iOS 小技巧总结，绝对有你想要的
CelLangwell
8年前
<p>在这里总结一些iOS开发中的小技巧，能大大方便我们的开发，持续更新。</p> <p>UITableView的Group样式下顶部空白处理</p> <pre> <code class="language-objectivec">//分组列表头部空白处理 UIView *view = [[UIViewalloc] initWithFrame:CGRectMake(0, 0, 0, 0.1)]; self.tableView.tableHeaderView = view; </code></pre> <p>UITableView的plain样式下，取消区头停滞效果</p> <pre> <code class="language-objectivec">- (void)scrollViewDidScroll:(UIScrollView *)scrollView { CGFloatsectionHeaderHeight = sectionHead.height; if (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); } } </code></pre> <p>那个，其实，还是用Group样式吧哈哈。</p> <p>获取某个view所在的控制器</p> <pre> <code class="language-objectivec">- (UIViewController *)viewController { UIViewController *viewController = nil; UIResponder *next = self.nextResponder; while (next) { if ([nextisKindOfClass:[UIViewControllerclass]]) { viewController = (UIViewController *)next; break; } next = next.nextResponder; } return viewController; } </code></pre> <p>两种方法删除NSUserDefaults所有记录</p> <pre> <code class="language-objectivec">//方法一 NSString *appDomain = [[NSBundlemainBundle] bundleIdentifier]; [[NSUserDefaultsstandardUserDefaults] removePersistentDomainForName:appDomain]; //方法二 - (void)resetDefaults { NSUserDefaults * defs = [NSUserDefaultsstandardUserDefaults]; NSDictionary * dict = [defsdictionaryRepresentation]; for (idkeyin dict) { [defsremoveObjectForKey:key]; } [defssynchronize]; } </code></pre> <p>打印系统所有已注册的字体名称</p> <pre> <code class="language-objectivec">#pragma mark - 打印系统所有已注册的字体名称 void enumerateFonts() { for(NSString *familyNamein [UIFontfamilyNames]) { NSLog(@"%@",familyName); NSArray *fontNames = [UIFontfontNamesForFamilyName:familyName]; for(NSString *fontNamein fontNames) { NSLog(@"\t|- %@",fontName); } } } </code></pre> <p>获取图片某一点的颜色</p> <pre> <code class="language-objectivec">- (UIColor*) getPixelColorAtLocation:(CGPoint)pointinImage:(UIImage *)image { UIColor* color = nil; CGImageRefinImage = image.CGImage; CGContextRefcgctx = [self createARGBBitmapContextFromImage:inImage]; if (cgctx == NULL) { return nil; /* error */ } size_t w = CGImageGetWidth(inImage); size_t h = CGImageGetHeight(inImage); CGRectrect = {{0,0},{w,h}}; CGContextDrawImage(cgctx, rect, inImage); unsigned char* data = CGBitmapContextGetData (cgctx); if (data != NULL) { int offset = 4*((w*round(point.y))+round(point.x)); int alpha = data[offset]; int red = data[offset+1]; int green = data[offset+2]; int blue = data[offset+3]; color = [UIColorcolorWithRed:(red/255.0f) green:(green/255.0f) blue: (blue/255.0f) alpha:(alpha/255.0f)]; } CGContextRelease(cgctx); if (data) { free(data); } return color; } </code></pre> <p>字符串反转</p> <pre> <code class="language-objectivec">第一种： - (NSString *)reverseWordsInString:(NSString *)str { NSMutableString *newString = [[NSMutableStringalloc] initWithCapacity:str.length]; for (NSInteger i = str.length - 1; i >= 0 ; i --) { unicharch = [strcharacterAtIndex:i]; [newStringappendFormat:@"%c", ch]; } return newString; } //第二种： - (NSString*)reverseWordsInString:(NSString*)str { NSMutableString *reverString = [NSMutableStringstringWithCapacity:str.length]; [strenumerateSubstringsInRange:NSMakeRange(0, str.length) options:NSStringEnumerationReverse | NSStringEnumerationByComposedCharacterSequences usingBlock:^(NSString *substring, NSRangesubstringRange, NSRangeenclosingRange, BOOL *stop) { [reverStringappendString:substring]; }]; return reverString; } </code></pre> <p>禁止锁屏，</p> <p>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。