(http://upload-images.jianshu.io/upload_images/1197386-a0a0fd650cb43047.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240)

• 按照提示的去操作似乎棉磨，還是不行岸沤铡！有人說是 【死循環(huán)】、【內(nèi)存泄漏】愈污、【版本問題】
• 其實都有道理。但是筆者這個的話雄右，是因為鳄梅，加載的圖片實在是太大了，導(dǎo)致出現(xiàn)的bug衩匣。
• 筆者檢測發(fā)現(xiàn)蕾总，在主線程消耗太多的資源，cup 一下子達(dá)到35%以上琅捏，肯定會閃退了生百。然后呢，搞個懶加載柄延，也解決不了蚀浆。最后，采用了異步加載的方式搜吧，視圖加載由原來的scrollView改成使用collectionview市俊。因為圖片是在是太大太多了，項目需求嘛滤奈！使用scrollView的話摆昧，你的圖片是一次性加載所有的資源！問題就在這里僵刮，一次性加載上百張圖片据忘，導(dǎo)致CPU和內(nèi)存暴漲鹦牛。閃退是不可避免的。如果是采用collectionView的話勇吊，它是有重用機(jī)制的曼追，性能、資源加載等問題基本解決了汉规。

2礼殊、個人的小總結(jié)： http://m.blog.csdn.net/article/details?id=52180380

3、iOS中的url編碼問題针史，下面拿出一個實例晶伦，要stringByAddingPercentEscapesUsingEncoding 來轉(zhuǎn)換：

Snip20160818_1.png

結(jié)果為null，肯定的啦啄枕！ 圖片加載顯示等婚陪，都要轉(zhuǎn)UTF8.

Snip20160818_2.png

4、自動布局Autolayout

屏幕快照 2016-08-19 13.47.35.png

5频祝、App迭代開發(fā)版本號的規(guī)則

首先我們的App第一版本首次上線, 比如以1.0.0為首次上線的版本號:

1.上線后突然發(fā)現(xiàn)一個嚴(yán)重的Bug那我們就要修復(fù)更新版本, 此時我們的版本號為1.0.1
所以說如果修復(fù)Bug或者優(yōu)化功能, 我們只修改疊加第三位數(shù)字, 其他不變

2.如果有了新的需求, 在原來的基礎(chǔ)上增加了一個新功能, 那么我們的版本號變?yōu)?.1.0, 需要清空第三位數(shù)字為0, 來疊加修改第二位數(shù)字

3.如果App需求功能大改, 更新量非常大, 那我們的版本號變?yōu)?.0.0, 需要疊加修改第一位數(shù)字, 清空其他數(shù)字為0

6泌参、設(shè)置圖片圓角

通常我們這么設(shè)置的:（少量可以使用該設(shè)置，但是使用的頻率多的話就不建議了）

//cornerRadius 設(shè)置為self.iconImage圖片寬度的一半(圓形圖片)
self.iconImage.layer.cornerRadius = 20;
self.iconImage.layer.masksToBounds = YES;

/** 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;
}

7常空、xib 的常見問題

(1) 如果在xib中有一個控件, 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;
  }
  (2)如果你的控制器的view是用xib創(chuàng)建的, 當(dāng)你拿到view的尺寸是不準(zhǔn)確的, 在這里我們就需要通過[UIScreen mainScreen].bounds拿到尺寸, 但是storyboard的尺寸是準(zhǔn)確的!

8沽一、出現(xiàn)方法同名

出現(xiàn)類似的錯誤的話，就是你的方法或?qū)傩岳觳冢诓煌念愅讼巢Ｏ旅娴膱D片我忘了標(biāo)記 duplicate 這個詞語了，意思是“重復(fù)”昆禽，在第6行可以看到該單詞蝗蛙。

Snip20160823_2.png

解決辦法：去掉或改變方法的名字就可以了。

以下是某作者的總結(jié)：（http://www.reibang.com/p/4523eafb4cd4）

• UITableView的Group樣式下頂部空白處理
  在viewWillAppear里面添加如下代碼：
  //分組列表頭部空白處理
  CGRect frame = myTableView.tableHeaderView.frame;
  frame.size.height = 0.1;
  UIView *headerView = [[UIView alloc] initWithFrame:frame];
  [myTableView setTableHeaderView:headerView];
  UITableView的plain樣式下为狸，取消區(qū)頭停滯效果

  • (void)scrollViewDidScroll:(UIScrollView *)scrollView
    {
    CGFloat sectionHeaderHeight = sectionHead.height;
    if (scrollView.contentOffset.y<=sectionHeaderHeight&&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);
    }
    }
    那個歼郭，其實，還是用Group樣式吧哈哈辐棒。
    獲取某個view所在的控制器

