For IOS, you can cancel the function execution delay. PerformSelector and cancelPreviousPerformReque

Print? <PRE class = plain name = "code"> @ interface NSObject (NSDelayedPerforming)
 
-(Void) specify mselector :( SEL) aSelector withObject :( id) anArgument afterDelay :( NSTimeInterval) delay inModes :( NSArray *) modes;
-(Void) specify mselector :( SEL) aSelector withObject :( id) anArgument afterDelay :( NSTimeInterval) delay;
+ (Void) cancelPreviousPerformRequestsWithTarget :( id) aTarget selector :( SEL) aSelector object :( id) anArgument;
+ (Void) cancelPreviousPerformRequestsWithTarget :( id) aTarget;
 
@ End </PRE> <BR>
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<PRE> </PRE>
<PRE class = cpp name = "code"> </PRE> <PRE class = cpp name = "code" sizcache = "1" sizset = "5"> cancelPreviousPerformRequestsWithTarget cannot cancel <PRE class = cpp name = "code">-(void) with Parameters) when mselector :( SEL) aSelector withObject :( id) anArgument afterDelay :( NSTimeInterval) delay; </PRE>, I wrote a bit of code to debug it and found that if there is a parameter, the cancellation parameters must be the same; otherwise, the cancellation cannot be successful.
<PRE> </PRE>
<PRE class = cpp name = "code"> </PRE> <PRE class = cpp name = "code"> Start delayed execution: </PRE> <PRE class = cpp name = "code"> [self defined mselector: @ selector (didRuninCurrModel :) withObject: [NSNumber numberWithBool: YES] afterDelay: 3.0f];

[Self defined mselector: @ selector (didRuninCurrModelNoArgument) withObject: nil afterDelay: 3.0f]; </PRE>
<P> <BR>
</P>
<P> If the following cancellation method is executed within three seconds, the result is: </P>
<P> </P>
<PRE class = cpp name = "code"> [NSObject cancelPreviousPerformRequestsWithTarget: self selector: @ selector (didRuninCurrModel :) object: [NSNumber numberWithBool: YES]; // YES.

[NSObject cancelPreviousPerformRequestsWithTarget: self selector: @ selector (didRuninCurrModel :) object: [NSNumber numberWithBool: NO]; // you cannot cancel the operation. Parameter Mismatch

[NSObject cancelPreviousPerformRequestsWithTarget: self selector: @ selector (didRuninCurrModel :) object: nil]; // The task cannot be canceled successfully. Parameter Mismatch

[NSObject cancelPreviousPerformRequestsWithTarget: self selector: @ selector (didRuninCurrModelNoArgument) object: nil]; // cancel

[NSObject cancelPreviousPerformRequestsWithTarget: self]; // you can successfully cancel all tasks.
[[Self class] cancelPreviousPerformRequestsWithTarget: self]; // you can successfully cancel all tasks. </PRE>
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[Plain]
@ Interface NSObject (callback)-(void) specify mselector :( SEL) aSelector withObject :( id) anArgument afterDelay :( partial) delay inModes :( NSArray *) modes;-(void) specify mselector :( SEL) aSelector withObject :( id) anArgument afterDelay :( NSTimeInterval) delay; + (void) identifier :( id) aTarget selector :( SEL) aSelector object :( id) anArgument; + (void) identifier :( id) aTarget; @ end @ interface NSObject (NSDelayedPerforming)

-(Void) specify mselector :( SEL) aSelector withObject :( id) anArgument afterDelay :( NSTimeInterval) delay inModes :( NSArray *) modes;
-(Void) specify mselector :( SEL) aSelector withObject :( id) anArgument afterDelay :( NSTimeInterval) delay;
+ (Void) cancelPreviousPerformRequestsWithTarget :( id) aTarget selector :( SEL) aSelector object :( id) anArgument;
+ (Void) cancelPreviousPerformRequestsWithTarget :( id) aTarget;

