问题
How can I create the bitmap from the canvas of custom view.
回答1:
There is no way to extract the Bitmap out of a Canvas. The only way you can access it is to pass it yourself when creating the canvas like this new Canvas(myBitmap) and keep the reference.
EDIT2: see @Alex comment blow - the approach of passing a Bitmap to the Canvas does not seem to work for more recent versions of Android.
EDIT : If you don't create the Canvas yourself, you could create a screen-sized Bitmap (or whatever size you need) and then pass it to the Canvas in onDraw calls like this: canvas.setBitmap(myBitmap).
回答2:
While there is no getBitmap() function for a canvas, since you are making a custom view, what you can do instead is write a function like this inside your view class.
public Bitmap get(){
return this.getDrawingCache();
}
This returns the Bitmap of the view, but it is important that in all your constructors you add this,
this.setDrawingCacheEnabled(true);
Otherwise getDrawingCache will return null
回答3:
I found out that Canvas has a setBitmap function, but not a getBitmap one. It's strange, but anyway, it enables me to create the bitmap myself and pass it to the canvas, retaining the reference.
来源：https://stackoverflow.com/questions/10847728/how-can-i-get-the-bitmap-of-the-canvas-i-get-in-ondraw