安卓共享首选项实现

Question

嗨，我尝试实现共享首选项，

但我尝试的所有内容似乎都不起作用。 我希望当有人单击列表视图中的项目时，它将有关该选择的数据存储在共享引用中。 当应用程序加载时，我希望它检查共享首选项，即：如果没有首选项，请转到此活动，否则转到另一个活动。 我也想知道是否当我被发送到另一个活动时，有一些首选项如何检索它们。这不是我第一次问这个问题，但我想我再问，因为我不是很清楚

这是我到目前为止尝试过的

protected void onListItemClick (ListView l, View v, int position, long id) { 
        Intent intent = new Intent(this, HomeActivity.class);
        try {
            Log.v("lc", "try1");
            JSONObject singleTeamDictionary = teamNamesArray.getJSONObject(position);
            Log.v("lc", "dictionary:" + singleTeamDictionary);
            Log.v("lc", "try2");
             ChosenTeam = (String) singleTeamDictionary.get("name");
             ChosenTeamId = (String) singleTeamDictionary.get("team_id");
             ChosenLeagueId = (String) singleTeamDictionary.get("league_id");
             ChosenDivisionID = (String) singleTeamDictionary.get("division_id");
             Log.v("lc", "try3");
             Log.v("lc", "ChosenTeam: " + ChosenTeam);
             Log.v("lc", "ChosenTeamId: " + ChosenTeamId);
             Log.v("lc", "ChosenLeagueId: " + ChosenLeagueId);
             Log.v("lc", "ChosenDivisionID: " + ChosenDivisionID);          

        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            Log.v("lc", "catch");
        }
        String curPos = Integer.toString(position);
    Log.v("lc", "teamPos: " + curPos);
    SharedPreferences preferences = getSharedPreferences("prefs", Context.MODE_PRIVATE);
    SharedPreferences.Editor editor = preferences.edit();
    editor.putString("ChosenMethod", "Team");
    editor.putString("ChosenTeam", ChosenTeam);
    editor.putString("ChosenTeamId", ChosenTeamId);
    editor.putString("ChosenLeagueId", ChosenLeagueId);
    editor.putString("ChosenDivisionID", ChosenDivisionID);
    editor.commit();

        //or just use the position:
        intent.putExtra("itemIndex", curPos);
        intent.putExtra("fullData", fulldata); //or just the part you want
        startActivity(intent);
    }

然后在介绍活动中

public void checkPreferences(){

    SharedPreferences preferences = getSharedPreferences("prefs", Context.MODE_PRIVATE);
    String ChosenMethod = preferences.getString("chosenTeam", ChosenTeam);

    //String ChosenMethod = preferences.getString("ChosenMethod", null);
//getPWDFromSP()

    //SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
     //Log.v("myapp", "prefs = " + preferences);
     //String ChosenMethod = preferences.getString("ChosenMethod", chosenMethod);
     Log.v("myapp", "ChosenMethod = " + ChosenMethod);
     if (ChosenMethod != null){
         Intent intent = new Intent(TheEvoStikLeagueActivity.this,Activity.class);
     }


}

            @Override
            public void onCreate(Bundle icicle) {
                    super.onCreate(icicle);
                    setContentView(R.layout.main);
                    checkPreferences();

Answer 1

"chosenTeam"与"ChosenTeam"不同。

Answer 2

希望这段代码对您有所帮助

private SharedPreferences sp;
private Editor e;
//create methods
//save method(string)
private void savePreferences(String key,String val){
    sp = getSharedPreferences("prefs", 0);
    e = sp.edit();
    e.putString(key , val);
    e.commit();
}
//get method
private String getPreferences(String key){
    sp = getSharedPreferences("prefs", 0);
    String value = sp.getString(key, "");
    return value;
}
//save String
savePreferences("yourKey","yourString");
//get Preferences
getPreferences("yourKey")
//check value saved or not
if(getPreferences("yourKey").equals(null)){
   //do something
   Log.i("value","null");
}
else{
   //do something
   Log.i("value","exists");
}

如果要保存整数或布尔值，可以编辑方法并根据需要返回值。