ios 基础知识点总结
Posted Eric博客
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1、设置UILabel行间距
NSMutableAttributedString* attrString = [[NSMutableAttributedString alloc] initWithString:label.text];
NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc] init];
[style setLineSpacing:20];
[attrString addAttribute:NSParagraphStyleAttributeName value:style range:NSMakeRange(0, label.text.length)];
label.attributedText = attrString;// 或者使用xib，看下gif图
Untitled.gif
2、当使用-performSelector:withObject:withObject:afterDelay:方法时，需要传入多参数问题
// 方法一、
// 把参数放进一个数组／字典，直接把数组／字典当成一个参数传过去，具体方法实现的地方再解析这个数组／字典
NSArray * array =
[NSArray arrayWithObjects: @"first", @"second", nil];
[self performSelector:@selector(fooFirstInput:) withObject: array afterDelay:15.0];
// 方法二、
// 使用NSInvocation
SEL aSelector = NSSelectorFromString(@"doSoming:argument2:");
NSInteger argument1 = 10;
NSString *argument2 = @"argument2";
if([self respondsToSelector:aSelector])
NSInvocation *inv = [NSInvocation invocationWithMethodSignature:[self methodSignatureForSelector:aSelector]];
[inv setSelector:aSelector];
[inv setTarget:self];
[inv setArgument:&(argument1) atIndex:2];
[inv setArgument:&(argument2) atIndex:3];
[inv performSelector:@selector(invoke) withObject:nil afterDelay:15.0];
3、UILabel显示不同颜色字体
NSMutableAttributedString * string = [[NSMutableAttributedString alloc] initWithString:label.text];
[string addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:NSMakeRange(0,5)];
[string addAttribute:NSForegroundColorAttributeName value:[UIColor greenColor] range:NSMakeRange(5,6)];
[string addAttribute:NSForegroundColorAttributeName value:[UIColor blueColor] range:NSMakeRange(11,5)];
label.attributedText = string;4、比较两个CGRect/CGSize/CGPoint是否相等
if (CGRectEqualToRect(rect1, rect2)) // 两个区域相等
// do some
if (CGPointEqualToPoint(point1, point2)) // 两个点相等
// do some
if (CGSizeEqualToSize(size1, size2)) // 两个size相等
// do some
5、比较两个NSDate相差多少小时
NSDate* date1 = someDate;
NSDate* date2 = someOtherDate;
NSTimeInterval distanceBetweenDates = [date1 timeIntervalSinceDate:date2];
double secondsInAnHour = 3600;
// 除以3600是把秒化成小时，除以60得到结果为相差的分钟数
NSInteger hoursBetweenDates = distanceBetweenDates / secondsInAnHour;6、每个cell之间增加间距
// 方法一，每个分区只显示一行cell，分区头当作你想要的间距(注意，从数据源数组中取值的时候需要用indexPath.section而不是indexPath.row)
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
return yourArry.count;
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
return 1;
-(CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section
return cellSpacingHeight;
// 方法二，在cell的contentView上加个稍微低一点的view，cell上原本的内容放在你的view上，而不是contentView上，这样能伪造出一个间距来。
// 方法三，自定义cell，重写setFrame：方法
- (void)setFrame:(CGRect)frame
frame.size.height -= 20;
[super setFrame:frame];
7、播放一张张连续的图片
// 加入现在有三张图片分别为animate_1、animate_2、animate_3
// 方法一
imageView.animationImages = @[[UIImage imageNamed:@"animate_1"], [UIImage imageNamed:@"animate_2"], [UIImage imageNamed:@"animate_3"]];
imageView.animationDuration = 1.0;
// 方法二
imageView.image = [UIImage animatedImageNamed:@"animate_" duration:1.0];
// 方法二解释下，这个方法会加载animate_为前缀的，后边0-1024，也就是animate_0、animate_1一直到animate_10248、加载gif图片
推荐使用这个框架 FLAnimatedImage
9、防止离屏渲染为image添加圆角
// image分类
- (UIImage *)circleImage
// NO代表透明
UIGraphicsBeginImageContextWithOptions(self.size, NO, 1);
// 获得上下文
CGContextRef ctx = UIGraphicsGetCurrentContext();
// 添加一个圆
CGRect rect = CGRectMake(0, 0, self.size.width, self.size.height);
// 方形变圆形
CGContextAddEllipseInRect(ctx, rect);
// 裁剪
CGContextClip(ctx);
// 将图片画上去
[self drawInRect:rect];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
10、查看系统所有字体
// 打印字体
for (id familyName in [UIFont familyNames])
NSLog(@"%@", familyName);
for (id fontName in [UIFont fontNamesForFamilyName:familyName]) NSLog(@" %@", fontName);
// 也可以进入这个网址查看 http://iosfonts.com/NSInteger i = arc4random();12、获取随机数小数(0-1之间)
#define ARC4RANDOM_MAX 0x100000000
double val = ((double)arc4random() / ARC4RANDOM_MAX);13、AVPlayer视频播放完成的通知监听
[[NSNotificationCenter defaultCenter]
addObserver:self
selector:@selector(videoPlayEnd)
name:AVPlayerItemDidPlayToEndTimeNotification
object:nil];14、判断两个rect是否有交叉
if (CGRectIntersectsRect(rect1, rect2))
15、判断一个字符串是否为数字
NSCharacterSet *notDigits = [[NSCharacterSet decimalDigitCharacterSet] invertedSet];
if ([str rangeOfCharacterFromSet:notDigits].location == NSNotFound)
// 是数字
else
// 不是数字
16、将一个view保存为pdf格式
- (void)createPDFfromUIView:(UIView*)aView saveToDocumentsWithFileName:(NSString*)aFilename
NSMutableData *pdfData = [NSMutableData data];
UIGraphicsBeginPDFContextToData(pdfData, aView.bounds, nil);
UIGraphicsBeginPDFPage();
CGContextRef pdfContext = UIGraphicsGetCurrentContext();
[aView.layer renderInContext:pdfContext];
UIGraphicsEndPDFContext();
NSArray* documentDirectories = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask,YES);
NSString* documentDirectory = [documentDirectories objectAtIndex:0];
NSString* documentDirectoryFilename = [documentDirectory stringByAppendingPathComponent:aFilename];
[pdfData writeToFile:documentDirectoryFilename atomically:YES];
NSLog(@"documentDirectoryFileName: %@",documentDirectoryFilename);
17、让一个view在父视图中心
child.center = [parent convertPoint:parent.center fromView:parent.superview];18、获取当前导航控制器下前一个控制器
- (UIViewController *)backViewController
NSInteger myIndex = [self.navigationController.viewControllers indexOfObject:self];
if ( myIndex != 0 && myIndex != NSNotFound )
return [self.navigationController.viewControllers objectAtIndex:myIndex-1];
else
return nil;
19、保存UIImage到本地
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *filePath = [[paths objectAtIndex:0] stringByAppendingPathComponent:@"Image.png"];
[UIImagePNGRepresentation(image) writeToFile:filePath atomically:YES];20、键盘上方增加工具栏
UIToolbar *keyboardDoneButtonView = [[UIToolbar alloc] init];
[keyboardDoneButtonView sizeToFit];
UIBarButtonItem *doneButton = [[UIBarButtonItem alloc] initWithTitle:@"Done"
style:UIBarButtonItemStyleBordered target:self
action:@selector(doneClicked:)];
[keyboardDoneButtonView setItems:[NSArray arrayWithObjects:doneButton, nil]];
txtField.inputAccessoryView = keyboardDoneButtonView;21、copy一个view
因为UIView没有实现copy协议，因此找不到copyWithZone方法，使用copy的时候导致崩溃
但是我们可以通过归档再解档实现copy，这相当于对视图进行了一次深拷贝，代码如下
id copyOfView =
[NSKeyedUnarchiver unarchiveObjectWithData:[NSKeyedArchiver archivedDataWithRootObject:originalView]];22、在image上绘制文字并生成新的image
UIFont *font = [UIFont boldSystemFontOfSize:12];
UIGraphicsBeginImageContext(image.size);
[image drawInRect:CGRectMake(0,0,image.size.width,image.size.height)];
CGRect rect = CGRectMake(point.x, point.y, image.size.width, image.size.height);
[[UIColor whiteColor] set];
[text drawInRect:CGRectIntegral(rect) withFont:font];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();23、判断一个view是否为另一个view的子视图
// 如果myView是self.view本身，也会返回yes
BOOL isSubView = [myView isDescendantOfView:self.view];24、判断一个字符串是否包含另一个字符串
// 方法一、这种方法只适用于iOS8之后，如果是配iOS8之前用方法二
if ([str containsString:otherStr]) NSLog(@"包含");
// 方法二
NSRange range = [str rangeOfString:otherStr];
if (range.location != NSNotFound) NSLog(@"包含");25、UICollectionView自动滚动到某行
// 重写viewDidLayoutSubviews方法
-(void)viewDidLayoutSubviews
[super viewDidLayoutSubviews];
[self.collectionView scrollToItemAtIndexPath:indexPath atScrollPosition:UICollectionViewScrollPositionCenteredVertically animated:NO];
26、修改系统UIAlertController
// 但是据说这种方法会被App Store拒绝(慎用！)
UIAlertController *alertVC = [UIAlertController alertControllerWithTitle:@"" message:@"" preferredStyle:UIAlertControllerStyleActionSheet];
NSMutableAttributedString *hogan = [[NSMutableAttributedString alloc] initWithString:@"我是一个大文本"];
[hogan addAttribute:NSFontAttributeName
value:[UIFont systemFontOfSize:30]
range:NSMakeRange(4, 1)];
[hogan addAttribute:NSForegroundColorAttributeName
value:[UIColor redColor]
range:NSMakeRange(4, 1)];
[alertVC setValue:hogan forKey:@"attributedTitle"];
UIAlertAction *button = [UIAlertAction actionWithTitle:@"Label text" style:UIAlertActionStyleDefault handler:^(UIAlertAction *action) ];
UIImage *accessoryImage = [UIImage imageNamed:@"1"];
[button setValue:accessoryImage forKey:@"image"];
[alertVC addAction:button];
[self presentViewController:alertVC animated:YES completion:nil];27、判断某一行的cell是否已经显示
CGRect cellRect = [tableView rectForRowAtIndexPath:indexPath];
BOOL completelyVisible = CGRectContainsRect(tableView.bounds, cellRect);28、让导航控制器pop回指定的控制器
NSMutableArray *allViewControllers = [NSMutableArray arrayWithArray:[self.navigationController viewControllers]];
for (UIViewController *aViewController in allViewControllers)
if ([aViewController isKindOfClass:[RequiredViewController class]])
[self.navigationController popToViewController:aViewController animated:NO];
29、动画修改label上的文字
// 方法一
CATransition *animation = [CATransition animation];
animation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];
animation.type = kCATransitionFade;
animation.duration = 0.75;
[self.label.layer addAnimation:animation forKey:@"kCATransitionFade"];
self.label.text = @"New";
// 方法二
[UIView transitionWithView:self.label
duration:0.25f
options:UIViewAnimationOptionTransitionCrossDissolve
animations:^
self.label.text = @"Well done!";
completion:nil];
// 方法三
[UIView animateWithDuration:1.0
animations:^
self.label.alpha = 0.0f;
self.label.text = @"newText";
self.label.alpha = 1.0f;
];30、判断字典中是否包含某个key值
if ([dic objectForKey:@"yourKey"])
NSLog(@"有这个值");
else
NSLog(@"没有这个值");
31、获取屏幕方向
UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;
if(orientation == 0) //Default orientation
//默认
else if(orientation == UIInterfaceOrientationPortrait)
//竖屏
else if(orientation == UIInterfaceOrientationLandscapeLeft)
// 左横屏
else if(orientation == UIInterfaceOrientationLandscapeRight)
//右横屏32、设置UIImage的透明度
// 方法一、添加UIImage分类
- (UIImage *)imageByApplyingAlpha:(CGFloat) alpha
UIGraphicsBeginImageContextWithOptions(self.size, NO, 0.0f);
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGRect area = CGRectMake(0, 0, self.size.width, self.size.height);
CGContextScaleCTM(ctx, 1, -1);
CGContextTranslateCTM(ctx, 0, -area.size.height);
CGContextSetBlendMode(ctx, kCGBlendModeMultiply);
CGContextSetAlpha(ctx, alpha);
CGContextDrawImage(ctx, area, self.CGImage);
