I noticed something very interesting. I have in my app the option to open the phone's gallery and the device asks what app to use, there I click on the gray area away from the dialog and saw this issue. I noticed how my activity goes from onPause, onSaveInstanceState back to onResume, it doesn't happen to visit onCreateView. I am doing transactions at onResume. So what I ended up doing is setting a flag being negated onPause, but being true onCreateView. if the flag is true onResume then do onCommit, otherwise commitAllowingStateLoss. I could go on and waste so much time but I wanted to check the lifecycle. I have a device which is sdkversion 23, and I don't get this issue, but I have another one which is 21, and there I see it.

谢谢@gunar，但我认为有更好的方法。

医生说:

*如果您提交的单个事务没有修改 *碎片回栈，强烈考虑使用 * {@link FragmentTransaction#commitNow()}代替。这有助于避免 *当应用程序中的其他代码未提交时，会产生不必要的副作用 *需要不同时间的事务。 ＊ * @return如果有任何待处理事务则返回true *执行。 * / executePendingTransactions();

所以使用commitNow替换:

fragmentTransaction.commit();
FragmentManager.executePendingTransactions()

这对我很管用……我自己发现的…希望对你有所帮助!

1)不要有全局的“静态”FragmentManager / FragmentTransaction。

2) onCreate，总是初始化FragmentManager再次!

样本如下:-

public abstract class FragmentController extends AnotherActivity{
protected FragmentManager fragmentManager;
protected FragmentTransaction fragmentTransaction;
protected Bundle mSavedInstanceState;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    mSavedInstanceState = savedInstanceState;
    setDefaultFragments();
}

protected void setDefaultFragments() {
    fragmentManager = getSupportFragmentManager();
    //check if on orientation change.. do not re-add fragments!
    if(mSavedInstanceState == null) {
        //instantiate the fragment manager

        fragmentTransaction = fragmentManager.beginTransaction();

        //the navigation fragments
        NavigationFragment navFrag = new NavigationFragment();
        ToolbarFragment toolFrag = new ToolbarFragment();

        fragmentTransaction.add(R.id.NavLayout, navFrag, "NavFrag");
        fragmentTransaction.add(R.id.ToolbarLayout, toolFrag, "ToolFrag");
        fragmentTransaction.commitAllowingStateLoss();

        //add own fragment to the nav (abstract method)
        setOwnFragment();
    }
}

只需在显示你的片段之前调用super.onPostResume()，或者在调用super.onPostResume()之后在onPostResume()方法中移动你的代码。这就解决了问题!

当一个Fragment或AppCompatActivity的状态通过onSaveInstanceState()保存时，它的UI被认为是不可变的，直到ON_START被调用。在保存状态后尝试修改UI可能会导致应用程序导航状态的不一致，这就是为什么FragmentManager会抛出异常，如果应用程序在保存状态后运行FragmentTransaction。参见commit()了解详细信息。

LiveData通过避免在观察者的关联生命周期至少不是STARTED时调用它的观察者来避免这种边缘情况。在幕后，它在决定调用其观察者之前调用isAtLeast()。

经过研究，这个问题的解决方案是做你的片段提交在onresume。

来源:https://wenchaojames.wordpress.com/2013/01/12/illegalstateexception-from-onactivityresult/