第203行开始查看我的评论和代码。我已经写了足够的分词和对你的认可，你今后需要做的只是将这些词分开，然后按你的意愿修改。

总之：您应该高度考虑重写您的测试以支持空间字符，如下所示：

final Random _random = new Random();
final String ALLOWED_CHARACTERS = "qwertyuiopasdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM1234567890";
final int textLength = _random.nextInt(80) + 20;
final StringBuilder builder = new StringBuilder();
for (int i = 0; i < textLength; ++i) {
    if (i % 7 == 0 && i != 0) {
        builder.append(" ");
    }
    builder.append(ALLOWED_CHARACTERS.charAt(_random.nextInt(ALLOWED_CHARACTERS.length())));
}
((AutoFitText) findViewById(R.id.textViewMessage)).setText(builder.toString());

这将产生非常美妙（和更现实）的结果 你会发现评论也可以帮助你开始这个问题。

祝你好运和最好的问候

Answer 4

我的要求是

• 单击ScalableTextView
• 打开listActivity并显示各种长度的字符串项。
• 从列表中选择文字。
• 将文本设置回另一个活动中的ScalableTextView。

我引用了链接：Auto Scale TextView Text to Fit within Bounds（包括评论）以及DialogTitle.java

我发现提供的解决方案很简单但不会动态更改文本框的大小。它很棒 列表视图中选定的文本长度大于 ScalableTextView中的现有文本长度。当选择长度小于ScalableTextView中现有文本的文本时，它不会增加文本的大小，显示较小尺寸的文本。

我修改了ScalableTextView.java，根据文本长度重新调整文本大小。这是我的ScalableTextView.java

public class ScalableTextView extends TextView
{
float defaultTextSize = 0.0f;

public ScalableTextView(Context context, AttributeSet attrs, int defStyle)
{
    super(context, attrs, defStyle);
    setSingleLine();
    setEllipsize(TruncateAt.END);
    defaultTextSize = getTextSize();
}

public ScalableTextView(Context context, AttributeSet attrs)
{
    super(context, attrs);
    setSingleLine();
    setEllipsize(TruncateAt.END);
    defaultTextSize = getTextSize();
}

public ScalableTextView(Context context)
{
    super(context);
    setSingleLine();
    setEllipsize(TruncateAt.END);
    defaultTextSize = getTextSize();
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
    setTextSize(TypedValue.COMPLEX_UNIT_PX, defaultTextSize);
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);

    final Layout layout = getLayout();
    if (layout != null)
    {
        final int lineCount = layout.getLineCount();
        if (lineCount > 0)
        {
            int ellipsisCount = layout.getEllipsisCount(lineCount - 1);
            while (ellipsisCount > 0)
            {
                final float textSize = getTextSize();

                // textSize is already expressed in pixels
                setTextSize(TypedValue.COMPLEX_UNIT_PX, (textSize - 1));

                super.onMeasure(widthMeasureSpec, heightMeasureSpec);
                ellipsisCount = layout.getEllipsisCount(lineCount - 1);
            }
        }
    }
}
}

快乐编码......

Answer 5

警告，Android 3（Honeycomb）和Android 4.0（冰淇淋三明治）中的错误

Androids版本：3.1 - 4.04有一个bug，即TextView中的setTextSize（）仅适用于第一次（第一次调用）。

Issue 22493: TextView height bug in Android 4.0 和 Issue 17343: button's height and text does not return to its original state after increase and decrease the text size on HoneyComb 中描述了该错误。

解决方法是在更改大小之前为分配给TextView的文本添加换行符：

final String DOUBLE_BYTE_SPACE = "\u3000";
textView.append(DOUBLE_BYTE_SPACE);

我在我的代码中使用它如下：

final String DOUBLE_BYTE_SPACE = "\u3000";
AutoResizeTextView textView = (AutoResizeTextView) view.findViewById(R.id.aTextView);
String fixString = "";
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.HONEYCOMB_MR1
   && android.os.Build.VERSION.SDK_INT <= android.os.Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1) {  
    fixString = DOUBLE_BYTE_SPACE;
}
textView.setText(fixString + "The text" + fixString);

我在文字的左右两侧加上这个“\ u3000”字符，让它保持居中。如果您将其对齐到左侧，则仅附加到右侧。当然它也可以嵌入AutoResizeTextView小部件，但我想在外面保留修复代码。

Answer 6

现在有了这个问题的官方解决方案。使用Android O自动调整TextViews可在支持库26中使用，并向后兼容到Android 4.0。

https://developer.android.com/preview/features/autosizing-textview.html

我不确定管理员是否删除了包含此信息的https://stackoverflow.com/a/42940171/47680。

Answer 7

我将解释这个属性如何逐步降低Android版本：

1-在项目gradle文件中导入android支持库26.x.x.如果IDE上没有支持库，它们将自动下载。

dependencies {
    compile 'com.android.support:support-v4:26.1.0'
    compile 'com.android.support:appcompat-v7:26.1.0'
    compile 'com.android.support:support-v13:26.1.0' }

allprojects {
    repositories {
        jcenter()
        maven {
            url "https://maven.google.com"
        }
    } }

2-打开你的布局XML文件，并像你的TextView一样重构这个标签。这种情况是：当在系统上填写字体大小时，将文本拟合到可用宽度，而不是自动换行。

<android.support.v7.widget.AppCompatTextView
            android:id="@+id/textViewAutoSize"
            android:layout_width="match_parent"
            android:layout_height="25dp"
            android:ellipsize="none"
            android:text="Auto size text with compatible lower android versions."
            android:textSize="12sp"
            app:autoSizeMaxTextSize="14sp"
            app:autoSizeMinTextSize="4sp"
            app:autoSizeStepGranularity="0.5sp"
            app:autoSizeTextType="uniform" />

Answer 8

从2018年6月开始，Android正式支持 Android 4.0（API级别14）及更高版本this feature。
使用Android 8.0（API级别26）及更高版本：

setAutoSizeTextTypeUniformWithConfiguration(int autoSizeMinTextSize, int autoSizeMaxTextSize, 
        int autoSizeStepGranularity, int unit);

Android 8.0之前的Android版本（API级别26）：

TextViewCompat.setAutoSizeTextTypeUniformWithConfiguration(TextView textView,
int autoSizeMinTextSize, int autoSizeMaxTextSize, int autoSizeStepGranularity, int unit)

查看我的详细信息answer。

Answer 9

将文本视图转换为图像，并在边界内缩放图像。

以下是有关如何将视图转换为图片的示例： Converting a view to Bitmap without displaying it in Android?

问题是，你的文字不可选，但它应该可以解决问题。我没有尝试过，所以我不确定它的外观（因为缩放）。

Answer 10

下面是avalancha TextView，增加了自定义Font的功能。

用法：

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:foo="http://schemas.android.com/apk/res-auto"
    android:layout_width="wrap_content"
    android:layout_height="match_parent" >

                <de.meinprospekt.androidhd.view.AutoFitText
                android:layout_width="wrap_content"
                android:layout_height="10dp"
                android:text="Small Text"
                android:textColor="#FFFFFF"
                android:textSize="100sp"
                foo:customFont="fonts/Roboto-Light.ttf" />

</FrameLayout>

不要忘记添加：xmlns：foo =“http://schemas.android.com/apk/res-auto”。字体应该在资产firectory

import java.util.ArrayList;
import java.util.List;

import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Paint;
import android.graphics.Typeface;
import android.os.Build;
import android.util.AttributeSet;
import android.util.Log;
import android.util.TypedValue;
import android.view.View;
import android.view.ViewGroup.LayoutParams;
import android.view.ViewTreeObserver;
import android.view.ViewTreeObserver.OnGlobalLayoutListener;
import android.widget.TextView;
import de.meinprospekt.androidhd.R;
import de.meinprospekt.androidhd.adapter.BrochuresHorizontalAdapter;
import de.meinprospekt.androidhd.util.LOG;

/**
 * https://stackoverflow.com/a/16174468/2075875 This class builds a new android Widget named AutoFitText which can be used instead of a TextView to
 * have the text font size in it automatically fit to match the screen width. Credits go largely to Dunni, gjpc, gregm and speedplane from
 * Stackoverflow, method has been (style-) optimized and rewritten to match android coding standards and our MBC. This version upgrades the original
 * "AutoFitTextView" to now also be adaptable to height and to accept the different TextView types (Button, TextClock etc.)
 * 
 * @author pheuschk
 * @createDate: 18.04.2013
 * 
 * combined with: https://stackoverflow.com/a/7197867/2075875
 */
@SuppressWarnings("unused")
public class AutoFitText extends TextView {

    private static final String TAG = AutoFitText.class.getSimpleName();