</p> <pre> <code class="language-objectivec">[UIApplicationsharedApplication].idleTimerDisabled = YES; 或 [[UIApplicationsharedApplication] setIdleTimerDisabled:YES]; </code></pre> <p>模态推出透明界面</p> <pre> <code class="language-objectivec">UIViewController *vc = [[UIViewControlleralloc] init]; UINavigationController *na = [[UINavigationControlleralloc] initWithRootViewController:vc]; if ([[[UIDevicecurrentDevice] systemVersion] floatValue] >= 8.0) { na.modalPresentationStyle = UIModalPresentationOverCurrentContext; } else { self.modalPresentationStyle=UIModalPresentationCurrentContext; } [self presentViewController:naanimated:YEScompletion:nil]; </code></pre> <p>Xcode调试不显示内存占用</p> <pre> <code class="language-objectivec">editSCheme 里面有个选项叫叫做enablezoombieObjects 取消选中 </code></pre> <p>显示隐藏文件</p> <pre> <code class="language-objectivec">//显示 defaultswritecom.apple.finderAppleShowAllFiles -bool true killallFinder //隐藏 defaultswritecom.apple.finderAppleShowAllFiles -bool false killallFinder </code></pre> <p>字符串按多个符号分割</p> <p style="text-align:center"><img src="https://simg.open-open.com/show/d41fd150b0550a5f70dbe2e3fb00451f.png"></p> <p>iOS跳转到App Store下载应用评分</p> <pre> <code class="language-objectivec">[[UIApplicationsharedApplication] openURL:[NSURLURLWithString:@"itms-apps://itunes.apple.com/WebObjects/MZStore.woa/wa/viewContentsUserReviews?type=Purple+Software&id=APPID"]]; </code></pre> <p>iOS 获取汉字的拼音</p> <pre> <code class="language-objectivec">+ (NSString *)transform:(NSString *)chinese { //将NSString装换成NSMutableString NSMutableString *pinyin = [chinesemutableCopy]; //将汉字转换为拼音(带音标) CFStringTransform((__bridgeCFMutableStringRef)pinyin, NULL, kCFStringTransformMandarinLatin, NO); NSLog(@"%@", pinyin); //去掉拼音的音标 CFStringTransform((__bridgeCFMutableStringRef)pinyin, NULL, kCFStringTransformStripCombiningMarks, NO); NSLog(@"%@", pinyin); //返回最近结果 return pinyin; } </code></pre> <p>手动更改iOS状态栏的颜色</p> <pre> <code class="language-objectivec">- (void)setStatusBarBackgroundColor:(UIColor *)color { UIView *statusBar = [[[UIApplicationsharedApplication] valueForKey:@"statusBarWindow"] valueForKey:@"statusBar"]; if ([statusBarrespondsToSelector:@selector(setBackgroundColor:)]) { statusBar.backgroundColor = color; } } </code></pre> <p>判断当前ViewController是push还是present的方式显示的</p> <pre> <code class="language-objectivec">NSArray *viewcontrollers=self.navigationController.viewControllers; if (viewcontrollers.count > 1) { if ([viewcontrollersobjectAtIndex:viewcontrollers.count - 1] == self) { //push方式 [self.navigationControllerpopViewControllerAnimated:YES]; } } else { //present方式 [self dismissViewControllerAnimated:YEScompletion:nil]; } </code></pre> <p>获取实际使用的LaunchImage图片</p> <pre> <code class="language-objectivec">- (NSString *)getLaunchImageName { CGSizeviewSize = self.window.bounds.size; // 竖屏 NSString *viewOrientation = @"Portrait"; NSString *launchImageName = nil; NSArray* imagesDict = [[[NSBundlemainBundle] infoDictionary] valueForKey:@"UILaunchImages"]; for (NSDictionary* dictin imagesDict) { CGSizeimageSize = CGSizeFromString(dict[@"UILaunchImageSize"]); if (CGSizeEqualToSize(imageSize, viewSize) && [viewOrientationisEqualToString:dict[@"UILaunchImageOrientation"]]) { launchImageName = dict[@"UILaunchImageName"]; } } return launchImageName; } </code></pre> <p>iOS在当前屏幕获取第一响应</p> <pre> <code class="language-objectivec">UIWindow * keyWindow = [[UIApplicationsharedApplication] keyWindow]; UIView * firstResponder = [keyWindowperformSelector:@selector(firstResponder)]; </code></pre> <p>判断对象是否遵循了某协议</p> <pre> <code class="language-objectivec">if ([self.selectedControllerconformsToProtocol:@protocol(RefreshPtotocol)]) { [self.selectedControllerperformSelector:@selector(onTriggerRefresh)]; } </code></pre> <p>判断view是不是指定视图的子视图</p> <pre> <code class="language-objectivec">BOOL isView = [textViewisDescendantOfView:self.view]; </code></pre> <p>NSArray 快速求总和 最大值 最小值 和 平均值</p> <pre> <code class="language-objectivec">NSArray *array = [NSArrayarrayWithObjects:@"2.0", @"2.3", @"3.0", @"4.0", @"10", nil]; CGFloatsum = [[array valueForKeyPath:@"@sum.floatValue"] floatValue]; CGFloatavg = [[array valueForKeyPath:@"@avg.floatValue"] floatValue]; CGFloatmax =[[array valueForKeyPath:@"@max.floatValue"] floatValue]; CGFloatmin =[[array valueForKeyPath:@"@min.floatValue"] floatValue]; NSLog(@"%f\n%f\n%f\n%f",sum,avg,max,min); </code></pre> <p>修改UITextField中Placeholder的文字颜色</p> <pre> <code class="language-objectivec">[textFieldsetValue:[UIColorredColor] forKeyPath:@"_placeholderLabel.textColor"]; </code></pre> <p>关于NSDateFormatter的格式</p> <pre> <code class="language-objectivec">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 </code></pre> <p>获取一个类的所有子类</p> <pre> <code class="language-objectivec">+ (NSArray *) allSubclasses { Class myClass = [self class]; NSMutableArray *mySubclasses = [NSMutableArrayarray]; unsigned int numOfClasses; Class *classes = objc_copyClassList(&numOfClasses;); for (unsigned int ci = 0; ci </code></pre> <p>监测IOS设备是否设置了代理，需要CFNetwork.framework</p> <pre> <code class="language-objectivec">NSDictionary *proxySettings = (__bridgeNSDictionary *)(CFNetworkCopySystemProxySettings()); NSArray *proxies = (__bridgeNSArray *)(CFNetworkCopyProxiesForURL((__bridgeCFURLRef_Nonnull)([NSURLURLWithString:@"http://www.baidu.com"]), (__bridgeCFDictionaryRef_Nonnull)(proxySettings))); NSLog(@"\n%@",proxies); NSDictionary *settings = proxies[0]; NSLog(@"%@",[settingsobjectForKey:(NSString *)kCFProxyHostNameKey]); NSLog(@"%@",[settingsobjectForKey:(NSString *)kCFProxyPortNumberKey]); NSLog(@"%@",[settingsobjectForKey:(NSString *)kCFProxyTypeKey]); if ([[settingsobjectForKey:(NSString *)kCFProxyTypeKey] isEqualToString:@"kCFProxyTypeNone"]) { NSLog(@"没代理"); } else { NSLog(@"设置了代理"); } </code></pre> <p>阿拉伯数字转中文格式</p> <pre> <code class="language-objectivec">+(NSString *)translation:(NSString *)arebic { NSString *str = arebic; NSArray *arabic_numerals = @[@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",@"9",@"0"]; NSArray *chinese_numerals = @[@"一",@"二",@"三",@"四",@"五",@"六",@"七",@"八",@"九",@"零"]; NSArray *digits = @[@"个",@"十",@"百",@"千",@"万",@"十",@"百",@"千",@"亿",@"十",@"百",@"千",@"兆"]; NSDictionary *dictionary = [NSDictionarydictionaryWithObjects:chinese_numeralsforKeys:arabic_numerals]; NSMutableArray *sums = [NSMutableArrayarray]; for (int i = 0; i </code></pre> <p>Base64编码与NSString对象或NSData对象的转换</p> <pre> <code class="language-objectivec">// Create NSData object NSData *nsdata = [@"iOS Developer Tips encoded in Base64" dataUsingEncoding:NSUTF8StringEncoding]; // Get NSString from NSData object in Base64 NSString *base64Encoded = [nsdatabase64EncodedStringWithOptions:0]; // Print the Base64 encoded string NSLog(@"Encoded: %@", base64Encoded); // Let's go the other way... // NSData from the Base64 encoded str NSData *nsdataFromBase64String = [[NSDataalloc] initWithBase64EncodedString:base64Encodedoptions:0]; // Decoded NSString from the NSData NSString *base64Decoded = [[NSStringalloc] initWithData:nsdataFromBase64Stringencoding:NSUTF8StringEncoding]; NSLog(@"Decoded: %@", base64Decoded); </code></pre> <p>取消UICollectionView的隐式动画</p> <p>UICollectionView在reloadItems的时候，默认会附加一个隐式的fade动画，有时候很讨厌，尤其是当你的cell是复合cell的情况下(比如cell使用到了UIStackView)。