Android的Broadcast应用说明一例

青旅半醒 2021-12-17 05:49 180阅读 0赞

程序A的Receiver：

![ExpandedBlockStart.gif][] ![ContractedBlock.gif][] receiver  =   new  BroadcastReceiver()  ![dot.gif][] \{  
![InBlock.gif][]  
![InBlock.gif][]            @Override  
![ExpandedSubBlockStart.gif][]![ContractedSubBlock.gif][]            public void onReceive(Context ctx, Intent intent) ![dot.gif][]\{  
![InBlock.gif][]                Log.i("TestActivity", "===============Broadcast Received:" \+ intent.getAction());  
![ExpandedSubBlockStart.gif][]![ContractedSubBlock.gif][]                if (intent.getAction().equals(RESPONSE\_ACTION)) ![dot.gif][]\{  
![InBlock.gif][]                    Uri uri = intent.getData();  
![InBlock.gif][]                    String location = "";  
![ExpandedSubBlockStart.gif][]![ContractedSubBlock.gif][]                    if (uri != null) ![dot.gif][]\{  
![InBlock.gif][]                        Log.i("TestActivity",  
![InBlock.gif][]                                "=======================parameter location:"  
![InBlock.gif][]                                        \+ uri.getQueryParameter("location"));  
![InBlock.gif][]                        Log.i("TestActivity", "======================= host:"  
![InBlock.gif][]                                \+ uri.getHost());  
![InBlock.gif][]                        Log.i("TestActivity", "======================= path:"  
![InBlock.gif][]                                \+ uri.getPath());  
![InBlock.gif][]                        location = uri.getQueryParameter("location");  
![InBlock.gif][]                        FileInputStream fis = null;  
![InBlock.gif][]                        ByteArrayOutputStream bos = null;  
![InBlock.gif][]                        File file = new File(location);  
![ExpandedSubBlockStart.gif][]![ContractedSubBlock.gif][]                        try ![dot.gif][]\{  
![InBlock.gif][]                            fis = new FileInputStream(file);  
![InBlock.gif][]                            bos = new ByteArrayOutputStream();  
![InBlock.gif][]                            byte\[\] data = new byte\[512\];  
![InBlock.gif][]                            int count = \-1;  
![ExpandedSubBlockStart.gif][]![ContractedSubBlock.gif][]                            while ((count = fis.read(data)) != \-1) ![dot.gif][]\{  
![InBlock.gif][]                                bos.write(data, 0, count);  
![ExpandedSubBlockEnd.gif][]                            \}  
![InBlock.gif][]                            String xml = new String(bos.toByteArray());  
![InBlock.gif][]                            Log.i("TestActivity", "xml1=" \+ xml);  
![InBlock.gif][]                            Toast.makeText(TestActivity.this, xml, Toast.LENGTH\_SHORT).show();  
![ExpandedSubBlockStart.gif][]![ContractedSubBlock.gif][]                        \} catch (Exception ex) ![dot.gif][]\{  
![InBlock.gif][]                            ex.printStackTrace();  
![ExpandedSubBlockStart.gif][]![ContractedSubBlock.gif][]                        \} finally ![dot.gif][]\{  
![InBlock.gif][]                            if (fis != null)  
![ExpandedSubBlockStart.gif][]![ContractedSubBlock.gif][]                                try ![dot.gif][]\{  
![InBlock.gif][]                                    fis.close();  
![ExpandedSubBlockStart.gif][]![ContractedSubBlock.gif][]                                \} catch (IOException e) ![dot.gif][]\{  
![InBlock.gif][]                                    // TODO Auto-generated catch block  
![InBlock.gif][]                                    e.printStackTrace();  
![ExpandedSubBlockEnd.gif][]                                \}  
![InBlock.gif][]                            if (bos != null)  
![ExpandedSubBlockStart.gif][]![ContractedSubBlock.gif][]                                try ![dot.gif][]\{  
![InBlock.gif][]                                    bos.close();  
![ExpandedSubBlockStart.gif][]![ContractedSubBlock.gif][]                                \} catch (IOException e) ![dot.gif][]\{  
![InBlock.gif][]                                    // TODO Auto-generated catch block  
![InBlock.gif][]                                    e.printStackTrace();  
![ExpandedSubBlockEnd.gif][]                                \}  
![ExpandedSubBlockEnd.gif][]                        \}  
![ExpandedSubBlockEnd.gif][]                    \}  
![ExpandedSubBlockEnd.gif][]                \}  
![ExpandedSubBlockEnd.gif][]            \}  
![InBlock.gif][]  
![ExpandedBlockEnd.gif][]        \} ;  
![None.gif][]        IntentFilter filter  =   new  IntentFilter();  
![None.gif][]        filter.addAction(RESPONSE\_ACTION);  
![None.gif][]        filter.addCategory(Intent.CATEGORY\_DEFAULT);  
![None.gif][]        filter.addDataScheme( "http " );  
![None.gif][]        registerReceiver(receiver, filter);

程序A的发送BC：

![ExpandedBlockStart.gif][] ![ContractedBlock.gif][]         btn.setOnClickListener( new  OnClickListener()  ![dot.gif][] \{  
![InBlock.gif][]  
![InBlock.gif][]            @Override  
![ExpandedSubBlockStart.gif][]![ContractedSubBlock.gif][]            public void onClick(View arg0) ![dot.gif][]\{  
![InBlock.gif][]                // TODO Auto-generated method stub  
![InBlock.gif][]                Uri uri = Uri.parse("http://www.xx.com/getDetails?id=123");  
![InBlock.gif][]                Intent in = new Intent();  
![InBlock.gif][]                in.setAction(REQUEST\_ACTION);  
![InBlock.gif][]                in.addCategory(Intent.CATEGORY\_DEFAULT);  
![InBlock.gif][]                in.setData(uri);  
![InBlock.gif][]                TestActivity.this.sendBroadcast(in);  
![ExpandedSubBlockEnd.gif][]            \}  
![ExpandedBlockEnd.gif][]        \} );

程序B的Receiver：

![None.gif][] @Override  
![ExpandedBlockStart.gif][]![ContractedBlock.gif][]     public   void  onReceive(Context context, Intent intent)  ![dot.gif][] \{  
![InBlock.gif][]        if(intent != null)  
![ExpandedSubBlockStart.gif][]![ContractedSubBlock.gif][]        ![dot.gif][]\{  
![InBlock.gif][]            Uri uri = intent.getData();  
![InBlock.gif][]            if(uri != null)  
![ExpandedSubBlockStart.gif][]![ContractedSubBlock.gif][]            ![dot.gif][]\{  
![InBlock.gif][]                Log.i("BGServiceReceiver", "=======================" \+ uri.getQueryParameter("id"));  
![InBlock.gif][]                intent.setClassName("com.backgroundservice",  
![InBlock.gif][]                "com.backgroundservice.TestBackgroundService");  
![InBlock.gif][]                context.startService(intent);  
![ExpandedSubBlockEnd.gif][]            \}  
![InBlock.gif][]                  
![ExpandedSubBlockEnd.gif][]        \}  
![InBlock.gif][]//        try \{  
![InBlock.gif][]//            Thread.sleep(5000);  
![InBlock.gif][]//        \} catch (InterruptedException e) \{  
![InBlock.gif][]//            // TODO Auto-generated catch block  
![InBlock.gif][]//            e.printStackTrace();  
![InBlock.gif][]//        \}  
![InBlock.gif][]      
![InBlock.gif][]  
![ExpandedBlockEnd.gif][]    \}

配置：

![None.gif][]          < receiver  android:name ="ServiceReceiver" >   
![None.gif][]             < intent-filter >   
![None.gif][]                 < action  android:name ="android.intent.action.STORE\_REQUEST" ></ action >   
![None.gif][]                 < category  android:name ="android.intent.category.DEFAULT" ></ category >   
![None.gif][]                 < data  android:scheme ="http" ></ data >   
![None.gif][]             </ intent-filter >   
![None.gif][]         </ receiver >

程序B的发送BC：

![None.gif][]         Intent in  =   new  Intent();  
![None.gif][]        in.setAction(RESPONSE\_ACTION);  
![None.gif][]        in.addCategory(Intent.CATEGORY\_DEFAULT);  
![None.gif][]        in.setData(Uri.parse( " http://www.xx.com/setList?location=/sdcard/xx.xml " ));  
![None.gif][]         this .sendBroadcast(in);

如果想让目标Activity或者Service接收到相应的Broadcast，就需要完全匹配目标Activity或者Service的IntentFilter，否则目标Filter无法接收到相应的Broadcast。注意：IntentFilter设置的时候都要默认带上CATEGORY\_DEFAULT，否则可能会造成潜在问题。  
文档中的说明如下：  
In principle, therefore, an Intent object with no categories should always pass this test, regardless of what's in the filter. That's mostly true. However, with one exception, Android treats all implicit intents passed to [startActivity()][startActivity] as if they contained at least one category: "`android.intent.category.DEFAULT`" (the `CATEGORY_DEFAULT` constant). Therefore, activities that are willing to receive implicit intents must include "`android.intent.category.DEFAULT`" in their intent filters.

TrackBack：[http://www.blogjava.net/TiGERTiAN/archive/2010/01/31/311413.html][http_www.blogjava.net_TiGERTiAN_archive_2010_01_31_311413.html]

转载于:https://www.cnblogs.com/hdjjun/archive/2010/06/02/1749859.html

[ExpandedBlockStart.gif]: http://www.blogjava.net/Images/OutliningIndicators/ExpandedBlockStart.gif
[ContractedBlock.gif]: http://www.blogjava.net/Images/OutliningIndicators/ContractedBlock.gif
[dot.gif]: /images/20211217/de83779811ed423a9e9a9901fa91de31.png
[InBlock.gif]: /images/20211217/644dfba49c6447eba8b7a3eca6367c6b.png
[ExpandedSubBlockStart.gif]: http://www.blogjava.net/Images/OutliningIndicators/ExpandedSubBlockStart.gif
[ContractedSubBlock.gif]: http://www.blogjava.net/Images/OutliningIndicators/ContractedSubBlock.gif
[ExpandedSubBlockEnd.gif]: /images/20211217/bda2fbaf0268495cafb61013ec57f8ef.png
[ExpandedBlockEnd.gif]: /images/20211217/8b04f124c1b345bbb3d26a26b47a3d96.png
[None.gif]: /images/20211217/84aa35c6d4db4552855bc8eb9ec08378.png
[startActivity]: http://www.blogjava.net/TiGERTiAN/archive/reference/android/content/Context.html#startActivity%28android.content.Intent%29
[http_www.blogjava.net_TiGERTiAN_archive_2010_01_31_311413.html]: http://www.blogjava.net/TiGERTiAN/archive/2010/01/31/311413.html