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我使用产生的自身(由Android工作室)SettingsActivity
。 我创建了一个Listener
后Preference
变化重新启动应用程序,但由于某种原因,我不能启动从这个Listener
新Intent
。如何在我的应用程序启动的意图在PreferenceChangeListener
下面是代码:
private static Preference.OnPreferenceChangeListener listener = new Preference.OnPreferenceChangeListener(){
@Override
public boolean onPreferenceChange(Preference preference, Object o) {
SettingsActivity settingsActivity = new SettingsActivity();
settingsActivity.restartApp();
return true;
}
};
和:
private void restartApp() {
Intent intent = new Intent(SettingsActivity.this, MainActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
SettingsActivity.this.finish();
startActivity(intent);
}
我不得不创建一个新的实例来这个班,因为我把从静态方法非静态方法。
侦听器从此方法调用:
private static void bindPreferenceSummaryToValue(Preference preference) {
// Set the listener to watch for value changes.
preference.setOnPreferenceChangeListener(sBindPreferenceSummaryToValueListener);
preference.setOnPreferenceChangeListener(listener);
// Trigger the listener immediately with the preference's
// current value.
sBindPreferenceSummaryToValueListener.onPreferenceChange(preference,
PreferenceManager
.getDefaultSharedPreferences(preference.getContext())
.getString(preference.getKey(), ""));
}
而且这种方法被称为从这里:
@TargetApi(Build.VERSION_CODES.HONEYCOMB)
public static class GeneralPreferenceFragment extends PreferenceFragment {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.pref_general);
setHasOptionsMenu(true);
bindPreferenceSummaryToValue(findPreference(getString(R.string.language_shared_pref_key)));
}
}
这是logcat的:
Process: appinventor.ai_itiel_maimon.Rubiks_cube, PID: 14454
java.lang.NullPointerException: Attempt to invoke virtual method 'android.app.ActivityThread$ApplicationThread android.app.ActivityThread.getApplicationThread()' on a null object reference
at android.app.Activity.startActivityForResult(Activity.java:4283)
at android.app.Activity.startActivityForResult(Activity.java:4230)
at android.app.Activity.startActivity(Activity.java:4567)
at android.app.Activity.startActivity(Activity.java:4535)
at appinventor.ai_itiel_maimon.Rubiks_cube.SettingsActivity.restartApp(SettingsActivity.java:59)
at appinventor.ai_itiel_maimon.Rubiks_cube.SettingsActivity.access$000(SettingsActivity.java:16)
at appinventor.ai_itiel_maimon.Rubiks_cube.SettingsActivity$2.onPreferenceChange(SettingsActivity.java:50)
at android.preference.Preference.callChangeListener(Preference.java:1173)
at android.preference.ListPreference.onDialogClosed(ListPreference.java:282)
at android.preference.DialogPreference.onDismiss(DialogPreference.java:424)
at android.app.Dialog$ListenersHandler.handleMessage(Dialog.java:1533)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:158)
at android.app.ActivityThread.main(ActivityThread.java:7229)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
我试图使重新启动应用程序的方法静态的,而是我如何使用上下文参数? –
我会用除去了'onPreferenceChangesListener' – Muzikant
了'static'开始和我不能改变听者不是静态的,因为它是必须是静态的静态方法调用。 –