Android undefined intent constructor错误?

本文选自StackOverflow（简称：SOF）精选问答汇总系列文章之一，本系列文章将为读者分享国外最优质的精彩问与答，供读者学习和了解国外最新技术。在Android中启动Service时出现“undefined intent constructor”的错误，怎么办？

问：Ram

我在Activity中尝试启动Service，但出现“undefined intent constructor”的报错信息。

MyService.java代码如下：

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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();     }     }

启动SampleService.java的代码如下：

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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中设定service的初值如下：

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

请大家帮我解决这个错误。

答：kalyan pvs

(最佳答案）

你不应该使用Service.this，而应该按如下方法改变class：

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

答：Raghunandan

做如下调整：

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

变为：

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

你没有设置类似于Intent(SampleService, MyService)的构造函数，在intent constructor参数设定上出现错误。

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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.

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

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