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
// 方法二、如果没有奇葩需求，干脆用UIImageView设置透明度
UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageWithName:@"yourImage"]];
imageView.alpha = 0.5;33、Attempt to mutate immutable object with insertString:atIndex:
这个错是因为你拿字符串调用insertString:atIndex:方法的时候，调用对象不是NSMutableString，应该先转成这个类型再调用
34、UIWebView添加单击手势不响应
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(webViewClick)];
tap.delegate = self;
[_webView addGestureRecognizer:tap];
// 因为webView本身有一个单击手势，所以再添加会造成手势冲突，从而不响应。需要绑定手势代理，并实现下边的代理方法
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
return YES;
35、获取手机RAM容量
// 需要导入#import <mach/mach.h>
mach_port_t host_port;
mach_msg_type_number_t host_size;
vm_size_t pagesize;
host_port = mach_host_self();
host_size = sizeof(vm_statistics_data_t) / sizeof(integer_t);
host_page_size(host_port, &pagesize);
vm_statistics_data_t vm_stat;
if (host_statistics(host_port, HOST_VM_INFO, (host_info_t)&vm_stat, &host_size) != KERN_SUCCESS)
NSLog(@"Failed to fetch vm statistics");
/* Stats in bytes */
natural_t mem_used = (vm_stat.active_count +
vm_stat.inactive_count +
vm_stat.wire_count) * pagesize;
natural_t mem_free = vm_stat.free_count * pagesize;
natural_t mem_total = mem_used + mem_free;
NSLog(@"已用: %u 可用: %u 总共: %u", mem_used, mem_free, mem_total);36、地图上两个点之间的实际距离
// 需要导入#import <CoreLocation/CoreLocation.h>
CLLocation *locA = [[CLLocation alloc] initWithLatitude:34 longitude:113];
CLLocation *locB = [[CLLocation alloc] initWithLatitude:31.05 longitude:121.76];
// CLLocationDistance求出的单位为米
CLLocationDistance distance = [locA distanceFromLocation:locB];37、在应用中打开设置的某个界面
// 打开设置->通用
[[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"prefs:root=General"]];
// 以下是设置其他界面
prefs:root=General&path=About
prefs:root=General&path=ACCESSIBILITY
prefs:root=AIRPLANE_MODE
prefs:root=General&path=AUTOLOCK
prefs:root=General&path=USAGE/CELLULAR_USAGE
prefs:root=Brightness
prefs:root=Bluetooth
prefs:root=General&path=DATE_AND_TIME
prefs:root=FACETIME
prefs:root=General
prefs:root=General&path=Keyboard
prefs:root=CASTLE
prefs:root=CASTLE&path=STORAGE_AND_BACKUP
prefs:root=General&path=INTERNATIONAL
prefs:root=LOCATION_SERVICES
prefs:root=ACCOUNT_SETTINGS
prefs:root=MUSIC
prefs:root=MUSIC&path=EQ
prefs:root=MUSIC&path=VolumeLimit
prefs:root=General&path=Network
prefs:root=NIKE_PLUS_IPOD
prefs:root=NOTES
prefs:root=NOTIFICATIONS_ID
prefs:root=Phone
prefs:root=Photos
prefs:root=General&path=ManagedConfigurationList
prefs:root=General&path=Reset
prefs:root=Sounds&path=Ringtone
prefs:root=Safari
prefs:root=General&path=Assistant
prefs:root=Sounds
prefs:root=General&path=SOFTWARE_UPDATE_LINK
prefs:root=STORE
prefs:root=TWITTER
prefs:root=FACEBOOK
prefs:root=General&path=USAGE prefs:root=VIDEO
prefs:root=General&path=Network/VPN
prefs:root=Wallpaper
prefs:root=WIFI
prefs:root=INTERNET_TETHERING
prefs:root=Phone&path=Blocked
prefs:root=DO_NOT_DISTURB38、在UITextView中显示html文本
UITextView *textView = [[UITextView alloc] initWithFrame:CGRectMake(20, 30, 100, 199)];
textView.backgroundColor = [UIColor redColor];
[self.view addSubview:textView];
NSString *htmlString = @"<h1>Header</h1><h2>Subheader</h2><p>Some <em>text</em></p>";
NSAttributedString *attributedString = [[NSAttributedString alloc] initWithData: [htmlString dataUsingEncoding:NSUnicodeStringEncoding] options: @ NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType documentAttributes: nil error: nil];
textView.attributedText = attributedString;39、监听scrollView是否滚动到了顶部／底部
-(void)scrollViewDidScroll: (UIScrollView*)scrollView
float scrollViewHeight = scrollView.frame.size.height;
float scrollContentSizeHeight = scrollView.contentSize.height;
float scrollOffset = scrollView.contentOffset.y;
if (scrollOffset == 0)
// 滚动到了顶部
else if (scrollOffset + scrollViewHeight == scrollContentSizeHeight)
// 滚动到了底部
40、UISlider增量／减量为固定值(假如为5)
- (void)setupSlider
UISlider *slider = [[UISlider alloc] init];
[self.view addSubview:slider];
[slider addTarget:self action:@selector(sliderAction:) forControlEvents:UIControlEventValueChanged];
slider.maximumValue = 100;
slider.minimumValue = 0;
slider.frame = CGRectMake(200, 20, 100, 30);
- (void)sliderAction:(UISlider *)slider
[slider setValue:((int)((slider.value + 2.5) / 5) * 5) animated:NO];
41、选中textField或者textView所有文本(我这里以textView为例)
[self.textView setSelectedTextRange:[self.textView textRangeFromPosition:self.textView.beginningOfDocument toPosition:self.textView.endOfDocument]]42、从导航控制器中删除某个控制器
// 方法一、知道这个控制器所处的导航控制器下标
NSMutableArray *navigationArray = [[NSMutableArray alloc] initWithArray: self.navigationController.viewControllers];
[navigationArray removeObjectAtIndex: 2];
self.navigationController.viewControllers = navigationArray;
// 方法二、知道具体是哪个控制器
NSArray* tempVCA = [self.navigationController viewControllers];
for(UIViewController *tempVC in tempVCA)
if([tempVC isKindOfClass:[urViewControllerClass class]])
[tempVC removeFromParentViewController];
43、隐藏UITextView/UITextField光标
textField.tintColor = [UIColor clearColor];44、当UITextView/UITextField中没有文字时，禁用回车键
