在開發過程中，我們總是會遇到各種小問題，其中有些問題不太容易解決，今天武林技術頻道小編為大家帶來iOS開發實用的小技巧，希望對你學習這方面知識有幫助。
1.設置navigationbar title顏色
UIColor *whiteColor = [UIColor whiteColor];NSDictionary *dic = [NSDictionary dictionaryWithObject:whiteColor forKey:NSForegroundColorAttributeName];[self.navigationController.navigationBar setTitleTextAttributes:dic];
2.獲取UIColor RGB
UIColor *color = [UIColor colorWithRed:0.0 green:0.0 blue:1.0 alpha:1.0];const CGFloat *components = CGColorGetComponents(color.CGColor);NSLog(@"Red: %f", components[0]);NSLog(@"Green: %f", components[1]);NSLog(@"Blue: %f", components[2]);NSLog(@"Alpha: %f", components[3]);
3.修改textField的placeholder的字體顏色、大小
[self.textField setValue:[UIColor redColor] forKeyPath:@"_placeholderLabel.textColor"];[self.textField setValue:[UIFont boldSystemFontOfSize:16] forKeyPath:@"_placeholderLabel.font"];
4.將color轉為UIImage
- (UIImage *)createImageWithColor:(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;}5.加載啟動圖的時候隱藏statusbar
在info.plist中加入Status bar is initially hidden 設置為YES
6.獲取按鈕title的size
/** * 獲取按鈕title的size */- (CGFloat)getBtnTitleWidth:(UIButton*)btn { CGSize titleSize = [btn.titleLabel.text sizeWithAttributes:@{NSFontAttributeName:btn.titleLabel.font}]; return titleSize;}7.設置Status bar顏色
UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, -20, ScreenWidth, 20)];[view setBackgroundColor:COLOR_APP_MAIN];[viewController.navigationController.navigationBar addSubview:view];
8.json轉dictionary，dictionary轉json
+ (NSString*)dictionaryToJson:(NSDictionary *)dic { NSError *parseError = nil; NSData *jsonData = [NSJSONSerialization dataWithJSONObject:dic options:NSJSONWritingPrettyPrinted error:&parseError]; return [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];}+(NSDictionary *)jsonToDic:(NSString*)jsonStr { NSData *jsonData = [jsonStr dataUsingEncoding:NSUTF8StringEncoding]; NSError *err; NSDictionary *dic = [NSJSONSerialization JSONObjectWithData:jsonData options:NSJSONReadingMutableContainers error:&err]; return dic;}9.是否允許推送
+(BOOL)isAllowedNotification{ if ([[UIDevice currentDevice].systemVersion floatValue] >= 8.0) { UIUserNotificationSettings *setting = [[UIApplication sharedApplication] currentUserNotificationSettings]; if(UIUserNotificationTypeNone != setting.types) { return YES; } } NSLog(@"不允許推送"); return NO;}10.磁盤空間相關
+ (NSString *)memoryFormatter:(long long)diskSpace { NSString *formatted; double bytes = 1.0 * diskSpace; double megabytes = bytes / MB; double gigabytes = bytes / GB; if (gigabytes >= 1.0) formatted = [NSString stringWithFormat:@"%.2f GB", gigabytes]; else if (megabytes >= 1.0) formatted = [NSString stringWithFormat:@"%.2f MB", megabytes]; else formatted = [NSString stringWithFormat:@"%.2f bytes", bytes]; NSLog(@"fotmatted=%@",formatted); return formatted;}+ (NSString *)totalDiskSpace { long long space = [[[[NSFileManager defaultManager] attributesOfFileSystemForPath:NSHomeDirectory() error:nil] objectForKey:NSFileSystemSize] longLongValue]; return [self memoryFormatter:space];}+ (NSString *)freeDiskSpace { long long freeSpace = [[[[NSFileManager defaultManager] attributesOfFileSystemForPath:NSHomeDirectory() error:nil] objectForKey:NSFileSystemFreeSize] longLongValue]; return [self memoryFormatter:freeSpace];}11.修改了leftBarButtonItem如何恢復系統側滑返回功能
//設置代理self.interactivePopGestureRecognizer.delegate = self;#pragma mark - <UIGestureRecognizerDelegate>//實現代理方法:return YES :手勢有效, NO :手勢無效- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer{ //當導航控制器的子控制器個數 大于1 手勢才有效 return self.childViewControllers.count > 1;}或者用第三方 UINavigationController+FDFullscreenPopGesture
12.使用UIAppearance在某個狀態下設置顏色,字體等不好使
只需要在對應的位置用layoutIfNeeded刷新一下就可以了
13.設置圓形圖片
/** 設置圓形圖片(放到分類中使用) */- (UIImage *)cutCircleImage { UIGraphicsBeginImageContextWithOptions(self.size, NO, 0.0); // 獲取上下文 CGContextRef ctr = UIGraphicsGetCurrentContext(); // 設置圓形 CGRect rect = CGRectMake(0, 0, self.size.width, self.size.height); CGContextAddEllipseInRect(ctr, rect); // 裁剪 CGContextClip(ctr); // 將圖片畫上去 [self drawInRect:rect]; UIImage *image = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return image;}14.如果在xib中有一個控件, 已經明確設置尺寸了,輸出的frame也是對的, 但是顯示出來的效果不一樣(比如尺寸變大了), 如果是這種情況一般就是autoresizingMask自動伸縮屬性在搞鬼!
解決辦法如下:
//xib的awakeFromNib方法中設置UIViewAutoresizingNone進行清空 - (void)awakeFromNib { self.autoresizingMask = UIViewAutoresizingNone;}15.通過圖片Data數據第一個字節 來獲取圖片擴展名
- (NSString *)contentTypeForImageData:(NSData *)data { uint8_t c; [data getBytes:&c length:1]; switch (c) { case 0xFF: return @"jpeg"; case 0x89: return @"png"; case 0x47: return @"gif"; case 0x49: case 0x4D: return @"tiff"; case 0x52: if ([data length] < 12) { return nil; } NSString *testString = [[NSString alloc] initWithData:[data subdataWithRange:NSMakeRange(0, 12)] encoding:NSASCIIStringEncoding]; if ([testString hasPrefix:@"RIFF"] && [testString hasSuffix:@"WEBP"]) { return @"webp"; } return nil; } return nil;}16.用0補全的方法
NSInteger count = 5;//02代表:如果count不足2位 用0在最前面補全(2代表總輸出的個數)NSString *string = [NSString stringWithFormat:@"%02zd",count];//輸出結果是: 05NSLog(@"%@", string);
以上就是關于iOS開發實用的小技巧，大家都了解了嗎?iOS開發是一門學問，要想做好，必須要好好的研習，推薦武林技術頻道給大家學習。
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