本文介绍了Android View.getDrawingCache 返回空值,只有空值的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
有没有人可以试着向我解释一下原因
Would anyone please try to explain to me why
public void addView(View child) {
child.setDrawingCacheEnabled(true);
child.setWillNotCacheDrawing(false);
child.setWillNotDraw(false);
child.buildDrawingCache();
if(child.getDrawingCache() == null) { //TODO Make this work!
Log.w("View", "View child's drawing cache is null");
}
setImageBitmap(child.getDrawingCache()); //TODO MAKE THIS WORK!!!
}
总是记录绘图缓存为空,并将位图设置为空?
ALWAYS logs that the drawing cache is null, and sets the bitmap to null?
我是否必须在设置缓存之前实际绘制视图?
Do I have to actually draw the view before the cache is set?
谢谢!
推荐答案
我也遇到了这个问题,找到了这个答案:
I was having this problem also and found this answer:
v.setDrawingCacheEnabled(true);
// this is the important code :)
// Without it the view will have a dimension of 0,0 and the bitmap will be null
v.measure(MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED),
MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED));
v.layout(0, 0, v.getMeasuredWidth(), v.getMeasuredHeight());
v.buildDrawingCache(true);
Bitmap b = Bitmap.createBitmap(v.getDrawingCache());
v.setDrawingCacheEnabled(false); // clear drawing cache
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