android在应用内如何打开第三方应用？QQ应用程序

private void openApp(String str){  
        //应用过滤条件  
        Intent mainIntent = new Intent(Intent.ACTION_MAIN, null);  
        mainIntent.addCategory(Intent.CATEGORY_LAUNCHER);  
        System.out.println("testrrr");  
        PackageManager mPackageManager = mContext.getPackageManager();  
        System.out.println("tesr");
        List<ResolveInfo> mAllApps = mPackageManager.queryIntentActivities(mainIntent, 0);  
        //按报名排序  
        Collections.sort(mAllApps, new ResolveInfo.DisplayNameComparator(mPackageManager));  
  
        for(ResolveInfo res : mAllApps){  
            //该应用的包名和主Activity  
            String pkg = res.activityInfo.packageName;  
            String cls = res.activityInfo.name;  
            System.out.println("pkg---" +pkg);  
           // System.out.println("打印出来的----" + str);  
  
            // 打开QQ pkg中包含"qq"，打开微信，pkg中包含"mm"  
            if(pkg.contains(str)){  
                ComponentName componet = new ComponentName(pkg, cls);  
                Intent intent = new Intent();  
                intent.setComponent(componet);  
                intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);  
                mContext.startActivity(intent);  
            }  
        }
 }