我正在尝试让 Activity 运行某个服务。
我按照教程here但是适应了我的代码，我不能让它工作，因为当我在启动并将它绑定到活动后调用服务时，我的接口（IMyRemoteCallsLoggingService）对象似乎没有正确创建连接.
几天来我一直在尝试完成这项工作，但我似乎无法摆脱NullPointException.
不知道我是否说清楚了，在这种情况下，代码如下：
public class MtprojectActivity extends Activity {
[...]
private boolean started = false;
private RemoteSmsLoggingServiceConnection SmsLoggingConn = null;
private RemoteCallsLoggingServiceConnection CallsLoggingConn = null;
private IMyRemoteCallsLoggingService callsLoggingService;
private IMyRemoteSmsLoggingService smsLoggingService;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
retrievePreferences();
Button prefBtn = (Button) findViewById(R.id.prefsBtn);
prefBtn.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// Explicit intent to call the preferences
Intent preferencesActivity = new Intent(getBaseContext(),
Preferences.class);
startActivity(preferencesActivity);
}
});
}
private void retrievePreferences() {
// Get the xml/preferences.xml preferences
SharedPreferences prefs = PreferenceManager
.getDefaultSharedPreferences(getBaseContext());
callsCheckbox = prefs.getBoolean("callsLogChk", false);
smsCheckbox = prefs.getBoolean("smsLogChk", false);
locationCheckbox = prefs.getBoolean("locationLogChk", false);
if (callsCheckbox) {
startCallsService();
bindCallsService();
try {
invokeCallsService();
} catch (RemoteException e) {
e.printStackTrace();
}
} else {
}
private void startCallsService() {
if (started) {
Toast.makeText(MtprojectActivity.this, "Service already started",
Toast.LENGTH_SHORT).show();
} else {
Intent i = new Intent();
i.setClassName("app.mtproject", "app.mtproject.CallsLoggingService");
startService(i);
started = true;
updateCallsServiceStatus();
Log.d(getClass().getSimpleName(), "startService()");
}
}
private void bindCallsService() {
if (CallsLoggingConn == null) {
CallsLoggingConn = new RemoteCallsLoggingServiceConnection();
Intent i = new Intent();
i.setClassName("app.mtproject", "app.mtproject.CallsLoggingService");
bindService(i, CallsLoggingConn, Context.BIND_AUTO_CREATE);
updateCallsServiceStatus();
Log.d(getClass().getSimpleName(), "bindService()");
} else {
Toast.makeText(MtprojectActivity.this,
"Cannot bind - service already bound", Toast.LENGTH_SHORT)
.show();
}
}
private void invokeCallsService() throws RemoteException {
if (CallsLoggingConn == null) {
Toast.makeText(MtprojectActivity.this,
"Cannot invoke - service not bound", Toast.LENGTH_SHORT)
.show();
} else {
callsLoggingService.dumpCallsLog();
TextView t = (TextView) findViewById(R.id.notApplicable);
t.setText("It worked!");
Log.d(getClass().getSimpleName(), "invokeService()");
}
}
class RemoteCallsLoggingServiceConnection implements ServiceConnection {
public void onServiceConnected(ComponentName className,
IBinder boundService) {
callsLoggingService = IMyRemoteCallsLoggingService.Stub
.asInterface((IBinder) boundService);
Log.d(getClass().getSimpleName(), "onServiceConnected()");
}
public void onServiceDisconnected(ComponentName className) {
callsLoggingService = null;
updateCallsServiceStatus();
Log.d(getClass().getSimpleName(), "onServiceDisconnected");
}
};
我在方法NullPointerException上是正确的，但我不确定是什么问题！callsLoggingService.dumpCallsLog()invokeCallsService()
这是服务的代码：
public class CallsLoggingService extends Service {
String date, duration, type;
private Handler serviceHandler;
private Task myTask = new Task();
@Override
public IBinder onBind(Intent arg0) {
Log.d(getClass().getSimpleName(), "onBind()");
return myRemoteCallsServiceStub;
}
private IMyRemoteCallsLoggingService.Stub myRemoteCallsServiceStub = new IMyRemoteCallsLoggingService.Stub() {
public void dumpCallsLog() throws RemoteException {
CallsLoggingService.this.dumpCallsLog();
}
};
@Override
public void onCreate() {
super.onCreate();
Log.d(getClass().getSimpleName(), "onCreate()");
}
@Override
public void onDestroy() {
super.onDestroy();
serviceHandler.removeCallbacks(myTask);
serviceHandler = null;
Log.d(getClass().getSimpleName(), "onDestroy()");
}
@Override
public void onStart(Intent intent, int startId) {
super.onStart(intent, startId);
serviceHandler = new Handler();
serviceHandler.postDelayed(myTask, 10L);
Log.d(getClass().getSimpleName(), "onStart()");
}
class Task implements Runnable {
public void run() {
try {
myRemoteCallsServiceStub.dumpCallsLog();
} catch (RemoteException e) {
e.printStackTrace();
}
serviceHandler.postDelayed(this, 86400000L);
Log.i(getClass().getSimpleName(), "Calling the dumpCallsLog");
}
}
private synchronized void dumpCallsLog() {
ContentResolver cr = getContentResolver();
String columns[] = new String[] { CallLog.Calls.DATE,
CallLog.Calls.DURATION, CallLog.Calls.TYPE };
Uri mContacts = CallLog.Calls.CONTENT_URI;
Cursor c = cr.query(mContacts, columns, // Which columns to return
null, // WHERE clause; which rows to return(all rows)
null, // WHERE clause selection arguments (none)
CallLog.Calls.DEFAULT_SORT_ORDER // Order-by clause
// (ascending
// by name)
);
if (c.moveToFirst()) {
do {
// Get the field values
date = c.getString(c.getColumnIndex(CallLog.Calls.DATE));
duration = c
.getString(c.getColumnIndex(CallLog.Calls.DURATION));
type = c.getString(c.getColumnIndex(CallLog.Calls.TYPE));
} while (c.moveToNext());
}
}
}
非常感谢大家的帮助！