我希望有一个特定的方法运行并重复自己,只要某个手指按下按钮就可以了。当手指不在按钮上时,我希望该方法停止重复
有没有办法检查在方法实现过程中是否仍然发生touchDown?救命啊!
答案 0 :(得分:13)
您可以使用UIControlEventTouchDown
控件事件来启动方法运行,使用UIControlEventTouchUpInside
或类似事件来检测按钮何时不再被“按下”。
设置按钮的操作,例如:
[myButton addTarget:self action:@selector(startButtonTouch:) forControlEvents:UIControlEventTouchDown];
[myButton addTarget:self action:@selector(endButtonTouch:) forControlEvents:UIControlEventTouchUpInside | UIControlEventTouchUpOutside];
(注意以上内容会导致按钮内外触摸以调用endButtonTouch:
方法。)
然后添加startButtonTouch:
和endButtonTouch
方法,例如:
- (void)startButtonTouch:(id)sender {
// start the process running...
}
- (void)endButtonTouch:(id)sender {
// stop the running process...
}
答案 1 :(得分:0)
借助鲍勃的答案,这是一个帮助者的观点
#import <UIKit/UIKit.h>
@interface YOIDCAutorepeatingButton : UIButton
// you COULD pinch pennies switching to nonatomic, but consider
// how much time it would take to debug if some day some moron decides without checking this spec
// to alter this prop off another thread
@property (atomic) NSTimeInterval delayUntilAutorepeatBegins;
@property NSTimeInterval delayBetweenPresses;
@property (weak) id<NSObject> recipient;
@property SEL touchActionOnRecipient;
@end
-------------&GT; .M
#import "YOIDCAutorepeatingButton.h"
@interface YOIDCAutorepeatingButton()
{
NSTimeInterval _pressStartedAt;
}
@end
@implementation YOIDCAutorepeatingButton
- (id)initWithCoder:(NSCoder *)aDecoder
{
self = [super initWithCoder:aDecoder];
if (self) {
[self addTarget:self action:@selector(startButtonTouch:) forControlEvents:UIControlEventTouchDown];
[self addTarget:self action:@selector(endButtonTouch:) forControlEvents:UIControlEventTouchUpInside | UIControlEventTouchUpOutside];
self.delayUntilAutorepeatBegins = .250;
self.delayBetweenPresses = .080;
}
return self;
}
-(void)killLastCharacter:(id)sender
{
[self.recipient performSelector:self.touchActionOnRecipient withObject:sender];
}
- (void)performAutorepeat:(id)sender
{
if(!self.delayBetweenPresses) {
// bail
return;
}
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(self.delayBetweenPresses * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
if(_pressStartedAt) {
[self killLastCharacter:sender];
[self performAutorepeat:sender];
}
});
}
- (void)startButtonTouch:(id)sender {
[self killLastCharacter:sender];
NSTimeInterval now = [NSDate timeIntervalSinceReferenceDate];
_pressStartedAt = now;
dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(self.delayUntilAutorepeatBegins * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
if(_pressStartedAt) {
[self killLastCharacter:sender];
[self performAutorepeat:sender];
}
});
}
- (void)endButtonTouch:(id)sender {
_pressStartedAt = 0;
}
@end
--------样本用法-------
- (IBAction)killLastDigit:(id)sender {
.....
- (void)viewDidLoad
{
assert(self.backSpace);
[YOIDCAutorepeatingButton class]; // if xib is in a bundle other than main gottal load the class
// otherwise you'd get -[UIButton setRecipient:]: unrecognized selector sent to instance
// on setRecipient:
self.backSpace.recipient = self;
self.backSpace.touchActionOnRecipient = @selector(killLastDigit:);