    /** Global min and max for text size. Remember: values are in pixels! */
    private final int MIN_TEXT_SIZE = 10;
    private final int MAX_TEXT_SIZE = 400;

    /** Flag for singleLine */
    private boolean mSingleLine = false;

    /**
     * A dummy {@link TextView} to test the text size without actually showing anything to the user
     */
    private TextView mTestView;

    /**
     * A dummy {@link Paint} to test the text size without actually showing anything to the user
     */
    private Paint mTestPaint;

    /**
     * Scaling factor for fonts. It's a method of calculating independently (!) from the actual density of the screen that is used so users have the
     * same experience on different devices. We will use DisplayMetrics in the Constructor to get the value of the factor and then calculate SP from
     * pixel values
     */
    private float mScaledDensityFactor;

    /**
     * Defines how close we want to be to the factual size of the Text-field. Lower values mean higher precision but also exponentially higher
     * computing cost (more loop runs)
     */
    private final float mThreshold = 0.5f;

    /**
     * Constructor for call without attributes --> invoke constructor with AttributeSet null
     * 
     * @param context
     */
    public AutoFitText(Context context) {
        this(context, null);
    }

    public AutoFitText(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(context, attrs);
    }

    public AutoFitText(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init(context, attrs);
    }

    private void init(Context context, AttributeSet attrs) {
        //TextViewPlus part https://stackoverflow.com/a/7197867/2075875
        TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.AutoFitText);
        String customFont = a.getString(R.styleable.AutoFitText_customFont);
        setCustomFont(context, customFont);
        a.recycle();

        // AutoFitText part
        mScaledDensityFactor = context.getResources().getDisplayMetrics().scaledDensity;
        mTestView = new TextView(context);

        mTestPaint = new Paint();
        mTestPaint.set(this.getPaint());

        this.getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {

            @Override
            public void onGlobalLayout() {
                // make an initial call to onSizeChanged to make sure that refitText is triggered
                onSizeChanged(AutoFitText.this.getWidth(), AutoFitText.this.getHeight(), 0, 0);
                // Remove the LayoutListener immediately so we don't run into an infinite loop
                //AutoFitText.this.getViewTreeObserver().removeOnGlobalLayoutListener(this);
                removeOnGlobalLayoutListener(AutoFitText.this, this);
            }
        });
    }

    public boolean setCustomFont(Context ctx, String asset) {
        Typeface tf = null;
        try {
        tf = Typeface.createFromAsset(ctx.getAssets(), asset);  
        } catch (Exception e) {
            LOG.e(TAG, "Could not get typeface: "+e.getMessage());
            return false;
        }

        setTypeface(tf);  
        return true;
    }

    @SuppressLint("NewApi")
    public static void removeOnGlobalLayoutListener(View v, ViewTreeObserver.OnGlobalLayoutListener listener){
        if (Build.VERSION.SDK_INT < 16) {
            v.getViewTreeObserver().removeGlobalOnLayoutListener(listener);
        } else {
            v.getViewTreeObserver().removeOnGlobalLayoutListener(listener);
        }
    }

    /**
     * Main method of this widget. Resizes the font so the specified text fits in the text box assuming the text box has the specified width. This is
     * done via a dummy text view that is refit until it matches the real target width and height up to a certain threshold factor
     * 
     * @param targetFieldWidth The width that the TextView currently has and wants filled
     * @param targetFieldHeight The width that the TextView currently has and wants filled
     */
    private void refitText(String text, int targetFieldWidth, int targetFieldHeight) {

        // Variables need to be visible outside the loops for later use. Remember size is in pixels
        float lowerTextSize = MIN_TEXT_SIZE;
        float upperTextSize = MAX_TEXT_SIZE;

        // Force the text to wrap. In principle this is not necessary since the dummy TextView
        // already does this for us but in rare cases adding this line can prevent flickering
        this.setMaxWidth(targetFieldWidth);