textField.enablesReturnKeyAutomatically = YES;45、字符串encode编码(编码url字符串不成功的问题)
// 我们一般用这个方法处理stringByAddingPercentEscapesUsingEncoding但是这个方法好想不会处理／和&这种特殊符号，这种情况就需要用下边这个方法处理
@implementation NSString (NSString_Extended)
- (NSString *)urlencode
NSMutableString *output = [NSMutableString string];
const unsigned char *source = (const unsigned char *)[self UTF8String];
int sourceLen = strlen((const char *)source);
for (int i = 0; i < sourceLen; ++i)
const unsigned char thisChar = source[i];
if (thisChar == ' ')
[output appendString:@"+"];
else if (thisChar == '.' || thisChar == '-' || thisChar == '_' || thisChar == '~' ||
(thisChar >= 'a' && thisChar <= 'z') ||
(thisChar >= 'A' && thisChar <= 'Z') ||
(thisChar >= '0' && thisChar <= '9'))
[output appendFormat:@"%c", thisChar];
else
[output appendFormat:@"%%%02X", thisChar];
return output;
46、计算UILabel上某段文字的frame
@implementation UILabel (TextRect)
- (CGRect)boundingRectForCharacterRange:(NSRange)range
NSTextStorage *textStorage = [[NSTextStorage alloc] initWithAttributedString:[self attributedText]];
NSLayoutManager *layoutManager = [[NSLayoutManager alloc] init];
[textStorage addLayoutManager:layoutManager];
NSTextContainer *textContainer = [[NSTextContainer alloc] initWithSize:[self bounds].size];
textContainer.lineFragmentPadding = 0;
[layoutManager addTextContainer:textContainer];
NSRange glyphRange;
[layoutManager characterRangeForGlyphRange:range actualGlyphRange:&glyphRange];
return [layoutManager boundingRectForGlyphRange:glyphRange inTextContainer:textContainer];
47、获取随机UUID
NSString *result;
if([[[UIDevice currentDevice] systemVersion] floatValue] > 6.0)
result = [[NSUUID UUID] UUIDString];
else
CFUUIDRef uuidRef = CFUUIDCreate(NULL);
CFStringRef uuid = CFUUIDCreateString(NULL, uuidRef);
CFRelease(uuidRef);
result = (__bridge_transfer NSString *)uuid;
48、仿苹果抖动动画
#define RADIANS(degrees) (((degrees) * M_PI) / 180.0)
- (void)startAnimate
view.transform = CGAffineTransformRotate(CGAffineTransformIdentity, RADIANS(-5));
[UIView animateWithDuration:0.25 delay:0.0 options:(UIViewAnimationOptionAllowUserInteraction | UIViewAnimationOptionRepeat | UIViewAnimationOptionAutoreverse) animations:^
view.transform = CGAffineTransformRotate(CGAffineTransformIdentity, RADIANS(5));
completion:nil];
- (void)stopAnimate
[UIView animateWithDuration:0.25 delay:0.0 options:(UIViewAnimationOptionAllowUserInteraction | UIViewAnimationOptionBeginFromCurrentState | UIViewAnimationOptionCurveLinear) animations:^
view.transform = CGAffineTransformIdentity;
completion:nil];
49、修改UISearBar内部背景颜色
UITextField *textField = [_searchBar valueForKey:@"_searchField"];
textField.backgroundColor = [UIColor redColor];50、UITextView滚动到顶部
// 方法一
[self.textView scrollRangeToVisible:NSMakeRange(0, 0)];
// 方法二
[self.textView setContentOffset:CGPointZero animated:YES];51、通知监听APP生命周期
UIApplicationDidEnterBackgroundNotification 应用程序进入后台
UIApplicationWillEnterForegroundNotification 应用程序将要进入前台
UIApplicationDidFinishLaunchingNotification 应用程序完成启动
UIApplicationDidFinishLaunchingNotification 应用程序由挂起变的活跃
UIApplicationWillResignActiveNotification 应用程序挂起(有电话进来或者锁屏)
UIApplicationDidReceiveMemoryWarningNotification 应用程序收到内存警告
UIApplicationDidReceiveMemoryWarningNotification 应用程序终止(后台杀死、手机关机等)
UIApplicationSignificantTimeChangeNotification 当有重大时间改变(凌晨0点，设备时间被修改，时区改变等)
UIApplicationWillChangeStatusBarOrientationNotification 设备方向将要改变
UIApplicationDidChangeStatusBarOrientationNotification 设备方向改变
UIApplicationWillChangeStatusBarFrameNotification 设备状态栏frame将要改变
UIApplicationDidChangeStatusBarFrameNotification 设备状态栏frame改变
UIApplicationBackgroundRefreshStatusDidChangeNotification 应用程序在后台下载内容的状态发生变化
UIApplicationProtectedDataWillBecomeUnavailable 本地受保护的文件被锁定,无法访问
UIApplicationProtectedDataWillBecomeUnavailable 本地受保护的文件可用了
52、触摸事件类型
UIControlEventTouchCancel 取消控件当前触发的事件
UIControlEventTouchDown 点按下去的事件
UIControlEventTouchDownRepeat 重复的触动事件
UIControlEventTouchDragEnter 手指被拖动到控件的边界的事件
UIControlEventTouchDragExit 一个手指从控件内拖到外界的事件
UIControlEventTouchDragInside 手指在控件的边界内拖动的事件
UIControlEventTouchDragOutside 手指在控件边界之外被拖动的事件
UIControlEventTouchUpInside 手指处于控制范围内的触摸事件
UIControlEventTouchUpOutside 手指超出控制范围的控制中的触摸事件
53、UITextField文字周围增加边距
// 子类化UITextField，增加insert属性
@interface WZBTextField : UITextField
@property (nonatomic, assign) UIEdgeInsets insets;
@end
// 在.m文件重写下列方法
- (CGRect)textRectForBounds:(CGRect)bounds
CGRect paddedRect = UIEdgeInsetsInsetRect(bounds, self.insets);
if (self.rightViewMode == UITextFieldViewModeAlways || self.rightViewMode == UITextFieldViewModeUnlessEditing)
return [self adjustRectWithWidthRightView:paddedRect];
return paddedRect;
- (CGRect)placeholderRectForBounds:(CGRect)bounds
CGRect paddedRect = UIEdgeInsetsInsetRect(bounds, self.insets);
if (self.rightViewMode == UITextFieldViewModeAlways || self.rightViewMode == UITextFieldViewModeUnlessEditing)
return [self adjustRectWithWidthRightView:paddedRect];
return paddedRect;
- (CGRect)editingRectForBounds:(CGRect)bounds
CGRect paddedRect = UIEdgeInsetsInsetRect(bounds, self.insets);
if (self.rightViewMode == UITextFieldViewModeAlways || self.rightViewMode == UITextFieldViewModeWhileEditing)
return [self adjustRectWithWidthRightView:paddedRect];
return paddedRect;
- (CGRect)adjustRectWithWidthRightView:(CGRect)bounds
CGRect paddedRect = bounds;
paddedRect.size.width -= CGRectGetWidth(self.rightView.frame);
return paddedRect;
54、监听UISlider拖动状态
// 添加事件
[slider addTarget:self action:@selector(sliderValurChanged:forEvent:) forControlEvents:UIControlEventValueChanged];
// 实现方法
- (void)sliderValurChanged:(UISlider*)slider forEvent:(UIEvent*)event
UITouch *touchEvent = [[event allTouches] anyObject];
switch (touchEvent.phase)
case UITouchPhaseBegan:
NSLog(@"开始拖动");
break;
case UITouchPhaseMoved:
NSLog(@"正在拖动");
break;
case UITouchPhaseEnded:
NSLog(@"结束拖动");
break;
default:
break;
55、设置UITextField光标位置
// textField需要设置的textField，index要设置的光标位置
- (void)cursorLocation:(UITextField *)textField index:(NSInteger)index
NSRange range = NSMakeRange(index, 0);
UITextPosition *start = [textField positionFromPosition:[textField beginningOfDocument] offset:range.location];
UITextPosition *end = [textField positionFromPosition:start offset:range.length];
[textField setSelectedTextRange:[textField textRangeFromPosition:start toPosition:end]];
56、去除webView底部黑色
[webView setBackgroundColor:[UIColor clearColor]];
[webView setOpaque:NO];
for (UIView *v1 in [webView subviews])
if ([v1 isKindOfClass:[UIScrollView class]])
for (UIView *v2 in v1.subviews)
if ([v2 isKindOfClass:[UIImageView class]])
v2.hidden = YES;
57、获取collectionViewCell在屏幕中的frame
UICollectionViewLayoutAttributes *attributes = [collectionView layoutAttributesForItemAtIndexPath:indexPath];
CGRect cellRect = attributes.frame;
CGRect cellFrameInSuperview = [collectionView convertRect:cellRect toView:[cv superview]];58、比较两个UIImage是否相等
- (BOOL)image:(UIImage *)image1 isEqualTo:(UIImage *)image2
NSData *data1 = UIImagePNGRepresentation(image1);
NSData *data2 = UIImagePNGRepresentation(image2);
return [data1 isEqual:data2];
59、解决当UIScrollView上有UIButton的时候，触摸到button滑动不了的问题
// 子类化UIScrollView，并重写以下方法
- (instancetype)initWithFrame:(CGRect)frame
if (self = [super initWithFrame:frame])
self.delaysContentTouches = NO;
return self;
- (BOOL)touchesShouldCancelInContentView:(UIView *)view
if ([view isKindOfClass:UIButton.class])
return YES;
return [super touchesShouldCancelInContentView:view];
60、UITextView中的文字添加阴影效果
- (void)setTextLayer:(UITextView *)textView color:(UIColor *)color
CALayer *textLayer = ((CALayer *)[textView.layer.sublayers objectAtIndex:0]);
textLayer.shadowColor = color.CGColor;
textLayer.shadowOffset = CGSizeMake(0.0f, 1.0f);
textLayer.shadowOpacity = 1.0f;
textLayer.shadowRadius = 1.0f;
61、MD5加密
+ (NSString *)md5:(NSString *)str
const char *concat_str = [str UTF8String];
unsigned char result[CC_MD5_DIGEST_LENGTH];
CC_MD5(concat_str, (unsigned int)strlen(concat_str), result);
NSMutableString *hash = [NSMutableString string];
for (int i =0; i <16; i++)
[hash appendFormat:@"%02X", result[i]];
return [hash uppercaseString];
62、base64加密
@interface NSData (Base64)
/**
* @brief 字符串base64后转data
*/
+ (NSData )dataWithBase64EncodedString:(NSString )string
if (![string length]) return nil;
NSData *decoded = nil;
#if __MAC_OS_X_VERSION_MIN_REQUIRED < __MAC_10_9 || __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_7_0 if (![NSData instancesRespondToSelector:@selector(initWithBase64EncodedString:options:)]) #pragma clang diagnostic push #pragma clang diagnostic ignored "-Wdeprecated-declarations" decoded = [[self alloc] initWithBase64Encoding:[string stringByReplacingOccurrencesOfString:@"[^A-Za-z0-9+/=]" withString:@"" options:NSRegularExpressionSearch range:NSMakeRange(0, [string length])]]; #pragma clang diagnostic pop else #endif decoded = [[self alloc] initWithBase64EncodedString:string options:NSDataBase64DecodingIgnoreUnknownCharacters]; return [decoded length]? decoded: nil; /** * @brief NSData转string * @param wrapWidth 换行长度 76 64 */ - (NSString *)base64EncodedStringWithWrapWidth:(NSUInteger)wrapWidth if (![self length]) return nil; NSString *encoded = nil; #if __MAC_OS_X_VERSION_MIN_REQUIRED < __MAC_10_9 || __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_7_0 if (![NSData instancesRespondToSelector:@selector(base64EncodedStringWithOptions:)]) #pragma clang diagnostic push #pragma clang diagnostic ignored "-Wdeprecated-declarations" encoded = [self base64Encoding]; #pragma clang diagnostic pop else #endif switch (wrapWidth) case 64: return [self base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength]; case 76: return [self base64EncodedStringWithOptions:NSDataBase64Encoding76CharacterLineLength]; default: encoded = [self base64EncodedStringWithOptions:(NSDataBase64EncodingOptions)0]; if (!wrapWidth || wrapWidth >= [encoded length]) return encoded; wrapWidth = (wrapWidth / 4) * 4; NSMutableString *result = [NSMutableString string]; for (NSUInteger i = 0; i < [encoded length]; i+= wrapWidth) if (i + wrapWidth >= [encoded length]) [result appendString:[encoded substringFromIndex:i]]; break; [result appendString:[encoded substringWithRange:NSMakeRange(i, wrapWidth)]]; [result appendString:@"\\r\\n"]; return result; /** * @brief NSData转string 换行长度默认64 */ - (NSString *)base64EncodedString return [self base64EncodedStringWithWrapWidth:0];
