Switch between Activities

How to switch between one activity to another :

There is sometime a case when you want to switch from one page to another. For instance, I am taking an example that we have a welcome activity and a register button through which on click of register button user moves to registration page.

This is achieve by using Intent object.

Intent: An Intent is exactly what it describes. It's an "intention" to do an action. An Intent is basically a message to say you did or want something to happen. Depending on the intent, apps or the OS might be listening for it and will react accordingly. Intents allow you to interact with components from the own and other applications.

Intents are objects of the android.content.Intent type.

It takes two parameters one is the context and other is the activity which will open.

startActivity() method you can define that the intent should be used to start an activity.

To perform such action you need to write following piece of code and then run the application.

MainActivity.java :

public class MainActivity extends Activity {

       Button register;

       @Override

       protected void onCreate(Bundle savedInstanceState) {

              super.onCreate(savedInstanceState);

              setContentView(R.layout.activity_main);

             

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

              register.setOnClickListener(new OnClickListener() {

                    

                     @Override

                     public void onClick(View arg0) {

                           Intent intent = new Intent(MainActivity.this,Register.class);

                           startActivity(intent);

                          

                     }

              });

       }

       @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;

       }

}

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:background="#000000"

    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="fill_parent"

        android:layout_height="wrap_content"

        android:layout_alignParentLeft="true"

        android:layout_alignParentTop="true"

        android:layout_marginTop="21dp"

        android:text="Welcome to \nApex TG India Pvt. Ltd."

        android:textColor="#ffffff"

        android:textSize="20dp" />

    <Button

        android:id="@+id/button1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_below="@+id/textView1"

        android:layout_centerHorizontal="true"

        android:layout_marginTop="38dp"

        android:text="Click Here to Register!"

        android:textColor="#ffffff" />

</RelativeLayout>

Register.java:

public class Register extends Activity {

       @Override

       protected void onCreate(Bundle savedInstanceState) {

              // TODO Auto-generated method stub

              super.onCreate(savedInstanceState);

              setContentView(R.layout.register);

       }

}

register.xml :

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

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

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:background="#000000">

    <TextView

        android:id="@+id/textView1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentLeft="true"

        android:layout_alignParentTop="true"

        android:layout_marginLeft="21dp"

        android:layout_marginTop="38dp"

        android:textColor="#ffffff"

        android:text="Name : " />

    <TextView

        android:id="@+id/textView2"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/textView1"

        android:layout_below="@+id/textView1"

        android:layout_marginTop="48dp"

        android:textColor="#ffffff"

        android:text="Password : " />

    <TextView

        android:id="@+id/textView3"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/textView2"

        android:layout_below="@+id/textView2"

        android:layout_marginTop="52dp"

        android:textColor="#ffffff"

        android:text="Email Id :" />

    <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="52dp"

        android:textColor="#ffffff"

        android:text="Phone No. :" />

    <TextView

        android:id="@+id/textView5"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignLeft="@+id/textView4"

        android:layout_below="@+id/textView4"

        android:layout_marginTop="46dp"

        android:textColor="#ffffff"

        android:text="Technology :" />

    <Button

        android:id="@+id/button2"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBaseline="@+id/button1"

        android:layout_alignBottom="@+id/button1"

        android:layout_alignParentRight="true"

        android:layout_marginRight="59dp"

        android:textColor="#ffffff"

        android:text="Cancel" />

    <EditText

        android:id="@+id/editText1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBaseline="@+id/textView1"

        android:layout_alignBottom="@+id/textView1"

        android:layout_toRightOf="@+id/textView5"

        android:ems="10" />

    <EditText

        android:id="@+id/editText2"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBaseline="@+id/textView2"

        android:layout_alignBottom="@+id/textView2"

        android:layout_alignLeft="@+id/editText1"

        android:ems="10"

        android:inputType="textPassword" />

    <EditText

        android:id="@+id/editText3"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_above="@+id/textView4"

        android:layout_alignLeft="@+id/editText2"

        android:ems="10"

        android:inputType="textEmailAddress" />

    <EditText

        android:id="@+id/editText4"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBaseline="@+id/textView4"

        android:layout_alignBottom="@+id/textView4"

        android:layout_toRightOf="@+id/textView5"

        android:ems="10"

        android:inputType="phone" />

    <CheckBox

        android:id="@+id/checkBox1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBaseline="@+id/textView5"

        android:layout_alignBottom="@+id/textView5"

        android:layout_centerHorizontal="true"

        android:textColor="#ffffff"

        android:text="Java" />

    <Button

        android:id="@+id/button1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignParentBottom="true"

        android:layout_marginBottom="19dp"

        android:layout_toLeftOf="@+id/checkBox1"

        android:text="Register"

        android:textColor="#ffffff" />

    <TextView

        android:id="@+id/textView6"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_above="@+id/button1"

        android:layout_alignLeft="@+id/textView5"

        android:layout_marginBottom="14dp"

        android:textColor="#ffffff"

        android:text="Qualification : " />

    <RadioButton

        android:id="@+id/radioButton1"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBottom="@+id/textView6"

        android:layout_toRightOf="@+id/button1"

        android:textColor="#ffffff"

        android:text="Btech" />

    <RadioButton

        android:id="@+id/radioButton2"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBaseline="@+id/radioButton1"

        android:layout_alignBottom="@+id/radioButton1"

        android:layout_alignLeft="@+id/checkBox2"

        android:text="MCA"

        android:textColor="#ffffff" />

    <CheckBox

        android:id="@+id/checkBox2"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:layout_alignBaseline="@+id/checkBox1"

        android:layout_alignBottom="@+id/checkBox1"

        android:layout_toRightOf="@+id/radioButton1"

        android:text="Android"

        android:textColor="#ffffff" />

</RelativeLayout>

Whenever you create a new Activity file it should be explicitly mention or define in AndroidManifest.xml as below,

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

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

    package="com.example.testdemo"

    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.testdemo.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="com.example.testdemo.Register"

            android:label="@string/app_name" >

       </activity>

    </application>

</manifest>