NSRunLoop cancelPerformSelectorsWithTarget 不起作用
我有以下代码,但没有得到我预期的结果。
#import "CancelPerformSelectorTestAppDelegate.h"
@implementation CancelPerformSelectorTestAppDelegate
@synthesize window;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
[window makeKeyAndVisible];
for(unsigned int i = 0; i < 10; i++){
NSTimeInterval waitThisLong = i;
[self performSelector:@selector(foo) withObject:nil afterDelay: waitThisLong];
}
[[NSRunLoop currentRunLoop] cancelPerformSelectorsWithTarget: self];
return YES;
}
- (void) foo {
static unsigned int timesCalled = 0;
++timesCalled;
NSLog(@"%s: I am called for the %d-st/nd/th time", __func__, timesCalled);
}
- (void)applicationWillResignActive:(UIApplication *)application {}
- (void)applicationDidBecomeActive:(UIApplication *)application {}
- (void)applicationWillTerminate:(UIApplication *)application {}
- (void)applicationDidReceiveMemoryWarning:(UIApplication *)application {}
- (void)dealloc {
[window release];
[super dealloc];
}
@end
我预计该函数将被调用大约 0 次,如果 CPU 运行缓慢,则可能调用 1 次。
该函数将执行 10 次! :( 总是。我做错了什么,我怎样才能达到我预期的结果?
预先感谢,非常感谢, 缺口
I have this following code and I am not getting the results I expected.
#import "CancelPerformSelectorTestAppDelegate.h"
@implementation CancelPerformSelectorTestAppDelegate
@synthesize window;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
[window makeKeyAndVisible];
for(unsigned int i = 0; i < 10; i++){
NSTimeInterval waitThisLong = i;
[self performSelector:@selector(foo) withObject:nil afterDelay: waitThisLong];
}
[[NSRunLoop currentRunLoop] cancelPerformSelectorsWithTarget: self];
return YES;
}
- (void) foo {
static unsigned int timesCalled = 0;
++timesCalled;
NSLog(@"%s: I am called for the %d-st/nd/th time", __func__, timesCalled);
}
- (void)applicationWillResignActive:(UIApplication *)application {}
- (void)applicationDidBecomeActive:(UIApplication *)application {}
- (void)applicationWillTerminate:(UIApplication *)application {}
- (void)applicationDidReceiveMemoryWarning:(UIApplication *)application {}
- (void)dealloc {
[window release];
[super dealloc];
}
@end
I expected the function to be called about 0 times, perhaps 1 if the CPU is having a slow day.
The function will execute 10 times! :( Always. What am I doing wrong, and how could I achieve the results I expected?
Thanks in advance, a lot,
Nick
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您想要使用 NSObject 类方法 +cancelPreviousPerformRequestsWithTarget:
例如,
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For example,
There's an example in the "handling tap gestures" section of the Event Handling Guide for multitouch events
你想要这个:
You want this: