iOS开发中一些常用的方法

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#pragma mark 处理图片
- (void)useImage:(UIImage *)image
{
    NSLog(@"with-----%f heught-----%f",image.size.width,image.size.height);
    
    float  scales = image.size.height / image.size.width; //图片比例
    NSLog(@"图片比例：%f",scales);
    
    UIImage * normalImg;
    
    if (image.size.width >300 || image.size.height > 300) {
        
        if (scales > 1) {
            
            normalImg = [self imageWithImageSimple:image scaledToSize:CGSizeMake(300 / scales, 300)];
            
        }else {
            
            normalImg = [self imageWithImageSimple:image scaledToSize:CGSizeMake(300 ,300 * scales)];
        }
    }
    else {
        
        normalImg = image;
    }
    
    NSLog(@"第一次处理后：with-----%f height-----%f",normalImg.size.width, normalImg.size.height);
    CGSize newSize = CGSizeMake(normalImg.size.width, normalImg.size.height);
    float kk = 1.0f;//图片压缩系数
    int mm;//压缩后的大小
    float aa = 1.0f;//图片压缩系数变化步长(可变)
    mm = (int)UIImageJPEGRepresentation(normalImg, kk).length;
    while (mm / 1024 > 300) {
        if (kk > aa + aa / 10) {
            kk -= aa;
            if (mm == (int)UIImageJPEGRepresentation(normalImg, kk).length) {
                break;
            }
            mm = (int)UIImageJPEGRepresentation(normalImg, kk).length;
        }else{
            aa /= 10;
        }
    }
    NSLog(@"KK:%f -- aa:%f",kk,aa);
#warning 图片压缩
    NSLog(@"第二次处理后：with-----%f height-----%f",normalImg.size.width, normalImg.size.height);
    NSData *newData;
    newData = UIImageJPEGRepresentation(normalImg, kk);//最后压缩结果
    
    if (newData.length/1024 > 300) {
        
        [APPRequest showAlert:@"提示" message:@"图片过大"];
       
    }else{
       
       // 上传图片网络请求

            
            }
        }];
    }
}

        NSDate *  timeDate = [NSDate date];
        NSTimeInterval nowInt = [timeDate timeIntervalSince1970]*1;
        NSDateFormatter  *dateformatter=[[NSDateFormatter alloc] init];
        [dateformatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
        NSDate* publishDate = [dateformatter dateFromString:[demandlist.publish_time substringToIndex:19]];
        NSTimeInterval publishInt = [publishDate timeIntervalSince1970]*1;
        NSTimeInterval cha = nowInt - publishInt;
        NSString *timeString=@"";

        if (cha/3600<1) {

            timeString = [NSString stringWithFormat:@"%f", cha/60];

            timeString = [timeString substringToIndex:timeString.length-7];

            timeString = [NSString stringWithFormat:@"%@分钟前发布", timeString];
        }

        if (cha/3600>1&&cha/86400<1) {

            timeString = [NSString stringWithFormat:@"%f", cha/3600];

            timeString = [timeString substringToIndex:timeString.length-7];

            timeString = [NSString stringWithFormat:@"%@小时前发布", timeString];

        }

        if (cha/86400>1)
        {

            timeString = [NSString stringWithFormat:@"%f", cha/86400];

            timeString = [timeString substringToIndex:timeString.length-7];

            timeString = [NSString stringWithFormat:@"%@天前发布", timeString];

        }

3.返回字符串所占的尺寸

//返回字符串所占用的尺寸.
-(CGSize)sizeWithFont:(UIFont *)font maxSize:(CGSize)maxSize
{    NSDictionary *attrs = @{NSFontAttributeName : font};   
 return [self boundingRectWithSize:maxSize options:NSStringDrawingUsesLineFragmentOrigin attributes:attrs context:nil].size;
}

4.tableView自动滑倒某一行

NSIndexPath *scrollIndexPath = [NSIndexPath indexPathForRow:10 inSection:0];
[[self tableView] scrollToRowAtIndexPath:scrollIndexPath
        atScrollPosition:UITableViewScrollPositionTop animated:YES];

