Questions

After the view executes onDetachedFromWindow, the view instance will still exist, but the handler in the view will be empty. When the handler in the view is used, an empty judgment needs to be made

Principle

The handler of the view is obtained through view.getHandler(), as shown in the figure below, the handler is obtained from mAttachInfo, mAttachInfo is assigned in dispatchAttachedToWindow, and empty in dispatchDetachedFromWindow, where dispatchAttachedToWindow will call the view's onAttachedToWindow, and dispatchDetachedFromWindow will call the view's onAttachedToWindowonDetachedFromWindow.

Conclusion

So first of all, we need to remove the handler's runnable or callback in the view's onDetachedFromWindow. At other times when the handler is used, the handler needs to make a short judgment.