使用意图将数据从活动传递到服务
如何获取从调用Activity传递的Android服务中的数据?
第一上下文(可以是活动/服务等)
你有几个select:
1)使用意图中的Bundle :
Intent mIntent = new Intent(this, Example.class); Bundle extras = mIntent.getExtras(); extras.putString(key, value);
2)创build一个新的Bundle
Intent mIntent = new Intent(this, Example.class); Bundle mBundle = new Bundle(); mBundle.extras.putString(key, value); mIntent.putExtras(mBundle);
3)使用Intent的putExtra()快捷方法
Intent mIntent = new Intent(this, Example.class); mIntent.putExtra(key, value);
新的上下文(可以是活动/服务等)
Intent myIntent = getIntent(); // this getter is just for example purpose, can differ if (myIntent !=null && myIntent.getExtras()!=null) String value = myIntent.getExtras().getString(key); }
注意: Bundle对所有的原始types,Parcelables和Serializables都有“get”和“put”方法。 我只是用string作示范。
为了精确地回答“如何通过从活动到服务的意图发送数据”这个问题,是否必须重写onStartCommand()
方法,它是您接收意图对象的地方:
当你创build一个Service
你应该重写onStartCommand()
方法,所以如果仔细看下面的签名,这就是你接收传递给它的intent
对象的地方:
public int onStartCommand(Intent intent, int flags, int startId)
因此,从活动开始,您将创buildintent对象来启动服务,然后将数据放入intent对象中,例如您想要将Activity
的UserID
传递给Service
:
Intent serviceIntent = new Intent(YourService.class.getName()) serviceIntent.putExtra("UserID", "123456"); context.startService(serviceIntent);
当服务启动时,它的onStartCommand()
方法将被调用,所以在这个方法中,你可以从intent对象中检索值(UserID)
public int onStartCommand (Intent intent, int flags, int startId) { String userID = intent.getStringExtra("UserID"); return START_STICKY; }
注意:上面的答案指定使用getIntent()
方法得到一个Intent,这个方法在服务上下文中是不正确的
如果你绑定你的服务,你会得到额外的onBind(Intent intent)
。
活动:
Intent intent = new Intent(this, LocationService.class); intent.putExtra("tour_name", mTourName); bindService(intent, mServiceConnection, BIND_AUTO_CREATE);
服务:
@Override public IBinder onBind(Intent intent) { mTourName = intent.getStringExtra("tour_name"); return mBinder; }
另一个可能性是使用intent.getAction:
服务中:
public class SampleService inherits Service{ static final String ACTION_START = "com.yourcompany.yourapp.SampleService.ACTION_START"; static final String ACTION_DO_SOMETHING_1 = "com.yourcompany.yourapp.SampleService.DO_SOMETHING_1"; static final String ACTION_DO_SOMETHING_2 = "com.yourcompany.yourapp.SampleService.DO_SOMETHING_2"; static final String ACTION_STOP_SERVICE = "com.yourcompany.yourapp.SampleService.STOP_SERVICE"; @Override public int onStartCommand(Intent intent, int flags, int startId) { String action = intent.getAction(); //System.out.println("ACTION: "+action); switch (action){ case ACTION_START: startingService(intent.getIntExtra("valueStart",0)); break; case ACTION_DO_SOMETHING_1: int value1,value2; value1=intent.getIntExtra("value1",0); value2=intent.getIntExtra("value2",0); doSomething1(value1,value2); break; case ACTION_DO_SOMETHING_2: value1=intent.getIntExtra("value1",0); value2=intent.getIntExtra("value2",0); doSomething2(value1,value2); break; case ACTION_STOP_SERVICE: stopService(); break; } return START_STICKY; } public void startingService(int value){ //calling when start } public void doSomething1(int value1, int value2){ //... } public void doSomething2(int value1, int value2){ //... } public void stopService(){ //...destroy/release objects stopself(); } }
在活动中:
public void startService(int value){ Intent myIntent = new Intent(SampleService.ACTION_START); myIntent.putExtra("valueStart",value); startService(myIntent); } public void serviceDoSomething1(int value1, int value2){ Intent myIntent = new Intent(SampleService.ACTION_DO_SOMETHING_1); myIntent.putExtra("value1",value1); myIntent.putExtra("value2",value2); startService(myIntent); } public void serviceDoSomething2(int value1, int value2){ Intent myIntent = new Intent(SampleService.ACTION_DO_SOMETHING_2); myIntent.putExtra("value1",value1); myIntent.putExtra("value2",value2); startService(myIntent); } public void endService(){ Intent myIntent = new Intent(SampleService.STOP_SERVICE); startService(myIntent); }
最后,在清单文件中:
<service android:name=".SampleService"> <intent-filter> <action android:name="com.yourcompany.yourapp.SampleService.ACTION_START"/> <action android:name="com.yourcompany.yourapp.SampleService.DO_SOMETHING_1"/> <action android:name="com.yourcompany.yourapp.SampleService.DO_SOMETHING_2"/> <action android:name="com.yourcompany.yourapp.SampleService.STOP_SERVICE"/> </intent-filter> </service>
活动:
int number = 5; Intent i = new Intent(this, MyService.class); i.putExtra("MyNumber", number); startService(i);
服务:
@Override public int onStartCommand(Intent intent, int flags, int startId) { if (intent != null && intent.getExtras() != null){ int number = intent.getIntExtra("MyNumber", 0); } }