分享一些iOS開發(fā)實(shí)用的小技巧

更新時(shí)間：2016年09月30日 14:06:48 作者：helloDolin

這篇文章主要給大家分享了一些iOS開發(fā)實(shí)用的小技巧，這些小技巧在大家開發(fā)iOS的時(shí)候還是相當(dāng)實(shí)用，有需要的朋友們下面來一起看看吧。

1.設(shè)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(zhuǎn)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(dòng)圖的時(shí)候隱藏statusbar

在info.plist中加入Status bar is initially hidden 設(shè)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(shè)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(zhuǎn)dictionary，dictionary轉(zhuǎn)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(guān)

+ (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(fù)系統(tǒng)側(cè)滑返回功能

 //設(shè)置代理
self.interactivePopGestureRecognizer.delegate = self;
#pragma mark - <UIGestureRecognizerDelegate>
//實(shí)現(xiàn)代理方法:return YES :手勢有效, NO :手勢無效
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
 //當(dāng)導(dǎo)航控制器的子控制器個(gè)數(shù) 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(gè)狀態(tài)下設(shè)置顏色,字體等不好使

只需要在對應(yīng)的位置用layoutIfNeeded刷新一下就可以了

13.設(shè)置圓形圖片

/** 設(shè)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(shè)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(gè)控件, 已經(jīng)明確設(shè)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(dòng)伸縮屬性在搞鬼!

解決辦法如下:

//xib的awakeFromNib方法中設(shè)置UIViewAutoresizingNone進(jìn)行清空

 - (void)awakeFromNib {
 self.autoresizingMask = UIViewAutoresizingNone;
}

15.通過圖片Data數(shù)據(jù)第一個(gè)字節(jié) 來獲取圖片擴(kuò)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(bǔ)全的方法

NSInteger count = 5;
//02代表:如果count不足2位 用0在最前面補(bǔ)全(2代表總輸出的個(gè)數(shù))
NSString *string = [NSString stringWithFormat:@"%02zd",count];
//輸出結(jié)果是: 05
NSLog(@"%@", string);

總結(jié)

以上就是這篇文章的全部內(nèi)容，希望本文中的這些小技巧能給大家開發(fā)iOS的時(shí)候提供一定的幫助，如果有疑問大家可以留言交流。

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