  • (UIViewController *)viewController
    {
    UIViewController *viewController = nil;
    UIResponder *next = self.nextResponder;
    while (next)
    {
    if ([next isKindOfClass:[UIViewController class]])
    {
    viewController = (UIViewController *)next;
    break;
    }
    next = next.nextResponder;
    }
    return viewController;
    }
    兩種方法刪除NSUserDefaults所有記錄

  //方法一
  NSString *appDomain = [[NSBundle mainBundle] bundleIdentifier];
  [[NSUserDefaults standardUserDefaults] removePersistentDomainForName:appDomain];

  //方法二

  • (void)resetDefaults
    {
    NSUserDefaults * defs = [NSUserDefaults standardUserDefaults];
    NSDictionary * dict = [defs dictionaryRepresentation];
    for (id key in dict)
    {
    [defs removeObjectForKey:key];
    }
    [defs synchronize];
    }
    打印系統(tǒng)所有已注冊的字體名稱

pragma mark - 打印系統(tǒng)所有已注冊的字體名稱

void enumerateFonts()
{
for(NSString *familyName in [UIFont familyNames])
{
NSLog(@"%@",familyName);
NSArray *fontNames = [UIFont fontNamesForFamilyName:familyName];
for(NSString *fontName in fontNames)
{
NSLog(@"\t|- %@",fontName);
}
}
}
獲取圖片某一點的顏色

• (UIColor*) getPixelColorAtLocation:(CGPoint)point inImage:(UIImage *)image
  {

  UIColor* color = nil;
  CGImageRef inImage = image.CGImage;
  CGContextRef cgctx = [self createARGBBitmapContextFromImage:inImage];

  if (cgctx == NULL) {
  return nil; /* error */
  }
  size_t w = CGImageGetWidth(inImage);
  size_t h = CGImageGetHeight(inImage);
  CGRect rect = {{0,0},{w,h}};

  CGContextDrawImage(cgctx, rect, inImage);
  unsigned char* data = CGBitmapContextGetData (cgctx);
  if (data != NULL) {
  int offset = 4((wround(point.y))+round(point.x));
  int alpha = data[offset];
  int red = data[offset+1];
  int green = data[offset+2];
  int blue = data[offset+3];
  color = [UIColor colorWithRed:(red/255.0f) green:(green/255.0f) blue:
  (blue/255.0f) alpha:(alpha/255.0f)];
  }
  CGContextRelease(cgctx);
  if (data) {
  free(data);
  }
  return color;
  }
  字符串反轉(zhuǎn)
  第一種：

• (NSString *)reverseWordsInString:(NSString *)str
  {
  NSMutableString *newString = [[NSMutableString alloc] initWithCapacity:str.length];
  for (NSInteger i = str.length - 1; i >= 0 ; i --)
  {
  unichar ch = [str characterAtIndex:i];
  [newString appendFormat:@"%c", ch];
  }
  return newString;
  }

//第二種：

• (NSString)reverseWordsInString:(NSString)str
  {
  NSMutableString *reverString = [NSMutableString stringWithCapacity:str.length];
  [str enumerateSubstringsInRange:NSMakeRange(0, str.length) options:NSStringEnumerationReverse | NSStringEnumerationByComposedCharacterSequences usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
  [reverString appendString:substring];
  }];
  return reverString;
  }
  禁止鎖屏病曾，
  默認(rèn)情況下，當(dāng)設(shè)備一段時間沒有觸控動作時漾根，iOS會鎖住屏幕泰涂。但有一些應(yīng)用是不需要鎖屏的，比如視頻播放器辐怕。
  [UIApplication sharedApplication].idleTimerDisabled = YES;
  或
  [[UIApplication sharedApplication] setIdleTimerDisabled:YES];
  模態(tài)推出透明界面
  UIViewController *vc = [[UIViewController alloc] init];
  UINavigationController *na = [[UINavigationController alloc] initWithRootViewController:vc];

if ([[[UIDevice currentDevice] systemVersion] floatValue] >= 8.0)
{
na.modalPresentationStyle = UIModalPresentationOverCurrentContext;
}
else
{
self.modalPresentationStyle=UIModalPresentationCurrentContext;
}

[self presentViewController:na animated:YES completion:nil];
Xcode調(diào)試不顯示內(nèi)存占用
editSCheme 里面有個選項叫叫做enable zoombie Objects 取消選中
顯示隱藏文件
//顯示
defaults write com.apple.finder AppleShowAllFiles -bool true
killall Finder

//隱藏
defaults write com.apple.finder AppleShowAllFiles -bool false
killall Finder
字符串按多個符號分割

image.png
iOS跳轉(zhuǎn)到App Store下載應(yīng)用評分
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"itms-apps://itunes.apple.com/WebObjects/MZStore.woa/wa/viewContentsUserReviews?type=Purple+Software&id=APPID"]];
iOS 獲取漢字的拼音

• (NSString *)transform:(NSString *)chinese
  {
  //將NSString裝換成NSMutableString
  NSMutableString *pinyin = [chinese mutableCopy];
  //將漢字轉(zhuǎn)換為拼音(帶音標(biāo))
  CFStringTransform((__bridge CFMutableStringRef)pinyin, NULL, kCFStringTransformMandarinLatin, NO);
  NSLog(@"%@", pinyin);
  //去掉拼音的音標(biāo)
  CFStringTransform((__bridge CFMutableStringRef)pinyin, NULL, kCFStringTransformStripCombiningMarks, NO);
  NSLog(@"%@", pinyin);
  //返回最近結(jié)果
  return pinyin;
  }
  手動更改iOS狀態(tài)欄的顏色

• (void)setStatusBarBackgroundColor:(UIColor *)color
  {
  UIView *statusBar = [[[UIApplication sharedApplication] valueForKey:@"statusBarWindow"] valueForKey:@"statusBar"];

  if ([statusBar respondsToSelector:@selector(setBackgroundColor:)])
  {
  statusBar.backgroundColor = color;
  }
  }
  判斷當(dāng)前ViewController是push還是present的方式顯示的
  NSArray *viewcontrollers=self.navigationController.viewControllers;

if (viewcontrollers.count > 1)
{
if ([viewcontrollers objectAtIndex:viewcontrollers.count - 1] == self)
{
//push方式
[self.navigationController popViewControllerAnimated:YES];
}
}
else
{
//present方式
[self dismissViewControllerAnimated:YES completion:nil];
}
獲取實際使用的LaunchImage圖片

• (NSString *)getLaunchImageName
  {
  CGSize viewSize = self.window.bounds.size;
  // 豎屏
  NSString viewOrientation = @"Portrait";
  NSString launchImageName = nil;
  NSArray imagesDict = [[[NSBundle mainBundle] infoDictionary] valueForKey:@"UILaunchImages"];
  for (NSDictionary dict in imagesDict)
  {
  CGSize imageSize = CGSizeFromString(dict[@"UILaunchImageSize"]);
  if (CGSizeEqualToSize(imageSize, viewSize) && [viewOrientation isEqualToString:dict[@"UILaunchImageOrientation"]])
  {
  launchImageName = dict[@"UILaunchImageName"];
  }
  }
  return launchImageName;
  }
  iOS在當(dāng)前屏幕獲取第一響應(yīng)
  UIWindow * keyWindow = [[UIApplication sharedApplication] keyWindow];
  UIView * firstResponder = [keyWindow performSelector:@selector(firstResponder)];
  判斷對象是否遵循了某協(xié)議
  if ([self.selectedController conformsToProtocol:@protocol(RefreshPtotocol)])
  {
  [self.selectedController performSelector:@selector(onTriggerRefresh)];
  }
  判斷view是不是指定視圖的子視圖
  BOOL isView = [textView isDescendantOfView:self.view];
  NSArray 快速求總和 最大值 最小值 和 平均值
  NSArray *array = [NSArray arrayWithObjects:@"2.0", @"2.3", @"3.0", @"4.0", @"10", nil];
  CGFloat sum = [[array valueForKeyPath:@"@sum.floatValue"] floatValue];
  CGFloat avg = [[array valueForKeyPath:@"@avg.floatValue"] floatValue];
  CGFloat max =[[array valueForKeyPath:@"@max.floatValue"] floatValue];
  CGFloat min =[[array valueForKeyPath:@"@min.floatValue"] floatValue];
  NSLog(@"%f\n%f\n%f\n%f",sum,avg,max,min);
  修改UITextField中Placeholder的文字顏色
  [textField setValue:[UIColor redColor] forKeyPath:@"_placeholderLabel.textColor"];
  關(guān)于NSDateFormatter的格式
  G: 公元時代逼蒙，例如AD公元
  yy: 年的后2位
  yyyy: 完整年
  MM: 月，顯示為1-12
  MMM: 月寄疏，顯示為英文月份簡寫,如 Jan
  MMMM: 月是牢，顯示為英文月份全稱僵井，如 Janualy
  dd: 日，2位數(shù)表示驳棱，如02
  d: 日批什，1-2位顯示，如 2
  EEE: 簡寫星期幾社搅，如Sun
  EEEE: 全寫星期幾驻债，如Sunday
  aa: 上下午，AM/PM
  H: 時形葬，24小時制合呐，0-23
  K：時，12小時制笙以，0-11
  m: 分淌实，1-2位
  mm: 分，2位
  s: 秒源织，1-2位
  ss: 秒翩伪，2位
  S: 毫秒
  獲取一個類的所有子類

• (NSArray *) allSubclasses
  {
  Class myClass = [self class];
  NSMutableArray *mySubclasses = [NSMutableArray array];
  unsigned int numOfClasses;
  Class *classes = objc_copyClassList(&numOfClasses;);
  for (unsigned int ci = 0; ci < numOfClasses; ci++)
  {
  Class superClass = classes[ci];
  do{
  superClass = class_getSuperclass(superClass);
  } while (superClass && superClass != myClass);

    if (superClass)
    {
        [mySubclasses addObject: classes[ci]];
    }
  

  }
  free(classes);
  return mySubclasses;
  }
  監(jiān)測IOS設(shè)備是否設(shè)置了代理，需要CFNetwork.framework
  NSDictionary *proxySettings = (__bridge NSDictionary *)(CFNetworkCopySystemProxySettings());
  NSArray *proxies = (__bridge NSArray *)(CFNetworkCopyProxiesForURL((__bridge CFURLRef _Nonnull)([NSURL URLWithString:@"http://www.baidu.com"]), (__bridge CFDictionaryRef _Nonnull)(proxySettings)));
  NSLog(@"\n%@",proxies);

NSDictionary *settings = proxies[0];
NSLog(@"%@",[settings objectForKey:(NSString *)kCFProxyHostNameKey]);
NSLog(@"%@",[settings objectForKey:(NSString *)kCFProxyPortNumberKey]);
NSLog(@"%@",[settings objectForKey:(NSString *)kCFProxyTypeKey]);

if ([[settings objectForKey:(NSString *)kCFProxyTypeKey] isEqualToString:@"kCFProxyTypeNone"])
{
NSLog(@"沒代理");
}
else
{
NSLog(@"設(shè)置了代理");
}
阿拉伯?dāng)?shù)字轉(zhuǎn)中文格式
+(NSString *)translation:(NSString *)arebic
{
NSString *str = arebic;
NSArray *arabic_numerals = @[@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",@"9",@"0"];
NSArray *chinese_numerals = @[@"一",@"二",@"三",@"四",@"五",@"六",@"七",@"八",@"九",@"零"];
NSArray *digits = @[@"個",@"十",@"百",@"千",@"萬",@"十",@"百",@"千",@"億",@"十",@"百",@"千",@"兆"];
NSDictionary *dictionary = [NSDictionary dictionaryWithObjects:chinese_numerals forKeys:arabic_numerals];

NSMutableArray *sums = [NSMutableArray array];
for (int i = 0; i < str.length; i ++) {
    NSString *substr = [str substringWithRange:NSMakeRange(i, 1)];
    NSString *a = [dictionary objectForKey:substr];
    NSString *b = digits[str.length -i-1];
    NSString *sum = [a stringByAppendingString:b];
    if ([a isEqualToString:chinese_numerals[9]])
    {
        if([b isEqualToString:digits[4]] || [b isEqualToString:digits[8]])
        {
            sum = b;
            if ([[sums lastObject] isEqualToString:chinese_numerals[9]])
            {
                [sums removeLastObject];
            }
        }else
        {
            sum = chinese_numerals[9];
        }

        if ([[sums lastObject] isEqualToString:sum])
        {
            continue;
        }
    }

    [sums addObject:sum];
}

NSString *sumStr = [sums componentsJoinedByString:@""];
NSString *chinese = [sumStr substringToIndex:sumStr.length-1];
NSLog(@"%@",str);
NSLog(@"%@",chinese);
return chinese;

}
Base64編碼與NSString對象或NSData對象的轉(zhuǎn)換
// Create NSData object
NSData *nsdata = [@"iOS Developer Tips encoded in Base64"
dataUsingEncoding:NSUTF8StringEncoding];

// Get NSString from NSData object in Base64
NSString *base64Encoded = [nsdata base64EncodedStringWithOptions:0];

// Print the Base64 encoded string
NSLog(@"Encoded: %@", base64Encoded);

// Let's go the other way...

// NSData from the Base64 encoded str
NSData *nsdataFromBase64String = [[NSData alloc]
initWithBase64EncodedString:base64Encoded options:0];

// Decoded NSString from the NSData
NSString *base64Decoded = [[NSString alloc]
initWithData:nsdataFromBase64String encoding:NSUTF8StringEncoding];
NSLog(@"Decoded: %@", base64Decoded);
取消UICollectionView的隱式動畫
UICollectionView在reloadItems的時候谈息，默認(rèn)會附加一個隱式的fade動畫，有時候很討厭凛剥，尤其是當(dāng)你的cell是復(fù)合cell的情況下(比如cell使用到了UIStackView)侠仇。下面幾種方法都可以幫你去除這些動畫
//方法一
[UIView performWithoutAnimation:^{
[collectionView reloadItemsAtIndexPaths:@[[NSIndexPath indexPathForItem:index inSection:0]]];
}];

//方法二
[UIView animateWithDuration:0 animations:^{
[collectionView performBatchUpdates:^{
[collectionView reloadItemsAtIndexPaths:@[[NSIndexPath indexPathForItem:index inSection:0]]];
} completion:nil];
}];

