How to add a property for a specific API level on Android?

Question

my app supports all android versions from API Level 19. So, in one of the app's activity, called About Activity, I have code for two API Levels : post API-21 and before that (as seen in screenshot links below).

This is the code of activity_about.xml for API level 21+. As you can see in this image, the name shown on the action bar is "Simple Weather" (name of the app). And also there is no back button here, which I need a lot.

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_about"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.a5corp.weather.AboutActivity">

<TextView
    android:text="TextView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/appName"
    android:layout_centerHorizontal="true"
    android:layout_marginBottom="13dp"
    android:id="@+id/appIcon"
    android:textAppearance="@android:style/TextAppearance.Material.Large"
    android:textAlignment="center"
    android:textColor="#ffbb33"
    android:textSize="96sp" />

<TextView
    android:text="@string/app_name"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/appName"
    android:textAppearance="@android:style/TextAppearance.Material.Medium"
    android:layout_centerVertical="true"
    android:layout_centerHorizontal="true" />

<TextView
    android:text="@string/source_code"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="62dp"
    android:id="@+id/sourceAt"
    android:textAppearance="@android:style/TextAppearance.Material.Large"
    android:layout_below="@+id/appName"
    android:layout_centerHorizontal="true" />

<TextView
    android:text="@string/dev_info"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="19dp"
    android:id="@+id/madeBy"
    android:textAppearance="@android:style/TextAppearance.Material.Medium"
    android:layout_alignTop="@+id/appName"
    android:layout_centerHorizontal="true" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:id="@+id/verText" />

This is the code of activity_about.xml for API Level below 21 (that means only level 19). As you can see in this image, there is a back button, and the name on the action bar is "About"

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_about"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.a5corp.weather.AboutActivity">

<TextView
    android:text="TextView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_above="@+id/appName"
    android:layout_centerHorizontal="true"
    android:layout_marginBottom="13dp"
    android:id="@+id/appIcon"
    android:textSize="96sp"
    android:textAlignment="center"
    android:textColor="#ffbb33" />

<TextView
    android:text="@string/app_name"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/appName"
    android:textSize="18sp"
    android:layout_centerVertical="true"
    android:layout_centerHorizontal="true" />

<TextView
    android:text="@string/source_code"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="62dp"
    android:id="@+id/sourceAt"
    android:textSize="22sp"
    android:layout_below="@+id/appName"
    android:layout_centerHorizontal="true"
    android:textColor="#000000" />

<TextView
    android:text="@string/dev_info"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="19dp"
    android:id="@+id/madeBy"
    android:layout_alignTop="@+id/appName"
    android:layout_centerHorizontal="true"
    android:textSize="18sp" />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentBottom="true"
    android:layout_centerHorizontal="true"
    android:id="@+id/verText" />

I want to have something like this for activity_about.xml for API Level 21+ as well. Can this be possible?

Here's my Android Manifest File.

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.a5corp.weather">

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

<application
    android:allowBackup="true"
    android:icon="@mipmap/app_icon"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity android:name="com.a5corp.weather.GlobalActivity"
        android:label="@string/app_name">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity
        android:name=".AboutActivity"
        android:label="About"
        android:parentActivityName="com.a5corp.weather.WeatherActivity">
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value="com.a5corp.weather.WeatherActivity" />
    </activity>
    <activity
        android:name=".WeatherActivity"
        android:label="@string/app_name"
        android:screenOrientation="portrait">
    </activity>
    <activity android:name=".FirstLaunch"
        android:label="Enter City"/>
</application>
</manifest>

Thank you, Aaditya

Answer 1

If your AboutActivity inherits from Activity , try this:

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

    android.app.ActionBar actionBar = getActionBar();
    if (actionBar != null) {
        actionBar.setTitle("my awesome title");
        actionBar.setDisplayHomeAsUpEnabled(true);
    }
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    if (item.getItemId() == android.R.id.home) {
        finish();
        return true;
    }
    return super.onOptionsItemSelected(item);
}

Or else, if your AboutActivity is a subclass of AppCompatActivity :

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

    android.support.v7.app.ActionBar actionBar = getSupportActionBar();
    if (actionBar != null) {
        actionBar.setTitle("my awesome title");
        actionBar.setDisplayHomeAsUpEnabled(true);
    }
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    if (item.getItemId() == android.R.id.home) {
        finish();
        return true;
    }
    return super.onOptionsItemSelected(item);
}

If neither works (ie ActionBar is null), you'll have to configure the styles and features in your layout and Activity so you can obtain an ActionBar.