iOS 知识-常用小技巧大杂烩

1. 打印View所有子视图

po [[self view]recursiveDescription]
2. layoutSubviews调用的调用时机
* 当视图第一次显示的时候会被调用* 当这个视图显示到屏幕上了,点击按钮* 添加子视图也会调用这个方法* 当本视图的大小发生改变的时候是会调用的* 当子视图的frame发生改变的时候是会调用的* 当删除子视图的时候是会调用的
3. NSString过滤特殊字符
// 定义一个特殊字符的集合NSCharacterSet *set = [NSCharacterSet characterSetWithCharactersInString:@"@／：；（）¥「」＂、[]{}#%-*+=_//|~＜＞$€^•'@#$%^&*()_+'/""];// 过滤字符串的特殊字符NSString *newString = [trimString stringByTrimmingCharactersInSet:set];
4. TransForm属性
//平移按钮CGAffineTransform transForm = self.buttonView.transform;self.buttonView.transform = CGAffineTransformTranslate(transForm, 10, 0);//旋转按钮CGAffineTransform transForm = self.buttonView.transform;self.buttonView.transform = CGAffineTransformRotate(transForm, M_PI_4);//缩放按钮self.buttonView.transform = CGAffineTransformScale(transForm, 1.2, 1.2);//初始化复位self.buttonView.transform = CGAffineTransformIdentity;
5. 去掉分割线多余15像素
首先在viewDidLoad方法加入以下代码： if ([self.tableView respondsToSelector:@selector(setSeparatorInset:)]) {        [self.tableView setSeparatorInset:UIEdgeInsetsZero];    }    if ([self.tableView respondsToSelector:@selector(setLayoutMargins:)]) {                [self.tableView setLayoutMargins:UIEdgeInsetsZero];}然后在重写willDisplayCell方法- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath{       if ([cell respondsToSelector:@selector(setSeparatorInset:)]) {                    [cell setSeparatorInset:UIEdgeInsetsZero];        }        if ([cell respondsToSelector:@selector(setLayoutMargins:)]) {                     [cell setLayoutMargins:UIEdgeInsetsZero];        }}
6. 计算方法耗时时间间隔
// 获取时间间隔#define TICK   CFAbsoluteTime start = CFAbsoluteTimeGetCurrent();#define TOCK   NSLog(@"Time: %f", CFAbsoluteTimeGetCurrent() - start)
7. Color颜色宏定义
// 随机颜色#define RANDOM_COLOR [UIColor colorWithRed:arc4random_uniform(256) / 255.0 green:arc4random_uniform(256) / 255.0 blue:arc4random_uniform(256) / 255.0 alpha:1]// 颜色(RGB)#define RGBCOLOR(r, g, b) [UIColor colorWithRed:(r)/255.0f green:(g)/255.0f blue:(b)/255.0f alpha:1]// 利用这种方法设置颜色和透明值，可不影响子视图背景色#define RGBACOLOR(r, g, b, a) [UIColor colorWithRed:(r)/255.0f green:(g)/255.0f blue:(b)/255.0f alpha:(a)]
8. Alert提示宏定义
#define Alert(_S_, ...) [[[UIAlertView alloc] initWithTitle:@"提示" message:[NSString stringWithFormat:(_S_), ##__VA_ARGS__] delegate:nil cancelButtonTitle:@"确定" otherButtonTitles:nil] show]
9. 让iOS应用直接退出
- (void)exitapplication {    AppDelegate *app = [UIApplication sharedApplication].delegate;    UIWindow *window = app.window;    [UIView animateWithDuration:1.0f animations:^{        window.alpha = 0;    } completion:^(BOOL finished) {        exit(0);    }];}
10. NSArray 快速求总和 最大值 最小值 和 平均值
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);
10. 修改Label中不同文字颜色
- (void)touchesEnded:(NSSet<UITouch> *)touches withEvent:(UIEvent *)event{    [self editStringColor:self.label.text editStr:@"好" color:[UIColor blueColor]];}- (void)editStringColor:(NSString *)string editStr:(NSString *)editStr color:(UIColor *)color {    // string为整体字符串, editStr为需要修改的字符串    NSRange range = [string rangeOfString:editStr];    NSMutableAttributedString *attribute = [[NSMutableAttributedString alloc] initWithString:string];    // 设置属性修改字体颜色UIColor与大小UIFont    [attribute addAttributes:@{NSForegroundColorAttributeName:color} range:range];    self.label.attributedText = attribute;}
