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];
//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.跳转到系统的相关界面:
/*

需要添加一个字段

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];

跳转到其他的界面的字段(不全,详细看链接)
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

原文链接：http://www.jianshu.com/p/19602f48309b

*/

8.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;
}

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的区头可以”不悬停”(可以直接百度搜到):

(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);
}

}
}