原代码
int flags = Canvas.MATRIX_SAVE_FLAG |
Canvas.CLIP_SAVE_FLAG |
Canvas.HAS_ALPHA_LAYER_SAVE_FLAG |
Canvas.FULL_COLOR_LAYER_SAVE_FLAG |
Canvas.CLIP_TO_LAYER_SAVE_FLAG;
int sc = canvas.saveLayer(0, 0, getWidth(), getHeight(), null, flags);
更改为
int sc = canvas.saveLayer(0, 0, getWidth(), getHeight(), null, Canvas.ALL_SAVE_FLAG);
原因根据源码查看，在api28中已经全部改为：ALL_SAVE_FLAGS，其他已经无效：
/**
* Restore everything when restore() is called (standard save flags).
* <p class="note"><strong>Note:</strong> for performance reasons, it is
* strongly recommended to pass this - the complete set of flags - to any
* call to <code>saveLayer()</code> and <code>saveLayerAlpha()</code>
* variants.
*
* <p class="note"><strong>Note:</strong> all methods that accept this flag
* have flagless versions that are equivalent to passing this flag.
*/
public static final int ALL_SAVE_FLAG = 0x1F;
private static void checkValidSaveFlags(int saveFlags) {
if (sCompatiblityVersion >= Build.VERSION_CODES.P
&& saveFlags != ALL_SAVE_FLAG) {
throw new IllegalArgumentException(
"Invalid Layer Save Flag - only ALL_SAVE_FLAGS is allowed");
}
