Android实现图片叠加效果的两种方法

public void first(View v) {
    // 防止出现Immutable bitmap passed to Canvas constructor错误
    Bitmap bitmap1 = BitmapFactory.decodeResource(getResources(),
        R.drawable.apple).copy(Bitmap.Config.ARGB_8888, true);
    Bitmap bitmap2 = ((BitmapDrawable) getResources().getDrawable(
        R.drawable.go)).getBitmap();
    Bitmap newBitmap = null;
    newBitmap = Bitmap.createBitmap(bitmap1);
    Canvas canvas = new Canvas(newBitmap);
    Paint paint = new Paint();
    int w = bitmap1.getWidth();
    int h = bitmap1.getHeight();
    int w_2 = bitmap2.getWidth();
    int h_2 = bitmap2.getHeight();
    paint.setColor(Color.GRAY);
    paint.setAlpha(125);
    canvas.drawRect(0, 0, bitmap1.getWidth(), bitmap1.getHeight(), paint);
    paint = new Paint();
    canvas.drawBitmap(bitmap2, Math.abs(w - w_2) / 2,
        Math.abs(h - h_2) / 2, paint);
    canvas.save(Canvas.ALL_SAVE_FLAG);
    // 存储新合成的图片
    canvas.restore();
    image.setImageBitmap(newBitmap);
}

public void second(View v) {
    Bitmap bitmap1 = ((BitmapDrawable) getResources().getDrawable(
        R.drawable.apple)).getBitmap();
    Bitmap bitmap2 = ((BitmapDrawable) getResources().getDrawable(
        R.drawable.go)).getBitmap();
    Drawable[] array = new Drawable[2];
    array[0] = new BitmapDrawable(bitmap1);
    array[1] = new BitmapDrawable(bitmap2);
    LayerDrawable la = new LayerDrawable(array);
    // 其中第一个参数为层的索引号，后面的四个参数分别为left、top、right和bottom
    la.setLayerInset(0, 0, 0, 0, 0);
    la.setLayerInset(1, 20, 20, 20, 20);
    image.setImageDrawable(la);
}

<layer-list xmlns:Android="http://schemas.android.com/apk/res/android">
  <item Android:drawable="@android:color/white" />
  <item Android:drawable="@drawable/logo_overlay" />
</layer-list>

<resources>
  <style name="LookupTheme" parent="@Android:style/Theme.Light.NoTitleBar">
    <item name="Android:windowBackground">@drawable/drawable-layer</item>
  </style>
</resources>

Resources resources = getResources();
Drawable[] layers = new Drawable[2];
layers[0] = r.getDrawable(R.drawable.white);
layers[1] = r.getDrawable(R.drawable.logo_overlay);
LayerDrawable layerDrawable = new LayerDrawable(layers)
((ImageView) findViewById(R.id.imageview)).setImageDrawable(layerDrawable);

<?xml version="1.0" encoding="UTF-8"?>
<layer-list
 xmlns:Android="http://schemas.android.com/apk/res/android">
  <item Android:id="@+id/user_faceback_drawable" android:drawable="@drawable/faceback" />
  <item Android:id="@+id/user_face_drawable" android:drawable="@drawable/h001" android:left="10.0dip" android:top="18.0dip" android:right="25.0dip" android:bottom="35.0dip" />
</layer-list>

<ImageView Android:id="@+id/faceImg" android:background="@drawable/login_head"
Android:layout_width="wrap_content" android:layout_height="wrap_content" />

Bitmap bm = BitmapFactory.decodeResource(getResources(),R.drawable.cwj);
Drawable[] array = new Drawable[3];
array[0] = new PaintDrawable(Color.BLACK); //黑色
array[1] = new PaintDrawable(Color.WHITE); //白色
array[2] = new BitmapDrawable(bm); //位图资源
LayerDrawable ld = new LayerDrawable(array); //参数为上面的Drawable数组
ld.setLayerInset(1, 1, 1, 1, 1); //第一个参数1代表数组的第二个元素，为白色
ld.setLayerInset(2, 2, 2, 2, 2); //第一个参数2代表数组的第三个元素，为位图资源
mImageView.setImageDrawable(ld);