android 启动其他应用的一段代码

1. private void startAppByPackageName(String packageName){  
2.         PackageInfo pi = null;  
3.         try {  
4.             pi = getPackageManager().getPackageInfo(packageName, 0);  
5.         } catch (NameNotFoundException e) {  
6.             e.printStackTrace();  
7.         }  
8.            
9.         Intent resolveIntent = new Intent(Intent.ACTION_MAIN, null);  
10.         resolveIntent.addCategory(Intent.CATEGORY_LAUNCHER);  
11.         resolveIntent.setPackage(pi.packageName);  
12.            
13.         List<ResolveInfo> apps = getPackageManager().queryIntentActivities(resolveIntent, 0);  
14.            
15.         ResolveInfo ri = apps.iterator().next();  
16.         if (ri != null ) {  
17.             String packageName1 = ri.activityInfo.packageName;  
18.             String className = ri.activityInfo.name;  
19.                
20.             Intent intent = new Intent(Intent.ACTION_MAIN);  
21.             intent.addCategory(Intent.CATEGORY_LAUNCHER);  
22.                
23.             ComponentName cn = new ComponentName(packageName1, className);  
24.                
25.             intent.setComponent(cn);  
26.             startActivity(intent);  
27.         }  
28.           
29.     }