//方法三
[UIView setAnimationsEnabled:NO];
[self.trackPanel performBatchUpdates:^{
[collectionView reloadItemsAtIndexPaths:@[[NSIndexPath indexPathForItem:index inSection:0]]];
} completion:^(BOOL finished) {
[UIView setAnimationsEnabled:YES];
}];
讓Xcode的控制臺支持LLDB類型的打印
打開終端輸入三條命令:
touch ~/.lldbinit
echo display @import UIKit >> ~/.lldbinit
echo target stop-hook add -o "target stop-hook disable" >> ~/.lldbinit
CocoaPods pod install/pod update更新慢的問題
pod install --verbose --no-repo-update
pod update --verbose --no-repo-update
如果不加后面的參數(shù)，默認(rèn)會升級CocoaPods的spec倉庫犁珠，加一個參數(shù)可以省略這一步逻炊，然后速度就會提升不少
UIImage 占用內(nèi)存大小
UIImage image = [UIImage imageNamed:@"aa"];
NSUInteger size = CGImageGetHeight(image.CGImage) * CGImageGetBytesPerRow(image.CGImage);
GCD timer定時器
dispatch_queue_t queue = dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0);
dispatch_source_t timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0,queue);
dispatch_source_set_timer(timer,dispatch_walltime(NULL, 0),1.0NSEC_PER_SEC, 0); //每秒執(zhí)行
dispatch_source_set_event_handler(timer, ^{
//@"倒計時結(jié)束，關(guān)閉"
dispatch_source_cancel(timer);
dispatch_async(dispatch_get_main_queue(), ^{

});

});
dispatch_resume(timer);
圖片上繪制文字 寫一個UIImage的category

• (UIImage *)imageWithTitle:(NSString *)title fontSize:(CGFloat)fontSize
  {
  //畫布大小
  CGSize size=CGSizeMake(self.size.width,self.size.height);
  //創(chuàng)建一個基于位圖的上下文
  UIGraphicsBeginImageContextWithOptions(size,NO,0.0);//opaque:NO scale:0.0

  [self drawAtPoint:CGPointMake(0.0,0.0)];

  //文字居中顯示在畫布上
  NSMutableParagraphStyle* paragraphStyle = [[NSParagraphStyle defaultParagraphStyle] mutableCopy];
  paragraphStyle.lineBreakMode = NSLineBreakByCharWrapping;
  paragraphStyle.alignment=NSTextAlignmentCenter;//文字居中

  //計算文字所占的size,文字居中顯示在畫布上
  CGSize sizeText=[title boundingRectWithSize:self.size options:NSStringDrawingUsesLineFragmentOrigin
  attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:fontSize]}context:nil].size;
  CGFloat width = self.size.width;
  CGFloat height = self.size.height;

  CGRect rect = CGRectMake((width-sizeText.width)/2, (height-sizeText.height)/2, sizeText.width, sizeText.height);
  //繪制文字
  [title drawInRect:rect withAttributes:@{ NSFontAttributeName:[UIFont systemFontOfSize:fontSize],NSForegroundColorAttributeName:[ UIColor whiteColor],NSParagraphStyleAttributeName:paragraphStyle}];

  //返回繪制的新圖形
  UIImage *newImage= UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();
  return newImage;
  }
  查找一個視圖的所有子視圖

• (NSMutableArray *)allSubViewsForView:(UIView *)view
  {
  NSMutableArray *array = [NSMutableArray arrayWithCapacity:0];
  for (UIView *subView in view.subviews)
  {
  [array addObject:subView];
  if (subView.subviews.count > 0)
  {
  [array addObjectsFromArray:[self allSubViewsForView:subView]];
  }
  }
  return array;
  }
  計算文件大小
  //文件大小

• (long long)fileSizeAtPath:(NSString *)path
  {
  NSFileManager *fileManager = [NSFileManager defaultManager];

  if ([fileManager fileExistsAtPath:path])
  {
  long long size = [fileManager attributesOfItemAtPath:path error:nil].fileSize;
  return size;
  }

  return 0;
  }

//文件夾大小

• (long long)folderSizeAtPath:(NSString *)path
  {
  NSFileManager *fileManager = [NSFileManager defaultManager];

  long long folderSize = 0;

  if ([fileManager fileExistsAtPath:path])
  {
  NSArray *childerFiles = [fileManager subpathsAtPath:path];
  for (NSString *fileName in childerFiles)
  {
  NSString *fileAbsolutePath = [path stringByAppendingPathComponent:fileName];
  if ([fileManager fileExistsAtPath:fileAbsolutePath])
  {
  long long size = [fileManager attributesOfItemAtPath:fileAbsolutePath error:nil].fileSize;
  folderSize += size;
  }
  }
  }

