How to fix this error ?
Error: error: expected ')' before 'postData'
NSTimer *timer;
timer = [NSTimer scheduledTimerWithTimeInterval:10.0 target:self
selector: #selector(postData:#"xyz")
userInfo:nil
repeats: YES];
Functions called as selectors from timers cannot have parameters. If I remember correctly, you can use userInfo, which passes an array or dictionary to the selector.
do something like this:
NSTimer *timer;
timer = [NSTimer scheduledTimerWithTimeInterval:10.0
target:self
selector: #selector(postData:)
userInfo:#"xyz"
repeats: YES];
- (void)postData:(NSTimer*)timer {
NSLog(#"userInfo = %#", timer.userInfo);
}
When we read the documentation of the method you are using, it seems it's not correctly called :
timer = [NSTimer scheduledTimerWithTimeInterval:10.0
target:self
selector:#selector(postData:)
userInfo:nil
repeats:YES];
And your postData must have the following signature :
- (void)postData:(NSTimer*)theTimer
Related
Why NSTimer sends positions every 5 seconds instead of every 60?
- (void)startTimer {
self.timer = [NSTimer scheduledTimerWithTimeInterval:60.0
target:self
selector:#selector(sendPosition)
userInfo:nil
repeats:YES];
}
- (void)stopTimer {
if(self.timer){
[self.timer invalidate];
self.timer = nil;
}
}
I suspect that there are multiple timers created due to multiple firing of startTimer function. To ensure that there is only one instance of such timer, you can implement the following.
- (void)startTimer {
// stop and remove timer first if it is already there
if(self.timer){
[self.timer invalidate];
self.timer = nil;
}
self.timer = [NSTimer scheduledTimerWithTimeInterval:60.0
target:self
selector:#selector(sendPosition)
userInfo:nil
repeats:YES];
}
This way, no matter how many times the startTimer was called,there is only one instance of it.
I'm trying to stop my NSTimer (no repeats) immediately but i can't.
my NSTimer do the following code:
-(void)timerAction:(NSTimer*)timer{
dispatch_queue_t serverDelaySimulationThread = dispatch_queue_create("com.xxx.serverDelay", nil);
dispatch_async(serverDelaySimulationThread, ^{
[NSThread sleepForTimeInterval:2.0];
dispatch_async(dispatch_get_main_queue(), ^{
//CALL WEBSERVICE RESPONSE IN HERE
});
});
}
Each time textField Did Change, i will invalidate NSTimer and recreate NSTimer!! All i want to execute a request to WEBSERVICES if the Delay time between 2 times user typing characters bigger than 2s. My code is following
-(void) textFieldDidChange:(id)sender{
[MyTimer invalidate];
MyTimer = nil;
MyTimer = [NSTimer scheduledTimerWithTimeInterval:0 target:self selector:#selector(timerAction:) userInfo:nil repeats:NO];
}
But, when i quickly type "ABCD" -> 2s after that, 4 webservices was called.
How can i stop NSTimer while it unfinished
Tks for advance!
-(BOOL) textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
[myTimer invalidate];
myTimer = nil;
myTimer = [NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:#selector(timerFired) userInfo:nil repeats:NO];
return YES;
}
This worked for me.
Your timer timeInterval is set to 0. So each time you type your timer fires. Change your code to look like this
MyTimer = [NSTimer scheduledTimerWithTimeInterval:2.0
target:self selector:#selector(timerAction:) userInfo:nil repeats:NO];
And it should work :)
The problem is you are implementing textdidchange delegate. So how many times you type text. It will get called. SO inside that you have written four letters. So definitely your NSTimer is calling four times your web service. I would suggest better to use - (void)controlTextDidEndEditing:(NSNotification *)aNotification So that whenever you enter or tabb out your webservice will called.
I'm trying to write my own fade-ins and fade-outs using the AVAudioPlayer as a helper.
My problem is this: I have two method definitions with the same name, but one takes an int and the other takes no parameters. Is there a way for me to tell NSTimer which one to call? Couldn't really make sense of the documentation:
https://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/nstimer_Class/Reference/NSTimer.html
-(void) stopWithFadeOut
{
if (_player.volume > 0.1) {
[self adjustVolume:-.1];
[NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:#selector(stopWithFadeOut) userInfo:NULL repeats:NO];
}
else {
[self stop];
}
}
and
-(void) stopWithFadeOut:(NSString *)speed
{
int incr = [speed intValue];
if (_player.volume > 0.1) {
[self adjustVolume:-incr];
[NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:#selector(stopWithFadeOut) userInfo:NULL repeats:NO];
}
else {
[self stop];
}
}
Those actually have different names. The colon is significant, so the name (and hence the argument to #selector()) of the second method is stopWithFadeOut:.*
To create the timer, then, you want:
[NSTimer scheduledTimerWithTimeInterval:0.1
target:self
selector:#selector(stopWithFadeOut:)
userInfo:NULL //^ Note! Colon!
repeats:NO];
However, this method is incorrect, because an NSTimer passes itself to its action method; it's not possible for you to pass in an arbitrary object. This is what the userInfo: parameter is for. You can sort of attach some object to the timer, and retrieve it inside the action method using the userInfo method, like so:
- (void)stopWithFadeOut: (NSTimer *)tim
{
NSString * speed = [tim userInfo];
int incr = [speed intValue];
if (_player.volume > 0.1) {
[self adjustVolume:-incr];
[NSTimer scheduledTimerWithTimeInterval:0.1
target:self
selector:#selector(stopWithFadeOut:)
userInfo:speed
repeats:NO];
}
(Also note that this means your first method isn't really a correct NSTimer action method, because it doesn't have the NSTimer parameter.)
