Activity异常销毁后，fragment重叠问题

1.原因分析:

           Activity长期处于后台,系统由于资源不足,activity被销毁了，fragment状态缓存下来了。由于重新进入activity,重新走了

onCreate方法，导致有一个fragment重新加入，造成fragment重叠

2.解决方法：

(1).通过Tag从前保存的数据中直接去读取

 @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mFragmentManager = getSupportFragmentManager();
        if (savedInstanceState != null) {
            homeFragment =(HomeFragment)mFragmentManager.findFragmentByTag(fragmentTag[0]);
            twoFragment = (TwoFragment) mFragmentManager.findFragmentByTag(fragmentTag[1]);
            myFragment = (MyFragment) mFragmentManager.findFragmentByTag(fragmentTag[2]);
        }
    }

 

(2).将新建的fragment的删除

 @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        mFragmentManager = getSupportFragmentManager();
        if (mFragmentManager.getFragments().size() > 0) {
            FragmentTransaction fragmentTransaction = mFragmentManager.beginTransaction();
            Iterator iterator = mFragmentManager.getFragments().iterator();
            while (iterator.hasNext()) {
                fragmentTransaction.remove(iterator.next());
            }
            fragmentTransaction.commit();
        }
    }

(3).不保存fragment状态（没试过）

 @Override
    protected void onSaveInstanceState(Bundle outState) {
        //super.onSaveInstanceState(outState);
    }

参考：https://blog.csdn.net/cui130/article/details/85378748