Android中的intentservice

 

Android中的intentservice

分类： JAVA 手机相关2011-07-30 11:55 427人阅读 评论(0)收藏 举报

在Android的应用中,往往需要在执行主界面的操作时,如果要执行耗时的操作,那么应该是另外开线程的,或者是用async或者handler,今天发现其实也可以用android中的一个Intentservice去实现。下面例子讲解下。

1 例子中是一个文本框，当用户输入内容后，模拟slepp 10秒，这个时候要是不分离线程，操作的话，用户再点界面，就会死死地停在那里，甚至是出现提示，要强行CLOSE，代码如下：

Java代码

1. EditText input = (EditText) findViewById(R.id.txt_input);   
2.  String strInputMsg = input.getText().toString();     
3.  SystemClock.sleep(30000); // 30 seconds, pretend to do work   TextView result = (TextView) findViewById(R.id.txt_result); result.setText(strInputMsg + " " + DateFormat.format("MM/dd/yy h:mmaa", System.currentTimeMillis()));   

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1. EditText input = (EditText) findViewById(R.id.txt_input);  
2.  String strInputMsg = input.getText().toString();    
3.  SystemClock.sleep(30000); // 30 seconds, pretend to do work   TextView result = (TextView) findViewById(R.id.txt_result); result.setText(strInputMsg + " " + DateFormat.format("MM/dd/yy h:mmaa", System.currentTimeMillis()));   

EditText input = (EditText) findViewById(R.id.txt_input); String strInputMsg = input.getText().toString(); SystemClock.sleep(30000); // 30 seconds, pretend to do work TextView result = (TextView) findViewById(R.id.txt_result); result.setText(strInputMsg + " " + DateFormat.format("MM/dd/yy h:mmaa", System.currentTimeMillis()));
 
2 下面是使用IntentService
   首先，我们搞一个类SimpleIntentService，继承了IntentService

Java代码

1. public class SimpleIntentService extends IntentService {   
2.     public static final String PARAM_IN_MSG = "imsg";   
3.     public static final String PARAM_OUT_MSG = "omsg";   
4.   
5.     public SimpleIntentService() {   
6.         super("SimpleIntentService");   
7.     }   
8.   
9.     @Override  
10.     protected void onHandleIntent(Intent intent) {   
11.   
12.         String msg = intent.getStringExtra(PARAM_IN_MSG);   
13.         SystemClock.sleep(3000); // 30 seconds  
14.         String resultTxt = msg + " "  
15.             + DateFormat.format("MM/dd/yy h:mmaa", System.currentTimeMillis());   
16.         Log.v("SimpleIntentService", "Handling msg: " + resultTxt);   
17.   
18.         Intent broadcastIntent = new Intent();   
19.         broadcastIntent.setAction(ResponseReceiver.ACTION_RESP);   
20.         broadcastIntent.addCategory(Intent.CATEGORY_DEFAULT);   
21.         broadcastIntent.putExtra(PARAM_OUT_MSG, resultTxt);   
22.         sendBroadcast(broadcastIntent);   
23.     }  

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1. public class SimpleIntentService extends IntentService {  
2.     public static final String PARAM_IN_MSG = "imsg";  
3.     public static final String PARAM_OUT_MSG = "omsg";  
4.   
5.     public SimpleIntentService() {  
6.         super("SimpleIntentService");  
7.     }  
8.   
9.     @Override  
10.     protected void onHandleIntent(Intent intent) {  
11.   
12.         String msg = intent.getStringExtra(PARAM_IN_MSG);  
13.         SystemClock.sleep(3000); // 30 seconds  
14.         String resultTxt = msg + " "  
15.             + DateFormat.format("MM/dd/yy h:mmaa", System.currentTimeMillis());  
16.         Log.v("SimpleIntentService", "Handling msg: " + resultTxt);  
17.   
18.         Intent broadcastIntent = new Intent();  
19.         broadcastIntent.setAction(ResponseReceiver.ACTION_RESP);  
20.         broadcastIntent.addCategory(Intent.CATEGORY_DEFAULT);  
21.         broadcastIntent.putExtra(PARAM_OUT_MSG, resultTxt);  
22.         sendBroadcast(broadcastIntent);  
23.     }  

public class SimpleIntentService extends IntentService { public static final String PARAM_IN_MSG = "imsg"; public static final String PARAM_OUT_MSG = "omsg"; public SimpleIntentService() { super("SimpleIntentService"); } @Override protected void onHandleIntent(Intent intent) { String msg = intent.getStringExtra(PARAM_IN_MSG); SystemClock.sleep(3000); // 30 seconds String resultTxt = msg + " " + DateFormat.format("MM/dd/yy h:mmaa", System.currentTimeMillis()); Log.v("SimpleIntentService", "Handling msg: " + resultTxt); Intent broadcastIntent = new Intent(); broadcastIntent.setAction(ResponseReceiver.ACTION_RESP); broadcastIntent.addCategory(Intent.CATEGORY_DEFAULT); broadcastIntent.putExtra(PARAM_OUT_MSG, resultTxt); sendBroadcast(broadcastIntent); }
   我们将跟主界面线程分离的操作都写在这里的ononHandleIntent中，这里首先通过
主线程传递的Intent中，获得用户文本框中输入的内容，放到变量msg中，然后
又建立一个Intent，把结果放到这个Intent中去，然后再sendBroadcast(broadcastIntent)广播出去，丢回给主线程。

