Switch Among Activities and Send Data in Android

Introduction

This article explains how to switch among Activities and send data in Android. Android Studio is used to create the sample.

This application will send data to another activity when you enter the data in the previous activity on a button click. For this, you need to create a Java class named MainActivity where you will use two textviews, two edittexts, and a button. So you will enter the data that you want to in another activity on a button click.

So to data you need to use an Intent. Intents are used to data and perform switching among activities. So to use Intent methods you will create the object of the intent and the context and activity on which you want to switch as a parameter. Now to transfer data you will call the putExtra() method that contains both the parameters of the string type. the data as a parameter in the putExtra() method and the intent object as a parameter in the startActivity() method.

Now create another Java class named Second that holds the sent data by the activity. Create the object of the intent and call the getStringExtra() method that will return the data in string formated by the MainActivity. Now set the data in textview by calling the setText method provided by the TextView class.

Step 1

Create a project like this:

"File" -> "New Project" -> "Android Application"

Step 2

Create an XML file named actvitymain.xml as in the following:

<?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"
android:background="#FFC6A9"
>
<TextView android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Enter Name: "/>
<EditText android:id="@+id/editText1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="10dip"/>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Enter Age: "
/>
<EditText android:id="@+id/editText2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginBottom="10dip"
android:inputType="number"/>
<Button android:id="@+id/sendButton"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Send"
android:layout_marginTop="15dip"/>
</LinearLayout>

Step 3

Create another XML file with the following contents:

<?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"
android:background="#FFC6A9">
<TextView android:id="@+id/textViewName"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_margin="15dip"
android:textSize="18dip"/>
<TextView android:id="@+id/txtViewAge"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_margin="15dip"
android:textSize="18dip"/>
<Button android:id="@+id/backButton"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="15dip"
android:text="Back"/>
</LinearLayout>

Step 4

Create a Java class file with the following contents:

package com.jsonparsingexample;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
public class MainActivity extends Activity {
// Initializing variables
EditText Name;
EditText Age;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Name = (EditText) findViewById(R.id.editText1);
Age = (EditText) findViewById(R.id.editText2);
Button btnNextScreen = (Button) findViewById(R.id.sendButton);
//Listening to button event
btnNextScreen.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
//Starting a new Intent
Intent nextScreen = new Intent(getApplicationContext(), SecondActivity.class);
//Sending data to another Activity
nextScreen.putExtra("Name", Name.getText().toString());
nextScreen.putExtra("Age", Age.getText().toString());
startActivity(nextScreen);
}
});
}
}

Step 5

Create another Java class file with the following contents:

package com.jsonparsingexample;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class SecondActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.second);
TextView txtName = (TextView) findViewById(R.id.textViewName);
TextView txtEmail = (TextView) findViewById(R.id.txtViewAge);
Button btnBack = (Button) findViewById(R.id.backButton);
Intent i = getIntent();
// Receiving the Data
String name = i.getStringExtra("Name");
String age = i.getStringExtra("Age");
Log.e("Second Screen", name + "." + age);
// Displaying Received data
txtName.setText(name);
txtEmail.setText(age);
// Binding Click event to Button
btnBack.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
//Closing SecondScreen Activity
finish();
}
});
}
}

Step 6

Add a Second Activity name in the Android manifest.xml file with the following contents:

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.jsonparsingexample"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="7"
android:targetSdkVersion="16" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.jsonparsingexample.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=".SecondActivity"></activity>
</application>
<uses-permission android:name="android.permission.INTERNET"/>
</manifest>

Step 7

Step 8

Step 9