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) {

                }

        }