Ramiro Ramiro - 4 months ago 133
Android Question

Android elevation not showing shadow on Button

Can't get button shadows to show up.



Stripped down my code to the minimal example:

activity_main.xml

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

<LinearLayout
android:id="@+id/main_layout"
android:layout_width="wrap_content"
android:layout_height="wrap_content">

<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="10dp"
android:layout_marginLeft="10dp">

<Button
android:id="@+id/my_button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_marginLeft="20dp"
android:elevation="10dp"
android:translationZ="10dp"
android:background="@android:color/holo_green_light"
android:text="BUTTON"/>

</RelativeLayout>

</LinearLayout>

</ScrollView>


I need that layout structure.

MainActivity.java

public class MainActivity extends AppCompatActivity {

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

}


Shadows is visible in Android Studio designer:

enter image description here

But not shown at runtime:

enter image description here

Tested on:


  • Genymotion Google Nexus 5X - Marshmallow 6.0.0 - API 23

  • Genymotion Google Nexus 5 - Lollipop 5.1.0 - API 22

  • Genymotion Samsung Galaxy S2 - Jelly Bean 4.1.1 - API 16

  • Hardware device, Samsung Galaxy S5 mini - KitKat 4.4.2 - API 19



All same result.

I'm using:


  • Android Studio 2.1.2

  • minSdkVersion 16

  • targetSdkVersion 24



Please create a new project in Adndroid Studio, Empty Activity template, then copy and paste that code into activity_main.xml and MainActivity.java so you can test and tell me.

Thanks!!

Answer

The default Button style under Material has a StateListAnimator that controls the android:elevation and android:translationZ properties.

just add this property to your Button. you can set your own using the android:stateListAnimator property.

android:stateListAnimator="@null"

full code :

        <Button
                android:id="@+id/my_button"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerHorizontal="true"
                android:layout_marginLeft="20dp"
                android:elevation="2dp"
                android:translationZ="2dp"
                android:stateListAnimator="@null"
                android:background="@android:color/holo_green_light"
                android:text="BUTTON">

UpDate :

for Understanding I set it 10dp..

xml code :

<RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_margin="20dp">

        <Button
            android:id="@+id/my_button"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerHorizontal="true"
            android:layout_marginLeft="20dp"
            android:elevation="10dp"
            android:translationZ="10dp"
            android:stateListAnimator="@null"
            android:background="@android:color/holo_green_light"
            android:text="BUTTON"/>

    </RelativeLayout>

enter image description here

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