elevation effect of overlapped view

This example show how elevation effect of overlapped view.

package com.blogspot.android_er.androidzelevation;

import android.os.Build;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.ImageView;
import android.widget.SeekBar;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {

    SeekBar seekBarZ1, seekBarZ2;
    ImageView image1;
    TextView text2;

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

        seekBarZ1 = (SeekBar)findViewById(R.id.z1);
        seekBarZ2 = (SeekBar)findViewById(R.id.z2);
        image1 = (ImageView)findViewById(R.id.image1);
        text2 = (TextView)findViewById(R.id.text2);

        seekBarZ1.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int i, boolean b) {
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                    image1.setZ(i);
                }
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {}

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {}
        });

        seekBarZ2.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int i, boolean b) {
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                    text2.setZ(i);
                    text2.setText("elevation: " + String.valueOf(i) + "px");
                }
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {}

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {}
        });
    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:padding="16dp"
    android:orientation="vertical"
    tools:context="com.blogspot.android_er.androidzelevation.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="20dp"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold"/>

    <SeekBar
        android:id="@+id/z1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:progress="10"
        android:max="50"/>
    <SeekBar
        android:id="@+id/z2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:progress="5"
        android:max="50"/>

    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <ImageView
            android:id="@+id/image1"
            android:layout_width="200dp"
            android:layout_height="200dp"
            android:elevation="10px"
            android:background="#90F0F0F0"
            android:src="@mipmap/ic_launcher"/>
        <TextView
            android:id="@+id/text2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:elevation="5px"
            android:textSize="40dp"
            android:background="#90F0F0F0"
            android:text="elevation: 5px"/>
    </FrameLayout>

</LinearLayout>

Change elevation at run-time, by calling setZ()

This example show how to change elevation of ImageView programmatically, by calling setZ().

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:padding="16dp"
    android:orientation="vertical"
    tools:context="com.blogspot.android_er.androidzelevation.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="20dp"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold"/>

    <SeekBar
        android:id="@+id/z"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:progress="20"
        android:max="100"/>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:orientation="vertical"
        android:gravity="center">
        <ImageView
            android:id="@+id/image"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:elevation="20dp"
            android:background="@android:color/background_dark"
            android:src="@mipmap/ic_launcher"/>
    </LinearLayout>

</LinearLayout>

package com.blogspot.android_er.androidzelevation;

import android.os.Build;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.ImageView;
import android.widget.SeekBar;

public class MainActivity extends AppCompatActivity {

    SeekBar seekBarZ;
    ImageView image;

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

        seekBarZ = (SeekBar)findViewById(R.id.z);
        image = (ImageView)findViewById(R.id.image);
        
        seekBarZ.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int i, boolean b) {
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
                    image.setZ(i);
                }
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {

            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {

            }
        });
    }
}

more:
- elevation effect of overlapped view

Example of applying android:elevation on ImageView

Example to apply android:elevation on ImageView.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:padding="16dp"
    android:orientation="vertical"
    tools:context="com.blogspot.android_er.androidzelevation.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="20dp"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold"/>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:orientation="vertical"
        android:gravity="center">
        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:elevation="20dp"
            android:src="@mipmap/ic_launcher"/>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:orientation="vertical"
        android:gravity="center">
        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:elevation="20dp"
            android:background="@android:color/background_dark"
            android:src="@mipmap/ic_launcher"/>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:orientation="vertical"
        android:gravity="center">
        <ImageView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:elevation="20dp"
            android:background="#FF0000"
            android:src="@mipmap/ic_launcher"/>
    </LinearLayout>

</LinearLayout>

Running on ASUS Zenfone 2 running Android 5.0

How it shown on Emulator running Android API 23 and API 19, and also Android Studio Design View:

Try android:elevation on TextView

Just try some effect of android:elevation on TextView, for various background.

layout/activity_main.xml

<LinearLayout 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"
    android:padding="20dp"
    android:orientation="vertical"
    tools:context=".MainActivity"
    android:background="#ffffff">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="20dp"
        android:layout_gravity="center_horizontal"
        android:autoLink="web"
        android:text="http://android-er.blogspot.com/"
        android:textStyle="bold"/>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="20dp"
        android:textSize="22dp"
        android:textStyle="bold"
        android:text="Simple TextView" />
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="20dp"
        android:textSize="22dp"
        android:textStyle="bold"
        android:text="TextView with elevation, no background"
        android:elevation="20dp" />
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="20dp"
        android:textSize="22dp"
        android:textStyle="bold"
        android:text="TextView with both elevation and background"
        android:background="#0000ff"
        android:elevation="20dp" />
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="20dp"
        android:textSize="22dp"
        android:textStyle="bold"
        android:text="TextView with both elevation and background (same as parent background)"
        android:background="#ffffff"
        android:elevation="20dp" />
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="20dp"
        android:textSize="22dp"
        android:textStyle="bold"
        android:textColor="#ffffff"
        android:text="TextView with both elevation and background (black)"
        android:background="#000000"
        android:elevation="20dp" />

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="20dp"
        android:textSize="22dp"
        android:textStyle="bold"
        android:text="TextView with both elevation and transparent background"
        android:background="#00000000"
        android:elevation="20dp" />

</LinearLayout>

Test on Nexus 7, Android 5.1.1

If hardwareAccelerated is disabled in AndroidManifest.xml by adding android:hardwareAccelerated="false" in <application>, the shadow effect will disappear. (tested on Nexus 7 running Android 5.1.1)

src/main/AndroidManifest.xml

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

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme"
        android:hardwareAccelerated="false" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

android:hardwareAccelerated="false"