NSIndexSet *indexSet=[[NSIndexSet alloc]initWithIndex:2];    
[tableview reloadSections:indexSet withRowAnimation:UITableViewRowAnimationAutomatic];    
//一个cell刷新    
NSIndexPath *indexPath=[NSIndexPath indexPathForRow:3 inSection:0];    
[tableView reloadRowsAtIndexPaths:[NSArray arrayWithObjects:indexPath,nil] withRowAnimation:UITableViewRowAnimationNone]; <span style="font-family: Arial, Helvetica, sans-serif;"> </span>

NSString *plistPath = [[NSBundle mainBundle] pathForResource:@"plistdemo" ofType:@"plist"];  
   NSMutableDictionary *data = [[NSMutableDictionary alloc] initWithContentsOfFile:plistPath];

    label.text = [NSString stringWithFormat:@" 视野头条:%@",home.title];

    NSString *str = [NSString stringWithFormat:@" 视野头条:%@",home.title];

    NSMutableAttributedString *titleStr = [[NSMutableAttributedString alloc]initWithString:str];

    NSRange range = [str rangeOfString:@"视野头条:"];

    [titleStr addAttribute:NSForegroundColorAttributeName value:[UIColor orangeColor] range:range];

    [label setAttributedText:titleStr];

   NSString *str = @"dhak d sh akdl ";
   NSString *strUrl = [str stringByReplacingOccurrencesOfString:@" " withString:@""];

给UIImage添加生成圆角图片的扩展API：
- (UIImage *)imageWithCornerRadius:(CGFloat)radius {
  CGRect rect = (CGRect){0.f, 0.f, self.size};
  UIGraphicsBeginImageContextWithOptions(self.size, NO, UIScreen.mainScreen.scale);
  CGContextAddPath(UIGraphicsGetCurrentContext(),
                   [UIBezierPath bezierPathWithRoundedRect:rect cornerRadius:radius].CGPath);
  CGContextClip(UIGraphicsGetCurrentContext());
  [self drawInRect:rect];
  UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

  UIGraphicsEndImageContext();

  return image;
}
//然后调用时就直接传一个圆角来处理：

imgView.image = [[UIImage imageNamed:@"test"] hyb_imageWithCornerRadius:4];
//最直接的方法就是使用如下属性设置：
imgView.layer.cornerRadius = 10;
// 这一行代码是很消耗性能的
imgView.clipsToBounds = YES;
//好处是使用简单，操作方便。坏处是离屏渲染（off-screen-rendering）需要消耗性能。对于图片比较多的视图上，不建议使用这种方法来设置圆角。通常来说，计算机系统中CPU、GPU、显示器是协同工作的。CPU计算好显示内容提交到GPU，GPU渲染完成后将渲染结果放入帧缓冲区。
//简单来说，离屏渲染，导致本该GPU干的活，结果交给了CPU来干，而CPU又不擅长GPU干的活，于是拖慢了UI层的FPS（数据帧率），并且离屏需要创建新的缓冲区和上下文切换，因此消耗较大的性能。

//1.验证邮箱
+ (BOOL)validateEmail:(NSString *)email
{
    NSString *emailRegex = @"[A-Z0-9a-z._%+-]+@[A-Za-z0-9.-]+\\.[A-Za-z]{2,4}";
    NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", emailRegex];
    return [emailTest evaluateWithObject:email];
}
//2.验证手机（简单的）
+ (BOOL)validatePhone:(NSString *)phone
{
    NSString *phoneRegex = @"1[3|5|7|8|][0-9]{9}";
    NSPredicate *phoneTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", phoneRegex];
    return [phoneTest evaluateWithObject:phone];
}
//验证手机（复杂的）
+ (BOOL)validatePhone:(NSString *)phone
{
       /**
        * 手机号码
        * 移动：134[0-8],135,136,137,138,139,150,151,157,158,159,182,187,188
        * 联通：130,131,132,152,155,156,185,186
        * 电信：133,1349,153,180,189
        */
       NSString * MOBILE = @"^1(3[0-9]|5[0-35-9]|8[025-9])\\d{8}$";
       /**
        10         * 中国移动：China Mobile
        11         * 134[0-8],135,136,137,138,139,150,151,157,158,159,182,187,188
        12         */
       NSString * CM = @"^1(34[0-8]|(3[5-9]|5[017-9]|8[278])\\d)\\d{7}$";
       /**
        15         * 中国联通：China Unicom
        16         * 130,131,132,152,155,156,185,186
        17         */
       NSString * CU = @"^1(3[0-2]|5[256]|8[56])\\d{8}$";
       /**
        20         * 中国电信：China Telecom
        21         * 133,1349,153,180,189
        22         */
       NSString * CT = @"^1((33|53|8[09])[0-9]|349)\\d{7}$";
       /**
        25         * 大陆地区固话及小灵通
        26         * 区号：010,020,021,022,023,024,025,027,028,029
        27         * 号码：七位或八位
        28         */
      // NSString * PHS = @"^0(10|2[0-5789]|\\d{3})\\d{7,8}$";

