Technology Lesson: Android beginner tutorial Part 78 Creating Preferences Activity

Wednesday, January 28, 2015

Android beginner tutorial Part 78 Creating Preferences Activity

In this tutorial we will create a preferences activity that can be invoked using the application menu.

First of all well need to create the xml that contains all the preferences in the settings menu. Go to the layout directory of your applications project and add a new file preferences.xml.

Add this code:

<?xml version="1.0" encoding="utf-8"?>
<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
    <CheckBoxPreference
        android:key="pref_mute"
        android:title="@string/pref_mute"
        android:summary="@string/pref_mute_summ"
        android:defaultValue="false" />

</PreferenceScreen>

The key property is used as an identificator for this setting. It has to be a unique string. The title value is the text representation of the setting, and summary is the description of the setting item.

Go to strings.xml file to set the missing string values:

<?xml version="1.0" encoding="utf-8"?>
<resources>

    <string name="app_name">CodeForFood Test Two</string>
    <string name="pref_mute">Mute</string>
    <string name="pref_mute_summ">Disable all the sound in the application</string>
    <string name="menu_settings">Settings</string>

</resources>

Create a new Activity in the same directory as the MainActivity.java class, call it TestPreferences.java.

Heres the code that applies the xml layout of the preferences page:

package com.example.codeforfoodtest_two;

import android.os.Bundle;
import android.preference.PreferenceActivity;

public class TestPreferences extends PreferenceActivity {

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    addPreferencesFromResource(R.layout.preferences);
}

}

Now go to AndroidManifest.file of the application and add this line to the application node:

<activity android:name="TestPreferences"></activity>

Doing so will tell Android that theres an Activity with that name in our application.

Now go to MainActivity.java class, add some code that creates an options menu and handles item selection in the menu. When the Settings item is selected, the preferences screen pops up:

package com.example.codeforfoodtest_two;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;

public class MainActivity extends Activity{

static final int IDM_SETTINGS = 101;

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

@Override
public boolean onCreateOptionsMenu(Menu menu){
menu.add(Menu.NONE, IDM_SETTINGS, Menu.NONE, R.string.menu_settings);
return(super.onCreateOptionsMenu(menu));
}

@Override
public boolean onOptionsItemSelected(MenuItem item){
if(item.getItemId()==IDM_SETTINGS){
Intent intent = new Intent();
intent.setClass(this, TestPreferences.class);
startActivity(intent);
}
return true;
}
}

And thats all for today! Changing the preference doesnt really do anything yet, but well work on that next time.

Thanks for reading!

Technology Lesson

Wednesday, January 28, 2015

Android beginner tutorial Part 78 Creating Preferences Activity

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