Come rimuovere le preferenze di Android dalla schermata

Question

Sto cercando di rimuovere una preferenza dallo schermo in modo che non è visibile se l'utente sta utilizzando uno SDK maggiore di 2.2. Ho trovato più risposte dicendo che getPreferenceScreen(). RemovePreference (thePreference) funzionerà, ma sto diventando FALSE restituito ogni volta che provo. Lo sto usando nel posto sbagliato? Qualche indizio dal mio codice?

public class Preferences extends PreferenceActivity implements OnSharedPreferenceChangeListener { 

private static final String POLLING_PREFERENCE = "update_frequency_list"; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

    // Load the preferences from an XML resource 
    addPreferencesFromResource(R.xml.preferences); 

    // Get a reference to the preferences 
    mPollPref = getPreferenceScreen().findPreference(POLLING_PREFERENCE); 

    //If the SDK is 2.2 or greater do not display polling preferences (using C2DM instead) 
    if(Build.VERSION.SDK_INT > 7) { 
     getPreferenceScreen().removePreference(mPollPref); 
    } 
} 
.... 
} 

Answer 1

Ok, il problema nel mio caso era che le mie preferenze erano divise in categorie e quando le preferenze sono categorizzate non puoi semplicemente ".removePreference" come stavamo cercando di fare. Ho dovuto fare riferimento la categoria contenente la preferenza ho voluto rimuovere e quindi rimuovere la preferenza da quella categoria in questo modo ..

public class Preferences extends PreferenceActivity implements OnSharedPreferenceChangeListener { 

private static final String POLLING_PREFERENCE = "update_frequency_list"; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
super.onCreate(savedInstanceState); 

// Load the preferences from an XML resource 
addPreferencesFromResource(R.xml.preferences); 

// Get a reference to the preferences 
mPollPref = getPreferenceScreen().findPreference(POLLING_PREFERENCE); 

//If the SDK is 2.2 or greater do not display polling preferences (using C2DM instead) 
if(Build.VERSION.SDK_INT > 7) { 
    PreferenceCategory notificationsCategory = (PreferenceCategory) findPreference("notifications_category"); 
    notificationsCategory.removePreference(mPollPref); 
} 
} 
.... 
} 

Suppongo che questo ha qualcosa a che fare con la possibilità di avere più preferenze con lo stesso chiave (per rimuovere quella corretta). Comunque grazie Vladimir per avermi seguito. Sicuramente non avrei trovato la risposta senza di te.

Answer 2

Il codice sembra avere ragione. Dirvi che il seguente codice funziona, appena provato:

package com.lid.ps.screens.edit_activity; 

import android.app.AlertDialog; 
import android.app.DatePickerDialog; 
import android.content.Context; 
import android.content.DialogInterface; 
import android.os.Bundle; 
import android.preference.*; 
import android.util.Log; 
import android.view.LayoutInflater; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.view.View; 
import android.widget.*; 
import com.lid.ps.bean.AbstractData; 
import com.lid.ps.bean.Action; 
import com.lid.ps.bean.ActionFactory; 
import com.lid.ps.bean.CommonAlertDialog; 
import com.lid.ps.bean.utils.DateTools; 
import com.lid.ps.model.Activity; 
import com.lid.ps.model.ActivityImpl; 
import com.lid.ps.screens.R; 

import java.util.Calendar; 

/** 
* User: Vladimir Ivanov 
* Date: 04.07.2010 
* Time: 9:58:17 
*/ 
public class EditActivityScreen extends PreferenceActivity 
    implements DatePickerDialog.OnDateSetListener, AbstractData<Activity> { 

private static final int MENU_DELETE_ACTIVITY = 0; 

private boolean create = true; 

public boolean isCreate() { 
    return create; 
} 

private Activity dataContainer; 

private EditTextPreference activityNamePref; 
private EditTextPreference activityDescPref; 
private Preference startDatePref; 
private CheckBoxPreference hiddenPref; 

private int year; 
private int monthOfYear; 
private int dayOfMonth; 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

    addPreferencesFromResource(R.xml.activity_prefs); 
    //this.setContentView(R.layout.edit_screen); 

    activityNamePref = (EditTextPreference) findPreference("name"); 

    activityDescPref = (EditTextPreference) findPreference("desc");   

    // We have to do this to get the save/cancel buttons to highlight on 
    // their own. 
    getListView().setItemsCanFocus(true); 