63、AES加密
#import <CommonCrypto/CommonCryptor.h>
@interface NSData (AES)
/**
* 利用AES加密数据
*/
- (NSData*)encryptedWithAESUsingKey:(NSString*)key andIV:(NSData*)iv
NSData *keyData = [key dataUsingEncoding:NSUTF8StringEncoding];
size_t dataMoved;
NSMutableData *encryptedData = [NSMutableData dataWithLength:self.length + kCCBlockSizeAES128];
CCCryptorStatus status = CCCrypt(kCCEncrypt,kCCAlgorithmAES128,kCCOptionPKCS7Padding,keyData.bytes,keyData.length,iv.bytes,self.bytes,self.length,encryptedData.mutableBytes, encryptedData.length,&dataMoved);
if (status == kCCSuccess)
encryptedData.length = dataMoved;
return encryptedData;
return nil;
/**
* @brief 利用AES解密据
*/
- (NSData*)decryptedWithAESUsingKey:(NSString*)key andIV:(NSData*)iv
NSData *keyData = [key dataUsingEncoding:NSUTF8StringEncoding];
size_t dataMoved;
NSMutableData *decryptedData = [NSMutableData dataWithLength:self.length + kCCBlockSizeAES128];
CCCryptorStatus result = CCCrypt(kCCDecrypt,kCCAlgorithmAES128,kCCOptionPKCS7Padding,keyData.bytes,keyData.length,iv.bytes,self.bytes,self.length,decryptedData.mutableBytes, decryptedData.length,&dataMoved);
if (result == kCCSuccess)
decryptedData.length = dataMoved;
return decryptedData;
return nil;
64、3DES加密
#import <CommonCrypto/CommonCryptor.h>
@interface NSData (3DES)
/**
* 利用3DES加密数据
*/
- (NSData*)encryptedWith3DESUsingKey:(NSString*)key andIV:(NSData*)iv
NSData *keyData = [key dataUsingEncoding:NSUTF8StringEncoding];
size_t dataMoved;
NSMutableData *encryptedData = [NSMutableData dataWithLength:self.length + kCCBlockSize3DES];
CCCryptorStatus result = CCCrypt(kCCEncrypt,kCCAlgorithm3DES,kCCOptionPKCS7Padding,keyData.bytes,keyData.length,iv.bytes,self.bytes,self.length,encryptedData.mutableBytes,encryptedData.length,&dataMoved);
if (result == kCCSuccess)
encryptedData.length = dataMoved;
return encryptedData;
return nil;
/**
* @brief 利用3DES解密数据
*/
- (NSData*)decryptedWith3DESUsingKey:(NSString*)key andIV:(NSData*)iv
NSData *keyData = [key dataUsingEncoding:NSUTF8StringEncoding];
size_t dataMoved;
NSMutableData *decryptedData = [NSMutableData dataWithLength:self.length + kCCBlockSize3DES];
CCCryptorStatus result = CCCrypt(kCCDecrypt,kCCAlgorithm3DES,kCCOptionPKCS7Padding,keyData.bytes,keyData.length,iv.bytes,self.bytes,self.length,decryptedData.mutableBytes,decryptedData.length,&dataMoved);
if (result == kCCSuccess)
decryptedData.length = dataMoved;
return decryptedData;
return nil;
65、单个页面多个网络请求的情况，需要监听所有网络请求结束后刷新UI
dispatch_group_t group = dispatch_group_create();
dispatch_queue_t serialQueue = dispatch_queue_create("com.wzb.test.www", DISPATCH_QUEUE_SERIAL);
dispatch_group_enter(group);
dispatch_group_async(group, serialQueue, ^
// 网络请求一
[WebClick getDataSuccess:^(ResponseModel *model)
dispatch_group_leave(group);
failure:^(NSString *err)
dispatch_group_leave(group);
];
);
dispatch_group_enter(group);
dispatch_group_async(group, serialQueue, ^
// 网络请求二
[WebClick getDataSuccess:getBigTypeRM onSuccess:^(ResponseModel *model)
dispatch_group_leave(group);
failure:^(NSString *errorString)
dispatch_group_leave(group);
];
);
dispatch_group_enter(group);
dispatch_group_async(group, serialQueue, ^
// 网络请求三
[WebClick getDataSuccess:^
dispatch_group_leave(group);
failure:^(NSString *errorString)
dispatch_group_leave(group);
];
);
// 所有网络请求结束后会来到这个方法
dispatch_group_notify(group, serialQueue, ^
dispatch_async(dispatch_get_global_queue(0, 0), ^
dispatch_async(dispatch_get_main_queue(), ^
// 刷新UI
);
);
);66、解决openUrl延时问题
// 方法一
dispatch_async(dispatch_get_main_queue(), ^
UIApplication *application = [UIApplication sharedApplication];
if ([application respondsToSelector:@selector(openURL:options:completionHandler:)])
[application openURL:URL options:@
completionHandler:nil];
else
[application openURL:URL];
);
// 方法二
[self performSelector:@selector(redirectToURL:) withObject:url afterDelay:0.1];
- (void) redirectToURL
UIApplication *application = [UIApplication sharedApplication];
if ([application respondsToSelector:@selector(openURL:options:completionHandler:)])
[application openURL:URL options:@
completionHandler:nil];
else
[application openURL:URL];
67、页面跳转实现翻转动画
// modal方式
TestViewController *vc = [[TestViewController alloc] init];
vc.view.backgroundColor = [UIColor redColor];
vc.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
[self presentViewController:vc animated:YES completion:nil];
// push方式
TestViewController *vc = [[TestViewController alloc] init];
vc.view.backgroundColor = [UIColor redColor];
[UIView beginAnimations:@"View Flip" context:nil];
[UIView setAnimationDuration:0.80];
[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
[UIView setAnimationTransition:UIViewAnimationTransitionFlipFromRight forView:self.navigationController.view cache:NO];
[self.navigationController pushViewController:vc animated:YES];
[UIView commitAnimations];68、tableView实现无限滚动
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
