我环顾四周，但在互联网上找不到这个，也没有找到Apple文档中的任何地方，所以我猜它不存在。
但是有一个iOS4块等效API来：
[button addTarget:self action:@selector(tappy:) forControlEvents:UIControlEventTouchUpInside];
我想这可以使用一个类别来实现，但是由于极端的懒惰而宁愿不写这个:)
像这样的东西会很棒：
[button handleControlEvent:UIControlEventTouchUpInside withBlock:^ { NSLog(@"I was tapped!"); }];
我刚刚实现了这个。它的工作就像一个魅力！
它甚至都不难。
typedef void (^ActionBlock)();
@interface UIBlockButton : UIButton {
ActionBlock _actionBlock;
}
-(void) handleControlEvent:(UIControlEvents)event
withBlock:(ActionBlock) action;
@end
@implementation UIBlockButton
-(void) handleControlEvent:(UIControlEvents)event
withBlock:(ActionBlock) action
{
_actionBlock = action;
[self addTarget:self action:@selector(callActionBlock:) forControlEvents:event];
}
-(void) callActionBlock:(id)sender{
_actionBlock();
}
@end
常见的Foundation / UI类增加了一个块库：BlocksKit。这是documentation。
它不是UIButton的子类，但添加了UIControl category：
[button addEventHandler:^(id sender) {
//do something
} forControlEvents:UIControlEventTouchUpInside];
集合（地图，过滤器等），视图相关的东西等也有块/功能添加。
注意：它与Swift不兼容。
这是一个工作类别实现。在它的当前形式中，这应该仅用于DEBUG。当用户交互和时间很重要时，我将此类与功能（包含在下面）一起用于测试各种代码。同样，这仅用于开发/调试目的，不应考虑用于生产，因此#ifdef DEBUG;）
#ifdef DEBUG
#import <objc/runtime.h>
static char UIButtonBlockKey;
@interface UIButton (UIBlockButton)
- (void)handleControlEvent:(UIControlEvents)event withBlock:(ActionBlock)block;
- (void)callActionBlock:(id)sender;
@end
@implementation UIButton (UIBlockButton)
- (void)handleControlEvent:(UIControlEvents)event withBlock:(ActionBlock)block {
objc_setAssociatedObject(self, &UIButtonBlockKey, block, OBJC_ASSOCIATION_COPY_NONATOMIC);
[self addTarget:self action:@selector(callActionBlock:) forControlEvents:event];
}
- (void)callActionBlock:(id)sender {
ActionBlock block = (ActionBlock)objc_getAssociatedObject(self, &UIButtonBlockKey);
if (block) {
block();
}
}
@end
void DSAddGlobalButton(NSString *title, ActionBlock block) {
UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[button setTitle:title forState:UIControlStateNormal];
[button handleControlEvent:UIControlEventTouchUpInside withBlock:block];
[button sizeToFit];
[button setFrame:(CGRect){{100.0f, 100.0f}, [button frame].size}];
UIView *firstView = [[[[UIApplication sharedApplication] keyWindow] subviews] objectAtIndex:0];
[firstView addSubview:button];
}
#endif
我创建了一个库来做这个！
它支持UIControl（UIButton），UIBarButtonItem和UIGestureRecognizer。它也支持使用CocoaPods。
https://github.com/lavoy/ALActionBlocks
// Assuming you have a UIButton named 'button'
[button handleControlEvents:UIControlEventTouchUpInside withBlock:^(id weakControl) {
NSLog(@"button pressed");
}];
安装
pod 'ALActionBlocks'
斯威夫特4
这是快速的解决方案
class ClosureSleeve {
let closure: () -> ()
init(attachTo: AnyObject, closure: @escaping () -> ()) {
self.closure = closure
objc_setAssociatedObject(attachTo, "[\(arc4random())]", self, .OBJC_ASSOCIATION_RETAIN)
}
@objc func invoke() {
closure()
}
}
extension UIControl {
func addAction(for controlEvents: UIControlEvents = .primaryActionTriggered, action: @escaping () -> ()) {
let sleeve = ClosureSleeve(attachTo: self, closure: action)
addTarget(sleeve, action: #selector(ClosureSleeve.invoke), for: controlEvents)
}
}
用法示例：
button.addAction {
print("button pressed")
}
我把这个问题彻底解决了，而不是解决这个问题的方法！对UIButton进行子类化会创建一个不值得的雷区。使用Shayne Sweeney的分类（我刚刚通过一系列调整更新了他的答案，以使他的示例生产准备就绪......希望他们能够快速获得批准）。
----- ORIG POST -----
如果您只分配UIControlEventTouchUpInside，那么Martin发布的代码应该可以工作......但是有一些问题：
在我的代码中，我依赖于块被视为object-c对象，它只适用于iOS4 +（而不是3.2）。当我想为按钮状态（即动画）做一些特殊的事情时，它对我很有用。您可以使用clickedButton块来处理正常点击。
#import <UIKit/UIKit.h>
@interface ButtWithBlockActions : UIButton {
void (^downBlock_)(void);
void (^upBlock_)(void);
void (^clickedBlock_)(void);
}
@property(nonatomic,retain) void (^downBlock)(void);
@property(nonatomic,retain) void (^upBlock)(void);
@property(nonatomic,retain) void (^clickedBlock)(void);
@end
#import "ButtWithBlockActions.h"
@implementation ButtWithBlockActions
- (void)dealloc {
[downBlock_ release];
[upBlock_ release];
[clickedBlock_ release];
[super dealloc];
}
- (void (^)(void))downBlock { return downBlock_; }
- (void) fireDownBlock { downBlock_(); }
- (void) setDownBlock:(void (^)(void))block {
if(downBlock_) {
[self removeTarget:self action:@selector(fireDownBlock) forControlEvents:UIControlEventTouchDown];
[self removeTarget:self action:@selector(fireDownBlock) forControlEvents:UIControlEventTouchDragEnter];
[downBlock_ release];
}
downBlock_ = [block copy];
if(downBlock_) {
[self addTarget:self action:@selector(fireDownBlock) forControlEvents:UIControlEventTouchDown];
[self addTarget:self action:@selector(fireDownBlock) forControlEvents:UIControlEventTouchDragEnter];
}
}
- (void (^)(void))upBlock { return upBlock_; }
- (void) fireUpBlock { upBlock_(); }
- (void) setUpBlock:(void (^)(void))block {
if(upBlock_) {
[self removeTarget:self action:@selector(fireUpBlock) forControlEvents:UIControlEventTouchUpInside];
[self removeTarget:self action:@selector(fireUpBlock) forControlEvents:UIControlEventTouchUpOutside];
[self removeTarget:self action:@selector(fireUpBlock) forControlEvents:UIControlEventTouchDragOutside];
[self removeTarget:self action:@selector(fireUpBlock) forControlEvents:UIControlEventTouchCancel];
[upBlock_ release];
}
upBlock_ = [block copy];
if(upBlock_) {
[self addTarget:self action:@selector(fireUpBlock) forControlEvents:UIControlEventTouchUpInside];
[self addTarget:self action:@selector(fireUpBlock) forControlEvents:UIControlEventTouchUpOutside];
[self addTarget:self action:@selector(fireUpBlock) forControlEvents:UIControlEventTouchDragOutside];
[self addTarget:self action:@selector(fireUpBlock) forControlEvents:UIControlEventTouchCancel];
}
}
- (void (^)(void))clickedBlock { return clickedBlock_; }
- (void) fireClickedBlock { clickedBlock_(); }
- (void) setClickedBlock:(void (^)(void))block {
if(clickedBlock_) {
[self removeTarget:self action:@selector(fireClickedBlock) forControlEvents:UIControlEventTouchUpInside];
[clickedBlock_ release];
}
clickedBlock_ = [block copy];
if(clickedBlock_) {
[self addTarget:self action:@selector(fireClickedBlock) forControlEvents:UIControlEventTouchUpInside];
}
}
@end
有REKit带来阻止潜在的能力。它使您能够使用Block向实例添加/覆盖方法。
使用REKit，您可以动态创建一个目标 - 响应buttonAction - 如下所示：
id target;
target = [[NSObject alloc] init];
[target respondsToSelector:@selector(buttonAction) withKey:nil usingBlock:^(id receiver) {
// Do something…
}];
[button addTarget:target action:@selector(buttonAction) forControlEvents:UIControlEventTouchUpInside];
您不需要创建子类或类别。
除了目标/操作范例之外，您还可以使用REKit进行委派模式。
我发现使用一个小帮手类很容易和多才多艺：
@interface Handler : NSObject
@end
@implementation Handler {
void (^block)(id);
}
+ (Handler *)create:(void (^)(id))block {
Handler *result = [[Handler alloc] init];
result->block = block;
return result;
}
- (void)call:(id)sender {
block(sender);
}
@end
并像这样使用它：
Handler *handler = [Handler create:^(id sender) {
// ... handle the event, using local state captured by the block ...
}];
// store the handler because the target is not retained in addTarget
[handlers addObject:handler];
[button addTarget:handler action:@selector(call:) forControlEvents:UIControlEventTouchUpInside];
我掀起的Swift扩展/基于类别的实现。使用OBJC关联对象不是反模式。 ：P
import UIKit
// MARK: UIControl Block based actions
typealias ActionBlock = (UIControl) -> ()
class UIButtonActionDelegate : NSObject {
let actionBlock : ActionBlock
init(actionBlock: ActionBlock) {
self.actionBlock = actionBlock
}
func triggerBlock(control : UIControl) {
actionBlock(control)
}
}
private var actionHandlersKey: UInt8 = 0
extension UIControl {
var actionHandlers: NSMutableArray { // cat is *effectively* a stored property
get {
return associatedObject(self, key: &actionHandlersKey, initialiser: { () -> NSMutableArray in
return NSMutableArray()
})
}
set { associateObject(self, key: &actionHandlersKey, value: newValue) }
}
func addBlockForEvents(events: UIControlEvents, block: ActionBlock) {
let actionDelegate = UIButtonActionDelegate(actionBlock: block)
actionHandlers.addObject(actionDelegate) // So it gets retained
addTarget(actionDelegate, action: #selector(UIButtonActionDelegate.triggerBlock(_:)), forControlEvents: events)
}
}
// MARK: Associated Object wrapper
func associatedObject<ValueType: AnyObject>(
base: AnyObject,
key: UnsafePointer<UInt8>,
initialiser: () -> ValueType)
-> ValueType {
if let associated = objc_getAssociatedObject(base, key)
as? ValueType { return associated }
let associated = initialiser()
objc_setAssociatedObject(base, key, associated,
.OBJC_ASSOCIATION_RETAIN)
return associated
}
func associateObject<ValueType: AnyObject>(
base: AnyObject,
key: UnsafePointer<UInt8>,
value: ValueType) {
objc_setAssociatedObject(base, key, value,
.OBJC_ASSOCIATION_RETAIN)
}