Custom Toolbar for all activities not working as expected?

Question

I want to set a custom toolbar with a back arrow (to go to the previous activity, which in this case is always back to main activity) for all activities except main activity.

As read from a couple of posts, I have created a custom toolbar activity and here is the code:

activity_toolbar_back_arrow.xml

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

<androidx.appcompat.widget.Toolbar
    android:layout_width="match_parent"
    android:layout_height="?attr/actionBarSize"
    android:background="@color/colorPrimary"
    app:title="My First App"
    android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
    app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
    android:id="@+id/toolbar_back_arrow"
    app:contentInsetLeft="0dp"
    app:contentInsetStart="0dp"
    app:contentInsetStartWithNavigation="0dp"/>
</LinearLayout>

ToolbarBackArrow.class

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import androidx.appcompat.widget.Toolbar;

public class ToolbarBackArrow extends AppCompatActivity {

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

    Toolbar toolbar = findViewById(R.id.toolbar_back_arrow);
    setSupportActionBar(toolbar);

    getSupportActionBar().setDisplayHomeAsUpEnabled(true);
}
}

Now an another activity is created that extends the above custom activity: VisionMission.java

import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
import android.os.Bundle;

public class VisionMission extends ToolbarBackArrow {

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

}
}

In the activity_vision_mission.xml, I have some code specific to just that activity.

As per the solutions, I read this should create a toolbar in the VisionMission activity, but it is not. What am I missing? In manifest, I have made theme as No ActionBar for all the activities.

Answer 1

No need to go for custom toolbar if your only requirement is back button.

In your manifest.xml file for the specified activity,

<activity
    android:name="com.example.app_name.A" ...>
    ...
</activity>
<!-- A child of the main activity -->
<activity
    android:name=".B"
    android:label="B"
    android:parentActivityName="the activity to go on back click" >
    <!--android:parentActivityName="com.examle.myparentactivity" -->
    <!-- Parent activity meta-data to support 4.0 and lower -->
    <meta-data
        android:name="android.support.PARENT_ACTIVITY"
        android:value="com.example.app_name.A" />
</activity>

It will automatically show the back button with desired behaviour.

Answer 2

It's because in your ToolbarBackArrow you are setting your layout first and then in VisionMission you're resetting the layout and old layout with your toolbar is being replaced by another call to setContentView. To achieve desired result use includes:

include_toolbar.xml:

<androidx.appcompat.widget.Toolbar
    android:layout_width="match_parent"
    android:layout_height="?attr/actionBarSize"
    android:background="@color/colorPrimary"
    app:title="My First App"
    android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
    app:popupTheme="@style/ThemeOverlay.AppCompat.Light"
    android:id="@+id/toolbar_back_arrow"
    app:contentInsetLeft="0dp"
    app:contentInsetStart="0dp"
    app:contentInsetStartWithNavigation="0dp"/>

activity_vision_mission.xml:

<LinearLayout
    ...>

   <include layout="@layout/include_toolbar" />

   ... Your other views ...

</LinearLayout>

and in super class ToolbarBackArrow

public class ToolbarBackArrow extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        // Not needed anymore
        // setContentView(R.layout.activity_toolbar_back_arrow);

        Toolbar toolbar = findViewById(R.id.toolbar_back_arrow);

        // always check because you can forget to add an 'include' and
        // toolbar will be null here, so you'll get NullPointerException
        if (toolbar != null) {
            setSupportActionBar(toolbar);
            getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        }
    }
}