  return folderSize;
  }
  UIView設(shè)置部分圓角
  你是不是也遇到過這樣的問題犁享，一個button或者label余素，只要右邊的兩個角圓角，或者只要一個圓角炊昆。該怎么辦呢桨吊。這就需要圖層蒙版來幫助我們了
  CGRect rect = view.bounds;
  CGSize radio = CGSizeMake(30, 30);//圓角尺寸
  UIRectCorner corner = UIRectCornerTopLeft|UIRectCornerTopRight;//這只圓角位置
  UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:rect byRoundingCorners:corner cornerRadii:radio];
  CAShapeLayer *masklayer = [[CAShapeLayer alloc]init];//創(chuàng)建shapelayer
  masklayer.frame = view.bounds;
  masklayer.path = path.CGPath;//設(shè)置路徑
  view.layer.mask = masklayer;
  取上整與取下整
  floor(x),有時候也寫做Floor(x)，其功能是“下取整”凤巨，即取不大于x的最大整數(shù) 例如：
  x=3.14视乐，floor(x)=3
  y=9.99999，floor(y)=9

與floor函數(shù)對應(yīng)的是ceil函數(shù)敢茁，即上取整函數(shù)佑淀。

ceil函數(shù)的作用是求不小于給定實數(shù)的最小整數(shù)。
ceil(2)=ceil(1.2)=cei(1.5)=2.00

floor函數(shù)與ceil函數(shù)的返回值均為double型
計算字符串字符長度彰檬，一個漢字算兩個字符
//方法一：

• (int)convertToInt:(NSString)strtemp
  {
  int strlength = 0;
  char p = (char)[strtemp cStringUsingEncoding:NSUnicodeStringEncoding];
  for (int i=0 ; i<[strtemp lengthOfBytesUsingEncoding:NSUnicodeStringEncoding] ;i++)
  {
  if (p)
  {
  p++;
  strlength++;
  }
  else
  {
  p++;
  }

  }
  return strlength;
  }

//方法二：
-(NSUInteger) unicodeLengthOfString: (NSString *) text
{
NSUInteger asciiLength = 0;
for (NSUInteger i = 0; i < text.length; i++)
{
unichar uc = [text characterAtIndex: i];
asciiLength += isascii(uc) ? 1 : 2;
}
return asciiLength;
}
給UIView設(shè)置圖片
UIImage *image = [UIImage imageNamed:@"image"];
self.MYView.layer.contents = (__bridge id _Nullable)(image.CGImage);
self.MYView.layer.contentsRect = CGRectMake(0, 0, 0.5, 0.5);
防止scrollView手勢覆蓋側(cè)滑手勢
[scrollView.panGestureRecognizerrequireGestureRecognizerToFail:self.navigationController.interactivePopGestureRecognizer];
去掉導(dǎo)航欄返回的back標(biāo)題
[[UIBarButtonItemappearance]setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60)forBarMetrics:UIBarMetricsDefault];
字符串中是否含有中文

• (BOOL)checkIsChinese:(NSString *)string
  {
  for (int i=0; i<string.length; i++)
  {
  unichar ch = [string characterAtIndex:i];
  if (0x4E00 <= ch && ch <= 0x9FA5)
  {
  return YES;
  }
  }
  return NO;
  }
  dispatch_group的使用
  dispatch_group_t dispatchGroup = dispatch_group_create();
  dispatch_group_enter(dispatchGroup);
  dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(1 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
  NSLog(@"第一個請求完成");
  dispatch_group_leave(dispatchGroup);
  });

  dispatch_group_enter(dispatchGroup);

  dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(10 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
  NSLog(@"第二個請求完成");
  dispatch_group_leave(dispatchGroup);
  });

  dispatch_group_notify(dispatchGroup, dispatch_get_main_queue(), ^(){
  NSLog(@"請求完成");
  });
  UITextField每四位加一個空格,實現(xiàn)代理

• (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
  {
  // 四位加一個空格
  if ([string isEqualToString:@""])
  {
  // 刪除字符
  if ((textField.text.length - 2) % 5 == 0)
  {
  textField.text = [textField.text substringToIndex:textField.text.length - 1];
  }
  return YES;
  }
  else
  {
  if (textField.text.length % 5 == 0)
  {
  textField.text = [NSString stringWithFormat:@"%@ ", textField.text];
  }
  }
  return YES;
  }
  獲取私有屬性和成員變量 #import <objc/runtime.h>
  //獲取私有屬性 比如設(shè)置UIDatePicker的字體顏色

