Person *p = [Person new];// 调用对象p的test方法

[p performSelector:@selector(test)];[person performSelector:@selector(test2:) withObject:@"传入参数"];

Person类代码：#import "Person.h"
@implementation Person
- (void)test
{NSLog(@"无参数的对象方法");
}
- (void)test2:(NSString *)str
{NSLog(@"带有参数的方法%@",str);
}
@end

// 对一个数组array的每个元素执行一次test方法

[array makeObjectsPerformSelector:@selector(test)];[array makeObjectsPerformSelector:@selector(test)  withObject:@"aaa"];
//对一个数组array进行排序

[array sortedArrayUsingSelector:@selector(compare:)];

#import <UIKit/UIKit.h>@interface TapView : UIView
//目标
@property(weak,nonatomic)id target;
//行为
@property(assign,nonatomic)SEL action;//自定义方法
-(void)addCustomtarget:(id)target andAction:(SEL)action;@end

#import "TapView.h"@implementation TapView//自定义方法
-(void)addCustomtarget:(id)target andAction:(SEL)action{_action = action;_target = target;
}-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{//当视图点击的时候,target去执行action的方法并把自己传过去.//首先代理不能是空,而且代理(代理是对象!)的类中有方法并且能传出过来.if (nil != _target && [[_target class] instancesRespondToSelector:_action]) {[_target performSelector:_action withObject:self];}
}

#import <Foundation/Foundation.h>
#import <objc/runtime.h>
#import "Debug.h" // not given; just an assert

@interface NSObject (Extras)// Enforce the rule that the selector used must return void.
- (void) performVoidReturnSelector:(SEL)aSelector withObject:(id)object;
- (void) performVoidReturnSelector:(SEL)aSelector;@end@implementation NSObject (Extras)// Apparently the reason the regular performSelect gives a compile time warning is that the system doesn't know the return type. I'm going to (a) make sure that the return type is void, and (b) disable this warning
// See http://stackoverflow.com/questions/7017281/performselector-may-cause-a-leak-because-its-selector-is-unknown- (void) checkSelector:(SEL)aSelector {// See http://stackoverflow.com/questions/14602854/objective-c-is-there-a-way-to-check-a-selector-return-valueMethod m = class_getInstanceMethod([self class], aSelector);char type[128];method_getReturnType(m, type, sizeof(type));NSString *message = [[NSString alloc] initWithFormat:@"NSObject+Extras.performVoidReturnSelector: %@.%@ selector (type: %s)", [self class], NSStringFromSelector(aSelector), type];NSLog(@"%@", message);if (type[0] != 'v') {message = [[NSString alloc] initWithFormat:@"%@ was not void", message];[Debug assertTrue:FALSE withMessage:message];}
}- (void) performVoidReturnSelector:(SEL)aSelector withObject:(id)object {[self checkSelector:aSelector];#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Warc-performSelector-leaks"// Since the selector (aSelector) is returning void, it doesn't make sense to try to obtain the return result of performSelector. In fact, if we do, it crashes the app.[self performSelector: aSelector withObject: object];
#pragma clang diagnostic pop
}- (void) performVoidReturnSelector:(SEL)aSelector {[self checkSelector:aSelector];#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Warc-performSelector-leaks"[self performSelector: aSelector];
#pragma clang diagnostic pop
}@end

#import <UIKit/UIKit.h>@protocol TouchViewDelegate <NSObject>
-(void)changeViewColor:(UIColor *)color;
@end@interface TouchView : UIView
//声明一个代理,这个代理遵守TouchViewDelegate协议,
@property(nonatomic,assign)id<TouchViewDelegate> delegate;
@end

#import "TouchView.h"@implementation TouchView//我们还是用touchesBegandian
-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{if (nil != self.delegate && [self.delegate respondsToSelector:@selector(changeViewColor:)]) {//我们传一个颜色到我们的ViewController去.[self.delegate changeViewColor:[UIColor brownColor]];}
}@end

运用代码：#import "ViewController.h"
#import "TouchView.h"//在这里ViewController 要遵守协议....
@interface ViewController ()<TouchViewDelegate>@property(nonatomic,strong)TouchView *touchView;@end@implementation ViewController- (void)viewDidLoad {[super viewDidLoad];self.touchView = [[TouchView alloc]initWithFrame:CGRectMake(100, 100, 100, 100)];self.touchView.backgroundColor = [UIColor redColor];//指定touchView的代理为ViewController.即为本身~self.touchView.delegate =self;[self.view addSubview: self.touchView];
}-(void)changeViewColor:(UIColor *)color{//现在参数color是有值的,这是因为在TouchView那个页面传过来的.self.touchView.backgroundColor = color;
}
@end

