Android共享的首选项使用的首选项工作像一个按钮

Question

我正在使用sharedpreferences框架，但是我在与其中一个首选项交互时遇到了一点麻烦。我想启用我的一个选项来重置我的应用程序。要做到这一点，我想要一个对话框出现在屏幕上的确定和取消。如果用户点击OK，我想做很多事情。

我可以在使用ImageView监听器的正常活动中编写所有这些。但是在SharedPreferences框架中，我不知道如何添加侦听器和操作。我想作为额外的奖励，我也需要与当前的SharedPreferences状态进行交互?

现在我有这个XML

<PreferenceCategory  android:title="Reset App">
    <Preference
        android:title="Reset App?"
        android:summary="Click here to reset the App to defaults."
        android:key="resetapp" />
</PreferenceCategory>

<PreferenceCategory  android:title="General Settings">
 <CheckBoxPreference
         android:title="Enable Sounds?"
         android:defaultValue="true"
         android:summary="A Tick here will enable sounds throughout body-mix-ology."
         android:key="enablesounds" />
 <CheckBoxPreference
         android:title="High performance Phone?"
         android:defaultValue="false"
         android:summary="If you have a high performance phone tick here to speed up body switching."
         android:key="highperformancephone" />
  </PreferenceCategory>

这是我的类文件

public class Preferences extends PreferenceActivity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.layout.preferences);
        //TODO
        // act on resetapp
        // prompt onscreen confirmation.
    }
    public AlertDialog createDialog() {
        return new AlertDialog.Builder(this)
        .setTitle("Reset App?")
        .setMessage("Are you sure? You will wipe all data from the app.")
        .setPositiveButton("OK", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int whichButton) {
                Toast.makeText(getBaseContext(), "App has been reset!", Toast.LENGTH_SHORT).show();
                //TODO
                // clear DB
                // reset sharedprefs.
            }
        })
        .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int whichButton) {
                Toast.makeText(getBaseContext(), "App was not reset", Toast.LENGTH_SHORT).show();
            }
        })
        .show();
   }

}

Answer 1

如果有一个带有"Are you sure you want do this?"的ListPreference和带有默认"No"的列表值"Yes"one_answers"No"呢?然后像这样回复任何"是"确认:

public void onSharedPreferenceChanged(SharedPreferences prefs, String key) {
    if (key.equals("resetapp") && prefs.getString(key,"").equals("Yes")) {
        // reset the value to "No" so that next time a preference change will be triggered
        prefs.edit().putString(key, "No").commit();
        // now do your awesome reset stuff ...
        Preference someOtherPref = findPreference(otherKey);
        ...
    }
}

别忘了把你的类定义改成:

public class Preferences extends PreferenceActivity implements OnSharedPreferenceChangeListener {

并注册eventlistener:

@Override
protected void onResume() {
    super.onResume();
    getPreferenceScreen().getSharedPreferences()
            .registerOnSharedPreferenceChangeListener(this);
}
@Override
protected void onPause() {
    super.onPause();
    getPreferenceScreen().getSharedPreferences()
            .unregisterOnSharedPreferenceChangeListener(this);
}