        // Padding should not be an issue since we never define it programmatically in this app
        // but just to to be sure we cut it off here
        targetFieldWidth = targetFieldWidth - this.getPaddingLeft() - this.getPaddingRight();
        targetFieldHeight = targetFieldHeight - this.getPaddingTop() - this.getPaddingBottom();

        // Initialize the dummy with some params (that are largely ignored anyway, but this is
        // mandatory to not get a NullPointerException)
        mTestView.setLayoutParams(new LayoutParams(targetFieldWidth, targetFieldHeight));

        // maxWidth is crucial! Otherwise the text would never line wrap but blow up the width
        mTestView.setMaxWidth(targetFieldWidth);

        if (mSingleLine) {
            // the user requested a single line. This is very easy to do since we primarily need to
            // respect the width, don't have to break, don't have to measure...

            /*************************** Converging algorithm 1 ***********************************/
            for (float testSize; (upperTextSize - lowerTextSize) > mThreshold;) {

                // Go to the mean value...
                testSize = (upperTextSize + lowerTextSize) / 2;

                mTestView.setTextSize(TypedValue.COMPLEX_UNIT_SP, testSize / mScaledDensityFactor);
                mTestView.setText(text);
                mTestView.measure(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED);

                if (mTestView.getMeasuredWidth() >= targetFieldWidth) {
                    upperTextSize = testSize; // Font is too big, decrease upperSize
                } else {
                    lowerTextSize = testSize; // Font is too small, increase lowerSize
                }
            }
            /**************************************************************************************/

            // In rare cases with very little letters and width > height we have vertical overlap!
            mTestView.measure(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED);

            if (mTestView.getMeasuredHeight() > targetFieldHeight) {
                upperTextSize = lowerTextSize;
                lowerTextSize = MIN_TEXT_SIZE;

                /*************************** Converging algorithm 1.5 *****************************/
                for (float testSize; (upperTextSize - lowerTextSize) > mThreshold;) {

                    // Go to the mean value...
                    testSize = (upperTextSize + lowerTextSize) / 2;

                    mTestView.setTextSize(TypedValue.COMPLEX_UNIT_SP, testSize / mScaledDensityFactor);
                    mTestView.setText(text);
                    mTestView.measure(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED);

                    if (mTestView.getMeasuredHeight() >= targetFieldHeight) {
                        upperTextSize = testSize; // Font is too big, decrease upperSize
                    } else {
                        lowerTextSize = testSize; // Font is too small, increase lowerSize
                    }
                }
                /**********************************************************************************/
            }
        } else {

            /*********************** Converging algorithm 2 ***************************************/
            // Upper and lower size converge over time. As soon as they're close enough the loop
            // stops
            // TODO probe the algorithm for cost (ATM possibly O(n^2)) and optimize if possible
            for (float testSize; (upperTextSize - lowerTextSize) > mThreshold;) {

                // Go to the mean value...
                testSize = (upperTextSize + lowerTextSize) / 2;

                // ... inflate the dummy TextView by setting a scaled textSize and the text...
                mTestView.setTextSize(TypedValue.COMPLEX_UNIT_SP, testSize / mScaledDensityFactor);
                mTestView.setText(text);

                // ... call measure to find the current values that the text WANTS to occupy
                mTestView.measure(MeasureSpec.UNSPECIFIED, MeasureSpec.UNSPECIFIED);
                int tempHeight = mTestView.getMeasuredHeight();
                // int tempWidth = mTestView.getMeasuredWidth();

                // LOG.debug("Measured: " + tempWidth + "x" + tempHeight);
                // LOG.debug("TextSize: " + testSize / mScaledDensityFactor);

                // ... decide whether those values are appropriate.
                if (tempHeight >= targetFieldHeight) {
                    upperTextSize = testSize; // Font is too big, decrease upperSize
                } else {
                    lowerTextSize = testSize; // Font is too small, increase lowerSize
                }
            }
            /**************************************************************************************/

            // It is possible that a single word is wider than the box. The Android system would
            // wrap this for us. But if you want to decide fo yourself where exactly to break or to
            // add a hyphen or something than you're going to want to implement something like this:
            mTestPaint.setTextSize(lowerTextSize);
            List<String> words = new ArrayList<String>();

            for (String s : text.split(" ")) {
                Log.i("tag", "Word: " + s);
                words.add(s);
            }
            for (String word : words) {
                if (mTestPaint.measureText(word) >= targetFieldWidth) {
                    List<String> pieces = new ArrayList<String>();
                    // pieces = breakWord(word, mTestPaint.measureText(word), targetFieldWidth);

