IllegalStateException: Can not perform this action after onSaveInstanceState

可能的原因之一：

Fragment 在显示或者隐藏，移除是出现Can not perform this action after onSaveInstanceState  #解决办法：onSaveInstanceState方法是在该Activity即将被销毁前调用，来保存Activity数据的，如果在保存玩状态后 再给它添加Fragment就会出错。解决办法就是把commit（）方法替换成 commitAllowingStateLoss()

可能的原因之二：Activity被系统回收之后，重建时恢复缓存的Fragment的原因  #解决办法之一：在Activity 回收时 onSaveInstanceState 中不缓存Fragment ,在OnCreate 中移除缓存相应Fragment数据，代码如下

    private static final String BUNDLE_FRAGMENTS_KEY = "android:support:fragments";
   
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        if (savedInstanceState != null && this.clearFragmentsTag()) {
            //重建时清除 fragment的状态
            savedInstanceState.remove(BUNDLE_FRAGMENTS_KEY);
        }
        super.onCreate(savedInstanceState);
    }


    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        if (outState != null && this.clearFragmentsTag()) {
            //销毁时不保存fragment的状态
            outState.remove(BUNDLE_FRAGMENTS_KEY);
        }
    }

    protected boolean clearFragmentsTag() {
        return true;
    }