Exercise: Intent & Bundle

In the previous exercise, I implemented one activity with two layout. In this exercise, I implement the same application, with same function and presentation, using two activity, HelloAndroid.java and HelloAndroid_2.java. The activity is switched using Intent, the data is passed using Bundle.

We can keep both layout, main.xml and main2.xml, no change.

We have to re-write HelloAndroid.java to two separated files, HelloAndroid.java and HelloAndroid_2.java.

HelloAndroid.java

package com.example.helloandroid3;

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

public class HelloAndroid extends Activity {
 
 private
  Button okButton;
  Button cancel1Button;
  EditText textName;
  EditText textPhonenumberIs;
  EditText textEmailIs;
  EditText textWebsiteIs;
  EditText textAddressIs;
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        
        startLayout1();
    }
    
    private Button.OnClickListener okOnClickListener = new Button.OnClickListener(){
     @Override
     public void onClick(View v) {
            textName = (EditText) findViewById(R.id.whoareyou);
            CharSequence textName_value = textName.getText();
            
            textPhonenumberIs = (EditText) findViewById(R.id.phonenumberIs);
            CharSequence textPhonenumberIs_value = textPhonenumberIs.getText();
            
            textEmailIs = (EditText) findViewById(R.id.emailIs);
            CharSequence textEmailIs_value = textEmailIs.getText();
            
            textWebsiteIs = (EditText) findViewById(R.id.websiteIs);
            CharSequence textWebsiteIs_value = textWebsiteIs.getText();
            
            textAddressIs = (EditText) findViewById(R.id.addressIs);
            CharSequence textAddressIs_value = textAddressIs.getText();
      
            Intent intent = new Intent();
            intent.setClass(HelloAndroid.this, HelloAndroid_2.class);
            
            Bundle bundle = new Bundle();
            bundle.putCharSequence("bName", textName_value);
            bundle.putCharSequence("bPhonenumber", textPhonenumberIs_value);
            bundle.putCharSequence("bEmail", textEmailIs_value);
            bundle.putCharSequence("bWebsite", textWebsiteIs_value);
            bundle.putCharSequence("bAddress", textAddressIs_value);
            
            intent.putExtras(bundle);
            
            startActivity(intent);
            finish();
     }
    };
   
    private Button.OnClickListener cancelOnClickListener = new Button.OnClickListener(){
       @Override
       public void onClick(View v) {
        finish();
       }
    };
    
    private void startLayout1(){
        setContentView(R.layout.main);
        okButton = (Button) findViewById(R.id.ok);
        okButton.setOnClickListener(okOnClickListener);
        cancel1Button = (Button) findViewById(R.id.cancel_1);
        cancel1Button.setOnClickListener(cancelOnClickListener);
    };
}

HelloAndroid_2.java

package com.example.helloandroid3;

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

public class HelloAndroid_2 extends Activity {
 
 private
  Button backButton;
  Button cancel2Button;
  TextView nameField;
  TextView phonenumberField;
  TextView emailField;
  TextView websiteField;
  TextView addressField;
 
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        
        startLayout2();
        
        Bundle bundle = this.getIntent().getExtras();
        CharSequence textName_value = bundle.getCharSequence("bName");
        nameField = (TextView) findViewById(R.id.name);
        nameField.setText("Hello "+textName_value);
        
        CharSequence textPhonenumberIs_value = bundle.getCharSequence("bPhonenumber");
  phonenumberField = (TextView) findViewById(R.id.phonenumber);
  phonenumberField.setText("Phone Number: "+textPhonenumberIs_value);
  
  CharSequence textEmailIs_value = bundle.getCharSequence("bEmail");
  emailField = (TextView) findViewById(R.id.email);
  emailField.setText("Email: "+textEmailIs_value);
  
  CharSequence textWebsiteIs_value = bundle.getCharSequence("bWebsite");
  websiteField = (TextView) findViewById(R.id.website);
  websiteField.setText("Website: "+textWebsiteIs_value);
  
  CharSequence textAddressIs_value = bundle.getCharSequence("bAddress");
  addressField = (TextView) findViewById(R.id.address);
  addressField.setText("Address: "+textAddressIs_value);
     };
    
    private Button.OnClickListener backOnClickListener = new Button.OnClickListener(){
     @Override
     public void onClick(View v) {
            Intent intent = new Intent();
            intent.setClass(HelloAndroid_2.this, HelloAndroid.class);
            
            startActivity(intent);
            finish();
     }
    };
    
    private Button.OnClickListener cancelOnClickListener = new Button.OnClickListener(){
       @Override
       public void onClick(View v) {
        finish();
       }
    };

    private void startLayout2(){
     setContentView(R.layout.main2);
     backButton = (Button) findViewById(R.id.back);
     backButton.setOnClickListener(backOnClickListener);
     cancel2Button = (Button) findViewById(R.id.cancel_2);
     cancel2Button.setOnClickListener(cancelOnClickListener);    
    };
}

Because we have two activity, so we have to modify the file AndroidManifest.xml, to include the additional activity.

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.example.helloandroid3"
      android:versionCode="1"
      android:versionName="1.0">
    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".HelloAndroid"
                  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=".HelloAndroid_2"></activity>
    </application>
    <uses-sdk android:minSdkVersion="2" />
</manifest> 

The project files can be downloaded here.