解决 IllegalStateException: Can not perform this action after onSaveInstanceState

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今天在修复外网崩溃时，发现有这个错误 IllegalStateException: Can not perform this action after onSaveInstanceState，详细堆栈信息如下：

java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
    at android.support.v4.app.FragmentManagerImpl.checkStateLoss(FragmentManager:1377)
    at android.support.v4.app.FragmentManagerImpl.popBackStackImmediate(FragmentManager:504)
    at android.support.v4.app.FragmentActivity.onBackPressed(FragmentActivity:178)
    at android.app.Activity.onKeyUp(Activity.java:2207)
    at android.view.KeyEvent.dispatch(KeyEvent.java:2664)
    at android.app.Activity.dispatchKeyEvent(Activity.java:2437)
    at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchKeyEvent(PhoneWindow.java:1975)
    at android.view.ViewRootImpl$ViewPostImeInputStage.processKeyEvent(ViewRootImpl.java:4013)
    at android.view.ViewRootImpl$ViewPostImeInputStage.onProcess(ViewRootImpl.java:3987)
    at android.view.ViewRootImpl$InputStage.deliver(ViewRootImpl.java:3553)
    at android.view.ViewRootImpl$InputStage.onDeliverToNext(ViewRootImpl.java:3603)
    at android.view.ViewRootImpl$InputStage.forward(ViewRootImpl.java:3572)
    at android.view.ViewRootImpl$AsyncInputStage.forward(ViewRootImpl.java:3679)
    at andro