</p> <p>下面几种方法都可以帮你去除这些动画</p> <pre> <code class="language-objectivec">//方法一 [UIViewperformWithoutAnimation:^{ [collectionViewreloadItemsAtIndexPaths:@[[NSIndexPathindexPathForItem:indexinSection:0]]]; }]; //方法二 [UIViewanimateWithDuration:0 animations:^{ [collectionViewperformBatchUpdates:^{ [collectionViewreloadItemsAtIndexPaths:@[[NSIndexPathindexPathForItem:indexinSection:0]]]; } completion:nil]; }]; //方法三 [UIViewsetAnimationsEnabled:NO]; [self.trackPanelperformBatchUpdates:^{ [collectionViewreloadItemsAtIndexPaths:@[[NSIndexPathindexPathForItem:indexinSection:0]]]; } completion:^(BOOL finished) { [UIViewsetAnimationsEnabled:YES]; }]; </code></pre> <p>让Xcode的控制台支持LLDB类型的打印</p> <pre> <code class="language-objectivec">打开终端输入三条命令: touch ~/.lldbinit echodisplay @importUIKit >> ~/.lldbinit echotargetstop-hookadd -o \"targetstop-hookdisable\" >> ~/.lldbinit </code></pre> <p>CocoaPods pod install/pod update更新慢的问题</p> <pre> <code class="language-objectivec">podinstall --verbose --no-repo-update podupdate --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 </code></pre> <p>UIImage 占用内存大小</p> <pre> <code class="language-objectivec">UIImage *image = [UIImageimageNamed:@"aa"]; NSUIntegersize = CGImageGetHeight(image.CGImage) * CGImageGetBytesPerRow(image.CGImage); </code></pre> <p>GCD timer定时器</p> <pre> <code class="language-objectivec">dispatch_queue_tqueue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0); dispatch_source_ttimer = 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, ^{ //@"倒计时结束，关闭" dispatch_source_cancel(timer); dispatch_async(dispatch_get_main_queue(), ^{ }); }); dispatch_resume(timer); </code></pre> <p>图片上绘制文字 写一个UIImage的category</p> <pre> <code class="language-objectivec">- (UIImage *)imageWithTitle:(NSString *)titlefontSize:(CGFloat)fontSize { //画布大小 CGSizesize=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 = [[NSParagraphStyledefaultParagraphStyle] 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 CGSizesizeText=[titleboundingRectWithSize:self.sizeoptions:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:[UIFontsystemFontOfSize:fontSize]}context:nil].size; CGFloatwidth = self.size.width; CGFloatheight = self.size.height; CGRectrect = CGRectMake((width-sizeText.width)/2, (height-sizeText.height)/2, sizeText.width, sizeText.height); //绘制文字 [titledrawInRect:rectwithAttributes:@{ NSFontAttributeName:[UIFontsystemFontOfSize:fontSize],NSForegroundColorAttributeName:[ UIColorwhiteColor],NSParagraphStyleAttributeName:paragraphStyle}]; //返回绘制的新图形 UIImage *newImage= UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return newImage; } </code></pre> <p>查找一个视图的所有子视图</p> <pre> <code class="language-objectivec">- (NSMutableArray *)allSubViewsForView:(UIView *)view { NSMutableArray *array = [NSMutableArrayarrayWithCapacity:0]; for (UIView *subViewin view.subviews) { [array addObject:subView]; if (subView.subviews.count > 0) { [array addObjectsFromArray:[self allSubViewsForView:subView]]; } } return array; } </code></pre> <p>计算文件大小</p> <pre> <code class="language-objectivec">//文件大小 - (long long)fileSizeAtPath:(NSString *)path { NSFileManager *fileManager = [NSFileManagerdefaultManager]; if ([fileManagerfileExistsAtPath:path]) { long long size = [fileManagerattributesOfItemAtPath:patherror:nil].fileSize; return size; } return 0; } //文件夹大小 - (long long)folderSizeAtPath:(NSString *)path { NSFileManager *fileManager = [NSFileManagerdefaultManager]; long long folderSize = 0; if ([fileManagerfileExistsAtPath:path]) { NSArray *childerFiles = [fileManagersubpathsAtPath:path]; for (NSString *fileNamein childerFiles) { NSString *fileAbsolutePath = [pathstringByAppendingPathComponent:fileName]; if ([fileManagerfileExistsAtPath:fileAbsolutePath]) { long long size = [fileManagerattributesOfItemAtPath:fileAbsolutePatherror:nil].fileSize; folderSize += size; } } } return folderSize; } </code></pre> <p>UIView设置部分圆角</p> <p>你是不是也遇到过这样的问题，一个button或者label，只要右边的两个角圆角，或者只要一个圆角。