@ End

[Cpp]
[Cpp]
Recently, we have seen that the callback parameter <PRE class = cpp name = "code">-(void) callback mselector :( SEL) aSelector withObject :( id) anArgument afterDelay :( NSTimeInterval) cannot be canceled) delay; </PRE>: A bit of code has been written for debugging. If a parameter is included, the parameters for cancellation must be consistent. Otherwise, the cancellation cannot be successful. <PRE> </PRE> <PRE class = cpp name = "code"> </PRE> <PRE class = cpp name = "code"> Start delayed execution: </PRE> <PRE class = cpp name = "code"> [self defined mselector: @ selector (didRuninCurrModel :) withObject: [NSNumber numberWithBool: YES] afterDelay: 3.0f]; [self defined mselector: @ selector (didRuninCurrModelNoArgument) withObject: nil afterDelay: 3.0f]; </PRE> <P> <BR> </P> <P> If the following cancellation method is executed within three seconds, the result is: </P> <PRE class = cpp name = "code"> [NSObject cancelPreviousPerformRequestsWithTarget: self selector: @ selector (didRuninCurrModel :) object: [NSNumber numberWithBool: YES]; // you can cancel the operation. [NSObject cancelPreviousPerformRequestsWithTarget: self selector: @ selector (didRuninCurrModel :) object: [NSNumber numberWithBool: NO]; // you cannot cancel the operation. The parameter does not match [NSObject cancelPreviousPerformRequestsWithTarget: self selector: @ selector (didRuninCurrModel :) object: nil]; // cannot be canceled successfully. The parameter does not match [NSObject failed: self selector: @ selector (didRuninCurrModelNoArgument) object: nil]; // you can successfully cancel [NSObject failed: self]; // you can successfully cancel all tasks. [[Self class] cancelPreviousPerformRequestsWithTarget: self]; // you can successfully cancel all tasks. </PRE> <P> </P> <BR> <P> <BR> </P> <PRE> </PRE> recently, we have seen that cancelPreviousPerformRequestsWithTarget cannot cancel [cpp] view plaincopyprint with parameters? -(Void) specify mselector :( SEL) aSelector withObject :( id) anArgument provided :( partial) delay;-(void) specify mselector :( SEL) aSelector withObject :( id) anArgument afterDelay :( partial) delay; in this case, I wrote a bit of code and debugged it. I found that if a parameter is included, the parameters to be canceled must be the same; otherwise, the cancellation cannot be successful.

[Cpp]
[Cpp]
Start delayed execution:
[Cpp]
[Self defined mselector: @ selector (optional :) withObject: [NSNumber numberWithBool: YES] afterDelay: 3.0f]; [self defined mselector: @ selector (optional) withObject: nil afterDelay: 3.0f]; [self defined mselector: @ selector (didRuninCurrModel :) withObject: [NSNumber numberWithBool: YES] afterDelay: 3.0f];

[Self defined mselector: @ selector (didRuninCurrModelNoArgument) withObject: nil afterDelay: 3.0f];

If the following cancellation method is executed within three seconds, the result is:

[Cpp] [NSObject cancelPreviousPerformRequestsWithTarget: self selector: @ selector (didRuninCurrModel :) object: [NSNumber numberWithBool: YES]; // The cancellation is successful. [NSObject cancelPreviousPerformRequestsWithTarget: self selector: @ selector (didRuninCurrModel :) object: [NSNumber numberWithBool: NO]; // you cannot cancel the operation. The parameter does not match [NSObject cancelPreviousPerformRequestsWithTarget: self selector: @ selector (didRuninCurrModel :) object: nil]; // cannot be canceled successfully. The parameter does not match [NSObject failed: self selector: @ selector (didRuninCurrModelNoArgument) object: nil]; // you can successfully cancel [NSObject failed: self]; // you can successfully cancel all tasks. [[Self class] cancelPreviousPerformRequestsWithTarget: self]; // you can successfully cancel all tasks. [NSObject cancelPreviousPerformRequestsWithTarget: self selector: @ selector (didRuninCurrModel :) object: [NSNumber numberWithBool: YES]; // the task can be canceled successfully.

[NSObject cancelPreviousPerformRequestsWithTarget: self selector: @ selector (didRuninCurrModel :) object: [NSNumber numberWithBool: NO]; // you cannot cancel the operation. Parameter Mismatch

[NSObject cancelPreviousPerformRequestsWithTarget: self selector: @ selector (didRuninCurrModel :) object: nil]; // The task cannot be canceled successfully. Parameter Mismatch

[NSObject cancelPreviousPerformRequestsWithTarget: self selector: @ selector (didRuninCurrModelNoArgument) object: nil]; // cancel

[NSObject cancelPreviousPerformRequestsWithTarget: self]; // you can successfully cancel all tasks.
[[Self class] cancelPreviousPerformRequestsWithTarget: self]; // you can successfully cancel all tasks.