android – 共享首选项仅保存第一次

该程序第一次创建首选项,但之后它永远不会更改它们.我很感激帮助理解为什么.

这是调用xml的PreferencesScreen.

public class PreferencesScreen extends PreferenceFragment{

private final String TAG = "PreferencesScreen";

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    Log.d(TAG,"OnCreate");
    addPreferencesFromresource(R.xml.prefs);
}

在首选项中,我有一个ListPreference和一个Preference,它调用一个活动来存储电子邮件.

<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" >

<PreferenceCategory android:title="information Collected">
    <ListPreference 
        android:key="loggins"
        android:title="Logs Stored"
        android:summary="Choose the top kind of logs do you want to store."
        android:dialogTitle="Choose Logs"
        android:entries="@array/logs"
        android:entryValues="@array/logsValues"/>
</PreferenceCategory>

 <PreferenceCategory android:title="Email Configurations">
        <Preference
              android:key="pushing"
              android:title="The Email Activity"
              android:summary="Just push">
             <intent android:action = "ADDING_EMAIL"/>
        </Preference>
 </PreferenceCategory>
</PreferenceScreen>

一切都在这里.问题出在所谓的……

public class AddingEmail extends ListActivity implements OnClickListener{       

private Set<String> emails; 
private EditText emailAdd;
SharedPreferences.Editor editor;

public void onCreate(Bundle savedInstanceState){
    super.onCreate(savedInstanceState);
    setContentView(R.layout.addingemail);
    Button add = (Button) findViewById(R.id.add);
    emailAdd = (EditText) findViewById(R.id.email);
    prefs = PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
    editor = prefs.edit();

    prefList = toArrayList(prefs.getStringSet("emailWrongs",null));
    add.setonClickListener(this);
}


public void onClick(View v) {
    Set<String> list = prefs.getStringSet("emailWrongs",null);
    String newEmail = emailAdd.getText().toString();        
    if (list==null){  //first time the preferences are called. 
        emails = new TreeSet<String>();
        editor.putStringSet("emailWrongs",emails);
        editor.apply();
    }
    if (newEmail != ""){
        emails=prefs.getStringSet("emailWrongs",null);
        emails.add(newEmail);
        editor.putStringSet("emailWrongs",emails);
        editor.apply();
    }
}

}

关键是它总是存储第一次很好,但如果我在添加另一封电子邮件时,首选项不会改变.他们看起来好像改变了,因为如果我打印它们会显示我添加的所有电子邮件,但偏好文件不会改变(在文件资源管理器中检查它).如果我重新启动或关闭并再次打开,则首选项仅包含我添加的第一封电子邮件.
问题是,如果我回到并更改ListPreference的首选项,那么它甚至存储我添加的电子邮件的所有更改.

希望我很清楚,它有很多代码,因为我想要非常明确.
感谢您的帮助.

解决方法

经过一个多星期的寻找错误,我发现了它.
我认为这对很多遇到同样麻烦的人都有帮助.

问题是,当我调用首选项来获取字符串集时,它只引用列表而不复制它.因此,我必须创建一个新列表并添加之前存储的所有元素,并添加新元素,然后使用编辑器更改新列表的首选项.
代码是这样的：

Set<String> list = prefs.getStringSet("emailWrongs",null); 
Set<String> newList = new TreeSet<String>();
String newEmail = emailAdd.getText().toString();         
if (newEmail != ""){ 
    if (list != null){
        for(String each: list){
            newList.add(each);
        }
    }
    newList.add(newEmail);
    editor.putStringSet("emailWrongs",newList);     
    editor.apply();      
}