如何解决Can not perform this action after onSaveInstanceState

先分析问题发生原因

private void checkStateLoss() {

    if (isStateSaved()) {

        throw new IllegalStateException(

        "Can not perform this action after onSaveInstanceState");

    }

}

public boolean isStateSaved() {

    // See saveAllState() for the explanation of this.  We do this for

    // all platform versions, to keep our behavior more consistent between

    // them.

    return mStateSaved ||mStopped;

}

通过分析源码我们找到，当activity执行了onSaveInstanceState或onStop方法后，操作子fragment系统会检测当前状态并抛出异常。

解决方法：

配合Lifecycle,我们只需要重写添加：

lifecycleScope?.launchWhenResumed{

    //show fragment dialog

}

这样系统会自动在resumed后再弹出dialogfragment，也能避免Can not perform this action after onSaveInstanceState
这样即使是activity在后台情况下返回前台，也会立即弹窗。