#import <UIKit/UIKit.h>//给block改名成MyBlock
typedef void(^MyBlock)(NSString *);@interface OtherViewController : UIViewController//ARC:语义设置使用strong即可
@property(nonatomic,strong)MyBlock block;@end

#import "OtherViewController.h"@interface OtherViewController ()
@property(nonatomic,strong)UITextField *textField;
@end@implementation OtherViewController- (void)viewDidLoad {[super viewDidLoad];self.textField = [[UITextField alloc]initWithFrame:CGRectMake(0, 100, 414, 40)];self.textField.backgroundColor = [UIColor lightGrayColor];self.view.backgroundColor = [UIColor whiteColor];[self.view addSubview: self.textField];
}-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{self.block(_textField.text);[self.navigationController popViewControllerAnimated:YES];
}
@end

运用代码：OtherViewController *otherVC = [[OtherViewController alloc]init];__weak typeof(self)weak = self;//给block赋值~otherVC.block = ^(NSString *string){weak.label.text = string;};[self.navigationController pushViewController:otherVC animated:YES];

#pragma clang diagnostic push  #pragma clang diagnostic ignored "-Wdeprecated-declarations"
//会报警告的方法，比如SEL
[TestFlight setDeviceIdentifier:[[UIDevice currentDevice] uniqueIdentifier]];  #pragma clang diagnostic pop  

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wunused-variable"   int a;   #pragma clang diagnostic pop 

#import <UIKit/UIKit.h>
//六边形Button
@interface HexagonButton : UIView
NS_ASSUME_NONNULL_BEGINtypedef void (^HexagonButtonBlock)();@property (nonatomic, strong) UIBezierPath *path;
@property (nonatomic, strong) CAShapeLayer *maskLayer;
@property (nonatomic, strong) HexagonButtonBlock block; //点击事件//添加点击事件
NS_ASSUME_NONNULL_END
@end

#import "HexagonButton.h"@implementation HexagonButton
- (instancetype) initWithFrame:(CGRect)frame
{if ([super initWithFrame:frame]) {self.backgroundColor = [UIColor brownColor];self.userInteractionEnabled = YES;//添加单击手势UITapGestureRecognizer * tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(click:)];[self addGestureRecognizer:tap];}return self;
}
- (void) layoutSubviews
{[super layoutSubviews];CGFloat SIZE = self.frame.size.width;// step 1: 生成六边形路径CGFloat longSide = SIZE * 0.5 * cosf(M_PI * 30 / 180);CGFloat shortSide = SIZE * 0.5 * sin(M_PI * 30 / 180);CGFloat k = SIZE * 0.5 - longSide;  //路径整体下移，保证六边形路径位于图形中间
    _path = [UIBezierPath bezierPath];[_path moveToPoint:CGPointMake(0, longSide  + k)];[_path addLineToPoint:CGPointMake(shortSide, + k)];[_path addLineToPoint:CGPointMake(shortSide + shortSide + shortSide,  k)];[_path addLineToPoint:CGPointMake(SIZE, longSide + k)];[_path addLineToPoint:CGPointMake(shortSide * 3, longSide * 2 + k)];[_path addLineToPoint:CGPointMake(shortSide, longSide * 2 + k)];[_path closePath];// step 2: 根据路径生成蒙板_maskLayer = [CAShapeLayer layer];//    _maskLayer.position = self.center;_maskLayer.path = [_path CGPath];// step 3: 添加蒙版self.layer.mask = _maskLayer;self.backgroundColor = [UIColor orangeColor];
}//点击事件
- (void) click:(UITapGestureRecognizer *) tap
{if (_block) {_block();}
}
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {//如果点击的区域在所创建的路径范围内if (CGPathContainsPoint(_path.CGPath, NULL, point, NO)) {return [super hitTest:point withEvent:event];}return nil;
}@end

    //创建六变形按钮HexagonButton * hexagonButton = [[HexagonButton alloc] initWithFrame:CGRectMake(20, 20, 100, 100)];hexagonButton.center = self.view.center;hexagonButton.block = ^(){NSLog(@"六边形区域被点击");};[self.view addSubview:hexagonButton];

var controllerArr = self.navigationController?.viewControllers//获取Controller数组
controllerArr?.removeAll()//移除controllerArr中保存的历史路径//重新添加新的路径
controllerArr?.append(self.navigationController?.viewControllers[0])
controllerArr?.append(C)
controllerArr?.append(B)//这时历史路径为（root -> c -> b）//将组建好的新的跳转路径 set进self.navigationController里
self.navigationController?.setViewControllers(controllerArr!, animated: true)//直接写入，完成跳转B页面的同时修改了之前的跳转路径