Question

我有一个TextView，其中每个单词都是一个ClickableSpan（实际上是ClickableSpan的一个自定义子类）。触摸单词时，应以粗体显示。 如果我在TextView上设置了textIsSelectable（false），它就可以正常工作。该单词会立即以粗体显示。但是，如果文本是可选的，则它将不起作用。但是-如果我触摸某个单词，然后关闭然后再打开屏幕，则当屏幕显示恢复时，该单词将以粗体显示。我已经尝试了所有可以想到的事情来强制重绘（使TextView无效，在TextView上强制调用Activity的onRestart（），refreshDrawableState（）等）。我想念什么？

这是我的ClickableSpan子类：

public class WordSpan extends ClickableSpan
{
    int id;
    private boolean marking = false;
    TextPaint tp;
    Typeface font;
    int color = Color.BLACK;

    public WordSpan(int id, Typeface font, boolean marked) {
        this.id = id;
        marking = marked;
        this.font = font;
    }

    @Override
    public void updateDrawState(TextPaint ds) {
        ds.setColor(color);
        ds.setUnderlineText(false);

        if (marking)
            ds.setTypeface(Typeface.create(font,Typeface.BOLD));

        tp = ds;
    }

    @Override
    public void onClick(View v) {
        // Empty here -- overriden in activity
    }

    public void setMarking(boolean m) {
        marking = m;
        updateDrawState(tp);
    }

    public void setColor(int col) {
        color = col;
    }
}

这是我的活动中的WordSpan实例化代码：

... looping through words

curSpan = new WordSpan(index,myFont,index==selectedWordId) {
    @Override
    public void onClick(View view) {
        handleWordClick(index,this);
        setMarking(true);
        tvText.invalidate();
    }
};

... continue loop code

这是我自定义的MovementMethod：

public static MovementMethod createMovementMethod ( Context context ) {
    final GestureDetector detector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() {
        @Override
        public boolean onSingleTapUp ( MotionEvent e ) {
            return true;
        }

        @Override
        public boolean onSingleTapConfirmed ( MotionEvent e ) {
            return false;
        }

        @Override
        public boolean onDown ( MotionEvent e ) {
            return false;
        }

        @Override
        public boolean onDoubleTap ( MotionEvent e ) {
            return false;
        }

        @Override
        public void onShowPress ( MotionEvent e ) {
            return;
        }
    });

    return new ScrollingMovementMethod() {

        @Override
        public boolean canSelectArbitrarily () {
            return true;
        }

        @Override
        public void initialize(TextView widget, Spannable text) {
            Selection.setSelection(text, text.length());
        }

        @Override
        public void onTakeFocus(TextView view, Spannable text, int dir) {

            if ((dir & (View.FOCUS_FORWARD | View.FOCUS_DOWN)) != 0) {
                if (view.getLayout() == null) {
                    // This shouldn't be null, but do something sensible if it is.
                    Selection.setSelection(text, text.length());
                }
            } else {
                Selection.setSelection(text, text.length());
            }
        }

        @Override
        public boolean onTouchEvent ( TextView widget, Spannable buffer, MotionEvent event ) {
            // check if event is a single tab
            boolean isClickEvent = detector.onTouchEvent(event);

            // detect span that was clicked
            if (isClickEvent) {
                int x = (int) event.getX();
                int y = (int) event.getY();

                x -= widget.getTotalPaddingLeft();
                y -= widget.getTotalPaddingTop();

                x += widget.getScrollX();
                y += widget.getScrollY();

                Layout layout = widget.getLayout();
                int line = layout.getLineForVertical(y);
                int off = layout.getOffsetForHorizontal(line, x);

                WordSpan[] link = buffer.getSpans(off, off, WordSpan.class);

                if (link.length != 0) {
                    // execute click only for first clickable span
                    // can be a for each loop to execute every one

                    if (event.getAction() == MotionEvent.ACTION_UP) {
                        link[0].onClick(widget);
                        return true;
                    }
                    else if (event.getAction() == MotionEvent.ACTION_DOWN) {
                        Selection.setSelection(buffer,
                                               buffer.getSpanStart(link[0]),
                                               buffer.getSpanEnd(link[0]));

                        return false;
                    }
                }
                else {

                }
            }

            // let scroll movement handle the touch
            return super.onTouchEvent(widget, buffer, event);
        }
    };
}

