Question

我的问题是：当我打开对话框片段时，我将realm和realm结果从活动发送到对话框片段。我总是将不同的领域结果发送到对话框片段，这取决于我点击活动。这是对话框片段中的代码，当我点击打开对话框片段时，我从活动接收领域和realmResults：

  public void setChangeNoteListener(ChangeNoteListener mChangeNoteListener, RealmResults<Drop> realmResults, Realm realm) {
        mNotelistener = mChangeNoteListener;
        mRealmResolts = realmResults;
        mRealm = realm;
    }

收到后，我用它们在对话框片段中显示一些数据。

问题是，当我改变应用程序方向时，应用程序会被粉碎，因为我不能再使用领域结果了。我的问题是，如何使用onSaveInstanceStat保存整个领域结果，并在应用方向更改时，再次使用该领域结果。

请注意，在领域结果不仅是一个项目，还有更多项目。

编辑：我用

从领域保存日期

 @Override
    public void onSaveInstanceState(Bundle outState) {
        Bundle argumetns = getArguments();
        int position = argumetns.getInt("POSITION");
        outState.putString("myTitle", String.valueOf(mRealmResolts.get(position).getWhat()));
        outState.putString("myNote", String.valueOf(mRealmResolts.get(position).getWhat_note()));
        super.onSaveInstanceState(outState);
    }

当我加载app我加载这样的应用程序：

public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        mBtnClose = (ImageButton) view.findViewById(R.id.btn_close_note);
        mBtnDelete = (ImageButton) view.findViewById(R.id.dialog_btn_delete_note);
        mEditTextTitle = (EditText) view.findViewById(R.id.dialog_text_naslov);
        mEditTextNote = (EditText) view.findViewById(R.id.dialog_text_note);
        mBtnEdit = (Button) view.findViewById(R.id.dialog_btn_edit);
        mBtnCompleted = (Button) view.findViewById(R.id.dialog_btn_completed);
        mBtnSave = (Button) view.findViewById(R.id.dialog_btn_save);
        mBtnForward = (ImageButton) view.findViewById(R.id.dialog_btn_forward);
        mBucketNoteTime = (BucketPickerView) view.findViewById(R.id.bpv_date_in_note);
        mBucketNoteTimeNonSelected = (BucketPickerView_Unselected) view.findViewById(R.id.bpv_date_in_note_unselected);
        mSwitchButton = (Switch) view.findViewById(R.id.switchButtonNote);
        mSwitchChangeDate = (Switch) view.findViewById(R.id.switchChangeDate);
        mSwitchNoteText = (TextView) view.findViewById(R.id.switchTextAbboveNote);
        dialogPickerButtonNote = (ImageView) view.findViewById(R.id.dialog_picker_button_note);


        mBtnClose.setOnClickListener(this);
        mBtnDelete.setOnClickListener(this);
        mBtnEdit.setOnClickListener(this);
        mBtnCompleted.setOnClickListener(this);
        mBtnSave.setOnClickListener(this);
        mBtnForward.setOnClickListener(this);
        dialogPickerButtonNote.setOnClickListener(this);

        if (savedInstanceState != null) {
            Log.d("realmtest", "onViewCreated: prvi");
            String mojStringTitle = savedInstanceState.getString("myTitle");
            String mojStringNote = savedInstanceState.getString("myNote");
            mEditTextTitle.setText(mojStringTitle);
            mEditTextNote.setText(mojStringNote);
            buttonWhenSaveVisibility();
            setTitleNoteTextToDialogNote();
        }
        else {
            buttonWhenSaveVisibility();

            setTitleNoteTextToDialogNote();
        }
  }

当我旋转screan并且在这行代码上调用方法setTitleNoteTextToDialogNote（）时（当我尝试从领域获取数据时），应用程序被粉碎。

        mEditTextTitle.setText(mRealmResolts.get(position).getWhat());

这是错误：

 Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'io.realm.RealmModel io.realm.RealmResults.get(int)' on a null object reference
                      at com.petar.android.simplenote.DialogNote.setTitleNoteTextToDialogNote(DialogNote.java:231)
                      at com.petar.android.simplenote.DialogNote.onViewCreated(DialogNote.java:134)
                      at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1127)
                      at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1290)
                      at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1272)
                      at android.support.v4.app.FragmentManagerImpl.dispatchActivityCreated(FragmentManager.java:2149)
                      at android.support.v4.app.FragmentController.dispatchActivityCreated(FragmentController.java:201)
                      at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:600)
                      at android.support.v7.app.AppCompatActivity.onStart(AppCompatActivity.java:178)
                      at com.petar.android.simplenote.ActivityMain.onStart(ActivityMain.java:296)
                      at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1248)
                      at android.app.Activity.performStart(Activity.java:6696)
                      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2628)
                      at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2726) 
                      at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4519) 
                      at android.app.ActivityThread.-wrap19(ActivityThread.java) 
                      at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1483) 
                      at android.os.Handler.dispatchMessage(Handler.java:102) 
                      at android.os.Looper.loop(Looper.java:154) 
                      at android.app.ActivityThread.main(ActivityThread.java:6119) 
                      at java.lang.reflect.Method.invoke(Native Method) 
                      at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886) 
                      at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

Answer 1

RealmResults<T>表示从Realm实例获取的查询结果。

Realm是一个数据库。它存储东西。这是一个持久性解决方案。

如果Realm中有某些内容，则表示您不必在onSaveInstanceState()中保留它，因为它已经存在于Realm文件中。

您应该只使用相同的RealmResults<T>参数重新创建sort，您应该没问题。

此外，在任何调用setChangeNoteListener中寻找您的错误，并且不会初始化RealmResults。

Android如何使用onSaveInstanceState保存领域结果以进行屏幕旋转

1 个答案: