Tutorial 5: Intent trong lập trình ứng dụng Android

<?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"
    >
	<TextView
		android:layout_width="fill_parent"
		android:layout_height="wrap_content"
		android:text="Activity 1 - Send value"
		android:typeface="normal"
		android:textSize="14px"
		android:textStyle="bold"
		android:textColor="#cccccc"
		android:background="#333333"
	/>
	<EditText
		android:id="@+id/value_edit"
		android:layout_width="fill_parent"
		android:layout_height="wrap_content"
		android:textSize="20px"
		android:gravity="center"
		android:lines="1"
		android:numeric="integer"
		/>
	<RelativeLayout
		android:layout_width="fill_parent"
		android:layout_height="fill_parent">
		<Button
			android:id="@+id/send_button"
			android:layout_width="fill_parent"
			android:layout_height="wrap_content"
			android:text="Send to Activity 2"
			android:layout_alignParentBottom="true"					
		/>
	</RelativeLayout>	
</LinearLayout>

<?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"
    >
	<TextView
		android:layout_width="fill_parent"
		android:layout_height="wrap_content"
		android:text="Activity 2 - Receive value"
		android:typeface="normal"
		android:textSize="14px"
		android:textStyle="bold"
		android:textColor="#cccccc"
		android:background="#333333"
	/>
	<EditText
		android:id="@+id/value_receive"
		android:layout_width="fill_parent"
		android:layout_height="wrap_content"
		android:textSize="20px"
		android:gravity="center"
		android:lines="1"
		android:numeric="integer"
		android:enabled="false"
		/>
	<RelativeLayout
		android:layout_width="fill_parent"
		android:layout_height="fill_parent">
		<Button
			android:id="@+id/call_button"
			android:layout_width="fill_parent"
			android:layout_height="wrap_content"
			android:text="Call Broadcast Receiver"
			android:layout_alignParentBottom="true"					
		/>
	</RelativeLayout>	
</LinearLayout>

package at.exam;

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;

public class Activity1 extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity1_layout);
        
        final EditText editValue = (EditText) findViewById(R.id.value_edit);
        final Button sendButton = (Button) findViewById(R.id.send_button);
        
        sendButton.setOnClickListener(new OnClickListener() {
			public void onClick(View v) {
				String valueString = editValue.getText().toString();
				long value;
				if (!valueString.equals("")) {
					value = Long.parseLong(valueString);
				}
				else {
					value = 0;
				}
				
				//Tạo 1 đối tượng Bundle để gửi đi cùng Intent
				Bundle sendBundle = new Bundle();
				sendBundle.putLong("value", value);
				
				//Tạo Intent để khởi chạy Activity2 và gắn sendBundble vào Intent
				Intent i = new Intent(Activity1.this, Activity2.class);
				i.putExtras(sendBundle);
				startActivity(i);
				
				//Giải phóng Activity1 khỏi Activity Stack vì ta sẽ ko quay lại nó nữa
				finish();
			}        	
        });
    }
}

package at.exam;

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;

public class Activity2 extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity2_layout);
        
        final EditText receiveValueEdit = (EditText) findViewById(R.id.value_receive);
        final Button callReceiverButton = (Button) findViewById(R.id.call_button);
        
        //Lấy về Bundle được gửi kèm Intent rồi lấy ra giá trị
        Bundle receiveBundle = this.getIntent().getExtras();
        final long receiveValue = receiveBundle.getLong("value");
        
        receiveValueEdit.setText(String.valueOf(receiveValue));
        
        callReceiverButton.setOnClickListener(new OnClickListener() {			
			public void onClick(View v) {
				//Khởi tạo 1 Intent để gửi tới BroadCast Receiver
				//Gắn giá trị vào Intent, lần này ko cần Bundle nữa
				Intent i = new Intent(Activity2.this, Receiver.class);
				i.putExtra("new value", receiveValue - 10);
				sendBroadcast(i);
			}
		});
    }
}

package at.exam;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.widget.Toast;

public class Receiver extends BroadcastReceiver{

	@Override
	public void onReceive(Context context, Intent intent) {
		long value = intent.getLongExtra("new value", -10) + 10;
		Toast toast = Toast.makeText(context, "Broadcast Receiver catch an Intent"
				+ " \n" + "The value is stored in the Intent is "
				+ String.valueOf(value), Toast.LENGTH_LONG);
		toast.show();
	}