11. 播放声音
  #import<AVFoundation>   //  1.获取音效资源的路径   NSString *path = [[NSBundle mainBundle]pathForResource:@"pour_milk" ofType:@"wav"];   //  2.将路劲转化为url   NSURL *tempUrl = [NSURL fileURLWithPath:path];   //  3.用转化成的url创建一个播放器   NSError *error = nil;   AVAudioPlayer *play = [[AVAudioPlayer alloc]initWithContentsOfURL:tempUrl error:&error];   self.player = play;   //  4.播放   [play play];
12. 检测是否IPad PRo
- (BOOL)isIpadPro{     UIScreen *Screen = [UIScreen mainScreen];     CGFloat width = Screen.nativeBounds.size.width/Screen.nativeScale;    CGFloat height = Screen.nativeBounds.size.height/Screen.nativeScale;           BOOL isIpad =[[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad;     BOOL hasIPadProWidth = fabs(width - 1024.f) < DBL xss=removed xss=removed xss=removed xss=removed xss=removed xss=removed xss=removed xss=removed xss=removed>> ~/.lldbinit    echo target stop-hook add -o /"target stop-hook disable/" >> ~/.lldbinit下次重新运行项目，然后就不报错了。
25. Label行间距
-（void）test{    NSMutableAttributedString *attributedString =       [[NSMutableAttributedString alloc] initWithString:self.contentLabel.text];    NSMutableParagraphStyle *paragraphStyle =  [[NSMutableParagraphStyle alloc] init];     [paragraphStyle setLineSpacing:3];    //调整行间距          [attributedString addAttribute:NSParagraphStyleAttributeName                          value:paragraphStyle                          range:NSMakeRange(0, [self.contentLabel.text length])];     self.contentLabel.attributedText = attributedString;}
26. UIImageView填充模式
@"UIViewContentModeScaleToFill",      // 拉伸自适应填满整个视图  @"UIViewContentModeScaleaspectFit",   // 自适应比例大小显示  @"UIViewContentModeScaleAspectFill",  // 原始大小显示  @"UIViewContentModeRedraw",           // 尺寸改变时重绘  @"UIViewContentModeCenter",           // 中间  @"UIViewContentModeTop",              // 顶部  @"UIViewContentModeBottom",           // 底部  @"UIViewContentModeLeft",             // 中间贴左  @"UIViewContentModeRight",            // 中间贴右  @"UIViewContentModeTopLeft",          // 贴左上  @"UIViewContentModeTopRight",         // 贴右上  @"UIViewContentModeBottomLeft",       // 贴左下  @"UIViewContentModeBottomRight",      // 贴右下
27. 宏定义检测block是否可用
#define BLOCK_EXEC&#40;block, ...&#41; if (block) { block(__VA_ARGS__); };   // 宏定义之前的用法 if (completionBlock)   {       completionBlock(arg1, arg2);   }    // 宏定义之后的用法 BLOCK_EXEC&#40;completionBlock, arg1, arg2&#41;;
28. Debug栏打印时自动把Unicode编码转化成汉字
// 有时候我们在xcode中打印中文,会打印出Unicode编码,还需要自己去一些在线网站转换,有了插件就方便多了。 DXXcodeConsoleUnicodePlugin 插件
29. 设置状态栏文字样式颜色
[[UIApplication sharedApplication] setStatusBarHidden:NO];[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];
30. 自动生成模型代码的插件
// 可自动生成模型的代码，省去写模型代码的时间ESJsonFormat-for-Xcode
31. iOS中的一些手势
轻击手势（TapGestureRecognizer）轻扫手势（SwipeGestureRecognizer）长按手势（LongPressGestureRecognizer）拖动手势（PanGestureRecognizer）捏合手势（PinchGestureRecognizer）旋转手势（RotationGestureRecognizer）
32. iOS 开发中一些相关的路径
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。证书路径~/Library/MobileDevice/Provisioning Profiles
33. 获取 iOS 路径的方法
获取家目录路径的函数NSString *homeDir = NSHomeDirectory();获取Documents目录路径的方法NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);NSString *docDir = [paths objectAtIndex:0];获取Documents目录路径的方法NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);NSString *cachesDir = [paths objectAtIndex:0];获取tmp目录路径的方法：NSString *tmpDir = NSTemporaryDirectory();
34. 字符串相关操作
去除所有的空格[str stringByReplacingOccurrencesOfString:@" " withString:@""]去除首尾的空格[str stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];- (NSString *)uppercaseString; 全部字符转为大写字母- (NSString *)lowercaseString 全部字符转为小写字母
35. CocoaPods pod install/pod update更新慢的问题
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。
36. MRC和ARC混编设置方式
在XCode中targets的build phases选项下Compile Sources下选择 不需要arc编译的文件双击输入 -fno-objc-arc 即可MRC工程中也可以使用ARC的类，方法如下：在XCode中targets的build phases选项下Compile Sources下选择要使用arc编译的文件双击输入 -fobjc-arc 即可
37. 把tableview里cell的小对勾的颜色改成别的颜色
_mTableView.tintColor = [UIColor redColor];
38. 调整tableview的separaLine线的位置
tableView.separatorInset = UIEdgeInsetsMake(0, 100, 0, 0);
39. 设置滑动的时候隐藏navigationbar
navigationController.hidesBarsOnSwipe = Yes
40. 自动处理键盘事件，实现输入框防遮挡的插件
IQKeyboardManagerhttps://github.com/hackiftekhar/IQKeyboardManager
41. Quartz2D相关
图形上下是一个CGContextRef类型的数据。图形上下文包含：1，绘图路径（各种各样图形）2，绘图状态（颜色，线宽，样式，旋转，缩放，平移）3，输出目标（绘制到什么地方去？UIView、图片）1，获取当前图形上下文CGContextRef ctx = UIGraphicsGetCurrentContext();2，添加线条CGContextMoveToPoint(ctx, 20, 20);3，渲染CGContextStrokePath(ctx);CGContextFillPath(ctx);4，关闭路径CGContextClosePath(ctx);5，画矩形CGContextAddRect(ctx, CGRectMake(20, 20, 100, 120));6，设置线条颜色[[UIColor redColor] setStroke];7， 设置线条宽度CGContextSetLineWidth(ctx, 20);8，设置头尾样式CGContextSetLineCap(ctx, kCGLineCapSquare);9，设置转折点样式CGContextSetLineJoin(ctx, kCGLineJoinBevel);10，画圆CGContextAddEllipseInRect(ctx, CGRectMake(30, 50, 100, 100));11，指定圆心CGContextAddArc(ctx, 100, 100, 50, 0, M_PI * 2, 1);12，获取图片上下文UIGraphicsGetImageFromCurrentImageContext();13，保存图形上下文CGContextSaveGState(ctx)14，恢复图形上下文CGContextRestoreGState(ctx)
42. 屏幕截图
    // 1. 开启一个与图片相关的图形上下文    UIGraphicsBeginImageContextWithOptions(self.view.bounds.size,NO,0.0);    // 2. 获取当前图形上下文    CGContextRef ctx = UIGraphicsGetCurrentContext();    // 3. 获取需要截取的view的layer    [self.view.layer renderInContext:ctx];    // 4. 从当前上下文中获取图片    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();    // 5. 关闭图形上下文    UIGraphicsEndImageContext();    // 6. 把图片保存到相册    UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
43. 隐藏导航栏上的返回字体
//SwiftUIBarButtonItem.appearance().setBackButtonTitlePositionAdjustment(UIOffsetMake(0, -60), forBarMetrics: .Default)//OC[[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60) forBarMetrics:UIBarMetricsDefault];
44. 解决tableview的分割线短一截
-(void)viewDidLayoutSubviews{if ([self.tableView respondsToSelector:@selector(setSeparatorInset:)]){ [self.tableView setSeparatorInset:UIEdgeInsetsMake(0,0,0,0)];}if ([self.tableView respondsToSelector:@selector(setLayoutMargins:)]) {[self.tableView setLayoutMargins:UIEdgeInsetsMake(0,0,0,0)]; }}-(void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath{if ([cell respondsToSelector:@selector(setSeparatorInset:)]) {[cell setSeparatorInset:UIEdgeInsetsZero]; } if ([cell respondsToSelector:@selector(setLayoutMargins:)]) {[cell setLayoutMargins:UIEdgeInsetsZero]; }}
45. 动态隐藏NavigationBar
//1.当我们的手离开屏幕时候隐藏- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset{ if(velocity.y > 0) {[self.navigationController setNavigationBarHidden:YES animated:YES];} else {[self.navigationController setNavigationBarHidden:NO animated:YES]; }}velocity.y这个量，在上滑和下滑时，变化极小（小数），但是因为方向不同，有正负之分，这就很好处理了。
//2.在滑动过程中隐藏//像safari(1) self.navigationController.hidesBarsOnSwipe = YES;(2)- (void)scrollViewDidScroll:(UIScrollView *)scrollView{ CGFloat offsetY = scrollView.contentOffset.y + __tableView.contentInset.top; CGFloat panTranslationY = [scrollView.panGestureRecognizer translationInView:self.tableView].y; if (offsetY > 64) { if (panTranslationY > 0) { //下滑趋势，显示 [self.navigationController setNavigationBarHidden:NO animated:YES];} else { //上滑趋势，隐藏 [self.navigationController setNavigationBarHidden:YES animated:YES]; }} else {[self.navigationController setNavigationBarHidden:NO animated:YES]; }}这里的offsetY > 64只是为了在视图滑过navigationBar的高度之后才开始处理，防止影响展示效果。panTranslationY是scrollView的pan手势的手指位置的y值，可能不是太好，因为panTranslationY这个值在较小幅度上下滑动时，可能都为正或都为负，这就使得这一方式不太灵敏.
效果图
46. 设置导航栏透明
//方法一:设置透明度[[[self.navigationController.navigationBar subviews]objectAtIndex:0] setAlpha:0.1];//方法二:设置背景图片/** * 设置导航栏,使其透明 **/- (void)setNavigationBarColor:(UIColor *)color targetController:(UIViewController *)targetViewController{//导航条的颜色 以及隐藏导航条的颜色targetViewController.navigationController.navigationBar.shadowImage = [[UIImage alloc]init]; CGRect rect=CGRectMake(0.0f, 0.0f, 1.0f, 1.0f); UIGraphicsBeginImageContext(rect.size);CGContextRef context = UIGraphicsGetCurrentContext(); CGContextSetFillColorWithColor(context, [color CGColor]); CGContextFillRect(context, rect); UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); [targetViewController.navigationController.navigationBar setBackgroundImage:theImage forBarMetrics:UIBarMetricsDefault];}
47. 设置字体和行间距
//设置字体和行间距 UILabel * lable = [[UILabel alloc]initWithFrame:CGRectMake(50, 100, 300, 200)]; lable.text = @"大家好,我是Frank_chun,在这里我们一起学习新的知识,总结我们遇到的那些坑,共同的学习,共同的进步,共同的努力,只为美好的明天!!!有问题一起相互的探讨--438637472!!!"; lable.numberOfLines = 0;lable.font = [UIFont systemFontOfSize:12];lable.backgroundColor = [UIColor grayColor]; [self.view addSubview:lable]; //设置每个字体之间的间距 //NSKernAttributeName 这个对象所对应的值是一个NSNumber对象(包含小数),作用是修改默认字体之间的距离调整,值为0的话表示字距调整是禁用的; NSMutableAttributedString * str = [[NSMutableAttributedString alloc]initWithString:lable.text attributes:@{NSKernAttributeName:@(5.0)}];//设置某写字体的颜色//NSForegroundColorAttributeName 设置字体颜色NSRange blueRange = NSMakeRange([[str string] rangeOfString:@"Frank_chun"].location, [[str string] rangeOfString:@"Frank_chun"].length); [str addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:blueRange]; NSRange blueRange1 = NSMakeRange([[str string] rangeOfString:@"438637472"].location, [[str string] rangeOfString:@"438637472"].length);[str addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:blueRange1];//设置每行之间的间距 //NSParagraphStyleAttributeName 设置段落的样式NSMutableParagraphStyle * par = [[NSMutableParagraphStyle alloc]init];[par setLineSpacing:20];//为某一范围内文字添加某个属性//NSMakeRange表示所要的范围,从0到整个文本的长度[str addAttribute:NSParagraphStyleAttributeName value:par range:NSMakeRange(0, lable.text.length)]; [lable setAttributedText:str];
效果图
48. 点击button倒计时
//第一种方法//点击button倒计时#import "ViewController.h"@interface ViewController ()@property (nonatomic, strong) UIButton * timeButton;@property (nonatomic, strong) NSTimer * timer;@property (nonatomic, strong)UIButton * btn;@end@implementation ViewController{ NSInteger _time;}- (void)viewDidLoad {[super viewDidLoad]; _time = 5; self.btn = [UIButton buttonWithType:UIButtonTypeCustom]; _btn.backgroundColor = [UIColor orangeColor];[_btn setTitle:@"获取验证码" forState:UIControlStateNormal]; _btn.titleLabel.font = [UIFont systemFontOfSize:15];[_timeButton setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];[_btn addTarget:self action:@selector(btnAction:) forControlEvents:UIControlEventTouchUpInside];[self refreshButtonWidth]; [self.view addSubview:self.btn];}- (void)refreshButtonWidth{ CGFloat width = 0; if (_btn.enabled){ width = 100; } else { width = 200;} _btn.center = CGPointMake(self.view.frame.size.width/2, 200);_btn.bounds = CGRectMake(0, 0, width, 40); //每次刷新，保证区域正确[_btn setBackgroundImage:[self imageWithColor:[UIColor orangeColor] andSize:_btn.frame.size] forState:UIControlStateNormal];[_btn setBackgroundImage:[self imageWithColor:[UIColor lightGrayColor] andSize:_btn.frame.size] forState:UIControlStateDisabled];}- (UIImage *)imageWithColor:(UIColor *)color andSize:(CGSize)aSize{ CGRect rect = CGRectMake(0.0f, 0.0f, aSize.width, aSize.height); UIGraphicsBeginImageContext(rect.size); CGContextRef context = UIGraphicsGetCurrentContext(); CGContextSetFillColorWithColor(context, [color CGColor]); CGContextFillRect(context, rect); UIImage *image = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext();return image;}- (void)btnAction:(UIButton *)sender{sender.enabled = NO;[self refreshButtonWidth];[sender setTitle:[NSString stringWithFormat:@"获取验证码(%zi)", _time] forState:UIControlStateNormal]; _timer = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(timeDown) userInfo:nil repeats:YES];}- (void)timeDown{ _time --; if (_time == 0) { [_btn setTitle:@"重新获取" forState:UIControlStateNormal]; _btn.enabled = YES; [self refreshButtonWidth]; [_timer invalidate]; _timer = nil; _time = 5 ; return; } [_btn setTitle:[NSString stringWithFormat:@"获取验证码(%zi)", _time] forState:UIControlStateNormal];}
//第二种方法#pragma mark -点击发送验证码- (void)sendMessage:(UIButton *)btn{if (self.phoneField.text.length == 0) { [self remindMessage:@"请输入正确的手机号"];}else{ __block int timeout=60; //倒计时时间 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, ^{ if(timeout<=0){ //倒计时结束，关闭 dispatch_source_cancel(_timer); dispatch_async(dispatch_get_main_queue(), ^{ // 设置界面的按钮显示 根据自己需求设置 [btn setTitle:@"发送验证码" forState:UIControlStateNormal]; btn.userInteractionEnabled = YES; }); }else{ int seconds = timeout % 60;NSString *strTime = [NSString stringWithFormat:@"%d", seconds];if ([strTime isEqualToString:@"0"]) { strTime = [NSString stringWithFormat:@"%d",60]; } dispatch_async(dispatch_get_main_queue(), ^{ //设置界面的按钮显示 根据自己需求设置 //NSLog(@"____%@",strTime);[UIView beginAnimations:nil context:nil];[UIView setAnimationDuration:1]; [btn setTitle:[NSString stringWithFormat:@"%@秒后重新发送",strTime] forState:UIControlStateNormal];[UIView commitAnimations]; btn.userInteractionEnabled = NO; }); timeout--; } }); dispatch_resume(_timer);}
效果图
49. UITextField默认占位符是居中显示,让其居上显示
textField.contentVerticalAlignment = UIControlContentVerticalAlignmentTop;
50. 解决同时按两个按钮进两个view的问题
[button setExclusiveTouch:YES];
51. 图片拉伸
UIImage* img=[UIImage imageNamed:@"2.png"];//原图UIEdgeInsets edge=UIEdgeInsetsMake(0, 10, 0,10);//UIImageResizingModeStretch：拉伸模式，通过拉伸UIEdgeInsets指定的矩形区域来填充图片//UIImageResizingModeTile：平铺模式，通过重复显示UIEdgeInsets指定的矩形区域来填充图img= [img resizableImageWithCapInsets:edge resizingMode:UIImageResizingModeStretch];self.imageView.image=img;
52. 修改textFieldplaceholder字体颜色和大小
textField.placeholder = @"username is in here!";  [textField setValue:[UIColor redColor] forKeyPath:@"_placeholderLabel.textColor"];  [textField setValue:[UIFont boldSystemFontOfSize:16] forKeyPath:@"_placeholderLabel.font"];
53. 修改状态栏字体颜色
只能设置两种颜色，黑色和白色，系统默认黑色设置为白色方法：（1）在plist里面添加Status bar style，值为UIStatusBarStyleLightContent（白色）或UIStatusBarStyleDefault（黑 色）（2）在Info.plist中设置UIViewControllerBasedStatusBarAppearance 为NO
54. 去掉导航栏下边的黑线
[self.navigationController.navigationBar setBackgroundImage:[[UIImage alloc] init] forBarMetrics:UIBarMetricsDefault];self.navigationController.navigationBar.shadowImage = [[UIImage alloc] init];
55. 修改pagecontrol颜色
_pageControl.currentPageIndicatorTintColor=SFQRedColor;_pageControl.pageIndicatorTintColor=SFQGrayColor;
56. 去掉UITableView的section的粘性，使其不会悬停
//有时候使用UITableView所实现的列表，会使用到section，但是又不希望它粘在最顶上而是跟随滚动而消失或者出现- (void)scrollViewDidScroll:(UIScrollView *)scrollView {      if (scrollView == _tableView) {          CGFloat sectionHeaderHeight = 36;        if (scrollView.contentOffset.y <= sectionHeaderHeight && scrollView.contentOffset.y >= 0) {              scrollView.contentInset = UIEdgeInsetsMake(-scrollView.contentOffset.y, 0, 0, 0);          } else if (scrollView.contentOffset.y >= sectionHeaderHeight) {              scrollView.contentInset = UIEdgeInsetsMake(-sectionHeaderHeight, 0, 0, 0);          }      }  }
57. 通过2D仿射函数实现小的动画效果(变大缩小) --可用于自定义pageControl中
[UIView animateWithDuration:0.3 animations:^{       imageView.transform = CGAffineTransformMakeScale(2, 2);       } completion:^(BOOL finished) {       imageView.transform = CGAffineTransformMakeScale(1.0, 1.0);       }];
58. UIImage与字符串互转
//图片转字符串  -(NSString *)UIImageToBase64Str:(UIImage *) image  {      NSData *data = UIImageJPEGRepresentation(image, 1.0f);      NSString *encodedImageStr = [data base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];      return encodedImageStr;  }//字符串转图片  -(UIImage *)Base64StrToUIImage:(NSString *)_encodedImageStr  {      NSData *_decodedImageData   = [[NSData alloc] initWithBase64Encoding:_encodedImageStr];      UIImage *_decodedImage      = [UIImage imageWithData:_decodedImageData];      return _decodedImage;  }
59. 判断NSString中是否包含中文
-(BOOL)isChinese:(NSString *)str{    NSString *match=@"(^[/u4e00-/u9fa5]+$)";    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF matches %@", match];    return [predicate evaluateWithObject:str];}
60. NSDate与NSString的相互转化
-(NSString *)dateToString:(NSDate *)date {  // 初始化时间格式控制器  NSDateFormatter *matter = [[NSDateFormatter alloc] init];  // 设置设计格式  [matter setDateFormat:@"yyyy-MM-dd hh:mm:ss zzz"];  // 进行转换  NSString *dateStr = [matter stringFromDate:date];  return dateStr;}-(NSDate *)stringToDate:(NSString *)dateStr {  // 初始化时间格式控制器  NSDateFormatter *matter = [[NSDateFormatter alloc] init];  // 设置设计格式  [matter setDateFormat:@"yyyy-MM-dd hh:mm:ss zzz"];  // 进行转换  NSDate *date = [matter dateFromString:dateStr];  return date;}