Question

已经多次询问了类似的问题，但我仍然很难理解图像的保存位置。我正在使用公认的this SO question解决方案。

我有cardview我要转换为图片并分享它（这是一个不同的问题）。我的cardview是：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
......
android.support.v7.widget.CardView
        android:id="@+id/cv_abtme"
        android:layout_width="368sp"
        android:layout_height="273dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="101dp"
        android:background="@color/colorPrimaryLight"
        app:cardBackgroundColor="@color/about_instagram_color"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">


        <ImageView
            android:id="@+id/imageView4"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:adjustViewBounds="true"
            android:scaleType="centerCrop"
            app:srcCompat="@mipmap/ic_launcher" />
        ....

    </android.support.v7.widget.CardView>

我正在尝试将其转换为：

public class AboutMeActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_about_me);
        ImageButton cvbutton= findViewById(R.id.imageButton_abtme);


        cvbutton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                getBitmapFromView(view);
                Snackbar.make(getCurrentFocus(),"Image Captured", Snackbar.LENGTH_LONG).show();
            }
        });
    }
    public static Bitmap getBitmapFromView(View view) {
        Bitmap returnedBitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(),Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(returnedBitmap);
        Drawable bgDrawable =view.getBackground();
        if (bgDrawable!=null)
            bgDrawable.draw(canvas);
        else
            canvas.drawColor(Color.WHITE);
        view.draw(canvas);
        return returnedBitmap;
    }
}

但我不知道它是如何工作的，因为我无法看到任何图像产生，但显然没有错误。

所以，问题是：

图片创建的路径是什么？
我是否需要一些权限才能保存并访问jpg？

Answer 1

图片创建的路径是什么？

根据您问题中的代码，它不会保存在任何地方。您没有编写任何代码来保存它。您创建了一个Bitmap对象，就是这样。

要将Bitmap保存为磁盘上的图像文件，请拨打compress()，指定图片类型，然后FileOutputStream到您要保存的位置。

Answer 2

这是我的代码正常工作。我希望这段代码可能会有所帮助

这里xml cardView

<android.support.v7.widget.CardView 
     xmlns:card_view="http://schemas.android.com/apk/res-auto"
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:id="@+id/card_view"
     android:layout_gravity="center"
     android:layout_width="250dp"
     android:layout_height="250dp"
     card_view:cardCornerRadius="4dp">

    <ImageView
        android:src="@drawable/img_"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</android.support.v7.widget.CardView>

此处代码将cardview下载为jpeg文件

找到cardview CardView cardView =（CardView）findViewById（R.id.card_view）; 的loadView（cardView）;

加载视图

 public void loadView(CardView cardView){

    try {
        cardView.setDrawingCacheEnabled(true);
        Bitmap bitmap =  loadBitmapFromView(cardView);
        cardView.setDrawingCacheEnabled(false);

        String mPath =
                Environment.getExternalStorageDirectory().toString() + "/sid.jpg";

        File imageFile = new File(mPath);
        FileOutputStream outputStream = new
                FileOutputStream(imageFile);
        int quality = 100;
        bitmap.compress(Bitmap.CompressFormat.JPEG, quality, outputStream);
        outputStream.flush();
        outputStream.close();

    } catch (Throwable e) {
        e.printStackTrace();
    }
}

从视图中获取位图

 public Bitmap loadBitmapFromView(View v) {
    DisplayMetrics dm = getResources().getDisplayMetrics();
    v.measure(View.MeasureSpec.makeMeasureSpec(dm.widthPixels, View.MeasureSpec.EXACTLY),
            View.MeasureSpec.makeMeasureSpec(dm.heightPixels, View.MeasureSpec.EXACTLY));
    v.layout(0, 0, v.getMeasuredWidth(), v.getMeasuredHeight());
    Bitmap returnedBitmap = Bitmap.createBitmap(v.getMeasuredWidth(),
            v.getMeasuredHeight(), Bitmap.Config.ARGB_8888);
    Canvas c = new Canvas(returnedBitmap);
    v.draw(c);

    return returnedBitmap;
}

cardview jpeg文件保存在ExternalStorage位置，文件名为sid.jpg。

MyCompleted Activity class

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    CardView cardView = (CardView) findViewById(R.id.card_view);
    loadView(cardView);
}
public void loadView(CardView cardView){

    try {
        cardView.setDrawingCacheEnabled(true);
        Bitmap bitmap =  loadBitmapFromView(cardView);
        cardView.setDrawingCacheEnabled(false);

        String mPath =
                Environment.getExternalStorageDirectory().toString() + "/sid.jpg";

        File imageFile = new File(mPath);
        FileOutputStream outputStream = new
                FileOutputStream(imageFile);
        int quality = 100;
        bitmap.compress(Bitmap.CompressFormat.JPEG, quality, outputStream);
        outputStream.flush();
        outputStream.close();

    } catch (Throwable e) {
        e.printStackTrace();
    }
}

public Bitmap loadBitmapFromView(View v) {
    DisplayMetrics dm = getResources().getDisplayMetrics();
    v.measure(View.MeasureSpec.makeMeasureSpec(dm.widthPixels, View.MeasureSpec.EXACTLY),
            View.MeasureSpec.makeMeasureSpec(dm.heightPixels, View.MeasureSpec.EXACTLY));
    v.layout(0, 0, v.getMeasuredWidth(), v.getMeasuredHeight());
    Bitmap returnedBitmap = Bitmap.createBitmap(v.getMeasuredWidth(),
            v.getMeasuredHeight(), Bitmap.Config.ARGB_8888);
    Canvas c = new Canvas(returnedBitmap);
    v.draw(c);

    return returnedBitmap;
}

}

在manifest文件上添加预存以保存jpeg文件

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

Answer 3

您正在传递按钮的视图对象。您必须将布局膨胀到视图对象中，然后才能将其传递给函数。这可能对您有帮助。 Create a Bitmap from a Layout/View before/without draw

将cardview转换为位图

3 个答案: