Question

我正在使用SD卡，所以试图在运行时获得权限。这是代码：

public class MainActivity extends AppCompatActivity implements FileListFragment.OnFragmentInteractionListener {

private static final int MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE = 111;

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

        if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE);
        }

         ...................
         ................
    }

@Override
    public void onRequestPermissionsResult(int requestCode,
                                           String permissions[], int[] grantResults) {
        switch (requestCode) {
            case MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE: {
                // If request is cancelled, the result arrays are empty.
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                    FileListFragment fileListFragment = FileListFragment.newInstance(0);  // **Error line**
        getSupportFragmentManager().beginTransaction()
                .add(R.id.fragment_container, fileListFragment)
                .commit();
                } else {

                    finish();
                }
                return;
            }
        }
    }

.............................
..................................
..........................

}

一旦我允许权限，它就会抛出“失败的结果ResultInfo {who = @ android：requestPermissions：，request = 111，result = -1，data = Intent {act = android.content。 pm.action.REQUEST_PERMISSIONS（有额外内容）}}到activity {com.kaushik.fileexplorer / com.kaushik.fileexplorer.MainActivity}：java.lang.IllegalStateException：在onSaveInstanceState“之后无法执行此操作。这是logcat的详细信息：

08-23 16:49:29.497 3215-3215/com.kaushik.fileexplorer E/AndroidRuntime: FATAL EXCEPTION: main
                                                                        Process: com.kaushik.fileexplorer, PID: 3215
                                                                        java.lang.RuntimeException: Failure delivering result ResultInfo{who=@android:requestPermissions:, request=111, result=-1, data=Intent { act=android.content.pm.action.REQUEST_PERMISSIONS (has extras) }} to activity {com.kaushik.fileexplorer/com.kaushik.fileexplorer.MainActivity}: java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
                                                                            at android.app.ActivityThread.deliverResults(ActivityThread.java:3699)
                                                                            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)
                                                                         Caused by: java.lang.IllegalStateException: Can not perform this action after onSaveInstanceState
                                                                            at android.support.v4.app.FragmentManagerImpl.checkStateLoss(FragmentManager.java:1533)
                                                                            at android.support.v4.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1551)
                                                                            at android.support.v4.app.BackStackRecord.commitInternal(BackStackRecord.java:696)
                                                                            at android.support.v4.app.BackStackRecord.commit(BackStackRecord.java:662)
                                                                            at com.kaushik.fileexplorer.MainActivity.onRequestPermissionsResult(MainActivity.java:76)
                                                                            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)

该代码有什么问题？

Answer 1

您应该添加commitAllowingStateLoss（）

 FileListFragment fileListFragment = FileListFragment.newInstance(0);  // **Error line**
        getSupportFragmentManager().beginTransaction()
                .add(R.id.fragment_container, fileListFragment)
                .commitAllowingStateLoss();

请检查this link

Answer 2

此错误是因为未保存活动状态，而您正在添加Fragment。

使用此代码：

FileListFragment fileListFragment = FileListFragment.newInstance(0); 
    getSupportFragmentManager().beginTransaction()
            .add(R.id.fragment_container, fileListFragment)
            .commitAllowingStateLoss();

并覆盖 onSaveInstanceState（）方法并从中删除 super（）。

Answer 3

使用commitAllowingStateLoss（）更像是一个hacky修复。

此问题与此问题非常相似，并得到了很好的解释here。

相反，最好在onRequestPermissionsResult中设置一个布尔标志，并在onPostResume（对于Activity）或onResume（对于Fragments）中使用它来提交事务。

onRequestPermissionsResult（）中的Android java.lang.IllegalStateException

3 个答案: