How to remove Android preferences from the screen

Question

I'm trying to remove a preference from the screen so it isn't visible if the user is using an SDK greater than 2.2. I've found several answers saying that getPreferenceScreen().removePreference(thePreference) will work, but I'm getting FALSE returned every time I try it. Am I using it in the wrong place? Any clue from my code?

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

Okay the issue in my case was that my preferences were separated into categories and when the preferences are categorized you can't simply ".removePreference" like we were trying to do. I first had to reference the category containing the preference I wanted to remove and then remove that preference from that category like so..

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);
}  
}  
....  
}

I assume this has something to do with the ability to have multiple preferences with the same key (in order to remove the correct one). Anyway thank you Vladimir for sticking with me. Definitely wouldn't have found the answer without you.

Answer 2

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

//Change language
    setApplicationLanguage();

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

Answer 3

Code seems to be right. Tell you that the following code works, just tested it:

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);
        }
    }
}

}

What about your check for sdk build? Does the code really go under the condition?

And please, check the name of your preference. May be you haven't got it with findPreference method.