Android Example-Change the Image on Activity Using Radio Button

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:orientation="vertical"

    tools:context=".MainActivity">

    <LinearLayout
        android:id="@+id/linearLayout"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center_horizontal"
        android:orientation="horizontal">

        <RadioGroup
            android:id="@+id/rg1"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:paddingTop="20dp"
            android:gravity="center_horizontal"
            android:orientation="horizontal">

            <RadioButton
                android:id="@+id/radioButton1"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Frag 1" />

            <RadioButton
                android:id="@+id/radioButton2"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Frag 2" />

            <RadioButton
                android:id="@+id/radioButton3"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Frag 3" />

            <RadioButton
                android:id="@+id/radioButton4"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"

                android:text="Frag 4" />

            <RadioButton
                android:id="@+id/radioButton5"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"

                android:text="Frag 5" />
        </RadioGroup>


    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:gravity="center">

        <ImageView
            android:id="@+id/imageView1"

            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@drawable/image1" />
    </LinearLayout>


</LinearLayout>

MainActivity.java

package in.kantapp.example4;

import android.app.Activity;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.RadioGroup;
import android.widget.RadioGroup.OnCheckedChangeListener;

public class MainActivity extends AppCompatActivity implements OnCheckedChangeListener {

    RadioGroup group1, group2;
    Button gen;
    ImageView img;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        group1 = (RadioGroup) findViewById(R.id.rg1);
        group1.setOnCheckedChangeListener((OnCheckedChangeListener) this);
        img = (ImageView) findViewById(R.id.imageView1);
       }

    @Override
    public void onCheckedChanged(RadioGroup group, int checkedId) {
        // TODO Auto-generated method stub
        switch (checkedId) {
            case R.id.radioButton1:
                img.setImageResource(R.drawable.image1);
                break;

            case R.id.radioButton2:
                img.setImageResource(R.drawable.image2);
                break;

            case R.id.radioButton3:
                img.setImageResource(R.drawable.image3);
                break;

            case R.id.radioButton4:
                img.setImageResource(R.drawable.image4);
                break;
            case R.id.radioButton5:
                img.setImageResource(R.drawable.image5);
                break;

            default:
                break;
        }
    }
}

Download Image:

Android Example - Activity Life Cycle

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<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="in.kantapp.example3.MainActivity">

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="New Button"
        android:id="@+id/button"
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true" />
</RelativeLayout>

MainActivity.java

package in.kantapp.example3;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.widget.Button;
import android.widget.Toast;

@SuppressLint("NewApi")
public class MainActivity extends AppCompatActivity {



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        notify("onCreate");

    }

    @Override
    protected void onPause() {
        super.onPause();
        notify("onPause");
    }

    @Override
    protected void onResume() {
        super.onResume();
        notify("onResume");
    }

    @Override
    protected void onStop() {
        super.onStop();
        notify("onStop");
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        notify("onDestroy");
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
        notify("onRestoreInstanceState");
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        notify("onSaveInstanceState");
    }

    private void notify(String methodName) {
        String name = this.getClass().getName();
        String[] strings = name.split("\\.");
        Toast.makeText(getApplicationContext(),
                methodName + "" + strings[strings.length - 1],
                Toast.LENGTH_LONG).show();
    }

}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="in.kantapp.example3">

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

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

</manifest>

Android TextView Example with String

activity_main.xml

<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/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello Programmer!" />

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_below="@+id/textView2"
        android:layout_marginTop="110dp"
        android:text="@string/my_text"
        android:textAppearance="?android:attr/textAppearanceLarge" />

</RelativeLayout>

MainActivity.java

package in.kantapp.example2;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

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

string.xml

<resources>
    <string name="app_name">Example 2</string>
    <string name="action_settings">Settings</string>
    <string name="hello_world">Hello world!</string>
    <string name="my_text">Definition of text!</string>

    <string-array name="operating_systems">
        <item>Android</item>
        <item>iPhone</item>
        <item>Windows Mobile</item>
        <item>Linux </item>
        <item>Windows 7.0</item>
        <item>Windows 8.0</item>
        <item>Windows 8.1</item>
        <item>Chrome OS</item>
        <item>Unix</item>
        <item>Symbian</item>
    </string-array>
</resources>

Simple Android Example

activity_main.xml

<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">

    <!-- This is a comment -->


    <!-- Create your comments like this -->

    <TextView
        android:id="@+id/textView2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/textView1"
        android:layout_alignParentTop="true"
        android:layout_marginTop="18dp" />

    <TextView
        android:id="@+id/textView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true"
        android:layout_marginTop="53dp"
        android:text="This is a Large Text View"
        android:textAppearance="?android:attr/textAppearanceLarge" />

    <TextView
        android:id="@+id/textView3"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/textView1"
        android:layout_below="@+id/textView1"
        android:layout_marginTop="16dp"
        android:text="This is Medium Text View"
        android:textAppearance="?android:attr/textAppearanceMedium" />

    <TextView
        android:id="@+id/textView4"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/textView3"
        android:layout_below="@+id/textView3"
        android:layout_marginTop="14dp"
        android:text="Small Text"
        android:textAppearance="?android:attr/textAppearanceSmall" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/textView4"
        android:layout_below="@+id/textView4"
        android:layout_marginTop="16dp"
        android:text="Button" />

    <ToggleButton
        android:id="@+id/toggleButton1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/button2"
        android:layout_alignBottom="@+id/button2"
        android:layout_alignParentRight="true"
        android:text="ToggleButton" />

    <Button
        android:id="@+id/button2"
        style="?android:attr/buttonStyleSmall"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignTop="@+id/button1"
        android:layout_centerHorizontal="true"
        android:text="Small Button" />

    <CheckBox
        android:id="@+id/checkBox1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignRight="@+id/toggleButton1"
        android:layout_below="@+id/toggleButton1"
        android:layout_marginTop="93dp"
        android:text="CheckBox"
        android:checked="false" />

    <CheckedTextView
        android:id="@+id/checkedTextView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBaseline="@+id/checkBox1"
        android:layout_alignBottom="@+id/checkBox1"
        android:layout_alignLeft="@+id/button1"
        android:text="CheckedTextView" />

    <RadioGroup
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_below="@+id/checkedTextView1"
        android:layout_marginTop="37dp"
        android:layout_alignRight="@+id/textView3"
        android:layout_alignEnd="@+id/textView3">

        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Male"
            android:id="@+id/radioButton"
            android:checked="false" />

        <RadioButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Female"
            android:id="@+id/radioButton2"
            android:checked="true" />
    </RadioGroup>

</RelativeLayout>

MainActivity.java

package in.kantapp.example1;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

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