李晓的博客

iOS开发——实用性技巧

2016/07/09 iOS开发

分享一些项目中常用的方法，可以保存起来，作为自己的工具集哦。

  • 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];
    //创建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];
    //创建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.创建一张实时模糊效果 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;
}
  • 8.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;
}
  • 9.让Plain风格的TableView的区头可以”不悬停”:

```objc

  • (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);
   }    } } ```f

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