Messenger Activity

This example is a simple messenger activity.

Algorithm:

1.) Create a new project by File-> New -> Android Project name it MessengerActivity.

2.) Write following into main.xml:

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<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:tools="http://schemas.android.com/tools"     android:id="@+id/mainLayout"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:orientation="vertical" >       <LinearLayout         android:layout_width="match_parent"         android:layout_height="wrap_content" >         <TextView             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:text="@string/message_prompt"             android:textAppearance="?android:attr/textAppearanceMedium" />         <EditText             android:id="@+id/message_field"             android:layout_width="match_parent"             android:layout_height="wrap_content"             android:ems="10"             android:hint="@string/message_hint" >             <requestFocus />         </EditText>     </LinearLayout>     <Button         android:layout_width="match_parent"         android:layout_height="wrap_content"         android:text="@string/add_message_button_label"         android:onClick="addMessageButtonHandler" />   </LinearLayout>

3.) Write following into values/strings.xml:

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<?xml version="1.0" encoding="utf-8"?> <resources>       <string name="app_name">MessangerActivity</string>     <string name="hello_world">Hello world!</string>     <string name="menu_settings">Settings</string>     <string name="title_activity_rotations_exercises">Rotations Exercises</string>     <string name="message_prompt">Message:</string>     <string name="font_size_prompt">Font size:</string>     <string name="add_message_button_label">Add Message</string>     <string name="message_hint">Your Message</string> </resources>

4.) Run for output.

Steps:

1.) Create a project named MessangerActivity and set the information as stated in the image.

Build Target: Android 4.0
Application Name: MessangerActivity
Package Name: com. example. MessangerActivity
Activity Name: MessangerActivity
Min SDK Version: 2.3

2.) Open MessengerActivity.java file and write following code there:

package com.example.messangeractivity;

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import java.util.ArrayList;   import android.app.Activity; import android.os.Bundle; import android.view.View; import android.widget.EditText; import android.widget.LinearLayout; import android.widget.TextView;   public class MessangerActivity extends Activity {     private LinearLayout mMainLayout;     private EditText mMessageField;     private ArrayList<String> mMessages = new ArrayList<String>();       @Override     public void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.main);         mMainLayout = (LinearLayout)findViewById(R.id.mainLayout);         mMessageField = (EditText)findViewById(R.id.message_field);     }           @Override     protected void onSaveInstanceState(Bundle outState) {         super.onSaveInstanceState(outState);         outState.putStringArrayList("messages", mMessages);     }       @Override     protected void onRestoreInstanceState(Bundle savedInstanceState) {         super.onRestoreInstanceState(savedInstanceState);         mMessages = savedInstanceState.getStringArrayList("messages");         for(String message: mMessages) {             addMessage(message);         }     }       public void addMessageButtonHandler(View clickedButton) {         String message = mMessageField.getText().toString();         if (!message.isEmpty()) {             mMessages.add(message);             addMessage(message);         }     }       private void addMessage(String message) {         TextView textV = new TextView(this);         textV.setText(message);         mMainLayout.addView(textV);      } }

3.) Compile and build the project.

Output

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