该怎么办呢。这就需要图层蒙版来帮助我们了</p> <pre> <code class="language-objectivec">CGRectrect = view.bounds; CGSizeradio = CGSizeMake(30, 30);//圆角尺寸 UIRectCornercorner = UIRectCornerTopLeft|UIRectCornerTopRight;//这只圆角位置 UIBezierPath *path = [UIBezierPathbezierPathWithRoundedRect:rectbyRoundingCorners:cornercornerRadii:radio]; CAShapeLayer *masklayer = [[CAShapeLayeralloc]init];//创建shapelayer masklayer.frame = view.bounds; masklayer.path = path.CGPath;//设置路径 view.layer.mask = masklayer; </code></pre> <p>取上整与取下整</p> <pre> <code class="language-objectivec">floor(x),有时候也写做Floor(x)，其功能是“下取整”，即取不大于x的最大整数 例如： x=3.14，floor(x)=3 y=9.99999，floor(y)=9 与floor函数对应的是ceil函数，即上取整函数。 ceil函数的作用是求不小于给定实数的最小整数。 ceil(2)=ceil(1.2)=cei(1.5)=2.00 floor函数与ceil函数的返回值均为double型 </code></pre> <p>计算字符串字符长度，一个汉字算两个字符</p> <pre> <code class="language-objectivec">//方法一： - (int)convertToInt:(NSString*)strtemp { int strlength = 0; char* p = (char*)[strtempcStringUsingEncoding:NSUnicodeStringEncoding]; for (int i=0 ; i </code></pre> <p>给UIView设置图片</p> <pre> <code class="language-objectivec">UIImage *image = [UIImageimageNamed:@"image"]; self.MYView.layer.contents = (__bridgeid_Nullable)(image.CGImage); self.MYView.layer.contentsRect = CGRectMake(0, 0, 0.5, 0.5); </code></pre> <p>防止scrollView手势覆盖侧滑手势</p> <pre> <code class="language-objectivec">[scrollView.panGestureRecognizerrequireGestureRecognizerToFail:self.navigationController.interactivePopGestureRecognizer]; </code></pre> <p>去掉导航栏返回的back标题</p> <pre> <code class="language-objectivec">[[UIBarButtonItemappearance]setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60)forBarMetrics:UIBarMetricsDefault]; </code></pre> <p>字符串中是否含有中文</p> <pre> <code class="language-objectivec">+ (BOOL)checkIsChinese:(NSString *)string { for (int i=0; i </code></pre> <p>dispatch_group的使用</p> <pre> <code class="language-objectivec"> dispatch_group_tdispatchGroup = dispatch_group_create(); dispatch_group_enter(dispatchGroup); dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{ NSLog(@"第一个请求完成"); dispatch_group_leave(dispatchGroup); }); dispatch_group_enter(dispatchGroup); dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(10 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{ NSLog(@"第二个请求完成"); dispatch_group_leave(dispatchGroup); }); dispatch_group_notify(dispatchGroup, dispatch_get_main_queue(), ^(){ NSLog(@"请求完成"); }); </code></pre> <p>UITextField每四位加一个空格,实现代理</p> <pre> <code class="language-objectivec">- (BOOL)textField:(UITextField *)textFieldshouldChangeCharactersInRange:(NSRange)rangereplacementString:(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.textsubstringToIndex:textField.text.length - 1]; } return YES; } else { if (textField.text.length % 5 == 0) { textField.text = [NSStringstringWithFormat:@"%@ ", textField.text]; } } return YES; } </code></pre> <p>获取私有属性和成员变量 #import</p> <pre> <code class="language-objectivec">//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([UIDatePickerclass], &count); for(int i = 0;i </code></pre> <pre> <code class="language-objectivec">//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([UIAlertActionclass], &count); for(int i =0;i </code></pre> <p>获取手机安装的应用</p> <pre> <code class="language-objectivec">Class c =NSClassFromString(@"LSApplicationWorkspace"); id s = [(id)c performSelector:NSSelectorFromString(@"defaultWorkspace")]; NSArray *array = [s performSelector:NSSelectorFromString(@"allInstalledApplications")]; for (iditemin array) { NSLog(@"%@",[itemperformSelector:NSSelectorFromString(@"applicationIdentifier")]); //NSLog(@"%@",[item performSelector:NSSelectorFromString(@"bundleIdentifier")]); NSLog(@"%@",[itemperformSelector:NSSelectorFromString(@"bundleVersion")]); NSLog(@"%@",[itemperformSelector:NSSelectorFromString(@"shortVersionString")]); } </code></pre> <p>判断两个日期是否在同一周 写在NSDate的category里面</p> <pre> <code class="language-objectivec">- (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 = [NSCalendarcurrentCalendar]; 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 NSUIntegercountSelf = [calenderordinalityOfUnit:NSCalendarUnitWeekdayinUnit:NSCalendarUnitYearforDate:self]; NSUIntegercountDate = [calenderordinalityOfUnit:NSCalendarUnitWeekdayinUnit:NSCalendarUnitYearforDate:date]; //相等就在同一周，不相等就不在同一周 return countSelf == countDate; } </code></pre> <p>应用内打开系统设置界面</p> <pre> <code class="language-objectivec">//iOS8之后 [[UIApplicationsharedApplication] openURL:[NSURLURLWithString: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。 </code></pre> <pre> <code class="language-objectivec">//iOS8之前 //先添加一个url type如下图，在代码中调用如下代码,即可跳转到设置页面的对应项 [[UIApplicationsharedApplication] openURL:[NSURLURLWithString:@"prefs:root=WIFI"]]; 可选值如下： About — prefs:root=General&path=About Accessibility — prefs:root=General&path=ACCESSIBILITY AirplaneModeOn — prefs:root=AIRPLANE_MODE Auto-Lock — prefs:root=General&path=AUTOLOCK Brightness — prefs:root=Brightness Bluetooth — prefs:root=General&path=Bluetooth Date & Time — prefs:root=General&path=DATE_AND_TIME FaceTime — prefs:root=FACETIME General — prefs:root=General Keyboard — prefs:root=General&path=Keyboard iCloud — prefs:root=CASTLE iCloudStorage & Backup — prefs:root=CASTLE&path=STORAGE_AND_BACKUP International — prefs:root=General&path=INTERNATIONAL LocationServices — prefs:root=LOCATION_SERVICES Music — prefs:root=MUSIC MusicEqualizer — prefs:root=MUSIC&path=EQ MusicVolumeLimit — prefs:root=MUSIC&path=VolumeLimit Network — prefs:root=General&path=Network Nike + iPod — prefs:root=NIKE_PLUS_IPOD Notes — prefs:root=NOTES Notification — prefs:root=NOTIFICATI*****_ID Phone — prefs:root=Phone Photos — prefs:root=Photos Profile — prefs:root=General&path=ManagedConfigurationList Reset — prefs:root=General&path=Reset Safari — prefs:root=Safari Siri — prefs:root=General&path=Assistant Sounds — prefs:root=Sounds SoftwareUpdate — prefs:root=General&path=SOFTWARE_UPDATE_LINK Store — prefs:root=STORE 推ter — prefs:root=推ter Usage — prefs:root=General&path=USAGE V*N — prefs:root=General&path=Network/V*N Wallpaper — prefs:root=Wallpaper Wi-Fi — prefs:root=WIFI </code></pre> <p style="text-align:center"><img src="https://simg.open-open.com/show/add370f21374a99032444a258ff2d08f.png"></p> <p>屏蔽触发事件，2秒后取消屏蔽</p> <pre> <code class="language-objectivec">[[UIApplicationsharedApplication] beginIgnoringInteractionEvents]; dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(2 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{ [[UIApplicationsharedApplication] endIgnoringInteractionEvents] }); </code></pre> <p>动画暂停再开始</p> <pre> <code class="language-objectivec">-(void)pauseLayer:(CALayer *)layer { CFTimeIntervalpausedTime = [layerconvertTime:CACurrentMediaTime() fromLayer:nil]; layer.speed = 0.0; layer.timeOffset = pausedTime; } -(void)resumeLayer:(CALayer *)layer { CFTimeIntervalpausedTime = [layertimeOffset]; layer.speed = 1.0; layer.timeOffset = 0.0; layer.beginTime = 0.0; CFTimeIntervaltimeSincePause = [layerconvertTime:CACurrentMediaTime() fromLayer:nil] - pausedTime; layer.beginTime = timeSincePause; } </code></pre> <p>fillRule原理</p> <p style="text-align:center"><img src="https://simg.open-open.com/show/01927ab282b99e0c91550ae6d7923d58.png"></p> <p>iOS中数字的格式化</p> <pre> <code class="language-objectivec">//通过NSNumberFormatter，同样可以设置NSNumber输出的格式。