Android- deprecated method warning regarding PreferenceActivity

PreferenceActivity() is deprecated, but PreferenceFragment() is now as well. PreferenceFragmentCompat() is now the way to go:

Add dependency

implementation "androidx.preference:preference:1.1.1"

Or in case you are still using the support library:

implementation "com.android.support:preference-v7:28.0.0"

Extend PreferenceFragmentCompat

class MyPreferenceFragment : PreferenceFragmentCompat() {
    override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
        addPreferencesFromResource(R.xml.app_preferences)
    }
}

Show your Fragment

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    supportFragmentManager.beginTransaction().replace(android.R.id.content, MyPreferenceFragment()).commit()
}

Specify preferenceTheme

In your AppTheme, add either of the following preference themes, depending of which one you think looks better:

<item name="preferenceTheme">@style/PreferenceThemeOverlay</item>
<item name="preferenceTheme">@style/PreferenceThemeOverlay.v14.Material</item>

As the method is deprecated, it is recommended that you don't use it in your code, as it is entirely possible that it can be removed in future versions of Android. However, I am yet to come across a deprecated method that has actually been removed from Android.

No alternative method is provided in the method's description because the preferred approach (as of API level 11) is to instantiate PreferenceFragment objects to load your preferences from a resource file. See the sample code here: PreferenceActivity

If you face a deprecation warning from a method like this :

addPreferencesFromResource(R.xml.default_values);

You have to use PreferenceFragment because API 11 and above requires such a method.

Here is an example of how to use PreferenceFragment :

1.Create /res/xml/preferences.xml to define our preferences.

 <PreferenceScreen
    xmlns:android="http://schemas.android.com/apk/res/android">

<PreferenceCategory
        android:title="PreferenceCategory A">

    <CheckBoxPreference
            android:key="checkbox_preference"
            android:title="title_checkbox_preference"
            android:summary="summary_checkbox_preference" />

</PreferenceCategory>

<PreferenceCategory
        android:title="PreferenceCategory B">

    <EditTextPreference
            android:key="edittext_preference"
            android:title="title_edittext_preference"
            android:summary="summary_edittext_preference"
            android:dialogTitle="dialog_title_edittext_preference" />

</PreferenceCategory>

2.Create PrefsFragment.java extends PreferenceFragment to addPreferencesFromResource.

   package com.example.androidpreferencefragment;

   import android.os.Bundle;
   import android.preference.PreferenceFragment;

   public class PrefsFragment extends PreferenceFragment {

   @Override
   public void onCreate(Bundle savedInstanceState) {
   // TODO Auto-generated method stub
   super.onCreate(savedInstanceState);

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

 }

3.Create SetPreferenceActivity.java to load PrefsFragment.

package com.example.androidpreferencefragment;

import android.app.Activity;
import android.os.Bundle;

public class SetPreferenceActivity extends Activity {

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  // TODO Auto-generated method stub
  super.onCreate(savedInstanceState);

  getFragmentManager().beginTransaction().replace(android.R.id.content,
                new PrefsFragment()).commit();
 }

}

4.Modify the main layout, /res/layout/activity_main.xml, to show the preference.

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:padding="@dimen/padding_medium"
    android:text="@string/hello_world"
    tools:context=".MainActivity" />

<CheckBox
    android:id="@+id/prefCheckBox"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:text="CheckBoxPreference" />

<TextView
    android:id="@+id/prefEditText"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content" />

</LinearLayout>

5.The main activity, MainActivity.java.

package com.example.androidpreferencefragment;

import android.os.Bundle;
import android.preference.PreferenceManager;
import android.app.Activity;
import android.content.Intent;
import android.content.SharedPreferences;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.CheckBox;
import android.widget.TextView;

public class MainActivity extends Activity {

 CheckBox prefCheckBox;
 TextView prefEditText;

    @Override
    public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    prefCheckBox = (CheckBox)findViewById(R.id.prefCheckBox);
 prefEditText = (TextView)findViewById(R.id.prefEditText);

 loadPref();
}

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.activity_main, menu);
    return true;
}

 @Override
 public boolean onOptionsItemSelected(MenuItem item) {

  /*
   * Because it's onlt ONE option in the menu.
   * In order to make it simple, We always start SetPreferenceActivity
   * without checking.
   */

  Intent intent = new Intent();
    intent.setClass(MainActivity.this, SetPreferenceActivity.class);
    startActivityForResult(intent, 0); 

    return true;
 }

  @Override
 protected void onActivityResult(int requestCode, int resultCode, Intent data) {
  // TODO Auto-generated method stub
  //super.onActivityResult(requestCode, resultCode, data);

  /*
   * To make it simple, always re-load Preference setting.
   */

  loadPref();
 }

 private void loadPref(){
  SharedPreferences mySharedPreferences =        PreferenceManager.getDefaultSharedPreferences(this);

  boolean my_checkbox_preference = mySharedPreferences.getBoolean("checkbox_preference", false);
  prefCheckBox.setChecked(my_checkbox_preference);

  String my_edittext_preference = mySharedPreferences.getString("edittext_preference", "");
  prefEditText.setText(my_edittext_preference);

 }

}

5.Finally, modify AndroidManifest.xml to add SetPreferenceActivity.

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.androidpreferencefragment"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
    android:minSdkVersion="11"
    android:targetSdkVersion="15" />

<application
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name=".MainActivity"
        android:label="@string/title_activity_main" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity
        android:name=".SetPreferenceActivity"
        android:label="@string/title_activity_main" >
    </activity>
</application>