Question

我正在寻找在xml布局中间显示画布的任何方法，即在Imageview上显示画布。我试过但位图返回null。

Bitmap b = Bitmap.createBitmap(img.getMeasuredWidth(),img.getMeasuredHeight(), Bitmap.Config.ARGB_8888);
    Canvas c = new Canvas(b);
    c.drawRect(0, 0, 200, 200, paint);

Answer 1

请将ImageView子类化，并在onDraw（）中绘制您的要求，如下所示。

public class CustomImageView extends ImageView{

public CustomImageView (Context context) {
    super(context);
}

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    Bitmap Bitmap.createBitmap(img.getMeasuredWidth(),img.getMeasuredHeight(), Bitmap.Config.ARGB_8888);
    Canvas c = new Canvas(b);
    c.drawRect(0, 0, 200, 200, paint);
}

}

Answer 2

使用此代码创建位图。

 public static Bitmap createScaledBitmap(String path, float scale, boolean filtering){
        Bitmap src = BitmapFactory.decodeFile(path);
        int width = (int)( src.getWidth() * scale + 0.5f);
        int height = (int)( src.getHeight() * scale + 0.5f);
        return Bitmap.createScaledBitmap(src, width, height, filtering);
      }

此处path是图像的路径，然后最终将此缩放位图放在Canvas中。

布局中间的画布，即ImageView Android？

2 个答案: