Example: Using Intent

After writing a single activity, there comes a need to transition to another activity to perform another task either with or without information from the first activity.

Android platform allows transition by means of Intent Interface.

In this example there are two activities - IntentActionDemo.java and IntentA.java that both extend the super class Activity. Do not forget to declare any new activity in the AndroidManifest.xml with permission.

I have introduced buttons in both activities which have a listener to allow an intent to transition from one intent to the other activity and vis-versa.
Simple intent example;
Note that optional step 2 was not used in our demo.
Step 1: Intent i = new Intent(context, NameOfClassToTransitionTo.class)

Step 2:(Optional)Intents can take various forms that make it even carry data in key/name pairs ie i.putExtra("key1", "My first Info")
i.putExtra("key2", "My second Info")

Step 3: startActivity(i)

IntentActionDemo.java

Code:


package com.protechtraining.com;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class IntentActionDemo extends Activity implements OnClickListener {
    /** Called when the activity is first created. */

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        Button button = (Button) findViewById(R.id.intentButton);
        button.setOnClickListener(this);

    }

    @Override
    public void onClick(View src) {
      Intent i = new Intent(this, IntentA.class);
      startActivity(i);
    }
}

IntentA.java

Code:


package com.protechtraining.com;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class IntentA extends Activity implements OnClickListener{

    @Override
    public void onClick(View src) {
      Intent i = new Intent(this, IntentActionDemo.class);
      startActivity(i);
    }

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.intenta);

        Button button = (Button) findViewById(R.id.ButtonIntentA);
        button.setOnClickListener(this);
    }
}

AndroidManifest.xml

Code:


<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.protechtraining.com"
      android:versionCode="1"
      android:versionName="1.0">
    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".IntentActionDemo"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

    <activity android:name="IntentA"></activity>
</application>
    <uses-sdk android:minSdkVersion="3" />

</manifest>

string.xml

Code:


<?xml version="1.0" encoding="utf-8"?>
<resources>
    <string name="hello">Hello</string>
    <string name="app_name">IntentActionDemo</string>
<string name="IntentA">Click Next intent</string>
<string name="world">World!</string>
<string name="Intent0">Click to Previous Intent</string>
</resources>

main.xml

Code:


<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView  
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    android:text="@string/hello"
    android:textSize="18sp"/>
<Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/intentButton" android:text="@string/IntentA"></Button>
</LinearLayout>

intenta.xml

Code:


<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content" android:orientation="vertical">

<TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/TextViewWorld" android:text="@string/world" android:textSize="18sp"></TextView>
<Button android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/ButtonIntentA" android:text="@string/Intent0"></Button>
</LinearLayout>

Screenshot

Source
https://www.protechtraining.com/static/tutorials/IntentActionDemo.zip