Answer 1

当文本设置为可选（TextView#setTextIsSelectable(true)）时，您的跨度将变得不可变。这是Understanding Spans上的一篇很好的文章，解释了跨度的可变性。我还认为this post有一些很好的解释

我不确定您的跨度如何变得一成不变。也许它们是可变的，但只是没有表现出来？目前尚不清楚。也许有人对此行为有一个解释。但是，现在，有一个解决方法：

旋转设备或关闭设备后再打开时，将重新创建或重新应用跨度。这就是为什么您看到更改。解决方法是不要单击时尝试更改跨度，而是以粗体显示的字体重新应用它。这样，更改将生效。您甚至都不需要致电invalidate()。跟踪加粗的跨度，以便以后单击另一个跨度时可以将其取消锁定。

这是结果：

这是主要活动。（请原谅所有硬编码，但这只是一个示例。）

MainActivity.java

public class MainActivity extends AppCompatActivity {

    private TextView mTextView;
    private WordSpan mBoldedSpan;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        Typeface myFont = Typeface.DEFAULT;

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mTextView = findViewById(R.id.textView);
        mTextView.setTextIsSelectable(true);

        mTextView.setMovementMethod(createMovementMethod(this));
        SpannableString ss = new SpannableString("Hello world! ");
        int[][] spanStartEnd = new int[][]{{0, 5}, {6, 12}};
        for (int i = 0; i < spanStartEnd.length; i++) {
            WordSpan wordSpan = new WordSpan(i, myFont, false) {
                @Override
                public void onClick(View view) {
//                handleWordClick(index, this); // Not sure what this does.
                    Spannable ss = (Spannable) mTextView.getText();
                    if (mBoldedSpan != null) {
                        reapplySpan(ss, mBoldedSpan, false);
                    }
                    reapplySpan(ss, this, true);
                    mBoldedSpan = this;
                }

                private void reapplySpan(Spannable spannable, WordSpan span, boolean isBold) {
                    int spanStart = spannable.getSpanStart(span);
                    int spanEnd = spannable.getSpanEnd(span);
                    span.setMarking(isBold);
                    spannable.setSpan(span, spanStart, spanEnd, Spanned.SPAN_INCLUSIVE_INCLUSIVE);
                }
            };
            ss.setSpan(wordSpan, spanStartEnd[i][0], spanStartEnd[i][1],
                       Spanned.SPAN_INCLUSIVE_INCLUSIVE);
        }

        mTextView.setText(ss, TextView.BufferType.SPANNABLE);
    }
    // All the other code follows without modification.
}

activity_main.xml

<android.support.constraint.ConstraintLayout 
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="30sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.04000002"
        tools:text="Hello World!" />

</android.support.constraint.ConstraintLayout>

这里是使用StyleSpan的版本。结果是相同的。

MainActivity.java

public class MainActivity extends AppCompatActivity {

    private TextView mTextView;
    private StyleSpan mBoldedSpan;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        Typeface myFont = Typeface.DEFAULT;

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mTextView = findViewById(R.id.textView);
        mTextView.setTextIsSelectable(true);

        mTextView.setMovementMethod(createMovementMethod(this));
        mBoldedSpan = new StyleSpan(android.graphics.Typeface.BOLD);
        SpannableString ss = new SpannableString("Hello world!");
        int[][] spanStartEnd = new int[][]{{0, 5}, {6, 12}};
        for (int i = 0; i < spanStartEnd.length; i++) {
            WordSpan wordSpan = new WordSpan(i, myFont, false) {
                @Override
                public void onClick(View view) {
//                handleWordClick(index, this); // Not sure what this does.
                    Spannable ss = (Spannable) mTextView.getText();
                    ss.setSpan(mBoldedSpan, ss.getSpanStart(this), ss.getSpanEnd(this),
                               Spanned.SPAN_INCLUSIVE_INCLUSIVE);
                }
            };
            ss.setSpan(wordSpan, spanStartEnd[i][0], spanStartEnd[i][1],
                       Spanned.SPAN_INCLUSIVE_INCLUSIVE);
        }

        mTextView.setText(ss, TextView.BufferType.SPANNABLE);
    }

 // All the other code follows without modification.
}

触摸时的粗体ClickableSpan

1 个答案: