java – 如何从片段访问服务函数,它绑定到Android中的父活动？
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我有一个带有viewpager片段的Android活动.在活动的onCreate方法中,我将服务绑定到不断在后台运行的服务.
在片段中,在某种条件下,我需要调用处理条件的服务中的函数.访问服务的正确方法是什么,并调用它的功能？
MainActivity.java
public class MainActivity extends AppCompatActivity {
private String TAG = "MainActivity";
DbHelper dbHelper;
SessionManager sessionManager;
SessionCache sessionCache;
Map<String, ?> userDetails;
protected SocketListener socketService;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
sessionManager = new SessionManager(getApplicationContext());
// Connect to background socketlistener service
Intent serviceIntent = new Intent(MainActivity.this, SocketListener.class);
startService(serviceIntent);
.
.
.
TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
tabLayout.addTab(tabLayout.newTab().setText("").setIcon(getResources().getDrawable(R.drawable.profileicon)));
tabLayout.addTab(tabLayout.newTab().setText("").setIcon(getResources().getDrawable(R.drawable.homeicon)));
tabLayout.addTab(tabLayout.newTab().setText("").setIcon(getResources().getDrawable(R.drawable.chaticon)));
tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
final NonSwipeableViewPager viewPager = (NonSwipeableViewPager) findViewById(R.id.view_pager);
final CustomPagerAdapter pagerAdapter = new CustomPagerAdapter
(getSupportFragmentManager(), tabLayout.getTabCount());
viewPager.setAdapter(pagerAdapter);
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
viewPager.setCurrentItem(1);
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
@Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabUnselected(TabLayout.Tab tab) {
}
@Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
}
private ServiceConnection serviceConnection = new ServiceConnection() {
@Override
public void onServiceConnected(ComponentName componentName, IBinder iBinder) {
socketService = ((SocketListener.LocalBinder) iBinder).getService();
}
@Override
public void onServiceDisconnected(ComponentName componentName) {
socketService = null;
}
};
}
这是我的服务.我连接到服务器,并不断收听更新.
SocketListener.java
package com.example.gopa2000.mobapps;
import android.app.Service;
import android.content.Intent;
import android.os.Binder;
import android.os.IBinder;
import android.util.Log;
import android.widget.Toast;
import java.net.URISyntaxException;
import io.socket.client.IO;
import io.socket.client.Socket;
import io.socket.emitter.Emitter;
public class SocketListener extends Service {
private static String TAG = "SocketListener";
private Socket socket;
public SocketListener() { }
@Override
public IBinder onBind(Intent intent) {
// TODO: Return the communication channel to the service.
return localBinder;
}
private final IBinder localBinder = new LocalBinder();
public class LocalBinder extends Binder {
public SocketListener getService(){
Log.i(TAG, "getService: Sitting in local binder.");
return SocketListener.this;
}
public void sendMessage(String message){
socket.emit("match", message);
}
}
@Override
public void onCreate() {
super.onCreate();
}
public void isBoundable(){
Log.i(TAG, "Bind like a baller.");
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
super.onStartCommand(intent, flags, startId);
Runnable connect = new ConnectSocket();
new Thread(connect).start();
return START_STICKY;
}
class ConnectSocket implements Runnable {
@Override
public void run() {
try {
socket = IO.socket(RESTClient.getURL());
socket.on(Socket.EVENT_CONNECT, new Emitter.Listener() {
@Override
public void call(Object... args) {
Log.i(TAG, "call: Connected to backend!");
}
});
socket.connect();
} catch (URISyntaxException e){
Log.e(TAG, "run: ", e);
}
}
}
public Socket getSocket(){
return this.socket;
}
}
这是我需要调用sendMessage(string)的片段.
public class MainViewFragment extends Fragment {
private final String TAG = "MVFragment";
private RecyclerView recyclerView;
private RecyclerView.LayoutManager layoutManager;
private RecyclerView.Adapter adapter;
private SessionManager sessionManager;
private ArrayList<CustomCard> cards;
private CardAdapter cardAdapter;
private Button btn;
private SwipeFlingAdapterView flingContainer;
private Map<String, ?> userDetails;
// hax
private static String userEmail;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.from(getContext()).inflate(R.layout.fragment_main_view, container, false);
.
.
flingContainer.setAdapter(adapter);
flingContainer.setFlingListener(new SwipeFlingAdapterView.onFlingListener(){
.
.
@Override
public void onRightCardExit(Object o) {
.
.
if(match){
// need to call sendMessage from the service here. <------------------------
sessionCache.addToMatchTable(Liker, Likee);
}
}
@Override
public void onAdapterAboutToEmpty(int i) {
}
@Override
public void onScroll(float v) {
}
});
flingContainer.setOnItemClickListener(new SwipeFlingAdapterView.OnItemClickListener(){
@Override
public void onItemClicked(int itemPosition, Object dataObject){
Toast.makeText(getActivity(), "Clicked!", Toast.LENGTH_SHORT).show();
Intent intent = new Intent(getActivity().getApplicationContext(), FullScreenCardLayout.class);
startActivity(intent);
}
});
return view;
}
解决方法:
首先,方法sendMessage(message)应该在服务内部而不是LocalBinder类
public class SocketListener extends Service {
public void sendMessage(String message){
socket.emit("match", message);
}
}
第二,从片段访问活动方法,您应该在片段内创建接口
interface MessageSender {
void sendMessage(String message);
}
然后在你的活动中实现它
public class MainActivity extends AppCompatActivity implements MessageSender {
@Override
public void sendMessage(String message) {
// call the service here
socketService.sendMessage(message);
}
}
在你的片段中,实现onAttach()并初始化接口实例
public class MainViewFragment extends Fragment {
private MessageSender mMessageSenderCallback;
@Override
public void onAttach(Context context) {
super.onAttach(context);
try {
mMessageSenderCallback = (MessageSender) context;
} catch (ClassCastException e) {
// Error, class doesn't implement the interface
}
}
@Override
public void onDetach() {
super.onDetach();
// Remove activity reference
mMessageSenderCallback = null;
}
}
要发送消息,请使用片段内的消息调用mMessageSenderCallback.sendMessage(message).
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