您好，我正在尝试在创建活动时设置提醒通知，但是， 调用scheduleClient.setAlarmForNotification（c）时，我收到空指针错误。
这是我调用错误的主要活动
MainActivity
public class MainActivity extends Activity {
// This is a handle so that we can call methods on our service
private ScheduleClient scheduleClient;
// This is the date picker used to select the date for our notification
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Create a new service client and bind our activity to this service
scheduleClient = new ScheduleClient(this);
scheduleClient.doBindService();
int day =3;
int month = 3;
int year = 2014;
// Create a new calendar set to the date chosen
// we set the time to midnight (i.e. the first minute of that day)
Calendar c = Calendar.getInstance();
c.set(year, month, day);
c.set(Calendar.HOUR_OF_DAY, 0);
c.set(Calendar.MINUTE, 0);
c.set(Calendar.SECOND, 0);
// Ask our service to set an alarm for that date, this activity talks to the client that talks to the service
scheduleClient.setAlarmForNotification(c);
//Notify the user what they just did
Toast.makeText(this, "Notification set for: "+ c.get(Calendar.DAY_OF_MONTH) +"/"+ (month+1) +"/"+ year, Toast.LENGTH_SHORT).show();
}
@Override
protected void onStop() {
// When our activity is stopped ensure we also stop the connection to the service
// this stops us leaking our activity into the system *bad*
if(scheduleClient != null)
scheduleClient.doUnbindService();
super.onStop();
}
}
AlarmTask.java
public class AlarmTask implements Runnable{
// The date selected for the alarm
private final Calendar date;
// The android system alarm manager
private final AlarmManager am;
// Your context to retrieve the alarm manager from
private final Context context;
public AlarmTask(Context context, Calendar date) {
this.context = context;
this.am = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
this.date = date;
}
@Override
public void run() {
// Request to start are service when the alarm date is upon us
// We don't start an activity as we just want to pop up a notification into the system bar not a full activity
Intent intent = new Intent(context, NotifyService.class);
intent.putExtra(NotifyService.INTENT_NOTIFY, true);
PendingIntent pendingIntent = PendingIntent.getService(context, 0, intent, 0);
// Sets an alarm - note this alarm will be lost if the phone is turned off and on again
am.set(AlarmManager.RTC, date.getTimeInMillis(), pendingIntent);
}
}
SchedulecClient
public class ScheduleClient {
// The hook into our service
private ScheduleService mBoundService;
// The context to start the service in
private Context mContext;
// A flag if we are connected to the service or not
private boolean mIsBound;
public ScheduleClient(Context context) {
mContext = context;
}
/**
* Call this to connect your activity to your service
*/
public void doBindService() {
// Establish a connection with our service
mContext.bindService(new Intent(mContext, ScheduleService.class), mConnection, Context.BIND_AUTO_CREATE);
mIsBound = true;
}
/**
* When you attempt to connect to the service, this connection will be called with the result.
* If we have successfully connected we instantiate our service object so that we can call methods on it.
*/
private ServiceConnection mConnection = new ServiceConnection() {
public void onServiceConnected(ComponentName className, IBinder service) {
// This is called when the connection with our service has been established,
// giving us the service object we can use to interact with our service.
mBoundService = ((ScheduleService.ServiceBinder) service).getService();
}
public void onServiceDisconnected(ComponentName className) {
mBoundService = null;
}
};
/**
* Tell our service to set an alarm for the given date
* @param c a date to set the notification for
*/
public void setAlarmForNotification(Calendar c){
mBoundService.setAlarm(c);
}
/**
* When you have finished with the service call this method to stop it
* releasing your connection and resources
*/
public void doUnbindService() {
if (mIsBound) {
// Detach our existing connection.
mContext.unbindService(mConnection);
mIsBound = false;
}
}
}
ScheduleService
public class ScheduleService extends Service {
/**
* Class for clients to access
*/
public class ServiceBinder extends Binder {
ScheduleService getService() {
return ScheduleService.this;
}
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.i("ScheduleService", "Received start id " + startId + ": " + intent);
// We want this service to continue running until it is explicitly stopped, so return sticky.
return START_STICKY;
}
@Override
public IBinder onBind(Intent intent) {
return mBinder;
}
// This is the object that receives interactions from clients. See
private final IBinder mBinder = new ServiceBinder();
/**
* Show an alarm for a certain date when the alarm is called it will pop up a notification
*/
public void setAlarm(Calendar c) {
// This starts a new thread to set the alarm
// You want to push off your tasks onto a new thread to free up the UI to carry on responding
new AlarmTask(this, c).run();
}
}
答案 0 :(得分：0)
制作一个功能。
public void onDateSelectedClickEvent(View v) {
// Get the date from our datepicker
int day = 3;
int month = 2;
int year = 2014;
// Create a new calendar set to the date chosen
// we set the time to midnight (i.e. the first minute of that day)
Calendar c = Calendar.getInstance();
c.set(year, month, day);
c.set(Calendar.HOUR_OF_DAY, 0);
c.set(Calendar.MINUTE, 0);
c.set(Calendar.SECOND, 0);
// Ask our service to set an alarm for that date, this activity talks to
// the client that talks to the service
scheduleClient.setAlarmForNotification(c);
// Notify the user what they just did
Toast.makeText(
this,
"Notification set for: " + day + "/" + (month + 1) + "/" + year,
Toast.LENGTH_SHORT).show();
}
现在在你的xml文件集中调用这个函数你想在xml文件中调用这个事件的按钮。喜欢
<Button
android:id="@+id/sel_btn"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:onClick="onDateSelectedClickEvent"
android:text="Notification" />
还从onCreate（）方法中删除该代码。必须确保您的所有服务都在AndroidManifest.xml文件中注册。