Objective-c 实用代码

1.磁盘总空间大小

• (CGFloat)diskOfAllSizeMBytes { CGFloat size = 0.0; NSError *error; NSDictionary *dic = [[NSFileManager defaultManager] attributesOfFileSystemForPath:NSHomeDirectory() error:&error]; if (error) { #ifdef DEBUG NSLog(@"error: %@", error.localizedDescription); #endif }else{ NSNumber *number = [dic objectForKey:NSFileSystemSize]; size = [number floatValue]/1024/1024; } return size; }

2.磁盘可用空间大小

• (CGFloat)diskOfFreeSizeMBytes { CGFloat size = 0.0; NSError *error; NSDictionary *dic = [[NSFileManager defaultManager] attributesOfFileSystemForPath:NSHomeDirectory() error:&error]; if (error) { #ifdef DEBUG NSLog(@"error: %@", error.localizedDescription); #endif }else{ NSNumber *number = [dic objectForKey:NSFileSystemFreeSize]; size = [number floatValue]/1024/1024; } return size; }

3.将字符串数组按照元素首字母顺序进行排序分组

• (NSDictionary *)dictionaryOrderByCharacterWithOriginalArray:(NSArray *)array { if (array.count == 0) { return nil; } for (id obj in array) { if (![obj isKindOfClass:[NSString class]]) { return nil; } } UILocalizedIndexedCollation *indexedCollation = [UILocalizedIndexedCollation currentCollation]; NSMutableArray *objects = [NSMutableArray arrayWithCapacity:indexedCollation.sectionTitles.count]; //建立27个分组数组 for (int i = 0; i < indexedCollation.sectionTitles.count; i++) { NSMutableArray *obj = [NSMutableArray array]; [objects addObject:obj]; } NSMutableArray *keys = [NSMutableArray arrayWithCapacity:objects.count]; //按字母顺序进行分组 NSInteger lastIndex = -1; for (int i = 0; i < array.count; i++) { NSInteger index = [indexedCollation sectionForObject:array[i] collationStringSelector:@selector(uppercaseString)]; [[objects objectAtIndex:index] addObject:array[i]]; lastIndex = index; } //去掉空数组 for (int i = 0; i < objects.count; i++) { NSMutableArray *obj = objects[i]; if (obj.count == 0) { [objects removeObject:obj]; } } //获取索引字母 for (NSMutableArray *obj in objects) { NSString *str = obj[0]; NSString *key = [self firstCharacterWithString:str]; [keys addObject:key]; } NSMutableDictionary *dic = [NSMutableDictionary dictionary]; [dic setObject:objects forKey:keys]; return dic; }

4.将字符串数组按照元素首字母顺序进行排序分组

• (NSDictionary *)dictionaryOrderByCharacterWithOriginalArray:(NSArray *)array { if (array.count == 0) { return nil; } for (id obj in array) { if (![obj isKindOfClass:[NSString class]]) { return nil; } } UILocalizedIndexedCollation *indexedCollation = [UILocalizedIndexedCollation currentCollation]; NSMutableArray *objects = [NSMutableArray arrayWithCapacity:indexedCollation.sectionTitles.count]; //建立27个分组数组 for (int i = 0; i < indexedCollation.sectionTitles.count; i++) { NSMutableArray *obj = [NSMutableArray array]; [objects addObject:obj]; } NSMutableArray *keys = [NSMutableArray arrayWithCapacity:objects.count]; //按字母顺序进行分组 NSInteger lastIndex = -1; for (int i = 0; i < array.count; i++) { NSInteger index = [indexedCollation sectionForObject:array[i] collationStringSelector:@selector(uppercaseString)]; [[objects objectAtIndex:index] addObject:array[i]]; lastIndex = index; } //去掉空数组 for (int i = 0; i < objects.count; i++) { NSMutableArray *obj = objects[i]; if (obj.count == 0) { [objects removeObject:obj]; } } //获取索引字母 for (NSMutableArray *obj in objects) { NSString *str = obj[0]; NSString *key = [self firstCharacterWithString:str]; [keys addObject:key]; } NSMutableDictionary *dic = [NSMutableDictionary dictionary]; [dic setObject:objects forKey:keys]; return dic; }

