iOS小技巧总结###
参考iOS_小松哥的iOS小技巧总结
总结日常代码生活中的小技巧，随时可用
阿拉伯数字转中文格式
阿拉伯数字转中文格式
UITextField每四位加一个空格,实现代理
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
// 四位加一个空格
if ([string isEqualToString:@""])
{
// 删除字符
if ((textField.text.length - 2) % 5 == 0)
{
textField.text = [textField.text substringToIndex:textField.text.length - 1];
}
return YES;
}
else
{
if (textField.text.length % 5 == 0)
{
textField.text = [NSString stringWithFormat:@"%@ ", textField.text];
}
}
return YES;
}
禁止锁屏
默认情况下，当设备一段时间没有触控动作时，iOS会锁住屏幕。但有一些应用是不需要锁屏的，比如视频播放器。
[UIApplication sharedApplication].idleTimerDisabled = YES;
或
[[UIApplication sharedApplication] setIdleTimerDisabled:YES];
iOS 获取汉字的拼音
+ (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;
}
手动更改iOS状态栏的颜色
- (void)setStatusBarBackgroundColor:(UIColor *)color
{
UIView *statusBar = [[[UIApplication sharedApplication] valueForKey:@"statusBarWindow"] valueForKey:@"statusBar"];
if ([statusBar respondsToSelector:@selector(setBackgroundColor:)])
{
statusBar.backgroundColor = color;
}
}
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);
修改UITextField中Placeholder的文字颜色
[textField setValue:[UIColor redColor] forKeyPath:@"_placeholderLabel.textColor"];
或
textField.tintColor = [UIColor redColor];
关于NSDateFormatter的格式
G: 公元时代，例如AD公元
yy: 年的后2位
yyyy: 完整年
MM: 月，显示为1-12
MMM: 月，显示为英文月份简写,如 Jan
MMMM: 月，显示为英文月份全称，如 Janualy
dd: 日，2位数表示，如02
d: 日，1-2位显示，如 2
EEE: 简写星期几，如Sun
EEEE: 全写星期几，如Sunday
aa: 上下午，AM/PM
H: 时，24小时制，0-23
K：时，12小时制，0-11
m: 分，1-2位
mm: 分，2位
s: 秒，1-2位
ss: 秒，2位
S: 毫秒
UIImage 占用内存大小
UIImage *image = [UIImage imageNamed:@"aa"];
NSUInteger size = CGImageGetHeight(image.CGImage) * CGImageGetBytesPerRow(image.CGImage);
图片上绘制文字 写一个UIImage的category
- (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;
}
计算文件大小
//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;
}
给UIView设置图片
UIImage *image = [UIImage imageNamed:@"image"];
self.MYView.layer.contents = (__bridge id _Nullable)(image.CGImage);
self.MYView.layer.contentsRect = CGRectMake(0, 0, 0.5, 0.5);
防止scrollView手势覆盖侧滑手势
[scrollView.panGestureRecognizerrequireGestureRecognizerToFail:self.navigationController.interactivePopGestureRecognizer];
获取私有属性和成员变量 #import
//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"];
}
}
获取手机安装的应用
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")]);
}
判断两个日期是否在同一周 写在NSDate的category里面
- (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;
}
应用内打开系统设置界面
//iOS8之后
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:UIApplicationOpenSettingsURLString]];
//如果App没有添加权限，显示的是设定界面。如果App有添加权限（例如通知），显示的是App的设定界面。
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
//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//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获取到webview的高度
CGFloat height = [[self.webView stringByEvaluatingJavaScriptFromString:@"document.body.offsetHeight"] floatValue];
navigationBar变为纯透明
//第一种方法
//导航栏纯透明
[self.navigationBar setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];
//去掉导航栏底部的黑线
self.navigationBar.shadowImage = [UIImage new];
//第二种方法
[[self.navigationBar subviews] objectAtIndex:0].alpha = 0;
navigationBar根据滑动距离的渐变色实现
//第一种
- (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;
}
//第二种
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
CGFloat offsetToShow = 200.0;
CGFloat alpha = 1 - (offsetToShow - scrollView.contentOffset.y) / offsetToShow;
[self.navigationController.navigationBar setShadowImage:[UIImage new]];
[self.navigationController.navigationBar setBackgroundImage:[self imageWithColor:[[UIColor orangeColor]colorWithAlphaComponent:alpha]] forBarMetrics:UIBarMetricsDefault];
}
//生成一张纯色的图片
- (UIImage *)imageWithColor:(UIColor *)color
{
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();
return theImage;
}
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。
描述文件路径
~/Library/MobileDevice/Provisioning Profiles
navigationItem的BarButtonItem如何紧靠屏幕右边界或者左边界？
一般情况下，右边的item会和屏幕右侧保持一段距离：
image.png
下面是通过添加一个负值宽度的固定间距的item来解决，也可以改变宽度实现不同的间隔：
UIImage *img = [[UIImage imageNamed:@"icon_cog"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
//宽度为负数的固定间距的系统item
UIBarButtonItem *rightNegativeSpacer = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil];
[rightNegativeSpacer setWidth:-15];
UIBarButtonItem *rightBtnItem1 = [[UIBarButtonItem alloc]initWithImage:img style:UIBarButtonItemStylePlain target:self action:@selector(rightButtonItemClicked:)];
UIBarButtonItem *rightBtnItem2 = [[UIBarButtonItem alloc]initWithImage:img style:UIBarButtonItemStylePlain target:self action:@selector(rightButtonItemClicked:)];
self.navigationItem.rightBarButtonItems = @[rightNegativeSpacer,rightBtnItem1,rightBtnItem2];
image1.png