• (void)setTextColor
  {
  //獲取所有的屬性伸刃，去查看有沒有對應(yīng)的屬性
  unsigned int count = 0;
  objc_property_t *propertys = class_copyPropertyList([UIDatePicker class], &count);
  for(int i = 0;i < count;i ++)
  {
  //獲得每一個屬性
  objc_property_t property = propertys[i];
  //獲得屬性對應(yīng)的nsstring
  NSString *propertyName = [NSString stringWithCString:property_getName(property) encoding:NSUTF8StringEncoding];
  //輸出打印看對應(yīng)的屬性
  NSLog(@"propertyname = %@",propertyName);
  if ([propertyName isEqualToString:@"textColor"])
  {
  [datePicker setValue:[UIColor whiteColor] forKey:propertyName];
  }
  }
  }
  //獲得成員變量 比如修改UIAlertAction的按鈕字體顏色
  unsigned int count = 0;
  Ivar *ivars = class_copyIvarList([UIAlertAction class], &count);
  for(int i =0;i < count;i ++)
  {
  Ivar ivar = ivars[i];
  NSString *ivarName = [NSString stringWithCString:ivar_getName(ivar) encoding:NSUTF8StringEncoding];
  NSLog(@"uialertion.ivarName = %@",ivarName);
  if ([ivarName isEqualToString:@"_titleTextColor"])
  {
  [alertOk setValue:[UIColor blueColor] forKey:@"titleTextColor"];
  [alertCancel setValue:[UIColor purpleColor] forKey:@"titleTextColor"];
  }
  }
  獲取手機(jī)安裝的應(yīng)用
  Class c =NSClassFromString(@"LSApplicationWorkspace");
  id s = [(id)c performSelector:NSSelectorFromString(@"defaultWorkspace")];
  NSArray *array = [s performSelector:NSSelectorFromString(@"allInstalledApplications")];
  for (id item in array)
  {
  NSLog(@"%@",[item performSelector:NSSelectorFromString(@"applicationIdentifier")]);
  //NSLog(@"%@",[item performSelector:NSSelectorFromString(@"bundleIdentifier")]);
  NSLog(@"%@",[item performSelector:NSSelectorFromString(@"bundleVersion")]);
  NSLog(@"%@",[item performSelector:NSSelectorFromString(@"shortVersionString")]);
  }
  判斷兩個日期是否在同一周 寫在NSDate的category里面

• (BOOL)isSameDateWithDate:(NSDate *)date
  {
  //日期間隔大于七天之間返回NO
  if (fabs([self timeIntervalSinceDate:date]) >= 7 * 24 *3600)
  {
  return NO;
  }

  NSCalendar *calender = [NSCalendar currentCalendar];
  calender.firstWeekday = 2;//設(shè)置每周第一天從周一開始
  //計算兩個日期分別為這年第幾周
  NSUInteger countSelf = [calender ordinalityOfUnit:NSCalendarUnitWeekday inUnit:NSCalendarUnitYear forDate:self];
  NSUInteger countDate = [calender ordinalityOfUnit:NSCalendarUnitWeekday inUnit:NSCalendarUnitYear forDate:date];

  //相等就在同一周谎砾，不相等就不在同一周
  return countSelf == countDate;
  }
  應(yīng)用內(nèi)打開系統(tǒng)設(shè)置界面
  //iOS8之后
  [[UIApplication sharedApplication] openURL:[NSURL URLWithString:UIApplicationOpenSettingsURLString]];
  //如果App沒有添加權(quán)限，顯示的是設(shè)定界面捧颅。如果App有添加權(quán)限（例如通知）景图，顯示的是App的設(shè)定界面。
  //iOS8之前
  //先添加一個url type如下圖隘道，在代碼中調(diào)用如下代碼,即可跳轉(zhuǎn)到設(shè)置頁面的對應(yīng)項
  [[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"prefs:root=WIFI"]];

可選值如下：
About — prefs:root=General&path=About
Accessibility — prefs:root=General&path=ACCESSIBILITY
Airplane Mode On — 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
Keyboard — prefs:root=General&path=Keyboard
iCloud — prefs:root=CASTLE
iCloud Storage & Backup — prefs:root=CASTLE&path=STORAGE_AND_BACKUP
International — prefs:root=General&path=INTERNATIONAL
Location Services — prefs:root=LOCATION_SERVICES
Music — prefs:root=MUSIC
Music Equalizer — prefs:root=MUSIC&path=EQ
Music Volume Limit — prefs:root=MUSIC&path=VolumeLimit
Network — prefs:root=General&path=Network
Nike + iPod — prefs:root=NIKE_PLUS_IPOD
Notes — prefs:root=NOTES
Notification — prefs:root=NOTIFICATI*****_ID
Phone — prefs:root=Phone
Photos — prefs:root=Photos
Profile — prefs:root=General&path=ManagedConfigurationList
Reset — prefs:root=General&path=Reset
Safari — prefs:root=Safari
Siri — prefs:root=General&path=Assistant
Sounds — prefs:root=Sounds
Software Update — prefs:root=General&path=SOFTWARE_UPDATE_LINK
Store — prefs:root=STORE
Twitter — prefs:root=TWITTER
Usage — prefs:root=General&path=USAGE
VPN — prefs:root=General&path=Network/VPN
Wallpaper — prefs:root=Wallpaper
Wi-Fi — prefs:root=WIFI