例如如下代码： NSNumberFormatter *formatter = [[NSNumberFormatteralloc] init]; formatter.numberStyle = NSNumberFormatterDecimalStyle; NSString *string = [formatterstringFromNumber:[NSNumbernumberWithInt:123456789]]; NSLog(@"Formatted number string:%@",string); //输出结果为：[1223:403] Formatted number string:123,456,789 //其中NSNumberFormatter类有个属性numberStyle，它是一个枚举型，设置不同的值可以输出不同的数字格式。该枚举包括： typedef NS_ENUM(NSUInteger, NSNumberFormatterStyle) { NSNumberFormatterNoStyle = kCFNumberFormatterNoStyle, NSNumberFormatterDecimalStyle = kCFNumberFormatterDecimalStyle, NSNumberFormatterCurrencyStyle = kCFNumberFormatterCurrencyStyle, NSNumberFormatterPercentStyle = kCFNumberFormatterPercentStyle, NSNumberFormatterScientificStyle = kCFNumberFormatterScientificStyle, NSNumberFormatterSpellOutStyle = kCFNumberFormatterSpellOutStyle }; //各个枚举对应输出数字格式的效果如下：其中第三项和最后一项的输出会根据系统设置的语言区域的不同而不同。 [1243:403] Formattednumberstring:123456789 [1243:403] Formattednumberstring:123,456,789 [1243:403] Formattednumberstring:￥123,456,789.00 [1243:403] Formattednumberstring:-539,222,988% [1243:403] Formattednumberstring:1.23456789E8 [1243:403] Formattednumberstring:一亿二千三百四十五万六千七百八十九 </code></pre> <p>如何获取WebView所有的图片地址，</p> <p>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</p> <pre> <code class="language-objectivec">//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 </code></pre> <pre> <code class="language-objectivec">//WKWebView - (void)webView:(WKWebView *)webViewdidFinishNavigation:(null_unspecifiedWKNavigation *)navigation { static NSString * const jsGetImages = @"function getImages(){\ var objs = document.getElementsByTagName(\"img\");\ var imgScr = '';\ for(var i=0;i </code></pre> <p>获取到webview的高度</p> <pre> <code class="language-objectivec">CGFloatheight = [[self.webViewstringByEvaluatingJavaScriptFromString:@"document.body.offsetHeight"] floatValue]; </code></pre> <p>navigationBar变为纯透明</p> <pre> <code class="language-objectivec">//第一种方法 //导航栏纯透明 [self.navigationBarsetBackgroundImage:[UIImagenew] forBarMetrics:UIBarMetricsDefault]; //去掉导航栏底部的黑线 self.navigationBar.shadowImage = [UIImagenew]; //第二种方法 [[self.navigationBarsubviews] objectAtIndex:0].alpha = 0; </code></pre> <p>tabBar同理</p> <pre> <code class="language-objectivec">[self.tabBarsetBackgroundImage:[UIImagenew]]; self.tabBar.shadowImage = [UIImagenew]; </code></pre> <p>navigationBar根据滑动距离的渐变色实现</p> <pre> <code class="language-objectivec">//第一种 - (void)scrollViewDidScroll:(UIScrollView *)scrollView { CGFloatoffsetToShow = 200.0;//滑动多少就完全显示 CGFloatalpha = 1 - (offsetToShow - scrollView.contentOffset.y) / offsetToShow; [[self.navigationController.navigationBarsubviews] objectAtIndex:0].alpha = alpha; } </code></pre> <pre> <code class="language-objectivec">//第二种 - (void)scrollViewDidScroll:(UIScrollView *)scrollView { CGFloatoffsetToShow = 200.0; CGFloatalpha = 1 - (offsetToShow - scrollView.contentOffset.y) / offsetToShow; [self.navigationController.navigationBarsetShadowImage:[UIImagenew]]; [self.navigationController.navigationBarsetBackgroundImage:[self imageWithColor:[[UIColororangeColor]colorWithAlphaComponent:alpha]] forBarMetrics:UIBarMetricsDefault]; } //生成一张纯色的图片 - (UIImage *)imageWithColor:(UIColor *)color { CGRectrect = CGRectMake(0.0f, 0.0f, 1.0f, 1.0f); UIGraphicsBeginImageContext(rect.size); CGContextRefcontext = UIGraphicsGetCurrentContext(); CGContextSetFillColorWithColor(context, [colorCGColor]); CGContextFillRect(context, rect); UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return theImage; } </code></pre> <p>iOS 开发中一些相关的路径</p> <pre> <code class="language-objectivec">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/ProvisioningProfiles </code></pre> <p>navigationItem的BarButtonItem如何紧靠屏幕右边界或者左边界？