我如何在Android Service
中获取从调用Activity
传递的数据?
我如何在Android Service
中获取从调用Activity
传递的数据?
如何从Activity发送数据到Service?要精确回答这个问题,您需要覆盖onStartCommand()
方法以接收意图对象:
当您创建一个Service
时,应该覆盖onStartCommand()
方法。如果您仔细看下面的签名,这是接收传递给它的intent
对象的地方:
public int onStartCommand(Intent intent, int flags, int startId)
因此,从一个活动中,您将创建意图对象来启动服务,然后将您的数据放入意图对象中。例如,您想要从Activity
传递UserID
到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,在这个方法中,您可以从意图对象中检索值(UserID),例如:
当服务启动时,它的onStartCommand()
方法将被调用,在这个方法中,您可以从意图对象中检索值(UserID),例如:
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()
方法获取Intent,但在服务的上下文中不正确。
第一个上下文(可为Activity/Service等)
对于服务,您需要重写onStartCommand,这样您就可以直接访问意图:intent
:
Override
public int onStartCommand(Intent intent, int flags, int startId) {
您有以下几个选项:
Intent mIntent = new Intent(this, Example.class);
Bundle extras = mIntent.getExtras();
extras.putString(key, value);
2) 创建一个新的 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);
新上下文(可以是Activity/Service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: Bundles(捆绑包)具有所有原始类型、可传递的对象和可序列化对象的“get”和“put”方法。我只是出于演示目的使用了字符串。
如果您绑定了服务,您将在onBind(Intent intent)
中获得额外的内容。
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;
}
Arrays.toString(yourAry[])
将会对你有所帮助。 - Martin Pfeffer另一种可能性是使用intent.getAction:
在服务中:
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Activity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);
}
}
以下是我如何将数据从Activity
传递到IntentService
。
我的应用程序中有这种情况。
1)发送数据(Activity代码)
Intent intent = new Intent(MusicActivity.class, DownloadSongService.class);
String songUrl = "something";
intent.putExtra(YOUR_KEY_SONG_NAME, songUrl);
startService(intent);
2) 在服务中获取数据(IntentService代码)
您可以在onHandleIntent()
方法中访问意图(intent)。
public class DownloadSongService extends IntentService {
@Override
protected void onHandleIntent(@Nullable Intent intent) {
String songUrl = intent.getStringExtra("YOUR_KEY_SONG_NAME");
// Download File logic
}
}
private void startFloatingWidgetService() {
startService(new Intent(MainActivity.this,FloatingWidgetService.class)
.setAction(FloatingWidgetService.ACTION_PLAY));
}
private void startFloatingWidgetService() {
startService(new Intent(FloatingWidgetService.ACTION_PLAY));
}
因为当你尝试第二个方法时,会出现以下错误:
java.lang.IllegalArgumentException: Service Intent must be explicit: Intent { act=com.floatingwidgetchathead_demo.SampleService.ACTION_START }那么你的服务应该像这样:
static final String ACTION_START = "com.floatingwidgetchathead_demo.SampleService.ACTION_START";
static final String ACTION_PLAY = "com.floatingwidgetchathead_demo.SampleService.ACTION_PLAY";
static final String ACTION_PAUSE = "com.floatingwidgetchathead_demo.SampleService.ACTION_PAUSE";
static final String ACTION_DESTROY = "com.yourcompany.yourapp.SampleService.ACTION_DESTROY";
@SuppressLint("LogConditional")
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
String action = intent.getAction();
//System.out.println("ACTION: "+action);
switch (action){
case ACTION_START:
Log.d(TAG, "onStartCommand: "+action);
break;
case ACTION_PLAY:
Log.d(TAG, "onStartCommand: "+action);
addRemoveView();
addFloatingWidgetView();
break;
case ACTION_PAUSE:
Log.d(TAG, "onStartCommand: "+action);
break;
case ACTION_DESTROY:
Log.d(TAG, "onStartCommand: "+action);
break;
}
return START_STICKY;
}
服务:启动服务可能会产生副作用,最好的方法是使用 Messenger 并传递数据。
private CallBackHandler mServiceHandler= new CallBackHandler(this);
private Messenger mServiceMessenger=null;
//flag with which the activity sends the data to service
private static final int DO_SOMETHING=1;
private static class CallBackHandler extends android.os.Handler {
private final WeakReference<Service> mService;
public CallBackHandler(Service service) {
mService= new WeakReference<Service>(service);
}
public void handleMessage(Message msg) {
//Log.d("CallBackHandler","Msg::"+msg);
if(DO_SOMETHING==msg.arg1)
mSoftKeyService.get().dosomthing()
}
}
操作:从Intent中获取Messenger,填充数据并将消息传递回服务。
private Messenger mServiceMessenger;
@Override
protected void onCreate(Bundle savedInstanceState) {
mServiceMessenger = (Messenger)extras.getParcelable("myHandler");
}
private void sendDatatoService(String data){
Intent serviceIntent= new
Intent(BaseActivity.this,Service.class);
Message msg = Message.obtain();
msg.obj =data;
msg.arg1=Service.DO_SOMETHING;
mServiceMessenger.send(msg);
}
val intent = Intent(context, RecorderService::class.java);
intent.putExtra("filename", filename);
context.startService(intent)
在编程服务中,
override fun onStartCommand(intent: Intent, flags: Int, startId: Int): Int {
super.onStartCommand(intent, flags, startId)
if (intent != null && intent.extras != null)
val filename = intent.getStringExtra("filename")
}
未能启动服务 Intent:未找到
。 - fullOfQuestion