android - beginDelayedTransition 不起作用，仅显示最终 View 位置

Question

我想将按钮移动到中心，显示它，然后移动到角落。

但它不会动，它立即出现在角落里。为什么？

更新 Android 5.1，API 22。

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
                // remember true position/size
                final RelativeLayout.LayoutParams layoutParams_= (RelativeLayout.LayoutParams) mapFollowButton.getLayoutParams();
                // create temp position/size from which will move
                final RelativeLayout.LayoutParams layoutParams = new RelativeLayout.LayoutParams((int) (150*density), (int) (150*density));
                layoutParams.addRule(RelativeLayout.CENTER_IN_PARENT);
                mapFollowButton.setLayoutParams(layoutParams);
                mapFollowButton.setVisibility(View.INVISIBLE);
                mapFollowButton.invalidate();

                final ChangeBounds transition= new ChangeBounds();
                transition.setDuration(1000L); 
                TransitionManager.beginDelayedTransition((ViewGroup) findViewById(R.id.mainRL),transition);
                //here expected to move to true position from center
                mapFollowButton.setLayoutParams(layoutParams_);
                mapFollowButton.setVisibility(View.VISIBLE);
} else
                mapFollowButton.setVisibility(View.VISIBLE);

Answer 1

好吧，我找到了解决方案。有效，但奇怪的是，没有提到这一点。只需要暂停一下，哪怕是10ms。其余相同。

                ....
                //mapFollowButton.invalidate();

                mapFollowButton.postDelayed(new Runnable() {
                    @Override
                    public void run() {
                        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.KITKAT) {
                            final ChangeBounds transition= new ChangeBounds();
                            transition.setDuration(1000L); 
                            TransitionManager.beginDelayedTransition((ViewGroup) findViewById(R.id.mainRL),transition);
                        }
                        mapFollowButton.setLayoutParams(layoutParams_);
                        mapFollowButton.setVisibility(View.VISIBLE);
                    }
                },10);