Android undefined intent constructor錯誤?

本文選自StackOverflow（簡稱：SOF）精選問答彙總系列文章之一，本系列文章將爲讀者分享國外最優質的精彩問與答，供讀者學習和了解國外最新技術。在Android中啓動Service時出現「undefined intent constructor」的錯誤，怎麼辦？

問：Ram

我在Activity中嘗試啓動Service，但出現「undefined intent constructor」的報錯信息。

MyService.java代碼以下：

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public class MyService extends Service {   @Override public IBinder onBind(Intent intent) {      return null ; }   public static boolean isInstanceCreated() {        return instance != null ;     }   @Override public void onCreate() {      Toast.makeText( this , "My Service Created" , Toast.LENGTH_LONG).show();      Log.d(TAG, "onCreate" );         instance = this ; }   @Override public void onDestroy() {      Toast.makeText( this , "My Service Stopped" , Toast.LENGTH_LONG).show();      Log.d(TAG, "onDestroy" );      instance = null ;   }   @Override public void onStart(Intent intent, int startid) {              Toast.makeText(getBaseContext(), "Service started" ,Toast.LENGTH_SHORT).show();      }     }

啓動SampleService.java的代碼以下：

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public class SampleService extends Activity{ @Override protected void onCreate(Bundle savedInstanceState) {      super .onCreate(savedInstanceState);      setContentView(R.layout.grid_activity);      Intent myintent = new Intent(SampleService. this ,MyService. this ); //Error show here..      startService(myintent);        }   }

在manifest file中設定service的初值以下：

1	<service android:enabled= "true" android:name= "com.MyApp.MyService" />

請你們幫我解決這個錯誤。

答：kalyan pvs

(最佳答案）

你不該該使用Service.this，而應該按以下方法改變class：

1	Intent myintent = new Intent(SampleService. this ,MyService.Class);

答：Raghunandan

作以下調整：

1	Intent myintent = new Intent(SampleService. this ,MyService. this );

變爲：

1 2	Intent myintent = new Intent(SampleService. this ,MyService.Class);   // first param is a context second param is a class in your case a MyServiceClass

你沒有設置相似於Intent(SampleService, MyService)的構造函數，在intent constructor參數設定上出現錯誤。

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public Intent (Context packageContext, Class<?> cls)   Added in API level 1 Create an intent for a specific component. All other fields (action, data, type, class) are null , though they can be modified later with explicit calls. This provides a convenient way to create an intent that is intended to execute a hard-coded class name, rather than relying on the system to find an appropriate class for you; see setComponent(ComponentName) for more information on the repercussions of this .   Parameters packageContext  A Context of the application package implementing this class. cls   The component class that is to be used for the intent.

原文連接：http://stackoverflow.com/questions/20068783/errorundefined-intent-constructor-when-start-service-in-android

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