3 在主线程中，这样启动：
 

Java代码

1. EditText input = (EditText) findViewById(R.id.txt_input);   
2.        String strInputMsg = input.getText().toString();   
3.   
4.        Intent msgIntent = new Intent(this, SimpleIntentService.class);   
5.        msgIntent.putExtra(SimpleIntentService.PARAM_IN_MSG, strInputMsg);   
6.        startService(msgIntent);  

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1. EditText input = (EditText) findViewById(R.id.txt_input);  
2.        String strInputMsg = input.getText().toString();  
3.   
4.        Intent msgIntent = new Intent(this, SimpleIntentService.class);  
5.        msgIntent.putExtra(SimpleIntentService.PARAM_IN_MSG, strInputMsg);  
6.        startService(msgIntent);  

EditText input = (EditText) findViewById(R.id.txt_input); String strInputMsg = input.getText().toString(); Intent msgIntent = new Intent(this, SimpleIntentService.class); msgIntent.putExtra(SimpleIntentService.PARAM_IN_MSG, strInputMsg); startService(msgIntent);
 
4 同时，在主线程中，也要有一个receive接收
 

Java代码

1. public class ResponseReceiver extends BroadcastReceiver {   
2.         public static final String ACTION_RESP = "com.mamlambo.intent.action.MESSAGE_PROCESSED";   
3.         @Override  
4.         public void onReceive(Context context, Intent intent) {   
5.               
6.             // Update UI, new "message" processed by SimpleIntentService  
7.            TextView result = (TextView) findViewById(R.id.txt_result);   
8.            String text = intent.getStringExtra(SimpleIntentService.PARAM_OUT_MSG);   
9.            result.setText(text);   
10.         }   
11.            
12.     }   
13.   
14.    

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1. public class ResponseReceiver extends BroadcastReceiver {  
2.         public static final String ACTION_RESP = "com.mamlambo.intent.action.MESSAGE_PROCESSED";  
3.         @Override  
4.         public void onReceive(Context context, Intent intent) {  
5.              
6.             // Update UI, new "message" processed by SimpleIntentService  
7.            TextView result = (TextView) findViewById(R.id.txt_result);  
8.            String text = intent.getStringExtra(SimpleIntentService.PARAM_OUT_MSG);  
9.            result.setText(text);  
10.         }  
11.           
12.     }  
13.   
14.    

public class ResponseReceiver extends BroadcastReceiver { public static final String ACTION_RESP = "com.mamlambo.intent.action.MESSAGE_PROCESSED"; @Override public void onReceive(Context context, Intent intent) { // Update UI, new "message" processed by SimpleIntentService TextView result = (TextView) findViewById(R.id.txt_result); String text = intent.getStringExtra(SimpleIntentService.PARAM_OUT_MSG); result.setText(text); } }
  当然，要注册这个broadcastReceiver,

Java代码

1. public void onCreate(Bundle savedInstanceState) {   
2.        super.onCreate(savedInstanceState);   
3.        setContentView(R.layout.main);   
4.           
5.        IntentFilter filter = new IntentFilter(ResponseReceiver.ACTION_RESP);   
6.        filter.addCategory(Intent.CATEGORY_DEFAULT);   
7.        receiver = new ResponseReceiver();   
8.        registerReceiver(receiver, filter);   
9.    }  

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1. public void onCreate(Bundle savedInstanceState) {  
2.        super.onCreate(savedInstanceState);  
3.        setContentView(R.layout.main);  
4.          
5.        IntentFilter filter = new IntentFilter(ResponseReceiver.ACTION_RESP);  
6.        filter.addCategory(Intent.CATEGORY_DEFAULT);  
7.        receiver = new ResponseReceiver();  
8.        registerReceiver(receiver, filter);  
9.    }  

public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); IntentFilter filter = new IntentFilter(ResponseReceiver.ACTION_RESP); filter.addCategory(Intent.CATEGORY_DEFAULT); receiver = new ResponseReceiver(); registerReceiver(receiver, filter); }
  可以看到，intent service还是比较清晰简单的，但至于性能方面，还是要继续学习，
迟点继续研究下这玩意哦