     NSPredicate *regextestmobile = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", MOBILE];
     NSPredicate *regextestcm = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", CM];
     NSPredicate *regextestcu = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", CU];
     NSPredicate *regextestct = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", CT];

    if (([regextestmobile evaluateWithObject:phone] == YES)
    || ([regextestcm evaluateWithObject:phone] == YES)
    || ([regextestct evaluateWithObject:phone] == YES)
    || ([regextestcu evaluateWithObject:phone] == YES))
    {
        if([regextestcm evaluateWithObject:phone] == YES) {
          NSLog(@"China Mobile");
        } else if([regextestct evaluateWithObject:phone] == YES) {
          NSLog(@"China Telecom");
        } else if ([regextestcu evaluateWithObject:phone] == YES) {
          NSLog(@"China Unicom");
        } else {
          NSLog(@"Unknow");
        }

        return YES;
    }
    else 
    {
        return NO;
    }
}

// 删除缓存
- (void)removeCache
{
    NSString *cachePath = [NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) lastObject];
    NSLog(@"%@",cachePath);
    NSArray *files = [[NSFileManager defaultManager] subpathsAtPath:cachePath];
    for (NSString *p in files) {
        NSString *path = [NSString stringWithFormat:@"%@/%@", cachePath, p];
        if ([[NSFileManager defaultManager] fileExistsAtPath:path]) {
            [[NSFileManager defaultManager] removeItemAtPath:path error:nil];
        }
    }
}
// 计算清除的缓存大小
- (CGFloat)floatWithPath:(NSString *)path
{
    CGFloat num = 0;
    NSFileManager *man = [NSFileManager defaultManager];
    if ([man fileExistsAtPath:path]) {
        NSEnumerator *childFile = [[man subpathsAtPath:path] objectEnumerator];
        NSString *fileName;
        while ((fileName = [childFile nextObject]) != nil) {
            NSString *fileSub = [path stringByAppendingPathComponent:fileName];
            num += [self fileSizeAtPath:fileSub];
        }
    }
    return num / (1024.0 * 1024.0);
}

//计算单个文件大小
- (long long)fileSizeAtPath:(NSString *)file
{
    NSFileManager *man = [NSFileManager defaultManager];
    if ([man fileExistsAtPath:file]) {
        return [[man attributesOfItemAtPath:file error:nil] fileSize];
    }
    return 0;
}

12 系统原生态二维码扫描（包括闪光灯，系统提示音）

#import <AVFoundation/AVFoundation.h>

#import <AudioToolbox/AudioToolbox.h> // 系统提示音
#define SCANVIEW_EdgeTop 40.0
#define SCANVIEW_EdgeLeft 50.0
#define TINTCOLOR_ALPHA 0.2 //浅色透明度
#define DARKCOLOR_ALPHA 0.5 //深色透明度
#define VIEW_WIDTH [UIScreen mainScreen].bounds.size.width
#define VIEW_HEIGHT [UIScreen mainScreen].bounds.size.height
/*
 ＊＊＊＊＊＊＊＊＊注意 ：系统原生态二维码扫描 苹果官方目前不支持扫扫描图册图片 ＊＊＊＊＊＊＊＊＊＊＊＊
 
 1.第一步 引入框架 AVFoundation.framework
 2.第二步 声明代理：AVCaptureMetadataOutputObjectsDelegate 。 define 几个东东用来画框、画线：
 

 
 */
@interface ViewController ()<AVCaptureMetadataOutputObjectsDelegate>
{
    AVCaptureSession * session;//输入输出的中间桥梁
    UIView *AVCapView;//此 view 用来放置扫描框、取消按钮、说明 label
    UIView *_QrCodeline;//上下移动绿色的线条
    NSTimer *_timer;
}
@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    [self createUI];
    // Do any additional setup after loading the view, typically from a nib.
}
#pragma mark 4.在某个方法中（我是点击扫描按钮）创建扫描界面，开始扫描
- (void)createUI{

    //创建一个 view 来放置扫描区域、说明 label、取消按钮
    UIView *tempView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, 320, [UIScreen mainScreen].bounds.size.height )];
    AVCapView = tempView;
    AVCapView.backgroundColor = [UIColor colorWithRed:54.f/255 green:53.f/255 blue:58.f/255 alpha:1];
    
    UIButton *cancelBtn = [[UIButton alloc]initWithFrame:CGRectMake(15, [UIScreen mainScreen].bounds.size.height - 100, 50, 25)];
    UILabel *label = [[UILabel alloc]initWithFrame:CGRectMake(15, 268, 290, 60)];
    label.numberOfLines = 0;
    label.text = @"小提示：将条形码或二维码对准上方区域中心即可";
    label.textColor = [UIColor grayColor];
    [cancelBtn setTitle:@"取消" forState: UIControlStateNormal];
    [cancelBtn setTitleColor:[UIColor grayColor] forState:UIControlStateNormal];
    [cancelBtn addTarget:self action:@selector(touchAVCancelBtn) forControlEvents:UIControlEventTouchUpInside];
    [AVCapView addSubview:label];
    [AVCapView addSubview:cancelBtn];
    [self.view addSubview:AVCapView];
    
    //画上边框
    UIView *topView = [[UIView alloc] initWithFrame:CGRectMake(SCANVIEW_EdgeLeft, SCANVIEW_EdgeTop, VIEW_WIDTH- 2 * SCANVIEW_EdgeLeft, 1)];
    topView.backgroundColor = [UIColor whiteColor];
    [AVCapView addSubview:topView];
    
    //画左边框
    UIView *leftView = [[UIView alloc] initWithFrame:CGRectMake(SCANVIEW_EdgeLeft, SCANVIEW_EdgeTop , 1,VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft )];
    leftView.backgroundColor = [UIColor whiteColor];
    [AVCapView addSubview:leftView];
    
    //画右边框
    UIView *rightView = [[UIView alloc] initWithFrame:CGRectMake(SCANVIEW_EdgeLeft + VIEW_WIDTH- 2 * SCANVIEW_EdgeLeft, SCANVIEW_EdgeTop , 1,VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft + 1)];
    rightView.backgroundColor = [UIColor whiteColor];
    [AVCapView addSubview:rightView];
    
    //画下边框
    UIView *downView = [[UIView alloc] initWithFrame:CGRectMake(SCANVIEW_EdgeLeft, SCANVIEW_EdgeTop + VIEW_WIDTH- 2 * SCANVIEW_EdgeLeft,VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft ,1 )];
    downView.backgroundColor = [UIColor whiteColor];
    [AVCapView addSubview:downView];
    
    //闪光灯
    UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
    btn.frame = CGRectMake(150, [UIScreen mainScreen].bounds.size.height - 100, 80, 35);
    [btn setTintColor:[UIColor grayColor]];
    
    [btn setTitle:@"闪光灯" forState:UIControlStateNormal];
    [btn addTarget:self action: @selector(OPEN:) forControlEvents:UIControlEventTouchUpInside];
    [AVCapView  addSubview:btn];
   
    
    //画中间的基准线
    _QrCodeline = [[UIView alloc] initWithFrame:CGRectMake(SCANVIEW_EdgeLeft + 1, SCANVIEW_EdgeTop, VIEW_WIDTH- 2 * SCANVIEW_EdgeLeft - 1, 2)];
    _QrCodeline.backgroundColor = [UIColor greenColor];
    [AVCapView addSubview:_QrCodeline];
    
