查找某个Service是否在运行与bindService隐性Intent有何不同，是否适应单通道

通过隐性Intent绑定bindService是按照包来顺序查找的，即使现在没有一个应用运行这个service，也有可能轮不到自己的应用。

如果通过查找某个service是否在运行，再来绑定它，这时规则不同，会导致一台设备上会有两个Service进程，这与单通道应用相违背。

/**
     * 把隐式Intent转为显式Intent 规则必须与bindService一样
     * @param context
     * @param implicitIntent
     * @return
     */
    private Intent createExplicitFromImplicitIntent(Context context, Intent implicitIntent) {  
        // Retrieve all services that can match the given intent  
        PackageManager pm = context.getPackageManager();  
        List<ResolveInfo> resolveInfo = pm.queryIntentServices(implicitIntent, 0);  
   
        // Make sure only one match was found  
        if (resolveInfo == null || resolveInfo.size() != 0) {  
            return null;  
        }  
   
        // Get component info and create ComponentName  
        ResolveInfo serviceInfo = resolveInfo.get(0);  
        String packageName = serviceInfo.serviceInfo.packageName;  
        String className = serviceInfo.serviceInfo.name;  
        ComponentName component = new ComponentName(packageName, className);  
   
        // Create a new intent. Use the old one for extras and such reuse  
        Intent explicitIntent = new Intent(implicitIntent);  
   
        // Set the component to be explicit  
        explicitIntent.setComponent(component);  
   
        return explicitIntent;  
    }  

上面这种通过在应用中查找的顺序就与bindService的顺序一样。

    //查找运行的服务
  private Intent createExplicitFromImplicitIntent(Context context, Intent implicitIntent) {  
        Intent explicitIntent = new Intent(implicitIntent);  
        ActivityManager myAM = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
         List<RunningServiceInfo> myList = myAM.getRunningServices(40);  
            if (myList.size() > 0) {  
                for (int i = 0; i < myList.size(); i++) {  
                    String mName = myList.get(i).service.getClassName().toString();  
                    if (mName.equals(PushService.class.getName())) {  
                         String packageName = myList.get(i).service.getPackageName();  
                         String className = mName;  
                         ComponentName component = new ComponentName(packageName, className);  
                         explicitIntent.setComponent(component);
                        return explicitIntent;
                    }  
                }  
            }  
        // Get component info and create ComponentName  
        String packageName = context.getPackageName();  
        String className = PushService.class.getName();  
        ComponentName component = new ComponentName(packageName, className);  
   
        // Set the component to be explicit  
        explicitIntent.setComponent(component);  
   
        return explicitIntent;  
    } 

上面这种的话就不同。

所以安桌5.0上不能用隐性Intent来bindService时，只能用上面那种方法来实现单通道。