获取取view的图片的两种方法

第一种: 从显示缓存中去获取图片,前提是该view必须可见

ImageView v = new ImageView(this);
        v.setBackgroundResource(R.drawable.icon);
        v.buildDrawingCache(true);
        v.buildDrawingCache();
        Bitmap bm = v.getDrawingCache();

第二种: 通过画布canvas方式获取,可以在不可见的状态下获取bitmap,不过,相对第一种较耗资源.

/**
     * 把View绘制到Bitmap上
     * 
     * @param view 需要绘制的View
     * @param width 该View的宽度
     * @param height 该View的高度
     * @return 返回Bitmap对象
     */
    private Bitmap getBitmapFromView(View view, int width, int height)
    {
                int widthSpec = View.MeasureSpec.makeMeasureSpec(width,
                    View.MeasureSpec.EXACTLY);
                int heightSpec = View.MeasureSpec.makeMeasureSpec(height,
                    View.MeasureSpec.EXACTLY);
                view.measure(widthSpec, heightSpec);
                view.layout(0, 0, width, height);
        Bitmap bitmap = Bitmap.createBitmap(width, height,
            Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);
        canvas.drawColor(Color.TRANSPARENT);
        canvas.setDrawFilter(new PaintFlagsDrawFilter(0, Paint.ANTI_ALIAS_FLAG
            | Paint.FILTER_BITMAP_FLAG));
        view.draw(canvas);

        return bitmap;
    }