                    // Add code to handle the pieces here...
                }
            }
        }

        /**
         * We are now at most the value of threshold away from the actual size. To rather undershoot than overshoot use the lower value. To match
         * different screens convert to SP first. See {@link http://developer.android.com/guide/topics/resources/more-resources.html#Dimension} for
         * more details
         */
        this.setTextSize(TypedValue.COMPLEX_UNIT_SP, lowerTextSize / mScaledDensityFactor);
        return;
    }

    /**
     * This method receives a call upon a change in text content of the TextView. Unfortunately it is also called - among others - upon text size
     * change which means that we MUST NEVER CALL {@link #refitText(String)} from this method! Doing so would result in an endless loop that would
     * ultimately result in a stack overflow and termination of the application
     * 
     * So for the time being this method does absolutely nothing. If you want to notify the view of a changed text call {@link #setText(CharSequence)}
     */
    @Override
    protected void onTextChanged(CharSequence text, int start, int lengthBefore, int lengthAfter) {
        // Super implementation is also intentionally empty so for now we do absolutely nothing here
        super.onTextChanged(text, start, lengthBefore, lengthAfter);
    }

    @Override
    protected void onSizeChanged(int width, int height, int oldWidth, int oldHeight) {
        if (width != oldWidth && height != oldHeight) {
            refitText(this.getText().toString(), width, height);
        }
    }

    /**
     * This method is guaranteed to be called by {@link TextView#setText(CharSequence)} immediately. Therefore we can safely add our modifications
     * here and then have the parent class resume its work. So if text has changed you should always call {@link TextView#setText(CharSequence)} or
     * {@link TextView#setText(CharSequence, BufferType)} if you know whether the {@link BufferType} is normal, editable or spannable. Note: the
     * method will default to {@link BufferType#NORMAL} if you don't pass an argument.
     */
    @Override
    public void setText(CharSequence text, BufferType type) {

        int targetFieldWidth = this.getWidth();
        int targetFieldHeight = this.getHeight();

        if (targetFieldWidth <= 0 || targetFieldHeight <= 0 || text.equals("")) {
            // Log.v("tag", "Some values are empty, AutoFitText was not able to construct properly");
        } else {
            refitText(text.toString(), targetFieldWidth, targetFieldHeight);
        }
        super.setText(text, type);
    }

    /**
     * TODO add sensibility for {@link #setMaxLines(int)} invocations
     */
    @Override
    public void setMaxLines(int maxLines) {
        // TODO Implement support for this. This could be relatively easy. The idea would probably
        // be to manipulate the targetHeight in the refitText-method and then have the algorithm do
        // its job business as usual. Nonetheless, remember the height will have to be lowered
        // dynamically as the font size shrinks so it won't be a walk in the park still
        if (maxLines == 1) {
            this.setSingleLine(true);
        } else {
            throw new UnsupportedOperationException("MaxLines != 1 are not implemented in AutoFitText yet, use TextView instead");
        }
    }

    @Override
    public void setSingleLine(boolean singleLine) {
        // save the requested value in an instance variable to be able to decide later
        mSingleLine = singleLine;
        super.setSingleLine(singleLine);
    }
}

已知错误： 不适用于Android 4.03 - 字体不可见或非常小（原始avalancha也不起作用） 以下是该错误的解决方法：https://stackoverflow.com/a/21851239/2075875

Answer 11

尝试将LayoutParams和MaxWidth以及MaxHeight添加到TextView。它将强制布局尊重父容器而不是溢出。

textview.setLayoutParams(new LayoutParams(LinearLayout.MATCH_PARENT,LinearLayout.WRAP_CONTENT));

int GeneralApproxWidthOfContainer = 400;
int GeneralApproxHeightOfContainer = 600;
textview.setMaxWidth(400);
textview.setMaxHeight(600);` 

Answer 12

试试这个

TextWatcher changeText = new TextWatcher() {
     @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {
                tv3.setText(et.getText().toString());
                tv3.post(new Runnable() {           
                    @Override
                    public void run() {
                    while(tv3.getLineCount() >= 3){                     
                            tv3.setTextSize((tv3.getTextSize())-1);                     
                        }
                    }
                });
            }