}

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="at.exam"
      android:versionCode="1"
      android:versionName="1.0">
    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".Activity1"
                  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=".Activity2"></activity>
		<receiver android:name=".Receiver"></receiver>
    </application>
    <uses-sdk android:minSdkVersion="3" />
</manifest>

        <activity android:name=".ExampleActivity" android:label="@string/activity_name">
            <intent-filter>
                <action android:name="android.intent.action.SENDTO" />
                <category android:name="android.intent.category.DEFAULT" />
                <data android:scheme="sms" />
            </intent-filter>
        </activity>

andoid:scheme

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="at.exam"
      android:versionCode="1"
      android:versionName="1.0">
    <application android:icon="@drawable/icon" android:label="@string/app_name">
        <activity android:name=".Example"
                  android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
            <intent-filter>
                <action android:name="android.intent.action.CALL_BUTTON" />
                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>
        </activity>

    </application>
    <uses-sdk android:minSdkVersion="3" />

</manifest>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
	android:orientation="vertical"
	>
	<TextView
		android:paddingTop="10px"
		android:id="@+id/number_display"
		android:layout_width="fill_parent"
		android:layout_height="wrap_content"
		android:textSize="30px"
		android:gravity="center"
		android:lines="2"
		android:background="#ffffff"
		android:textColor="#000000"
		/>
	<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
	    android:layout_width="fill_parent"
	    android:layout_height="fill_parent"
	    >
		<TableRow 
	    android:gravity="center"		
	    android:paddingTop="30px"        
	    >
	    	<Button
	    		android:id="@+id/button1"
	    		android:layout_width="80px"
	    		android:layout_height="80px"
	    		android:gravity="center"
	    		android:text="1"
	    		android:textSize="25px"
	    		
	    	/>
	    	<Button
	    		android:id="@+id/button2"
	    		android:layout_width="80px"
	    		android:layout_height="80px"
	    		android:gravity="center"
	    		android:text="2"
	    		android:textSize="25px"	    		
	    	/>
	    	<Button
	    		android:id="@+id/button3"
	    		android:layout_width="80px"
	    		android:layout_height="80px"
	    		android:gravity="center"
	    		android:text="3"
	    		android:textSize="25px"	    		
	    	/>
	    </TableRow>
	    <TableRow 
	    android:gravity="center"		        
	    >
	    	<Button
	    		android:id="@+id/button4"
	    		android:layout_width="80px"
	    		android:layout_height="80px"
	    		android:gravity="center"
	    		android:text="4"
	    		android:textSize="25px"
	    		
	    	/>
	    	<Button
	    		android:id="@+id/button5"
	    		android:layout_width="80px"
	    		android:layout_height="80px"
	    		android:gravity="center"
	    		android:text="5"
	    		android:textSize="25px"	    		
	    	/>
	    	<Button
	    		android:id="@+id/button6"
	    		android:layout_width="80px"
	    		android:layout_height="80px"
	    		android:gravity="center"
	    		android:text="6"
	    		android:textSize="25px"	    		
	    	/>
	    </TableRow>
	    <TableRow 
	    android:gravity="center"		        
	    >
	    	<Button
	    		android:id="@+id/button7"
	    		android:layout_width="80px"
	    		android:layout_height="80px"
	    		android:gravity="center"
	    		android:text="7"
	    		android:textSize="25px"
	    		