5.对图片进行滤镜处理 // 怀旧 --> CIPhotoEffectInstant 单色 --> CIPhotoEffectMono // 黑白 --> CIPhotoEffectNoir 褪色 --> CIPhotoEffectFade // 色调 --> CIPhotoEffectTonal 冲印 --> CIPhotoEffectProcess // 岁月 --> CIPhotoEffectTransfer 铬黄 --> CIPhotoEffectChrome // CILinearToSRGBToneCurve, CISRGBToneCurveToLinear, CIGaussianBlur, CIBoxBlur, CIDiscBlur, CISepiaTone, CIDepthOfField

• (UIImage *)filterWithOriginalImage:(UIImage *)image filterName:(NSString *)name { CIContext *context = [CIContext contextWithOptions:nil]; CIImage *inputImage = [[CIImage alloc] initWithImage:image]; CIFilter *filter = [CIFilter filterWithName:name]; [filter setValue:inputImage forKey:kCIInputImageKey]; CIImage *result = [filter valueForKey:kCIOutputImageKey]; CGImageRef cgImage = [context createCGImage:result fromRect:[result extent]]; UIImage *resultImage = [UIImage imageWithCGImage:cgImage]; CGImageRelease(cgImage); return resultImage; }

6.对图片进行模糊处理 // CIGaussianBlur ---> 高斯模糊 // CIBoxBlur ---> 均值模糊(Available in iOS 9.0 and later) // CIDiscBlur ---> 环形卷积模糊(Available in iOS 9.0 and later) // CIMedianFilter ---> 中值模糊, 用于消除图像噪点, 无需设置radius(Available in iOS 9.0 and later) // CIMotionBlur ---> 运动模糊, 用于模拟相机移动拍摄时的扫尾效果(Available in iOS 9.0 and later)

• (UIImage *)blurWithOriginalImage:(UIImage *)image blurName:(NSString *)name radius:(NSInteger)radius { CIContext *context = [CIContext contextWithOptions:nil]; CIImage *inputImage = [[CIImage alloc] initWithImage:image]; CIFilter *filter; if (name.length != 0) { filter = [CIFilter filterWithName:name]; [filter setValue:inputImage forKey:kCIInputImageKey]; if (![name isEqualToString:@"CIMedianFilter"]) { [filter setValue:@(radius) forKey:@"inputRadius"]; } CIImage *result = [filter valueForKey:kCIOutputImageKey]; CGImageRef cgImage = [context createCGImage:result fromRect:[result extent]]; UIImage *resultImage = [UIImage imageWithCGImage:cgImage]; CGImageRelease(cgImage); return resultImage; }else{ return nil; } }

7.跳转到系统的相关界面: /*

• 须要添加一个字段
• 蓝色的项目工程文件 -> Info -> URL Types -> 添加一个 -> 设置URL Sch**** 为 prefs的url

NSURL *url = [NSURL URLWithString:@"prefs:root=WIFI"]; [[UIApplication sharedApplication] openURL:url];

跳转到其余的界面的字段(不全,详细看连接) 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

原文连接：http://www.jianshu.com/p/19602f48309b

*/

8.建立一张实时模糊效果 View (毛玻璃效果) //Avilable in iOS 8.0 and later

• (UIVisualEffectView *)effectViewWithFrame:(CGRect)frame { UIBlurEffect *effect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleLight]; UIVisualEffectView *effectView = [[UIVisualEffectView alloc] initWithEffect:effect]; effectView.frame = frame; return effectView; }

9.设置Label的行间距

• (void)setLineSpaceWithString:(UILabel *)label {

  NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:label.text]; NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init]; [paragraphStyle setLineSpacing:3];

  //调整行间距 [attributedString addAttribute:NSParagraphStyleAttributeName value:paragraphStyle range:NSMakeRange(0, [label.text length])]; label.attributedText = attributedString; }

10.让Plain风格的TableView的区头能够”不悬停”(能够直接百度搜到):

• (void)scrollViewDidScroll:(UIScrollView *)scrollView { if(scrollView == self.myTab) { CGFloat sectionHeaderHeight = 40; 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);
     }

  } }