方法

Extension methods: 

//取消单击事件（上次执行的请求）

+ (void)cancelPreviousPerformRequestsWithTarget:(id)aTarget selector:(SEL)aSelector object:(nullable id)anArgument;

[NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(singTap) object:nil];

 //延迟调用

- (void)performSelector:(SEL)aSelector withObject:(nullable id)anArgument afterDelay:(NSTimeInterval)delay;

[self performSelector:@selector(singTap) withObject:nil afterDelay:.5];

 //transform

CGAffineTransformMakeScale 在原来的基础上缩放

CGAffineTransformeScale 在自身的基础上缩放

//重写setFrame方法

//重写setFrame方法
-(void)setFrame:(CGRect)frame{
/*
 1、取出初始化的时候answerView的frame
 2、用传过来的frame中的origin来代替初始化的frame
 3、把最终的frame给answerView
 */
    CGRect frame1 = self.frame;
  
    frame1.origin = frame.origin;
    //不能直接写成 self.frame = frame,因为在setFrame方法中不能调用setFrame方法，父类的setFrame方法是直接赋值
    [super setFrame:frame1];
}

  //创建一个NSTimer定时器，需要手动销毁

//
//  ViewController.m
//  03-UIImageViewDemo
//
//  Created by qingyun on 16/3/24.
//  Copyright © 2016年 河南青云信息技术有限公司. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()
@property (nonatomic, strong) NSTimer *timer;
@end

@implementation ViewController

-(void)changeImageHighlightedState{
    UIImageView *imageView = [self.view viewWithTag:101];
    imageView.highlighted = !imageView.highlighted;
}

- (void)viewDidLoad {
    [super viewDidLoad];
    
#if 0
    UIImage *image = [UIImage imageNamed:@"dog1"];
    UIImage *highlightedImage = [UIImage imageNamed:@"dog2"];
    //创建并添加imageView
    UIImageView *imageView = [[UIImageView alloc] initWithImage:image highlightedImage:highlightedImage];
    [self.view addSubview:imageView];
    //frame
    imageView.frame = CGRectMake(100, 100, 100, 100);
    imageView.tag = 101;
    
    [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(changeImageHighlightedState) userInfo:nil repeats:YES];
#else
   //添加火焰视图
    UIImageView *fireView = [[UIImageView alloc] initWithFrame:self.view.bounds];
    [self.view addSubview:fireView];
    
    //创建一个可变数组，存储图片
    NSMutableArray *images = [NSMutableArray array];
    for (int i = 0; i < 17; i++) {
        //注意，图片格式非png的话，需要指定后缀名
        NSString *imageName = [NSString stringWithFormat:@"campFire%02d.gif",i + 1];
        UIImage *image = [UIImage imageNamed:imageName];
        [images addObject:image];
    }
    //设置帧动画数组
    fireView.animationImages = images;
    //设置动画时间
    fireView.animationDuration = 1;
    //重复次数(0代表无限)
    fireView.animationRepeatCount = 0;
    //启动动画
    [fireView startAnimating];
    
#endif
    
    _timer = [NSTimer scheduledTimerWithTimeInterval:0.01 target:self selector:@selector(flySnow) userInfo:nil repeats:YES];
    
    // Do any additional setup after loading the view, typically from a nib.
}

-(void)flySnow{
    //创建雪花
    UIImage *snow = [UIImage imageNamed:@"flake"];
    UIImageView *snowView = [[UIImageView alloc] initWithImage:snow];
    [self.view addSubview:snowView];
    //设置起始位置
    int screenW = [UIScreen mainScreen].bounds.size.width;
    //雪花的起始X
    int x1 = arc4random() % screenW;
    //雪花的随机倍数
    double scale = 1.0 + (arc4random() % 100) / 100.0;
    snowView.frame = CGRectMake(x1, -(30 * scale), 30 * scale, 30 * scale);
   
    //动画时间随机倍数
    double durationScale = 1.0 + (arc4random() % 100) / 100.0;
    
    //设置结束位置
    [UIView animateWithDuration:5 * durationScale animations:^{
        //雪花最终的随机倍数
        double scale2 = 1.0 + (arc4random() % 100) / 100.0;
        int x2 = arc4random() % screenW;
        int screenH = [UIScreen mainScreen].bounds.size.height;
        snowView.frame = CGRectMake(x2, screenH - 20 *scale2, 20 * scale2, 20 * scale2);
    } completion:^(BOOL finished) {
        [snowView removeFromSuperview];
    }];
}


-(void)dealloc{
    [_timer invalidate];
    _timer = nil;
}
- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

- (void)dealloc{

[_timer invalidate];

_timer = nil;

}

//如果输入的不是数字  判断字符串内容是否是有效数字

（例）

一丶 if ((![_cometextField.text integerValue] || ![_outTextField.text integerValue]))

二丶obj.keyboardType = UIKeyboardTypeDecimalPad; （设置键盘的类型）

三丶通过 UITextFieldDelegate 的 shouldChangeCharactersInRange: 方法

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    //return [self validateNumberByASCII:string];
   //return [self validateNumberByRange:string];
     return [self validateNumberByRegExp:string]; //推荐方式
}

四丶正则表达式  （代码中方法为自定义方法）

/**
      *  『正则表达式；推荐使用，不用循环遍历，控制更灵活』判断字符串内容是否是有效数字
      *
      *  @param string 需要验证的字符串
      *
      *  @return 字符串内容是否是有效数字
      */
- (BOOL)validateNumberByRegExp:(NSString *)string {
  BOOL isValid = YES;
  NSUInteger len = string.length;
  if (len > 0) {
        NSString *numberRegex = @"^[0-9]*$";
        NSPredicate *numberPredicate = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", numberRegex];
      isValid = [numberPredicate evaluateWithObject:string];
  }
  return isValid;
}

五丶字符范围   （代码中方法为自定义方法）

/**
 *  『字符范围』判断字符串内容是否是有效数字
 *
 *  @param string 需要验证的字符串
 *
 *  @return 字符串内容是否是有效数字
 */
    
- (BOOL)validateNumberByRange:(NSString *)string {
         BOOL isValid = YES;
         NSUInteger len = string.length;
        if (len > 0) {
   NSCharacterSet *validNumberCS = [NSCharacterSet characterSetWithCharactersInString:@"0123456789"];
   NSUInteger singleStrIndex = 0;
   do {
          NSString *singleStr = [string substringWithRange:NSMakeRange(singleStrIndex, 1)];
           NSRange range = [singleStr rangeOfCharacterFromSet:validNumberCS];
      if (range.length == 0) {
          isValid = NO;
            break;
        }
      singleStrIndex++;
      } while (singleStrIndex < len);
    }
  return isValid;
}

六丶ASCII码

/**
   *  『ASCII码』判断字符串内容是否是有效数字
   *
   *  @param string 需要验证的字符串
   *
   *  @return 字符串内容是否是有效数字
   */


- (BOOL)validateNumberByASCII:(NSString *)string {

    BOOL isValid = YES;
        NSUInteger len = string.length;
        if (len > 0) {
                 for (NSUInteger i=0; i<len; i++) {
                         NSUInteger asciiCode = [string characterAtIndex:i];
                         if (asciiCode < 48 || asciiCode > 57) {
                                 isValid = NO;
                                 break;
                             }
                   }
           }
       return isValid;
}

 //图片渲染

UIImage *image = [[UIImage imageNamed:@"stepper"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];