CGFloat actualPosition = scrollView.contentOffset.y;
CGFloat contentHeight = scrollView.contentSize.height - scrollView.frame.size.height;
if (actualPosition >= contentHeight)
[self.dataArr addObjectsFromArray:self.dataArr];
[self.tableView reloadData];
69、代码方式调整屏幕亮度
// brightness属性值在0-1之间，0代表最小亮度，1代表最大亮度
[[UIScreen mainScreen] setBrightness:0.5];70、获取当前应用CUP用量
float cpu_usage()
kern_return_t kr;
task_info_data_t tinfo;
mach_msg_type_number_t task_info_count;
task_info_count = TASK_INFO_MAX;
kr = task_info(mach_task_self(), TASK_BASIC_INFO, (task_info_t)tinfo, &task_info_count);
if (kr != KERN_SUCCESS)
return -1;
task_basic_info_t basic_info;
thread_array_t thread_list;
mach_msg_type_number_t thread_count;
thread_info_data_t thinfo;
mach_msg_type_number_t thread_info_count;
thread_basic_info_t basic_info_th;
uint32_t stat_thread = 0; // Mach threads
basic_info = (task_basic_info_t)tinfo;
// get threads in the task
kr = task_threads(mach_task_self(), &thread_list, &thread_count);
if (kr != KERN_SUCCESS)
return -1;
if (thread_count > 0)
stat_thread += thread_count;
long tot_sec = 0;
long tot_usec = 0;
float tot_cpu = 0;
int j;
for (j = 0; j < (int)thread_count; j++)
thread_info_count = THREAD_INFO_MAX;
kr = thread_info(thread_list[j], THREAD_BASIC_INFO,
(thread_info_t)thinfo, &thread_info_count);
if (kr != KERN_SUCCESS)
return -1;
basic_info_th = (thread_basic_info_t)thinfo;
if (!(basic_info_th->flags & TH_FLAGS_IDLE))
tot_sec = tot_sec + basic_info_th->user_time.seconds + basic_info_th->system_time.seconds;
tot_usec = tot_usec + basic_info_th->user_time.microseconds + basic_info_th->system_time.microseconds;
tot_cpu = tot_cpu + basic_info_th->cpu_usage / (float)TH_USAGE_SCALE * 100.0;
// for each thread
kr = vm_deallocate(mach_task_self(), (vm_offset_t)thread_list, thread_count * sizeof(thread_t));
assert(kr == KERN_SUCCESS);
return tot_cpu;
71、float数据取整四舍五入
CGFloat f = 4.65;
NSLog(@"%d", (int)f); // 打印结果4
CGFloat f = 4.65;
NSLog(@"%d", (int)round(f)); // 打印结果572、删除UISearchBar系统默认边框
// 方法一
searchBar.searchBarStyle = UISearchBarStyleMinimal;
// 方法二
[searchBar setBackgroundImage:[[UIImage alloc]init]];
// 方法三
searchBar.barTintColor = [UIColor whiteColor];73、为UICollectionViewCell设置圆角和阴影
cell.contentView.layer.cornerRadius = 2.0f;
cell.contentView.layer.borderWidth = 1.0f;
cell.contentView.layer.borderColor = [UIColor clearColor].CGColor;
cell.contentView.layer.masksToBounds = YES;
cell.layer.shadowColor = [UIColor lightGrayColor].CGColor;
cell.layer.shadowOffset = CGSizeMake(0, 2.0f);
cell.layer.shadowRadius = 2.0f;
cell.layer.shadowOpacity = 1.0f;
cell.layer.masksToBounds = NO;
cell.layer.shadowPath = [UIBezierPath bezierPathWithRoundedRect:cell.bounds cornerRadius:cell.contentView.layer.cornerRadius].CGPath;74、让正在滑动的scrollView停止滚动(不是禁止，而是暂时停止滚动)
[scrollView setContentOffset:scrollView.contentOffset animated:NO];75、使用xib设置UIView的边框、圆角
圆角和边框看下图即可设置
xib设置圆角边框.png
但是增加layer.borderColor的keyPath设置边框颜色并不能起作用，后来查了资料，这里应该用layer.borderUIColor，但是这里设置的颜色不起作用，无论设置什么颜色显示出来的都是黑色的。后来又去查了下，有种解决方案是给CALayer添加一个分类，提供一个
- (void)setBorderUIColor:(UIColor *)color;方法就可以解决了，实现如下：
xib设置边框颜色.png
#import "CALayer+BorderColor.h"
@implementation CALayer (BorderColor)
- (void)setBorderUIColor:(UIColor *)color
self.borderColor = color.CGColor;
76、根据经纬度获取城市等信息
// 创建经纬度
CLLocation *location = [[CLLocation alloc] initWithLatitude:latitude longitude:longitude];
//创建一个译码器
CLGeocoder *cLGeocoder = [[CLGeocoder alloc] init];
[cLGeocoder reverseGeocodeLocation:userLocation completionHandler:^(NSArray *placemarks, NSError *error)
CLPlacemark *place = [placemarks objectAtIndex:0];
// 位置名
NSLog(@"name,%@",place.name);
// 街道
NSLog(@"thoroughfare,%@",place.thoroughfare);
// 子街道
NSLog(@"subThoroughfare,%@",place.subThoroughfare);
// 市
NSLog(@"locality,%@",place.locality);
// 区
NSLog(@"subLocality,%@",place.subLocality);
// 国家
NSLog(@"country,%@",place.country);
];
/* CLPlacemark中属性含义
name 地名
thoroughfare 街道
subThoroughfare 街道相关信息，例如门牌等
locality 城市
subLocality 城市相关信息，例如标志性建筑
administrativeArea 直辖市
subAdministrativeArea 其他行政区域信息（自治区等）
postalCode 邮编
ISOcountryCode 国家编码
country 国家
inlandWater 水源，湖泊
ocean 海洋
areasOfInterest 关联的或利益相关的地标
*/77、如何防止添加多个NSNotification观察者？
// 解决方案就是添加观察者之前先移除下这个观察者
[[NSNotificationCenter defaultCenter] removeObserver:observer name:name object:object];
[[NSNotificationCenter defaultCenter] addObserver:observer selector:selector name:name object:object];78、将一个xib添加到另外一个xib上
// 假设你的自定义view名字为CustomView，你需要在CustomView.m中重写 `- (instancetype)initWithCoder:(NSCoder *)aDecoder` 方法，代码如下：
- (instancetype)initWithCoder:(NSCoder *)aDecoder
if ((self = [super initWithCoder:aDecoder]))
[self addSubview:[[[NSBundle mainBundle] loadNibNamed:@"CustomView" owner:self options:nil] objectAtIndex:0]];
return self;
将一个xib添加到另外一个xib上.png
79、处理字符串，使其首字母大写
NSString *str = @"abcdefghijklmn";
NSString *resultStr;
if (str && str.length > 0)
resultStr = [str stringByReplacingCharactersInRange:NSMakeRange(0,1) withString:[[str substringToIndex:1] capitalizedString]];
NSLog(@"%@", resultStr);80、判断一个UIAlertView/UIAlertController是否显示
