我在市场上从我的应用程序获得用户报告,交付以下异常:

java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
at android.app.FragmentManagerImpl.checkStateLoss(FragmentManager.java:1109)
at android.app.FragmentManagerImpl.popBackStackImmediate(FragmentManager.java:399)
at android.app.Activity.onBackPressed(Activity.java:2066)
at android.app.Activity.onKeyUp(Activity.java:2044)
at android.view.KeyEvent.dispatch(KeyEvent.java:2529)
at android.app.Activity.dispatchKeyEvent(Activity.java:2274)
at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1803)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112)
at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchKeyEvent(PhoneWindow.java:1855)
at com.android.internal.policy.impl.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1277)
at android.app.Activity.dispatchKeyEvent(Activity.java:2269)
at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1803)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112)
at android.widget.TabHost.dispatchKeyEvent(TabHost.java:297)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112)
at android.view.ViewGroup.dispatchKeyEvent(ViewGroup.java:1112)
at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchKeyEvent(PhoneWindow.java:1855)
at com.android.internal.policy.impl.PhoneWindow.superDispatchKeyEvent(PhoneWindow.java:1277)
at android.app.Activity.dispatchKeyEvent(Activity.java:2269)
at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1803)
at android.view.ViewRoot.deliverKeyEventPostIme(ViewRoot.java:2880)
at android.view.ViewRoot.handleFinishedEvent(ViewRoot.java:2853)
at android.view.ViewRoot.handleMessage(ViewRoot.java:2028)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:132)
at android.app.ActivityThread.main(ActivityThread.java:4028)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:491)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:844)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:602)
at dalvik.system.NativeStart.main(Native Method)

显然这与FragmentManager有关,而我并不使用它。堆栈跟踪没有显示任何我自己的类,所以我不知道这个异常发生在哪里以及如何防止它。

为了记录:我有一个tabhost,在每个选项卡中都有一个在活动之间切换的ActivityGroup。


当前回答

我得到这个异常时,我按下后退按钮取消意图选择器在我的地图片段活动。 我通过替换onResume(在那里我初始化片段)的代码来解决这个问题,onstart()和应用程序工作正常。希望能有所帮助。

其他回答

注意,使用transaction.commitAllowingStateLoss()可能会给用户带来糟糕的体验。有关为什么会抛出这个异常的更多信息,请参阅这篇文章。

异常在这里抛出(在FragmentActivity中):

@Override
public void onBackPressed() {
    if (!mFragments.getSupportFragmentManager().popBackStackImmediate()) {
        super.onBackPressed();
    }
}

在FragmentManager.popBackStatckImmediate()中,FragmentManager.checkStateLoss()首先被调用。这就是IllegalStateException的原因。参见下面的实现:

private void checkStateLoss() {
    if (mStateSaved) { // Boom!
        throw new IllegalStateException(
                "Can not perform this action after onSaveInstanceState");
    }
    if (mNoTransactionsBecause != null) {
        throw new IllegalStateException(
                "Can not perform this action inside of " + mNoTransactionsBecause);
    }
}

我通过使用一个标志来标记Activity的当前状态来解决这个问题。以下是我的解决方案:

public class MainActivity extends AppCompatActivity {
    /**
     * A flag that marks whether current Activity has saved its instance state
     */
    private boolean mHasSaveInstanceState;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        mHasSaveInstanceState = true;
        super.onSaveInstanceState(outState);
    }

    @Override
    protected void onResume() {
        super.onResume();
        mHasSaveInstanceState = false;
    }

    @Override
    public void onBackPressed() {
        if (!mHasSaveInstanceState) {
            // avoid FragmentManager.checkStateLoss()'s throwing IllegalStateException
            super.onBackPressed();
        }
    }
}

这里有一个不同的解决方法。

使用私有成员变量,你可以将返回的数据设置为一个意图,然后在super.onResume();

像这样:

private Intent mOnActivityResultIntent = null; 

@Override
protected void onResume() {
    super.onResume();
    if(mOnActivityResultIntent != null){
        ... do things ...
        mOnActivityResultIntent = null;
    }
 }

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data){
    if(data != null){
        mOnActivityResultIntent = data;
    }
}

在我的情况下,我在一个叫做onActivityResult的覆盖方法中得到了这个错误。在挖掘之后,我才发现也许我之前需要打电话给“超级”。 我加进去了,效果很好

override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
    super.onActivityResult(requestCode, resultCode, data); //<--- THIS IS THE SUPPER CALL
    if (resultCode == Activity.RESULT_OK && requestCode == 0) {
        mostrarFragment(FiltroFragment.newInstance())
    }

}

也许你只需要在代码之前的任何重写上添加一个“super”。

如果状态保存,请使用remove()而不是popup()。

   private void removeFragment() {
    FragmentManager fragmentManager = getSupportFragmentManager();
    if (fragmentManager.isStateSaved()) {
        List<Fragment> fragments = fragmentManager.getFragments();
        if (fragments != null && !fragments.isEmpty()) {
            fragmentManager.beginTransaction().remove(fragments.get(fragments.size() - 1)).commitAllowingStateLoss();
        }
    }
}