Android4.0 開啟硬體加速後部分應用執行出錯。

出現異常：

12-20 15:18:19.543: E/AndroidRuntime(26301): FATAL EXCEPTION: main
12-20 15:18:19.543: E/AndroidRuntime(26301): java.lang.UnsupportedOperationException
12-20 15:18:19.543: E/AndroidRuntime(26301): at android.view.GLES20Canvas.clipPath(GLES20Canvas.java:429)
12-20 15:18:19.543: E/AndroidRuntime(26301): at cn.hpc.ui.MyView.drawArea(MyView.java:66)

關閉硬體加速則執行正常。

原因在這裡

http://developer.android.com/guide/topics/graphics/hardware-accel.html

Hardware Acceleration

Beginning in Android 3.0 (API level 11), the Android 2D rendering pipeline is designed to better support hardware acceleration.

從Android 3.0（API Level 11）開始，Android的2D渲染管線可以更好的支援硬體加速。硬體加速使用GPU進行View上的繪製操作。

... ...

Unsupported Drawing Operations

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

問題找到，

解決方法：

有4種控制元件硬體加速的方法。

1 Application level

In your Android manifest file, add the following attribute to the<application>tag to enable hardware acceleration for your entire application:

在應用程式AndroidManifest.xml檔案中，為application標籤新增如下的屬性即可為整個應用程式true開啟、false關閉硬體加速

<application android:hardwareAccelerated="false" ...> 

2 Activity level

<application android:hardwareAccelerated="true">
    <activity ... />
    <activity android:hardwareAccelerated="false" />
</application>

getWindow().setFlags(
    WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED,
    WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED);

myView.setLayerType(View.LAYER_TYPE_SOFTWARE, null);