First Case of Intent in Android

Intent

An intent is an abstract description of an operation to be performed. In simple words we can say that an intent is basically used to notify the Android system about the occurrence of an event.

Procedure

 

Use the following procedure:

1. Start Eclipse IDE.
2. Create a new project.
3. Create two Java files, one is MainActivity.java and the other is a.java.
4. Create two XML files, one is activity_main.xml file and second is other.xml for layout design.
5. In the first case of an intent we add an activity with an intent filter in the manifest file.
   
   For instance:
   
   <activity
   android:name="A"
   android:label="@string/app_name" >
   <intent-filter>
   <action android:name="abhijeet" />
   <category android:name="android.intent.category.DEFAULT" />
   </intent-filter>
   </activity>
    
6. Then look up the button by its id in the MainActivity.java file and declare a string in it.
7. Then in the onclick function declare an intent.
   
   For example:
   
   public void onClick(View v) {
   Intent i=new Intent(str);
   startActivity(i);
   }

The code is given below.

MainActivity.java

package com.example.intentistcaseeeee;

 

import android.os.Bundle;

import android.app.Activity;

import android.content.Intent;

import android.view.Menu;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

 

public class MainActivity extends Activity implements OnClickListener

{

    Button b1;

    String str="abhijeet";

    @Override

    protected void onCreate(Bundle savedInstanceState)

    {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        b1=(Button)findViewById(R.id.button1);

        b1.setOnClickListener(this);

    }

    public void onClick(View v)

    {

        // TODO Auto-generated method stub

        Intent i=new Intent(str);

        startActivity(i);

    }

} 

<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/hello_world" />

 

  <Button

  android:id="@+id/button1"

  android:layout_width="wrap_content"

  android:layout_height="wrap_content"

  android:layout_below="@+id/textView1"

  android:layout_marginTop="52dp"

  android:layout_toRightOf="@+id/textView1"

  android:text="Button" />

</RelativeLayout>

A.java

package com.example.intentistcaseeeee;

import android.app.Activity;

import android.os.Bundle;

public class A extends Activity

{

    @Override

    protected void onCreate(Bundle savedInstanceState)

    {

        // TODO Auto-generated method stub

        super.onCreate(savedInstanceState);

        setContentView(R.layout.other);

    }

}

Other.xml

 

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

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical" >

  <Spinner

  android:id="@+id/spinner1"

  android:layout_width="match_parent"

  android:layout_height="wrap_content" />

  <RadioButton

  android:id="@+id/radioButton1"

  android:layout_width="wrap_content"

  android:layout_height="wrap_content"

  android:text="RadioButton" />

  <CheckBox

  android:id="@+id/checkBox1"

  android:layout_width="wrap_content"

  android:layout_height="wrap_content"

  android:text="CheckBox" />

</LinearLayout>

 

AndroidManifest.xml

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

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="com.example.intentistcaseeeee"

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="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>

    <activity

    android:name="A"

    android:label="@string/app_name" >

      <intent-filter>

        <action android:name="abhijeet" />

        <category android:name="android.intent.category.DEFAULT" />

      </intent-filter>

    </activity>

  </application>

</manifest>

Output

By clicking on the Button: