java - 在 Android 中使用 SharedPreferences 存储数据

Question

我是 Android 编程新手，以前从未涉足过保存值或设置。我看过Storage Options我尝试实现 SharedPreferences。从我的角度来看，当我创建一个新事件时，我告诉它提取一些数据，并将 TextView 设置为该值。然而它永远不会设置 TextView；我似乎无法弄清楚出了什么问题。

createEvent 这是我创建要存储的值的地方。

@Override
protected void onCreate(Bundle savedInstanceState) {
    LayoutInflater inflater = this.getLayoutInflater();
    final View vView = inflater.inflate(R.layout.fragment_main, null);
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    mNavigationDrawerFragment = (NavigationDrawerFragment)
            getFragmentManager().findFragmentById(R.id.navigation_drawer);
    mTitle = getTitle();

    // Set up the drawer.
    mNavigationDrawerFragment.setUp(
            R.id.navigation_drawer,
            (DrawerLayout) findViewById(R.id.drawer_layout));

    SharedPreferences settings = getPreferences(0);
    int iEventCounter = settings.getInt("eventCounter", 0);
    if (iEventCounter > 0){
        String eventName1 = settings.getString("event1Name", "Name of Event");
        TextView eventLabelName = (TextView)vView.findViewById(R.id.section_label);
        eventLabelName.setText(eventName1);
    }
    else if (iEventCounter == 0 || iEventCounter < 0){
        TextView eventLabelName = (TextView)vView.findViewById(R.id.section_label);
        eventLabelName.setText("There is no event stored in memory.");
    }
}

eventAdd(这是我将数据提交到 SharedPreferences 的位置

public int eventAdd(String sName, String sDate) {
    LayoutInflater inflater = this.getLayoutInflater();
    final View vView = inflater.inflate(R.layout.fragment_main, null);
    TextView eventLabelName = (TextView)vView.findViewById(R.id.testTextView);
    eventLabelName.setText("test"); //Never changes
    SharedPreferences settings = getPreferences(0); //Create SharedPreferences
    SharedPreferences.Editor editor = settings.edit(); //Create editor
    iEventCounter = settings.getInt("eventCounter", 0);
    iEventCounter = iEventCounter+1;
    editor.putInt("eventCounter", iEventCounter); //Put values for first Event into SharedPreferences
    editor.putString("event1Name", sName);
    editor.putString("event1Date", sDate);
    // Commit the edits!
    editor.commit();

    //Change Label based on number of Events thus far.
    if (iEventCounter > 0){
        String eventName1 = settings.getString("event1Name", "Name of Event");

        eventLabelName.setText(eventName1);
    }
    else if (iEventCounter == 0 || iEventCounter < 0){
        eventLabelName.setText("There is no event stored in memory.");
    }
    return iEventCounter;
    //eventLabelName.setText(iEventCounter); Doesn't do anything, doesn't change Text.
}

我没有收到错误，应用程序没有崩溃，只是不起作用。有人能看出这里有什么问题吗？任何帮助将不胜感激。

Answer 1

您正在膨胀 View ，但未将其设置为 Activity 的内容。所以您看不到任何变化。

final View vView = inflater.inflate(R.layout.fragment_main, null); 
setContentView(R.layout.activity_main);

也许你应该使用；

setContentView(mView);

或者，如果您想将 activity_main 设置为 Activity 的内容，请进行更改；

vView.findViewById

到

findViewById

尝试重构您的代码。有一些不必要的代码。