iOS 常用小技巧总结
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 *)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//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(block, ...) 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(completionBlock, arg1, arg2);
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
IQKeyboardManager
https://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[[UIBarButtonItemappearance]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();returnimage;
}
- (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:0.1target: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_tqueue=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=[imgresizableImageWithCapInsets:edgeresizingMode: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);
}elseif(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:0.3animations:^{
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];
returnen codedImageStr;
}
//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];returndateStr;
}
-(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;
}
文章出处：iOS 知识-常用小技巧大杂烩
