Android - Intent and Intent Filters

Intent - Message is passed between ativities, content providers, broadcast receivers, services etc.

Android intents are mainly used to:

• Launch an activity
• Dial a phone call etc.
• Start the service
• Display a web page
• Display a list of contacts
• Broadcast a message

Intent Types are 

1. Implicit Intent : It moves one activity another predefined activity.

Intent intent=new Intent(Intent.ACTION_VIEW);  

intent.setData(Uri.parse("https://www.google.co.in"));  

startActivity(intent);  

2. Explicit Intent: It move one activity another activity.

Intent i = new Intent(getApplicationContext(), SecondActivity.class); 

startActivity(i);  

Code: 

Implicit Intent- 

package com.example.intent;

import android.app.Activity;

import android.content.Intent;

import android.net.Uri;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

public class IntentActivty extends Activity {

 Button implicit, explicit;

 @Override

 protected void onCreate(Bundle savedInstanceState) {

  super.onCreate(savedInstanceState);

  setContentView(R.layout.activity_main);

 

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

  explicit = (Button)findViewById(R.id.button2);

 

  implicit.setOnClickListener(new OnClickListener() {

  

   @Override

   public void onClick(View v) {

    // TODO Auto-generated method stub

     //String url=editText1.getText().toString();  

              Intent intent=new Intent(Intent.ACTION_VIEW,Uri.parse("http://vvkishor.blogspot.in"));  

              startActivity(intent);

   }

  });

 

  explicit.setOnClickListener(new OnClickListener() {

  

   @Override

   public void onClick(View v) {

    // TODO Auto-generated method stub

     //String url=editText1.getText().toString();  

              Intent intent=new Intent(IntentActivty.this, SecondActivity.class);  

              startActivity(intent);

   }

  });

 }

}

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="com.example.intent.MainActivity" >

    <Button

        android:id="@+id/button1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentTop="true"

        android:layout_centerHorizontal="true"

        android:layout_marginTop="183dp"

        android:text="Implicit Intent" />

    <Button

        android:id="@+id/button2"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_below="@+id/button1"

        android:layout_centerHorizontal="true"

        android:layout_marginTop="32dp"

        android:text="Explicit Intent" />

</RelativeLayout>

SecondActivity.class - 

package com.example.intent;

import android.app.Activity;

import android.os.Bundle;

public class SecondActivity extends Activity{

 @Override

 protected void onCreate(Bundle savedInstanceState) {

  // TODO Auto-generated method stub

  super.onCreate(savedInstanceState);

  setContentView(R.layout.second);

 }

}

second.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="com.example.intent.MainActivity" >

    <TextView

        android:id="@+id/text"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentTop="true"

        android:layout_centerHorizontal="true"

        android:layout_marginTop="183dp"

        android:text="Second Class" />

</RelativeLayout>

AndroidManifest.xml

 Register your SecondActvity class and give internet permissions 

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

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

    package="com.example.intent"

    android:versionCode="1"

    android:versionName="1.0" >

    <uses-sdk

        android:minSdkVersion="8"

        android:targetSdkVersion="21" />

    <uses-permission android:name="android.permission.INTERNET"/>

    <application

        android:allowBackup="true"

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name"

        android:theme="@style/AppTheme" >

        <activity

            android:name=".IntentActivty"

            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=".SecondActivity"></activity>

    </application>

</manifest>

Screens 

 

Home page Implicit  Second page

Android Login page

Create login page login.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:layout_gravity="center"
    android:background="#000"
    android:gravity="center"
    android:orientation="vertical" >

    <EditText
        android:id="@+id/userName"
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:layout_margin="10dp"
        android:background="#fff"
        android:hint="UserName" />

    <EditText
        android:id="@+id/password"
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:layout_margin="10dp"
        android:layout_marginTop="20dp"
        android:background="#fff"
        android:hint="Password"
        android:password="true" />

    <Button
        android:id="@+id/submit"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:layout_margin="10dp"
        android:layout_marginTop="10dp"
        android:text="Login" />

</LinearLayout>

Create a  Login.class in src/Login.class

package com.example.loginpage;

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;

import android.widget.EditText;

import android.widget.Toast;

public class Login extends Activity {

EditText userName, password;

Button login;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

userName = (EditText)findViewById(R.id.userName);

password = (EditText)findViewById(R.id.password);

login = (Button)findViewById(R.id.submit);

login.setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

if (userName.getText().toString().equals("")) {

Toast.makeText(getApplicationContext(), "Please enter username", Toast.LENGTH_SHORT).show();

}else if (password.getText().toString().equals("")) {

Toast.makeText(getApplicationContext(), "Please enter password", Toast.LENGTH_SHORT).show();

}else {

Intent in = new Intent(Login.this, LoginSuccess.class);

startActivity(in);

}

}

});

}

}

After successfully login it redirect to LoginSuccess.class find it below class and login_success.xml

login_success.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"

    android:gravity="center" >

    

    <TextView android:id="@+id/text"

        android:layout_width="match_parent"

        android:layout_height="wrap_content"

        android:text="Login Success"

        android:textColor="#000"

        android:gravity="center"/>

</LinearLayout>

src/LoginSuccess.class - 

package com.example.loginpage;

import android.app.Activity;

import android.os.Bundle;

public class LoginSuccess  extends Activity{

@Override

protected void onCreate(Bundle savedInstanceState) {

// TODO Auto-generated method stub

super.onCreate(savedInstanceState);

setContentView(R.layout.login_success);

}

}

Register your class into AndroidManifest.xml

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

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

    package="com.example.loginpage"

    android:versionCode="1"

    android:versionName="1.0" >

    <uses-sdk

        android:minSdkVersion="8"

        android:targetSdkVersion="21" />

    <application

        android:allowBackup="true"

        android:icon="@drawable/ic_launcher"

        android:label="@string/app_name"

        android:theme="@style/AppTheme" >

        <activity

            android:name=".Login"

            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=".LoginSuccess"></activity>

    </application>

</manifest>

Screens

login-

Login success -