Android - split view with button on top - android-layout

Question

I am trying to split screen in android and trying to overlay a button on top of divider
Below is the current and expected
Below is my XML layout file
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#FF0000"
android:weightSum="2">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:background="#ff0000" />
<RelativeLayout
android:background="#00ff00"
android:layout_height="0dp"
android:layout_width="match_parent"
android:layout_weight="1">
<ImageButton
android:id="#+id/imageButton"
android:layout_width="90sp"
android:layout_height="90sp"
app:srcCompat="#drawable/exchange"
android:layout_centerHorizontal="true"
android:layout_marginTop="-45dp"/>
</RelativeLayout>
</LinearLayout>

Answer 1

You can achieve this by aligning the layout in an ordered way or also by using the Constraint Layout.
demo.xml
[![<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:weightSum="2"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:background="#android:color/holo_red_light">
</RelativeLayout>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:background="#android:color/holo_blue_dark">
</RelativeLayout>
</LinearLayout>
<ImageButton
android:id="#+id/imageButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
app:srcCompat="#android:drawable/btn_dialog" />
</RelativeLayout>][1]][1]

Answer 2

Probably the simplest way to take what you have and make it work would be to use a FrameLayout to wrap your existing layout:
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<!-- your current LinearLayout goes here, except for the ImageButton -->
<ImageButton
android:id="#+id/imageButton"
android:layout_width="90sp"
android:layout_height="90sp"
android:layout_gravity="center"
app:srcCompat="#drawable/exchange"/>
</FrameLayout>
The android:layout_gravity attribute is the key here; that will float your button in the center of the screen.
While the above will work, I'd recommend using ConstraintLayout instead:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#FF0000"
android:orientation="vertical">
<RelativeLayout
android:id="#+id/top"
android:layout_width="0dp"
android:layout_height="0dp"
android:background="#ff0000"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toTopOf="#+id/bottom"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"/>
<RelativeLayout
android:id="#+id/bottom"
android:layout_width="0dp"
android:layout_height="0dp"
android:background="#00ff00"
app:layout_constraintTop_toBottomOf="#+id/top"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"/>
<ImageButton
android:id="#+id/imageButton"
android:layout_width="90sp"
android:layout_height="90sp"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:srcCompat="#drawable/exchange"/>
</androidx.constraintlayout.widget.ConstraintLayout>
By doing it this way, you flatten everything into a single view group.

Answer 3

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:id="#+id/topView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:weightSum="1"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
</LinearLayout>
<ImageButton
android:id="#+id/imageButton"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
app:srcCompat="#android:drawable/btn_dialog" />
<LinearLayout
android:id="#+id/bottomView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:weightSum="1"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
</LinearLayout>
</RelativeLayout>