当用户在运行时权限对话框中单击拒绝时显示 DialogFragment

Question

我试图在用户点击 android 的 "allow/deny permission" 对话框中的 "Deny" 后立即显示一个 DialogFragment 6 但是我收到了这个错误：

    Caused by: java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
  at android.support.v4.app.FragmentManagerImpl.checkStateLoss(FragmentManager.java:1448)
  at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1466)
  at android.support.v4.app.BackStackRecord.commitInternal(BackStackRecord.java:634)
  at android.support.v4.app.BackStackRecord.commit(BackStackRecord.java:613)
  at android.support.v4.app.DialogFragment.show(DialogFragment.java:139)
  at android.support.v4.app.FragmentActivity.onRequestPermissionsResult(FragmentActivity.java:802)
  at android.app.Activity.dispatchRequestPermissionsResult(Activity.java:6553)
  at android.app.Activity.dispatchActivityResult(Activity.java:6432)
  at android.app.ActivityThread.deliverResults(ActivityThread.java:3695)
  at android.app.ActivityThread.handleSendResult(ActivityThread.java:3742) 
  at android.app.ActivityThread.-wrap16(ActivityThread.java) 
  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1393) 
  at android.os.Handler.dispatchMessage(Handler.java:102) 
  at android.os.Looper.loop(Looper.java:148) 
  at android.app.ActivityThread.main(ActivityThread.java:5417) 
  at java.lang.reflect.Method.invoke(Native Method) 
  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

我的对话框代码很标准

  protected void showDialog(DialogFragment diag)
    {
        if (diag != null && !diag.isAdded())
            diag.show(getSupportFragmentManager(), "dialog");
    }

如何解决这个问题？

Answer 1

因此，有几个解决方案，none 特别漂亮。这意味着您的 Activity 的 FragmentManager 尚未处于以安全方式提交 FragmentTransactions 的有效状态（尽管在这种特殊情况下，它应该始终是。）

1) 使用.commitAllowingStateLoss()代替.show():

这是最简单的修复方法，尽管我不完全清楚不使用 .show() 方法会产生什么差异，这些方法在内部设置了一些标志。似乎工作正常。

getSupportFragmentManager()
        .beginTransaction()
        .add(diag, "dialog")
        .commitAllowingStateLoss();

1) Post .show() 作为 Runnable on a Handler:

// Initialize a Handler ahead of time and keep it around
private Handler mHandler = new Handler();

...

// after getting denied:
mHandler.post(new Runnable() {
    @Override
    public void run() {
        // Show your dialog
    }
}

...

@Override
protected void onStop() {
    super.onStop();

    // Clear out the Runnable for an unlikely edge case where your
    // Activity goes to stopped state before the Runnable executes
    mHandler.removeCallbacksAndMessages(null);
}

2) 设置标志并在 onResume() 中显示对话框

private boolean mPermissionDenied;

@Override
public void onRequestPermissionsResult(...) {
    // If denied...
    mPermissionDenied = true;   
}

@Override
protected void onResume() {
    super.onResume();

    if (mPermissionDenied) {
        mPermissionDenied = false;
        // Show your dialog
    }
}

Answer 2

我还想补充一些我刚刚发现的东西。如果我用 getSupportFragmentManager().beginTransaction() 在我现有的代码上切换 getSupportFragmentManager() 它工作正常。下面的代码

   protected void showDialog(final DialogFragment diag)
    {
        cancelDialog();
        if (diag != null && !diag.isAdded())
            diag.show(getSupportFragmentManager().beginTransaction(), "dialog");
    }

不知道为什么这会像我想要的那样工作。

Answer 3

在用户点击拒绝后显示一个对话框并不是指南所说的。您应该仅在第二次请求之前显示许可 rational。您可以在这里查看自动管理：Permission library

当用户在运行时权限对话框中单击拒绝时显示 DialogFragment

Show DialogFragment when user clicks deny on Runtime permissions dialog

android

android-dialogfragment

android-6.0-marshmallow