我正在尝试在我的应用中实现通知功能，该功能会根据特定的用户输入日期设置通知。我试图实现这个网站的方法：http://blog.blundell-apps.com/notification-for-a-user-chosen-time/，只是它不起作用！我试图理解这个问题，但我无法弄清楚如何解决这个问题。在ScheduleClient类中似乎出现了问题，因为LogCat告诉我，当ProductsAdd类打开时，服务绑定，但是当我单击保存按钮时尝试设置警报时，在ClientService的第62行给出了Nullpointerexception。 mBoundService.setAlarm（c）中）。所以服务绑定但不会连接。有人可以告诉我这里我做错了吗？
ProductsAdd class：
public class ProductsAdd extends Activity implements OnClickListener{
Button bSave, bDelete, bCancel;
EditText etName, etAmount , etDate;
Spinner sUnit;
Time today = new Time(Time.getCurrentTimezone());
// This is a handle so that we can call methods on our service
private ScheduleClient scheduleClient;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
this.setContentView(R.layout.products_add);
Log.d("WTF", "ProductsAdd.java opened");
initiate();
// Create a new service client and bind our activity to this service
scheduleClient = new ScheduleClient(this);
scheduleClient.doBindService();
// Create an ArrayAdapter using the string array and default spinner layout
ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(this, R.array.units_array, android.R.layout.simple_spinner_item);
// Specify the layout to use when the list of choices appears
adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);;
// Apply the adapter to the spinner
sUnit.setAdapter(adapter);
// Set product name which is passed from an activity
Intent getProductFeatures = getIntent();
String productName = getProductFeatures.getStringExtra("productName");
String productUnit = getProductFeatures.getStringExtra("productUnit");
etName.setText(productName);
//Set spinner to right value:
int spinnerPosition = adapter.getPosition(productUnit);
sUnit.setSelection(spinnerPosition);
today.setToNow();
String timestamp = today.format("%d-%m-%Y");
etDate.setText(timestamp);
}
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
switch (v.getId()){
case R.id.bSave:
Log.d("WTF", "ProductsAdd: Save button pressed");
try{
//Get info from edittexts
String name = etName.getText().toString();
String amount = etAmount.getText().toString();
String unit = sUnit.getSelectedItem().toString();
String date = etDate.getText().toString();
Log.d("WTF", "Extracted unit from ProductsAdd is: " + unit);
//Set date alarm
//Get day, month and year in separate integers
String sDay = date.substring(0, 2);
String sMonth = date.substring(3, 5);
String sYear = date.substring(6, 10);
int month = Integer.parseInt(sMonth);
int day = Integer.parseInt(sDay);
int year = Integer.parseInt(sYear);
//Create new calendar to set date chosen
Calendar c = Calendar.getInstance();
c.set(day,month,year);
//Set time to midnight
c.set(Calendar.HOUR_OF_DAY, 0);
c.set(Calendar.MINUTE,0);
c.set(Calendar.SECOND, 0);
//Ask service to set alarm for date
scheduleClient.setAlarmForNotification(c);
//Notify user of alarm
Toast.makeText(this, "Notification set for: "+ day +"-"+ (month+1), 5);
//Create new database entry
DatabaseCustom entry = new DatabaseCustom(ProductsAdd.this);
entry.open();
entry.createEntry(name, amount, unit, date);
entry.close();
Log.d("WTF", "ProductsAdd: Save product in database successfull");
} catch(Exception e){
e.printStackTrace();
Log.d("WTF", "ProductsAdd error: Failed to save product in database: " + e);
}
//Go to product list
Intent sOpenProducts = new Intent(ProductsAdd.this,
Products.class);
startActivity(sOpenProducts);
finish();
break;
case R.id.bCancel:
Log.d("WTF", "ProductsAdd: Cancel button pressed");
Intent cOpenProducts = new Intent(ProductsAdd.this,
Products.class);
startActivity(cOpenProducts);
finish();
break;
}
}
private void initiate(){
//Link java variables to the corresponding xml elements
bSave = (Button)findViewById(R.id.bSave);
bCancel = (Button)findViewById(R.id.bCancel);
etName = (EditText)findViewById(R.id.etName);
etAmount = (EditText)findViewById(R.id.etAmount);
etDate = (EditText)findViewById(R.id.etDate);
sUnit = (Spinner)findViewById(R.id.sUnit);
//Set button OnClickListeners
bSave.setOnClickListener(this);
bCancel.setOnClickListener(this);
}
}
ScheduleClient类：
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() {
Log.d("WTF", "ScheduleClient: service bound");
// 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.
Log.d("WTF", "ScheduleClient: service connected");
mBoundService = ((ScheduleService.ServiceBinder) service).getService();
}
public void onServiceDisconnected(ComponentName className) {
mBoundService = null;
Log.d("WTF", "ScheduleClient: service disconnected");
}
};
/**
* 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);
Log.d("WTF", "ScheduleClient: alarm set");
}
/**
* 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;
Log.d("WTF", "ScheduleClient: service unbound");
}
}
}
如果需要，我可以添加ScheduleClient类使用的ScheduleService，AlarmTask和NotifyService！