// UIAlertView自带属性
if (alert.visible)
NSLog(@"显示了");
else
NSLog(@"未显示");
// UIAlertController没有visible属性，需要自己判断，添加一个全局变量 BOOL visible
UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"Title" message:@"message" preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction *alertAction = [UIAlertAction actionWithTitle:@"ActionTitle" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action)
self.visible = NO;
];
UIAlertAction *calcelAction = [UIAlertAction actionWithTitle:@"calcelTitle" style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action)
self.visible = NO;
];
[alertController addAction:alertAction];
[alertController addAction:calcelAction];
[self presentViewController:alertController animated:YES completion:^
self.visible = YES;
];81、获取字符串中的数字
- (NSString *)getNumberFromStr:(NSString *)str
NSCharacterSet *nonDigitCharacterSet = [[NSCharacterSet decimalDigitCharacterSet] invertedSet];
return [[str componentsSeparatedByCharactersInSet:nonDigitCharacterSet] componentsJoinedByString:@""];
NSLog(@"%@", [self getNumberFromStr:@"a0b0c1d2e3f4fda8fa8fad9fsad23"]); // 0012348892382、为UIView的某个方向添加边框
// 添加UIView分类
// UIView+WZB.h
#import <UIKit/UIKit.h>
/** 边框方向 - WZBBorderDirectionTop: 顶部 - WZBBorderDirectionLeft: 左边 - WZBBorderDirectionBottom: 底部 - WZBBorderDirectionRight: 右边 */
typedef NS_ENUM(NSInteger, WZBBorderDirectionType)
WZBBorderDirectionTop = 0,
WZBBorderDirectionLeft,
WZBBorderDirectionBottom,
WZBBorderDirectionRight
;
@interface UIView (WZB)
/** 为UIView的某个方向添加边框 @param direction 边框方向 @param color 边框颜色 @param width 边框宽度 */
- (void)wzb_addBorder:(WZBBorderDirectionType)direction color:(UIColor *)color width:(CGFloat)width;
@end
// UIView+WZB.m
#import "UIView+WZB.h"
@implementation UIView (WZB)
- (void)wzb_addBorder:(WZBBorderDirectionType)direction color:(UIColor *)color width:(CGFloat)width
CALayer *border = [CALayer layer];
border.backgroundColor = color.CGColor;
switch (direction)
case WZBBorderDirectionTop:
border.frame = CGRectMake(0.0f, 0.0f, self.bounds.size.width, width);
break;
case WZBBorderDirectionLeft:
border.frame = CGRectMake(0.0f, 0.0f, width, self.bounds.size.height);
break;
case WZBBorderDirectionBottom:
border.frame = CGRectMake(0.0f, self.bounds.size.height - width, self.bounds.size.width, width);
break;
case WZBBorderDirectionRight:
border.frame = CGRectMake(self.bounds.size.width - width, 0, width, self.bounds.size.height);
break;
default: break;
[self.layer addSublayer:border];
83、通过属性设置UISwitch、UIProgressView等控件的宽高
mySwitch.transform = CGAffineTransformMakeScale(5.0f, 5.0f);
progressView.transform = CGAffineTransformMakeScale(5.0f, 5.0f);84、自动搜索功能，用户连续输入的时候不搜索，用户停止输入的时候自动搜索(我这里设置的是0.5s，可根据需求更改)
// 输入框文字改变的时候调用
-(void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText
// 先取消调用搜索方法
[NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(searchNewResult) object:nil];
// 0.5秒后调用搜索方法
[self performSelector:@selector(searchNewResult) withObject:nil afterDelay:0.5];
85、修改UISearchBar的占位文字颜色
// 方法一（推荐使用）
UITextField *searchField = [searchBar valueForKey:@"_searchField"];
[searchField setValue:[UIColor blueColor] forKeyPath:@"_placeholderLabel.textColor"];
// 方法二（已过期）
[[UILabel appearanceWhenContainedIn:[UISearchBar class], nil] setTextColor:[UIColor redColor]];
// 方法三（已过期）
NSDictionary *placeholderAttributes = @NSForegroundColorAttributeName : [UIColor redColor], NSFontAttributeName : [UIFont fontWithName:@"HelveticaNeue" size:15],;
NSAttributedString *attributedPlaceholder = [[NSAttributedString alloc] initWithString:searchBar.placeholder attributes:placeholderAttributes];
[[UITextField appearanceWhenContainedIn:[UISearchBar class], nil] setAttributedPlaceholder:attributedPlaceholder];86、某个界面多个事件同时响应引起的问题(比如，两个button同时按push到新界面，两个都会响应，可能导致push重叠)
// UIView有个属性叫做exclusiveTouch，设置为YES后，其响应事件会和其他view互斥(有其他view事件响应的时候点击它不起作用)
view.exclusiveTouch = YES;
// 一个一个设置太麻烦了，可以全局设置
[[UIView appearance] setExclusiveTouch:YES];
// 或者只设置button
[[UIButton appearance] setExclusiveTouch:YES];87、修改tabBar的frame
// 子类化UITabBarViewController，我这里以修改tabBar高度为例，重写viewWillLayoutSubviews方法
#import "WZBTabBarViewController.h"
@interface WZBTabBarViewController ()
@end
@implementation WZBTabBarViewController
- (void)viewWillLayoutSubviews
CGRect tabFrame = self.tabBar.frame;
tabFrame.size.height = 100;
tabFrame.origin.y = self.view.frame.size.height - 100;
self.tabBar.frame = tabFrame;
@end
88、修改键盘背景颜色
// 设置某个键盘颜色
textField.keyboardAppearance = UIKeyboardAppearanceAlert;
// 设置工程中所有键盘颜色
[[UITextField appearance] setKeyboardAppearance:UIKeyboardAppearanceAlert];89、修改image颜色
UIImage *image = [UIImage imageNamed:@"test"];
imageView.image = [image imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
CGRect rect = CGRectMake(0, 0, image.size.width, image.size.height);
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextClipToMask(context, rect, image.CGImage);
CGContextSetFillColorWithColor(context, [[UIColor redColor] CGColor]);
CGContextFillRect(context, rect);
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
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