知识点小结

iOS开发技巧小结

目录
  1. 1. 引言
  2. 2. 实用小技巧
  3. 3. 开发技巧

引言

好久没写blog了，最近映客游戏直播相关的工作告一个段落，抽出些时间写个blog，和大家分享一下平时开发中使用过的一些小技巧，希望大家能帮着一起补充。

实用小技巧

  1. 通过多个符号进行分割字符串

    1
    2
    3
    NSString *str = @"abcd,efg,hijk;lmn.opq";
    NSCharacterSet *set = [NSCharacterSet characterSetWithCharactersInString:@",;."];
    NSLog(@"%@",[str componentsSeparatedByCharactersInSet:set]);

    ​

  2. 判断View是不是指定视图的子视图

    1
    BOOL isView = [textView isDescendantOfView:self.view];

    ​

  3. 修改UITextField中Placeholder的字体颜色、大小

    1
    2
    [self.textField setValue:[UIColor redColor] forKeyPath:@"_placeholderLabel.textColor"];
    [self.textField setValue:[UIFont boldSystemFontOfSize:16] forKeyPath:@"_placeholderLabel.font"];

    ​

  4. 获取 UIImage 占用的内存大小

    1
    2
    UIImage *image = [UIImage imageNamed:@"abc"];
    NSUInteger size  = CGImageGetHeight(image.CGImage) * CGImageGetBytesPerRow(image.CGImage);

    ​

  5. GCD 定时器

    1
    2
    3
    4
    5
    6
    7
    dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
    dispatch_source_t timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0,queue);
    dispatch_source_set_timer(timer,dispatch_walltime(NULL, 0),1.0*NSEC_PER_SEC, 0); //每秒执行
    dispatch_source_set_event_handler(timer, ^{
        //执行定时器代码
    });
    dispatch_resume(timer);

    ​

  6. 浮点数取整

    1
    2
    3
    4
    CGFloat x;
    (int)x : 强转为整形，四舍五入
    floor(x) : 向下取整
    ceil(x) : 向上取整。

    ​

  7. 给UIView设置背景图片

    1
    2
    UIImage *image = [UIImage imageNamed:@"image"];
    self.myView.layer.contents = (__bridge id _Nullable)(image.CGImage);

    ​

  8. 给UIView设置部分圆角（只要右边的两个角圆角，或者只要一个圆角，通过蒙版实现）

    1
    2
    3
    4
    5
    6
    7
    8
    CGRect rect = view.bounds;
    CGSize radio = CGSizeMake(30, 30);//圆角尺寸
    UIRectCorner corner = UIRectCornerTopLeft|UIRectCornerTopRight;//圆角位置
    UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:rect byRoundingCorners:corner cornerRadii:radio];
    CAShapeLayer *masklayer = [[CAShapeLayer alloc]init];//创建shapelayer
    masklayer.frame = view.bounds;
    masklayer.path = path.CGPath;//设置路径
    view.layer.mask = masklayer;

    ​

  9. 防止scrollView手势覆盖侧滑手势

    1
    [scrollView.panGestureRecognizerrequireGestureRecognizerToFail:self.navigationController.interactivePopGestureRecognizer];

    ​

  10. 去掉导航栏返回的back标题

    1
    [[UIBarButtonItemappearance]setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60)forBarMetrics:UIBarMetricsDefault];

    ​

  11. 动画暂停再开始

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    -(void)pauseLayer:(CALayer *)layer
    {
        CFTimeInterval pausedTime = [layer convertTime:CACurrentMediaTime() fromLayer:nil];
        layer.speed = 0.0;
        layer.timeOffset = pausedTime;
    }
    -(void)resumeLayer:(CALayer *)layer
    {
        CFTimeInterval pausedTime = [layer timeOffset];
        layer.speed = 1.0;
        layer.timeOffset = 0.0;
        layer.beginTime = 0.0;
        CFTimeInterval timeSincePause = [layer convertTime:CACurrentMediaTime() fromLayer:nil] - pausedTime;
        layer.beginTime = timeSincePause;
    }

    ​

  12. navigationBar根据滑动距离的渐变色实现

    1
    2
    3
    4
    5
    6
    - (void)scrollViewDidScroll:(UIScrollView *)scrollView
    {
        CGFloat offsetToShow = 200.0;//滑动多少就完全显示
        CGFloat alpha = 1 - (offsetToShow - scrollView.contentOffset.y) / offsetToShow;
        [[self.navigationController.navigationBar subviews] objectAtIndex:0].alpha = alpha;
    }

    ​

  13. UIWebView设置User-Agent

    1
    2
    3
    4
    5
    //设置
    NSDictionary *dic = @{@"UserAgent":@"your UserAgent"};
    [[NSUserDefaults standardUserDefaults] registerDefaults:dic];
    //获取
    NSString *agent = [self.WebView stringByEvaluatingJavaScriptFromString:@"navigator.userAgent"];

    ​

  14. 获取UIColor的RGBA值

    1
    2
    3
    4
    5
    6
    UIColor *color = [UIColor colorWithRed:0.2 green:0.3 blue:0.9 alpha:1.0];
    const CGFloat *components = CGColorGetComponents(color.CGColor);
    NSLog(@"Red: %.1f", components[0]);
    NSLog(@"Green: %.1f", components[1]);
    NSLog(@"Blue: %.1f", components[2]);
    NSLog(@"Alpha: %.1f", components[3]);

    ​

  15. 判断两个日期是否在同一周

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    - (BOOL)isSameDateWithDate:(NSDate *)date
    {
        //日期间隔大于七天之间返回NO
        if (fabs([self timeIntervalSinceDate:date]) >= 7 * 24 *3600)
        {
            return NO;
        }
        NSCalendar *calender = [NSCalendar currentCalendar];
        calender.firstWeekday = 2;//设置每周第一天从周一开始
        //计算两个日期分别为这年第几周
        NSUInteger countSelf = [calender ordinalityOfUnit:NSCalendarUnitWeekday inUnit:NSCalendarUnitYear forDate:self];
        NSUInteger countDate = [calender ordinalityOfUnit:NSCalendarUnitWeekday inUnit:NSCalendarUnitYear forDate:date];
        //相等就在同一周，不相等就不在同一周
        return countSelf == countDate;
    }

    ​

  16. 字符串反转

    1
    2
    3
    4
    5
    6
    7
    8
    - (NSString*)reverseWordsInString:(NSString*)str
    {    
         NSMutableString *reverString = [NSMutableString stringWithCapacity:str.length];    
         [str enumerateSubstringsInRange:NSMakeRange(0, str.length) options:NSStringEnumerationReverse | NSStringEnumerationByComposedCharacterSequences  usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) { 
              [reverString appendString:substring];                         
          }];    
         return reverString;
    }

    ​

  17. iOS 获取汉字的拼音

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    + (NSString *)transform:(NSString *)chinese
    {    
        //将NSString装换成NSMutableString 
        NSMutableString *pinyin = [chinese mutableCopy];    
        //将汉字转换为拼音(带音标)    
        CFStringTransform((__bridge CFMutableStringRef)pinyin, NULL, kCFStringTransformMandarinLatin, NO);    
        NSLog(@"%@", pinyin);    
        //去掉拼音的音标    
        CFStringTransform((__bridge CFMutableStringRef)pinyin, NULL, kCFStringTransformStripCombiningMarks, NO);    
        NSLog(@"%@", pinyin);    
        //返回最近结果    
        return pinyin;
     }

    ​

  18. NSArray 快速求总和 最大值 最小值 和 平均值

    1
    2
    3
    4
    5
    6
    NSArray *array = [NSArray arrayWithObjects:@"2.0", @"2.3", @"3.0", @"4.0", @"10", nil];
    CGFloat sum = [[array valueForKeyPath:@"@sum.floatValue"] floatValue];
    CGFloat avg = [[array valueForKeyPath:@"@avg.floatValue"] floatValue];
    CGFloat max =[[array valueForKeyPath:@"@max.floatValue"] floatValue];
    CGFloat min =[[array valueForKeyPath:@"@min.floatValue"] floatValue];
    NSLog(@"%f\n%f\n%f\n%f",sum,avg,max,min);

    ​

  19. 计算文件（夹）大小

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    //文件大小
    - (long long)fileSizeAtPath:(NSString *)path
    {
        NSFileManager *fileManager = [NSFileManager defaultManager];
        if ([fileManager fileExistsAtPath:path])
        {
            long long size = [fileManager attributesOfItemAtPath:path error:nil].fileSize;
            return size;
        }
        return 0;
    }
    //文件夹大小
    - (long long)folderSizeAtPath:(NSString *)path
    {
        NSFileManager *fileManager = [NSFileManager defaultManager];
        long long folderSize = 0;
        if ([fileManager fileExistsAtPath:path])
        {
            NSArray *childerFiles = [fileManager subpathsAtPath:path];
            for (NSString *fileName in childerFiles)
            {
                NSString *fileAbsolutePath = [path stringByAppendingPathComponent:fileName];
                if ([fileManager fileExistsAtPath:fileAbsolutePath])
                {
                    long long size = [fileManager attributesOfItemAtPath:fileAbsolutePath error:nil].fileSize;
                    folderSize += size;
                }
            }
        }
        return folderSize;
    }

    ​

  20. 图片上绘制文字

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    - (UIImage *)imageWithTitle:(NSString *)title fontSize:(CGFloat)fontSize
    {
        //画布大小
        CGSize size=CGSizeMake(self.size.width,self.size.height);
        //创建一个基于位图的上下文
        UIGraphicsBeginImageContextWithOptions(size,NO,0.0);//opaque:NO  scale:0.0
        [self drawAtPoint:CGPointMake(0.0,0.0)];
        //文字居中显示在画布上
        NSMutableParagraphStyle* paragraphStyle = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];
        paragraphStyle.lineBreakMode = NSLineBreakByCharWrapping;
        paragraphStyle.alignment=NSTextAlignmentCenter;//文字居中
        //计算文字所占的size,文字居中显示在画布上
        CGSize sizeText=[title boundingRectWithSize:self.size options:NSStringDrawingUsesLineFragmentOrigin
                                         attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:fontSize]}context:nil].size;
        CGFloat width = self.size.width;
        CGFloat height = self.size.height;
        CGRect rect = CGRectMake((width-sizeText.width)/2, (height-sizeText.height)/2, sizeText.width, sizeText.height);
        //绘制文字
        [title drawInRect:rect withAttributes:@{ NSFontAttributeName:[UIFont systemFontOfSize:fontSize],NSForegroundColorAttributeName:[ UIColor whiteColor],NSParagraphStyleAttributeName:paragraphStyle}];
        //返回绘制的新图形
        UIImage *newImage= UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        return newImage;
    }

    ​

    开发技巧

    上面说的是一些开发中会用到的一些实用的方法。下面具体说一下开发中可能会需要实用的一些技巧。

  21. 显示隐藏文件

    1
    2
    3
    4
    5
    6
    7
    //显示
    defaults write com.apple.finder AppleShowAllFiles -bool true
    killall Finder
    //隐藏
    defaults write com.apple.finder AppleShowAllFiles -bool false
    killall Finder

    ​

  22. 获取一个类的所有子类

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    + (NSArray *) allSubclasses
    {
        Class myClass = [self class];
        NSMutableArray *mySubclasses = [NSMutableArray array];
        unsigned int numOfClasses;
        Class *classes = objc_copyClassList(&numOfClasses;);
        for (unsigned int ci = 0; ci < numOfClasses; ci++)
        {
            Class superClass = classes[ci];
            do{
                superClass = class_getSuperclass(superClass);
            } while (superClass && superClass != myClass);
            if (superClass)
            {
                [mySubclasses addObject: classes[ci]];
            }
        }
        free(classes);
        return mySubclasses;
    }

    ​

  23. 监测IOS设备是否设置了代理，需要CFNetwork.framework

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    NSDictionary *proxySettings = (__bridge NSDictionary *)(CFNetworkCopySystemProxySettings());
    NSArray *proxies = (__bridge NSArray *)(CFNetworkCopyProxiesForURL((__bridge CFURLRef _Nonnull)([NSURL URLWithString:@"http://www.baidu.com"]), (__bridge CFDictionaryRef _Nonnull)(proxySettings)));
    NSLog(@"\n%@",proxies);
    NSDictionary *settings = proxies[0];
    NSLog(@"%@",[settings objectForKey:(NSString *)kCFProxyHostNameKey]);
    NSLog(@"%@",[settings objectForKey:(NSString *)kCFProxyPortNumberKey]);
    NSLog(@"%@",[settings objectForKey:(NSString *)kCFProxyTypeKey]);
    if ([[settings objectForKey:(NSString *)kCFProxyTypeKey] isEqualToString:@"kCFProxyTypeNone"])
    {
         NSLog(@"没代理");
    }
    else
    {
         NSLog(@"设置了代理");
    }

    ​

  24. 让Xcode的控制台支持LLDB类型的打印

    1
    2
    3
    4
    打开终端输入三条命令:
    touch ~/.lldbinit
    echo display @import UIKit >> ~/.lldbinit
    echo target stop-hook add -o \"target stop-hook disable\" >> ~/.lldbinit

    ​

  25. CocoaPods pod install/pod update更新慢的问题

    1
    2
    3
    pod install --verbose --no-repo-update 
    pod update --verbose --no-repo-update
    如果不加后面的参数，默认会升级CocoaPods的spec仓库，加一个参数可以省略这一步，然后速度就会提升不少

    ​

  26. 查找一个视图的所有子视图

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    - (NSMutableArray *)allSubViewsForView:(UIView *)view
    {
        NSMutableArray *array = [NSMutableArray arrayWithCapacity:0];
        for (UIView *subView in view.subviews)
        {
            [array addObject:subView];
            if (subView.subviews.count > 0)
            {
                [array addObjectsFromArray:[self allSubViewsForView:subView]];
            }
        }
        return array;
    }

    ​

  27. 获取私有属性和成员变量 #import 

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    //获取私有属性 比如设置UIDatePicker的字体颜色
    - (void)setTextColor
    {
        //获取所有的属性，去查看有没有对应的属性
        unsigned int count = 0;
        objc_property_t *propertys = class_copyPropertyList([UIDatePicker class], &count);
        for(int i = 0;i < count;i ++)
        {
            //获得每一个属性
            objc_property_t property = propertys[i];
            //获得属性对应的nsstring
            NSString *propertyName = [NSString stringWithCString:property_getName(property) encoding:NSUTF8StringEncoding];
            //输出打印看对应的属性
            NSLog(@"propertyname = %@",propertyName);
            if ([propertyName isEqualToString:@"textColor"])
            {
                [datePicker setValue:[UIColor whiteColor] forKey:propertyName];
            }
        }
    }
    //获得成员变量 比如修改UIAlertAction的按钮字体颜色
        unsigned int count = 0;
        Ivar *ivars = class_copyIvarList([UIAlertAction class], &count);
        for(int i =0;i < count;i ++)
        {
            Ivar ivar = ivars[i];
            NSString *ivarName = [NSString stringWithCString:ivar_getName(ivar) encoding:NSUTF8StringEncoding];
            NSLog(@"uialertion.ivarName = %@",ivarName);
            if ([ivarName isEqualToString:@"_titleTextColor"])
            {
                [alertOk setValue:[UIColor blueColor] forKey:@"titleTextColor"];
                [alertCancel setValue:[UIColor purpleColor] forKey:@"titleTextColor"];
            }
        }

    ​

  28. 获取手机安装的应用

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    Class c =NSClassFromString(@"LSApplicationWorkspace");
    id s = [(id)c performSelector:NSSelectorFromString(@"defaultWorkspace")];
    NSArray *array = [s performSelector:NSSelectorFromString(@"allInstalledApplications")];
    for (id item in array)
    {
        NSLog(@"%@",[item performSelector:NSSelectorFromString(@"applicationIdentifier")]);
        //NSLog(@"%@",[item performSelector:NSSelectorFromString(@"bundleIdentifier")]);
        NSLog(@"%@",[item performSelector:NSSelectorFromString(@"bundleVersion")]);
        NSLog(@"%@",[item performSelector:NSSelectorFromString(@"shortVersionString")]);
    }

    ​

  29. 获取硬盘总容量与可用容量

    1
    2
    3
    4
    5
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSDictionary *attributes = [fileManager attributesOfFileSystemForPath:NSHomeDirectory() error:nil];
    NSLog(@"容量%.2fG",[attributes[NSFileSystemSize] doubleValue] / (powf(1024, 3)));
    NSLog(@"可用%.2fG",[attributes[NSFileSystemFreeSize] doubleValue] / powf(1024, 3));

    ​

  30. 获取WebView所有的图片地址

    在网页加载完成时，通过js获取图片和添加点击的识别方式

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    //UIWebView
    - (void)webViewDidFinishLoad:(UIWebView *)webView
    {
        //这里是js，主要目的实现对url的获取
        static  NSString * const jsGetImages =
        @"function getImages(){\
        var objs = document.getElementsByTagName(\"img\");\
        var imgScr = '';\
        for(var i=0;i<objs.length;i++){\
        imgScr = imgScr + objs[i].src + '+';\
        };\
        return imgScr;\
        };";
        [webView stringByEvaluatingJavaScriptFromString:jsGetImages];//注入js方法
        NSString *urlResult = [webView stringByEvaluatingJavaScriptFromString:@"getImages()"];
        NSArray *urlArray = [NSMutableArray arrayWithArray:[urlResult componentsSeparatedByString:@"+"]];
        //urlResurlt 就是获取到得所有图片的url的拼接；mUrlArray就是所有Url的数组
    }
    //WKWebView
    - (void)webView:(WKWebView *)webView didFinishNavigation:(null_unspecified WKNavigation *)navigation
    {
        static  NSString * const jsGetImages =
        @"function getImages(){\
        var objs = document.getElementsByTagName(\"img\");\
        var imgScr = '';\
        for(var i=0;i<objs.length;i++){\
        imgScr = imgScr + objs[i].src + '+';\
        };\
        return imgScr;\
        };";
        [webView evaluateJavaScript:jsGetImages completionHandler:nil];
        [webView evaluateJavaScript:@"getImages()" completionHandler:^(id _Nullable result, NSError * _Nullable error) {
            NSLog(@"%@",result);
        }];
    }

  31. iOS 开发中一些相关的路径

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    模拟器的位置:
    /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs 
    文档安装位置:
    /Applications/Xcode.app/Contents/Developer/Documentation/DocSets
    插件保存路径:
    ~/Library/ApplicationSupport/Developer/Shared/Xcode/Plug-ins
    自定义代码段的保存路径:
    ~/Library/Developer/Xcode/UserData/CodeSnippets/ 
    如果找不到CodeSnippets文件夹，可以自己新建一个CodeSnippets文件夹。
    描述文件路径
    ~/Library/MobileDevice/Provisioning Profiles

    ​

  32. 打印系统所有已注册的字体名称

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    void enumerateFonts()
    {
        for(NSString *familyName in [UIFont familyNames])
       {
            NSLog(@"%@",familyName);               
            NSArray *fontNames = [UIFont fontNamesForFamilyName:familyName];       
            for(NSString *fontName in fontNames)
           {
                NSLog(@"\t|- %@",fontName);
           }
       }
    }

    ​

本作品采用 署名-非商业性使用-相同方式共享 2.5 中国大陆 (CC BY-NC-SA 2.5)协议 进行许可，欢迎转载，但转载请注明来自SarielTang，并保持转载后文章内容的完整。本人保留所有版权相关权利。

本文永久链接：http://sarieltang.github.io/2017/04/09/知识点小结/2017-04-09/index/