Question

我在点击按钮时生成图像。用于创建图像的布局当前在活动中不可见。矢量图像是布局的背景，但我看到的只是黑色图像。

<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="370dp"
    android:layout_height="400dp"
    android:background="@drawable/ic_background">

    <TextView
        android:id="@+id/address"
        android:layout_width="match_parent"
        android:textColor="@color/white"
        android:textSize="40sp"
        android:textStyle="bold"
        android:gravity="center"
        android:layout_height="wrap_content"/>
</LinearLayout>

生成图像

private void generateAndShareImage(){
    final LayoutInflater inflater = (LayoutInflater)this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    final View view = inflater.inflate(R.layout.image_address, null);
    final TextView addressView = (TextView) view.findViewById(R.id.address);
    addressView.setText("Test Address");

    final Bitmap cardImage = getBitmapFromView(view);
    //store image in external storage
    String savedImagePath = storeImage(cardImage);
    if(savedFilePath != null){
        scanGallery(savedImagePath);
    }
}

private void scanGallery(final String path) {
    try {
        MediaScannerConnection.scanFile(getBaseContext(), new String[] { path },null, new MediaScannerConnection.OnScanCompletedListener() {
            public void onScanCompleted(String path, Uri uri) {
            }
        });
    } catch (Exception e) {
        Log.e("Error scanning gallery",e.getMessage());
    }
}

private Bitmap getBitmapFromView(@NonNull  final View view){
    final Bitmap bitmap = Bitmap.createBitmap(370, 400, Bitmap.Config.ARGB_8888);
    final Canvas canvas = new Canvas(bitmap);
    view.draw(canvas);
    return bitmap;
}

有什么问题？

Answer 1

您首先需要measure和layout您的观点：

int spec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED);
view.measure(spec, spec); 
view.layout(0, 0, view.getMeasuredWidth(), view.getMeasuredHeight());
final Bitmap cardImage = getBitmapFromView(view);

以上代码应该有效。

最好传递getBitmapFromView(view, width, height)中用于Bitmap.createBitmap()的测量视图的维度，而不是使用硬编码值。

检查一下其他调整Converting a view to Bitmap without displaying it in Android?

顺便说一句，你不能使用370，如果你真的需要使用硬编码的数字，那么请使用它：

float dp_370 = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 370, context.getResources().getDisplayMetrics());

要了解密度独立像素在Android中的工作原理，请阅读： What is the difference between "px", "dp", "dip" and "sp" on Android?

和

https://material.io/guidelines/layout/units-measurements.html#units-measurements-scaleable-pixels-sp

修改

以下是我用来查看ImageView中生成的位图的工作代码示例：

final LayoutInflater inflater = (LayoutInflater)this.getSystemService(Context.LAYOUT_INFLATER_SERVICE); final View test = inflater.inflate(R.layout.test, null); int spec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED); test.measure(spec, spec); int measuredWidth = test.getMeasuredWidth(); int measuredHeight = test.getMeasuredHeight(); test.layout(0, 0, measuredWidth, measuredHeight); final Bitmap bitmap = Bitmap.createBitmap(measuredWidth, measuredHeight, Bitmap.Config.ARGB_8888); final Canvas canvas = new Canvas(bitmap); test.draw(canvas); //now show this inside an ImageView ImageView image = (ImageView) findViewById(R.id.image); image.setImageBitmap(bitmap);

Android - 保存布局，因为图像显示黑色图像

1 个答案: