开启硬件加速之后，许多2D的绘制方法会抛出异常

需要注意的方法如下：

 

• Canvas
  • clipPath()
  • clipRegion()
  • drawPicture()
  • drawTextOnPath()
  • drawVertices()
• Paint
  • setLinearText()
  • setMaskFilter()
  • setRasterizer()
• Xfermodes
  • AvoidXfermode
  • PixelXorXfermode

In addition, some operations behave differently with hardware acceleration enabled:

• Canvas
  • clipRect(): XOR, Difference and ReverseDifference clip modes are ignored. 3D transforms do not apply to the clip rectangle
  • drawBitmapMesh(): colors array is ignored
• Paint
  • setDither(): ignored
  • setFilterBitmap(): filtering is always on
  • setShadowLayer(): works with text only

• PorterDuffXfermode
  • PorterDuff.Mode.DARKEN will be equivalent to SRC_OVER when blending against the framebuffer.
  • PorterDuff.Mode.LIGHTEN will be equivalent to SRC_OVER when blending against the framebuffer.
  • PorterDuff.Mode.OVERLAY will be equivalent to SRC_OVER when blending against the framebuffer.
• ComposeShader
  • ComposeShader can only contain shaders of different types (a BitmapShader and a LinearGradient for instance, but not two instances of BitmapShader )
  • ComposeShader cannot contain a ComposeShader

如在Canvas.clipPath时会抛出异常

UnsupportedOperationException in GLES20Canvas.clipPath with hardware acceleration disabled on view

解决办法：在程序中通过反射禁掉硬件加速

private static Method getMethod(Class<?> clazz, String name, Class<?>... parameterTypes) {
                try {
                        return clazz.getMethod(name, parameterTypes);
                }
                catch (NoSuchMethodException e) {
                        return null;
                }
        }

        public static void disableHardwareAcceleration(View view) {
                try {
        Method setLayerTypeMethod = getMethod(View.class, "setLayerType", int.class,
                        Paint.class);

                        if (setLayerTypeMethod != null) {
                                int layerType = 1; // View.LAYER_TYPE_SOFTWARE
                                setLayerTypeMethod.invoke(view, layerType, null);
                        }
                }
                catch (Exception ignored) {
                }
        }