    
    // 先让基准线运动一次，避免定时器的时差
    [UIView animateWithDuration:1.2 animations:^{
        
        _QrCodeline.frame = CGRectMake(SCANVIEW_EdgeLeft + 1, VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft + SCANVIEW_EdgeTop , VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft - 1, 2);
        
    }];
    
    [self performSelector:@selector(createTimer) withObject:nil afterDelay:0.4];
    
    
    AVCaptureDevice * device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    //创建输入流
    AVCaptureDeviceInput * input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];
    //创建输出流
    AVCaptureMetadataOutput * output = [[AVCaptureMetadataOutput alloc]init];
    //设置代理 在主线程里刷新
    [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
    
    //初始化链接对象
    session = [[AVCaptureSession alloc]init];
    //高质量采集率
    [session setSessionPreset:AVCaptureSessionPresetHigh];
    
    [session addInput:input];
    [session addOutput:output];
    //设置扫码支持的编码格式(如下设置条形码和二维码兼容)
    output.metadataObjectTypes=@[AVMetadataObjectTypeQRCode,AVMetadataObjectTypeEAN13Code, AVMetadataObjectTypeEAN8Code, AVMetadataObjectTypeCode128Code];
    
    AVCaptureVideoPreviewLayer * layer = [AVCaptureVideoPreviewLayer layerWithSession:session];
    layer.videoGravity=AVLayerVideoGravityResizeAspectFill;
    layer.frame = CGRectMake(SCANVIEW_EdgeLeft, SCANVIEW_EdgeTop, VIEW_WIDTH- 2 * SCANVIEW_EdgeLeft, 220);
    [AVCapView.layer insertSublayer:layer atIndex:0];
    //开始捕获
    [session startRunning];

}
#pragma mark 调用闪光灯
- (void)OPEN:(UIButton *)btn{

    btn.selected = !btn.isSelected;
    
    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    
    if ([device hasTorch]) {
        
        [device lockForConfiguration:nil];
        
    if (btn.selected) {
        
        [device setTorchMode:AVCaptureTorchModeOn];
        
    }else{
    
          [device setTorchMode:AVCaptureTorchModeOff];
    }
           [device unlockForConfiguration];

    }
}
- (void)touchAVCancelBtn{

    //取消按钮的响应时间
}
#pragma mark 5.实现定时器、还有基准线的滚动方法
- (void)createTimer
{
    _timer=[NSTimer scheduledTimerWithTimeInterval:1.1 target:self selector:@selector(moveUpAndDownLine) userInfo:nil repeats:YES];
}

- (void)stopTimer
{
    if ([_timer isValid] == YES) {
        [_timer invalidate];
        _timer = nil;
    }
    
}
// 滚来滚去 :D :D :D
- (void)moveUpAndDownLine
{
    CGFloat YY = _QrCodeline.frame.origin.y;
    
    if (YY != VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft + SCANVIEW_EdgeTop ) {
        [UIView animateWithDuration:1.2 animations:^{
            _QrCodeline.frame = CGRectMake(SCANVIEW_EdgeLeft + 1, VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft + SCANVIEW_EdgeTop , VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft - 1,2);
        }];
    }else {
        [UIView animateWithDuration:1.2 animations:^{
            _QrCodeline.frame = CGRectMake(SCANVIEW_EdgeLeft + 1, SCANVIEW_EdgeTop, VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft - 1,2);
        }];
        
    }
}
#pragma mark 6.扫描成功后，想干嘛干嘛，就在这个代理方法里面实现就行了

-(void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection{
    if (metadataObjects.count>0) {
        //[session stopRunning];
        AVMetadataMachineReadableCodeObject * metadataObject = [metadataObjects objectAtIndex : 0 ];
        //输出扫描字符串
        NSLog(@"%@",metadataObject.stringValue);
        AudioServicesPlaySystemSound(1307);
        [session stopRunning];
        [self stopTimer];
        //[AVCapView removeFromSuperview];
      
    }
}

13.URL

13.2  KVO详解

13.3 iOS9适配

13.4 NSTimer内存问题
13.5 MJRefresh使用详情

13.6 推送

iOS开发中一些常用的方法

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原文地址：http://blog.csdn.net/u013043666/article/details/51353386