Android ImageButton Control

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A ImageButton is a AbsoluteLayout which enables you to specify the exact location of its children. This shows a button with an image (instead of text) that can be pressed or clicked by the user.

ImageButton Attributes

Following are the important attributes related to ImageButton control. You can check Android official documentation for complete list of attributes and related methods which you can use to change these attributes are run time.

Inherited from android.widget.ImageView Class:

AttributeDescription
android:adjustViewBoundsSet this to true if you want the ImageView to adjust its bounds to preserve the aspect ratio of its drawable.
android:baselineThis is the offset of the baseline within this view.
android:baselineAlignBottomIf true, the image view will be baseline aligned with based on its bottom edge.
android:cropToPaddingIf true, the image will be cropped to fit within its padding.
android:srcThis sets a drawable as the content of this ImageView.

Inherited from android.view.View Class:

AttributeDescription
android:backgroundThis is a drawable to use as the background.
android:contentDescriptionThis defines text that briefly describes content of the view.
android:idThis supplies an identifier name for this view,
android:onClickThis is the name of the method in this View's context to invoke when the view is clicked.
android:visibilityThis controls the initial visibility of the view.

Example

This example will take you through simple steps to show how to create your own Android application using Linear Layout and ImageButton.

StepDescription
1You will use Eclipse IDE to create an Android application and name it as GUIDemo5 under a package com.example.guidemo5 as explained in the Hello World Example chapter.
2Modify src/MainActivity.java file to add a click event.
2Modify the default content of res/layout/activity_main.xml file to include Android UI control.
3Define required constants in res/values/strings.xml file
4Run the application to launch Android emulator and verify the result of the changes done in the application.

Following is the content of the modified main activity file src/com.example.guidemo5/MainActivity.java. This file can include each of the fundamental lifecycle methods.

package com.example.guidemo5;

import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageButton;
import android.widget.Toast;

public class MainActivity extends Activity {
	
	ImageButton imgButton;

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

          addListenerOnButton();
        }

	private void addListenerOnButton() {
		
          imgButton = (ImageButton) findViewById
          (R.id.imageButton1);

          imgButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View view) {
              Toast.makeText(MainActivity.this,"ImageButton 
              Clicked : tutorialspoint.com", 
              Toast.LENGTH_SHORT).show();
            }
          });		
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
         /* Inflate the menu; this adds items to the action bar            
         if it is present */
         getMenuInflater().inflate(R.menu.main, menu);
         return true;
     }
}

Following will be the content of res/layout/activity_main.xml file:

<RelativeLayout 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: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=".MainActivity" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/example_imagebutton" />

    <ImageButton
        android:id="@+id/imageButton1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignRight="@+id/textView1"
        android:layout_below="@+id/textView1"
        android:layout_marginRight="35dp"
        android:layout_marginTop="32dp" 
        android:contentDescription=
        "@string/android_launcher_image"
        android:src="@drawable/ic_launcher" />

</RelativeLayout>

Following will be the content of res/values/strings.xml to define these new constants:

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

    <string name="app_name">GUIDemo5</string>
    <string name="action_settings">Settings</string>
    <string name="example_imagebutton">Example showing ImageButton</string>
    <string name="android_launcher_image"></string>

</resources>

Following is the default content of AndroidManifest.xml:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.guidemo5"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.guidemo5.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>

Let's try to run your GUIDemo5 application. I assume you had created your AVD while doing environment setup. To run the app from Eclipse, open one of your project's activity files and click Run Eclipse Run Icon icon from the toolbar. Eclipse installs the app on your AVD and starts it and if everything is fine with your setup and application, it will display following Emulator window:

Android ImageButton Control

The following screen will appear after ImageButton is clicked:

Android ImageButton Control

Exercise:

I will recommend to try above example with different attributes of ImageButton in Layout XML file as well at programming time to have different look and feel of the ImageButton. Try to make it editable, change to font color, font family, width, textSize etc and see the result. You can also try above example with multiple ImageButton controls in one activity.



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