Image.png
動畫暫停再開始
-(void)pauseLayer:(CALayer *)layer
{
CFTimeInterval pausedTime = [layer convertTime:CACurrentMediaTime() fromLayer:nil];
layer.speed = 0.0;
layer.timeOffset = pausedTime;
}

-(void)resumeLayer:(CALayer *)layer
{
CFTimeInterval pausedTime = [layer timeOffset];
layer.speed = 1.0;
layer.timeOffset = 0.0;
layer.beginTime = 0.0;
CFTimeInterval timeSincePause = [layer convertTime:CACurrentMediaTime() fromLayer:nil] - pausedTime;
layer.beginTime = timeSincePause;
}
fillRule原理

Image.png
iOS中數(shù)字的格式化
//通過NSNumberFormatter症歇，同樣可以設(shè)置NSNumber輸出的格式。例如如下代碼：
NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
formatter.numberStyle = NSNumberFormatterDecimalStyle;
NSString *string = [formatter stringFromNumber:[NSNumber numberWithInt:123456789]];
NSLog(@"Formatted number string:%@",string);
//輸出結(jié)果為：[1223:403] Formatted number string:123,456,789

//其中NSNumberFormatter類有個屬性numberStyle谭梗，它是一個枚舉型忘晤，設(shè)置不同的值可以輸出不同的數(shù)字格式。該枚舉包括：
typedef NS_ENUM(NSUInteger, NSNumberFormatterStyle) {
NSNumberFormatterNoStyle = kCFNumberFormatterNoStyle,
NSNumberFormatterDecimalStyle = kCFNumberFormatterDecimalStyle,
NSNumberFormatterCurrencyStyle = kCFNumberFormatterCurrencyStyle,
NSNumberFormatterPercentStyle = kCFNumberFormatterPercentStyle,
NSNumberFormatterScientificStyle = kCFNumberFormatterScientificStyle,
NSNumberFormatterSpellOutStyle = kCFNumberFormatterSpellOutStyle
};
//各個枚舉對應(yīng)輸出數(shù)字格式的效果如下：其中第三項和最后一項的輸出會根據(jù)系統(tǒng)設(shè)置的語言區(qū)域的不同而不同激捏。
[1243:403] Formatted number string:123456789
[1243:403] Formatted number string:123,456,789
[1243:403] Formatted number string:￥123,456,789.00
[1243:403] Formatted number string:-539,222,988%
[1243:403] Formatted number string:1.23456789E8
[1243:403] Formatted number string:一億二千三百四十五萬六千七百八十九
如何獲取WebView所有的圖片地址设塔，
在網(wǎng)頁加載完成時，通過js獲取圖片和添加點擊的識別方式
//UIWebView

• (void)webViewDidFinishLoad:(UIWebView *)webView
  {
  //這里是js远舅，主要目的實現(xiàn)對url的獲取
  static NSString * const jsGetImages =
  @"function getImages(){
  var objs = document.getElementsByTagName("img");
  var imgScr = '';
  for(var i=0;i<objs.length;i++){
  imgScr = imgScr + objs[i].src + '+';
  };
  return imgScr;
  };";

  [webView stringByEvaluatingJavaScriptFromString:jsGetImages];//注入js方法
  NSString *urlResult = [webView stringByEvaluatingJavaScriptFromString:@"getImages()"];
  NSArray *urlArray = [NSMutableArray arrayWithArray:[urlResult componentsSeparatedByString:@"+"]];
  //urlResurlt 就是獲取到得所有圖片的url的拼接闰蛔；mUrlArray就是所有Url的數(shù)組
  }
  //WKWebView

• (void)webView:(WKWebView *)webView didFinishNavigation:(null_unspecified WKNavigation *)navigation
  {
  static NSString * const jsGetImages =
  @"function getImages(){
  var objs = document.getElementsByTagName("img");
  var imgScr = '';
  for(var i=0;i<objs.length;i++){
  imgScr = imgScr + objs[i].src + '+';
  };
  return imgScr;
  };";

  [webView evaluateJavaScript:jsGetImages completionHandler:nil];
  [webView evaluateJavaScript:@"getImages()" completionHandler:^(id _Nullable result, NSError * _Nullable error) {
  NSLog(@"%@",result);
  }];
  }
  獲取到webview的高度
  CGFloat height = [[self.webView stringByEvaluatingJavaScriptFromString:@"document.body.offsetHeight"] floatValue];
  navigationBar變?yōu)榧兺该?/strong>
  //第一種方法
  //導(dǎo)航欄純透明
  [self.navigationBar setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];
  //去掉導(dǎo)航欄底部的黑線
  self.navigationBar.shadowImage = [UIImage new];