</p> <p>一般情况下，右边的item会和屏幕右侧保持一段距离：</p> <p style="text-align:center"><img src="https://simg.open-open.com/show/6c1173152def7016be89942277836a21.png"></p> <p>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：</p> <pre> <code class="language-objectivec">UIImage *img = [[UIImageimageNamed:@"icon_cog"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal]; //宽度为负数的固定间距的系统item UIBarButtonItem *rightNegativeSpacer = [[UIBarButtonItemalloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpacetarget:nilaction:nil]; [rightNegativeSpacersetWidth:-15]; UIBarButtonItem *rightBtnItem1 = [[UIBarButtonItemalloc]initWithImage:imgstyle:UIBarButtonItemStylePlaintarget:selfaction:@selector(rightButtonItemClicked:)]; UIBarButtonItem *rightBtnItem2 = [[UIBarButtonItemalloc]initWithImage:imgstyle:UIBarButtonItemStylePlaintarget:selfaction:@selector(rightButtonItemClicked:)]; self.navigationItem.rightBarButtonItems = @[rightNegativeSpacer,rightBtnItem1,rightBtnItem2]; </code></pre> <p style="text-align:center"><img src="https://simg.open-open.com/show/16302ade932d57a7d7fcb3f0af8030a7.png"></p> <p>NSString进行URL编码和解码</p> <pre> <code class="language-objectivec">NSString *string = @"http://abc.com?aaa=你好&bbb=tttee"; //编码 打印：http://abc.com?aaa=%E4%BD%A0%E5%A5%BD&bbb=tttee string = [string stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSetURLQueryAllowedCharacterSet]]; //解码 打印：http://abc.com?aaa=你好&bbb=tttee string = [string stringByRemovingPercentEncoding]; </code></pre> <p>UIWebView设置User-Agent。</p> <pre> <code class="language-objectivec">//设置 NSDictionary *dic = @{@"UserAgent":@"your UserAgent"}; [[NSUserDefaultsstandardUserDefaults] registerDefaults:dic]; //获取 NSString *agent = [self.WebViewstringByEvaluatingJavaScriptFromString:@"navigator.userAgent"]; </code></pre> <p>获取硬盘总容量与可用容量:</p> <pre> <code class="language-objectivec">NSFileManager *fileManager = [NSFileManagerdefaultManager]; NSDictionary *attributes = [fileManagerattributesOfFileSystemForPath:NSHomeDirectory() error:nil]; NSLog(@"容量%.2fG",[attributes[NSFileSystemSize] doubleValue] / (powf(1024, 3))); NSLog(@"可用%.2fG",[attributes[NSFileSystemFreeSize] doubleValue] / powf(1024, 3)); </code></pre> <p>获取UIColor的RGBA值</p> <pre> <code class="language-objectivec">UIColor *color = [UIColorcolorWithRed: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]); </code></pre> <p>修改textField的placeholder的字体颜色、大小</p> <pre> <code class="language-objectivec">[self.textFieldsetValue:[UIColorredColor] forKeyPath:@"_placeholderLabel.textColor"]; [self.textFieldsetValue:[UIFontboldSystemFontOfSize:16] forKeyPath:@"_placeholderLabel.font"]; </code></pre> <p>AFN移除JSON中的NSNull</p> <pre> <code class="language-objectivec">AFJSONResponseSerializer *response = [AFJSONResponseSerializerserializer]; response.removesKeysWithNullValues = YES; </code></pre> <p>ceil()和floor()</p> <p>ceil() 功 能：返回大于或者等于指定表达式的最小整数</p> <p>floor() 功 能：返回小于或者等于指定表达式的最大整数</p> <p>UIWebView里面的图片自适应屏幕</p> <p>在webView加载完的代理方法里面这样写：</p> <pre> <code class="language-objectivec">- (void)webViewDidFinishLoad:(UIWebView *)webView { NSString *js = @"function imgAutoFit() { \ var imgs = document.getElementsByTagName('img'); \ for (var i = 0; i </code></pre> <p> </p> <p> </p> <p>来自：http://ios.jobbole.com/91214/</p> <p> </p>