    // Grab the content view so we can modify it. 
    FrameLayout content = (FrameLayout) getWindow().getDecorView() 
      .findViewById(android.R.id.content); 

    // Get the main ListView and remove it from the content view. 
    ListView lv = getListView(); 
    content.removeView(lv); 

    // Create the new LinearLayout that will become the content view and 
    // make it vertical. 
    LinearLayout ll = new LinearLayout(this); 
    ll.setOrientation(LinearLayout.VERTICAL); 

    // Have the ListView expand to fill the screen minus the save/cancel 
    // buttons. 
    LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(
      LinearLayout.LayoutParams.FILL_PARENT, 
      LinearLayout.LayoutParams.WRAP_CONTENT); 
    lp.weight = 1; 
    ll.addView(lv, lp); 

    // Inflate the buttons onto the LinearLayout. 
    View v = LayoutInflater.from(this).inflate(
      R.layout.edit_screen, ll); 

    startDatePref = findPreference("time"); 

    hiddenPref = (CheckBoxPreference) findPreference("hidden"); 

    // Initialize buttons 
    Button cancelButton = (Button) v.findViewById(R.id.cancel_activity); 
    Button saveButton = (Button) v.findViewById(R.id.save_activity); 

    cancelButton.setOnClickListener(new CancelOnClickListener()); 
    saveButton.setOnClickListener(new SaveOnClickListener()); 

    setContentView(ll); 

    // if edit mode... 
    if (getIntent() != null && getIntent().getExtras() != null) { 
     // some stuff 
} 

@Override 
public boolean onPreferenceTreeClick(PreferenceScreen preferenceScreen, 
            Preference preference) { 
    if (preference == startDatePref) { 
     new DatePickerDialog(this, this, year, monthOfYear, dayOfMonth).show(); 
    } 

    return super.onPreferenceTreeClick(preferenceScreen, preference); 
} 

private void popAlarmSetToast(Context context) { 
    String toastText;  
    //... 
    final Toast toast = Toast.makeText(context, toastText, Toast.LENGTH_LONG); 
    toast.show(); 
} 

/** 
* updates the preference summary. 
* 
* @param datePicker date picker 
* @param i   year 
* @param i1   month 
* @param i2   day 
*/ 
@Override 
public void onDateSet(DatePicker datePicker, int i, int i1, int i2) { 
    year = i; 
    monthOfYear = i1; 
    dayOfMonth = i2; 
    updateDate(); 
} 

private void updateDate() { 
    startDatePref.setSummary(
      new StringBuilder() 
        // Month is 0 based so add 1 
        .append(year).append("-") 
        .append(monthOfYear + 1).append("-") 
        .append(dayOfMonth).append(" ")); 
} 


private class CancelOnClickListener implements View.OnClickListener { 

    public void onClick(View view) { 
     // go back to the previous page 
     final Action action = ActionFactory.createAction("back_edit_activity"); 
     if (action != null) { 
      action.doAction(EditActivityScreen.this); 
     } 
    } 
} 

private class SaveOnClickListener implements View.OnClickListener { 

    public void onClick(View view) { 

     // validation 
     if (activityNamePref.getSummary() == null || activityNamePref.getSummary().length() == 0) { 
      AlertDialog dialog = new AlertDialog.Builder(EditActivityScreen.this).create(); 
      dialog.setTitle(R.string.validation_failed); 
      dialog.setMessage(EditActivityScreen.this.getResources().getString(R.string.activity_create_fail)); 
      dialog.setButton(AlertDialog.BUTTON_POSITIVE, "OK", new DialogInterface.OnClickListener() { 
       @Override 
       public void onClick(DialogInterface dialogInterface, int i) { 
       } 
      }); 
      dialog.show(); 
     } else { 
      final Action action = ActionFactory.createAction("save_edit_activity"); 
      if (action != null) { 
       action.doAction(EditActivityScreen.this); 
      } 
      popAlarmSetToast(EditActivityScreen.this); 
     } 
    } 
} 

}

E il tuo assegno per sdk costruire? Il codice va davvero sotto le condizioni?

E per favore, controllare il nome di vostra preferenza. Potresti non averlo con il metodo findPreference.

Answer 3

//remove all preferences 
    mPollPref = getPreferenceScreen(); 
    mPollPref.removeAll(); 

//Change language 
    setApplicationLanguage(); 

//and rebuild 
    addPreferencesFromResource(R.xml.preferences);