preferences android error
<p>i have a problem with this line,eclipse wrote to me "addPreferencesFromResource is undefined for the MainActivity" and wrote error for me at this line:</p>

<pre><code>addPreferencesFromResource(R.xml.preferences);
</code></pre>

<p>also i import:</p>

<pre><code>import android.net.ConnectivityManager;
import android.net.wifi.WifiManager;
import android.os.BatteryManager;
import android.os.Bundle;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.telephony.TelephonyManager;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.CheckBox;
import android.preference.PreferenceActivity;
import android.widget.SeekBar;
import android.view.View.OnClickListener;
import android.preference.EditTextPreference;
import android.preference.PreferenceActivity;
import android.preference.PreferenceManager;
</code></pre>

<p>how can i fix it?</p>

<p>thanks alot</p>