*The compiler wouldn't have let you declare or define two methods with the same name in one class, and the parameter type doesn't count as part of the selector, so trying to create -(void)dumblethwaite:(int)circumstance; and -(void)dumblethwaite:(NSString *)jinxopotamus; in one class doesn't work.
So this is what I came up with. Thanks Josh.
-(void) pauseWithFadeOut
{
NSNumber *incr = [[NSNumber alloc] initWithFloat:0.1];
while (_player.volume > 0.1) {
[NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:#selector(fadeOut) userInfo:incr repeats:NO];
}
}
-(void)fadeOut: (NSTimer*) deleg
{
int incr = (int) [deleg userInfo];
if (_player.volume > 0.1) {
[self adjustVolume:-incr];
}
}
-(void) pauseWithFadeOut:(NSString *)speed
{
NSNumber *incr = [[NSNumber alloc] initWithFloat:[speed floatValue]];
while (_player.volume > 0.1) {
[NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:#selector(fadeOut) userInfo:incr repeats:NO];
}
[self pause];
}
-(void) stopWithFadeOut
{
NSNumber *incr = [[NSNumber alloc] initWithFloat:0.1];
while (_player.volume > 0.1) {
[NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:#selector(fadeOut) userInfo:incr repeats:NO];
}
}
-(void) stopWithFadeOut:(NSString *)speed
{
NSNumber *incr = [[NSNumber alloc] initWithFloat:[speed floatValue]];
while (_player.volume > 0.1) {
[NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:#selector(fadeOut) userInfo:incr repeats:NO];
}
[self stop];
}
can I pass a method as an argument?
I don't succeed to pass the method targetOpenView in the example below:
-(void) targetTimeView:(id)sender {
[self TimeViewWithtimeInterval:.6 selector:targetOpenView]; //targetOpenView does NOT work
}
-(void) timeViewWithtimeInterval:(float)interval selector:openViewMethod{
[NSTimer scheduledTimerWithTimeInterval:interval target:self selector:#selector(openViewMethod) userInfo:nil repeats:NO];
}
Any suggestions how I could make this work? Thanks!
You need the #selector compiler directive to extract the select from a method name, like you did when creating the timer:
[self TimeViewWithtimeInterval:.6 selector:#selector(targetOpenView)];
And define your argument to the type SEL:
-(void) TimeViewWithtimeInterval:(float)interval selector:(SEL)openViewMethod
{
...
}
Then, when passing the argument to the NSTimer method you can leave off the #selector since the type is already a selector:
[NSTimer scheduledTimerWithTimeInterval:interval target:self
selector:#selector(openViewMethod) /* here */
userInfo:nil repeats:NO];
[NSTimer scheduledTimerWithTimeInterval:interval target:self
selector:openViewMethod /* pass it directly */
userInfo:nil repeats:NO];
I have a timer calling a method but this method takes one paramether:
theTimer = [NSTimer scheduledTimerWithTimeInterval:animationInterval target:self selector:#selector(timer) userInfo:nil repeats:YES];
should be
theTimer = [NSTimer scheduledTimerWithTimeInterval:animationInterval target:self selector:#selector(timer:game) userInfo:nil repeats:YES];
now this syntax doesn't seems to be right. I tried with NSInvocation but I got some problems:
timerInvocation = [NSInvocation invocationWithMethodSignature:
[self methodSignatureForSelector:#selector(timer:game)]];
theTimer = [NSTimer scheduledTimerWithTimeInterval:animationInterval
invocation:timerInvocation
repeats:YES];
How should I use Invocation?
Given this definition:
- (void)timerFired:(NSTimer *)timer
{
...
}
You then need to use #selector(timerFired:) (that's the method name without any spaces or argument names, but including the colons). The object you want to pass (game ?) is passed via the userInfo: part:
theTimer = [NSTimer scheduledTimerWithTimeInterval:animationInterval
target:self
selector:#selector(timerFired:)
userInfo:game
repeats:YES];
In your timer method, you can then access this object via the timer object's userInfo method:
- (void)timerFired:(NSTimer *)timer
{
Game *game = [timer userInfo];
...
}
As #DarkDust points out, NSTimer expects its target method to have a particular signature. If for some reason you can't conform to that, you can instead use an NSInvocation as you suggest, but in that case you need to fully initialise it with the selector, target and arguments. Eg:
timerInvocation = [NSInvocation invocationWithMethodSignature:
[self methodSignatureForSelector:#selector(methodWithArg1:and2:)]];
// configure invocation
[timerInvocation setSelector:#selector(methodWithArg1:and2:)];
[timerInvocation setTarget:self];
[timerInvocation setArgument:&arg1 atIndex:2]; // argument indexing is offset by 2 hidden args
[timerInvocation setArgument:&arg2 atIndex:3];
theTimer = [NSTimer scheduledTimerWithTimeInterval:animationInterval
invocation:timerInvocation
repeats:YES];
Calling invocationWithMethodSignature on its own doesn't do all that, it just creates an object that is able to be filled in in the right manner.
You can pass NSDictionary with named objects (like myParamName => myObject) through userInfo parameter like this
theTimer = [NSTimer scheduledTimerWithTimeInterval:animationInterval
target:self
selector:#selector(timer:)
userInfo:#{#"myParamName" : myObject}
repeats:YES];
Then in timer: method:
- (void)timer:(NSTimer *)timer {
id myObject = timer.userInfo[#"myParamName"];
...
}