            @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) {}

            @Override public void afterTextChanged(Editable s) { }
        };

Answer 13

如果您正在寻找更轻松的事情：

 public MyTextView extends TextView{

    public void resize(String text, float textViewWidth, float textViewHeight) {
       Paint p = new Paint();
       Rect bounds = new Rect();
       p.setTextSize(1);
       p.getTextBounds(text, 0, text.length(), bounds);
       float widthDifference = (textViewWidth)/bounds.width();
       float heightDifference = (textViewHeight);
       textSize = Math.min(widthDifference, heightDifference);
       setTextSize(TypedValue.COMPLEX_UNIT_PX, textSize);
}

Answer 14

快速修复@Malachiasz描述的问题

我已通过在自动调整大小类中添加自定义支持来修复此问题：

public void setTextCompat(final CharSequence text) {
    setTextCompat(text, BufferType.NORMAL);
}

public void setTextCompat(final CharSequence text, BufferType type) {
    // Quick fix for Android Honeycomb and Ice Cream Sandwich which sets the text only on the first call
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB_MR1 &&
        Build.VERSION.SDK_INT <= Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1) {
        super.setText(DOUBLE_BYTE_WORDJOINER + text + DOUBLE_BYTE_WORDJOINER, type);
    } else {
        super.setText(text, type);
    }
}

@Override
public CharSequence getText() {
    String originalText = super.getText().toString();
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB_MR1 &&
        Build.VERSION.SDK_INT <= Build.VERSION_CODES.ICE_CREAM_SANDWICH_MR1) {
        // We try to remove the word joiners we added using compat method - if none found - this will do nothing.
        return originalText.replaceAll(DOUBLE_BYTE_WORDJOINER, "");
    } else {
        return originalText;
    }
}

只需拨打yourView.setTextCompat(newTextValue)而不是yourView.setText(newTextValue)

Answer 15

从Android O开始，可以在xml：

中自动调整文本大小

https://developer.android.com/preview/features/autosizing-textview.html

  <TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    app:autoSizeTextType="uniform"
    app:autoSizeMinTextSize="12sp"
    app:autoSizeMaxTextSize="100sp"
    app:autoSizeStepGranularity="2sp"
  />

  

Android O允许您指示TextView使文本大小   自动扩展或收缩以填充其布局   TextView的特性和边界。这个设置成功了   使用动态更容易在不同屏幕上优化文本大小   内容。

     

支持库26.0 Beta为自动调整提供全面支持   在Android之前运行Android版本的设备上的TextView功能   O.该库提供对Android 4.0（API级别14）和   更高。 android.support.v4.widget包中包含   TextViewCompat类用于访问向后兼容的功能   方式。

Answer 16

在尝试使用Android官方Autosizing TextView后，我发现您的Android版本是否低于Android 8.0（API级别26），则需要使用android.support.v7.widget.AppCompatTextView，并确保您的支持库版本高于26.0 .0。示例：

<android.support.v7.widget.AppCompatTextView
    android:layout_width="130dp"
    android:layout_height="32dp"
    android:maxLines="1"
    app:autoSizeMaxTextSize="22sp"
    app:autoSizeMinTextSize="12sp"
    app:autoSizeStepGranularity="2sp"
    app:autoSizeTextType="uniform" />

更新：

根据@ android-developer的回复，我检查了AppCompatActivity源代码，并在onCreate中找到了这两行

final AppCompatDelegate delegate = getDelegate(); delegate.installViewFactory();

和AppCompatDelegateImpl的{​​{1}}

中

createView

它使用 if (mAppCompatViewInflater == null) { mAppCompatViewInflater = new AppCompatViewInflater(); } 膨胀视图，当AppCompatViewInflater createView时，它将对“ TextView”使用AppCompatTextView。

AppCompatViewInflater

在我的项目中，我不使用public final View createView(){ ... View view = null; switch (name) { case "TextView": view = new AppCompatTextView(context, attrs); break; case "ImageView": view = new AppCompatImageView(context, attrs); break; case "Button": view = new AppCompatButton(context, attrs); break; ... } ，因此我需要在xml中使用AppCompatActivity。