android 圖片疊加效果——兩種方法的簡介與內容 ，帶解決Immutable bitmap passed to Canvas constructor錯誤

第一種是通過canvas畫出來的效果:

public void first(View v) {

        // 防止出現Immutable bitmap passed to Canvas constructor錯誤
        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);
        // 存儲新合成的圖片
        canvas.restore();

        image.setImageBitmap(newBitmap);
    }

public void first(View v) {

        // 防止出現Immutable bitmap passed to Canvas constructor錯誤
        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);
        // 存儲新合成的圖片
        canvas.restore();

        image.setImageBitmap(newBitmap);
    }

 

Canvas canvas = new Canvas(newBitmap); 當以newBitmap創建Canvas時，所以操作都已經在該圖上實現了。

該例子可以想做是播放器開始播放的效果，計算好中間位置，先覆蓋一層透明灰色的正方形，然后在中間畫上自己播放的按鈕。

 

第二種是使用系統的LayerDrawable類，該類主要用來控制多個圖片的結合：

 

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);
        // 其中第一個參數為層的索引號，后面的四個參數分別為left、top、right和bottom
        la.setLayerInset(0, 0, 0, 0, 0);
        la.setLayerInset(1, 20, 20, 20, 20);
        image.setImageDrawable(la);
    }

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);
        // 其中第一個參數為層的索引號，后面的四個參數分別為left、top、right和bottom
        la.setLayerInset(0, 0, 0, 0, 0);
        la.setLayerInset(1, 20, 20, 20, 20);
        image.setImageDrawable(la);
    }

 

關聯數組array，控制每一層的位置

 裝載自：http://blog.csdn.net/gh102/article/details/6719624

注意：上面防止出現Immutable bitmap passed to Canvas constructor錯誤

原因是如果不用copy的方法，直接引用會對資源文件進行修改，而android是不允許在代碼里修改res文件里的圖片