	    	/>
	    	<Button
	    		android:id="@+id/button8"
	    		android:layout_width="80px"
	    		android:layout_height="80px"
	    		android:gravity="center"
	    		android:text="8"
	    		android:textSize="25px"	    		
	    	/>
	    	<Button
	    		android:id="@+id/button9"
	    		android:layout_width="80px"
	    		android:layout_height="80px"
	    		android:gravity="center"
	    		android:text="9"
	    		android:textSize="25px"	    		
	    	/>
	    </TableRow>
	    <TableRow
	    android:layout_width="fill_parent" 
	    android:layout_height="wrap_content" 
	    android:gravity="center"	
	    >
	    	<Button
	    		android:id="@+id/button_star"
	    		android:layout_width="80px"
	    		android:layout_height="80px"
	    		android:gravity="center"
	    		android:text="*"
	    		android:textSize="25px"	    		
	    	/>
	    	<Button
	    		android:id="@+id/button0"
	    		android:layout_width="80px"
	    		android:layout_height="80px"
	    		android:gravity="center"
	    		android:text="0"
	    		android:textSize="25px"	    		
	    	/>
	    	<Button
	    		android:id="@+id/button_clear"
	    		android:layout_width="80px"
	    		android:layout_height="80px"
	    		android:gravity="center"
	    		android:text="Clear"
	    		android:textSize="25px"	    		
	    	/>
	    </TableRow>
	</TableLayout>
</LinearLayout>

package at.exam;

import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

public class Example extends Activity {   
    Button button1, button2, button3;
    Button button4, button5, button6;
    Button button7, button8, button9;
    Button button0, buttonStar, buttonClear;
    
    TextView numberView;
    
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        numberView = (TextView) findViewById(R.id.number_display);
        
        button1 = (Button) findViewById(R.id.button1);
        button2 = (Button) findViewById(R.id.button2);
        button3 = (Button) findViewById(R.id.button3);
        
        button4 = (Button) findViewById(R.id.button4);
        button5 = (Button) findViewById(R.id.button5);
        button6 = (Button) findViewById(R.id.button6);
        
        button7 = (Button) findViewById(R.id.button7);
        button8 = (Button) findViewById(R.id.button8);
        button9 = (Button) findViewById(R.id.button9);
        
        button0 = (Button) findViewById(R.id.button0);
        buttonStar = (Button) findViewById(R.id.button_star);
        buttonClear = (Button) findViewById(R.id.button_clear);        
        
        button1.setOnClickListener(this.appendString("1"));
        button2.setOnClickListener(this.appendString("2"));
        button3.setOnClickListener(this.appendString("3"));        
        button4.setOnClickListener(this.appendString("4"));
        button5.setOnClickListener(this.appendString("5"));
        button6.setOnClickListener(this.appendString("6"));        
        button7.setOnClickListener(this.appendString("7"));
        button8.setOnClickListener(this.appendString("8"));
        button9.setOnClickListener(this.appendString("9"));        
        button0.setOnClickListener(this.appendString("0"));
        buttonStar.setOnClickListener(this.appendString("*"));
        
        buttonClear = (Button) findViewById(R.id.button_clear);
        buttonClear.setOnClickListener(new OnClickListener() {			
			public void onClick(View v) {
				numberView.setText("");				
			}
		});
    }
    
    public OnClickListener appendString(final String number) {
    	return new OnClickListener() {
			public void onClick(View arg0) {
				numberView.append(number);				
			}    		
    	};
    }
    
    public boolean onCreateOptionsMenu(Menu menu) {
    	super.onCreateOptionsMenu(menu);
    	menu.add(0, Menu.FIRST, 0,"Exit" ).setIcon(android.R.drawable.ic_delete);
    	return true;
    }
    
    public boolean onOptionsItemSelected(MenuItem item) {
    	switch (item.getItemId()) {
    		case Menu.FIRST: {
    			finish();
    			break;
    		}
    	}
    	return false;
    }
}