iOS 知識-常用小技巧大雜燴
1. 列印View所有子檢視
po [[self view]recursiveDescription]
2. layoutSubviews呼叫的呼叫時機
* 當檢視第一次顯示的時候會被呼叫
* 當這個檢視顯示到螢幕上了,點選按鈕
* 新增子檢視也會呼叫這個方法
* 當本檢視的大小發生改變的時候是會呼叫的
* 當子檢視的frame發生改變的時候是會呼叫的
* 當刪除子檢視的時候是會呼叫的
3. NSString過濾特殊字元
// 定義一個特殊字元的集合
NSCharacterSet *set = [NSCharacterSet characterSetWithCharactersInString:
@"@/:;()¥「」"、[]{}#%-*+=_\\|~<>$€^•'@#$%^&*()_+'\""];
// 過濾字串的特殊字元
NSString *newString = [trimString stringByTrimmingCharactersInSet:set];
4. TransForm屬性
//平移按鈕
CGAffineTransform transForm = self.buttonView.transform;
self.buttonView.transform = CGAffineTransformTranslate(transForm, 10, 0);
//旋轉按鈕
CGAffineTransform transForm = self.buttonView.transform;
self.buttonView.transform = CGAffineTransformRotate(transForm, M_PI_4);
//縮放按鈕
self.buttonView.transform = CGAffineTransformScale(transForm, 1.2 , 1.2);
//初始化復位
self.buttonView.transform = CGAffineTransformIdentity;
5. 去掉分割線多餘15畫素
首先在viewDidLoad方法加入以下程式碼:
if ([self.tableView respondsToSelector:@selector(setSeparatorInset:)]) {
[self.tableView setSeparatorInset:UIEdgeInsetsZero];
}
if ([self.tableView respondsToSelector:@selector(setLayoutMargins:)]) {
[self.tableView setLayoutMargins:UIEdgeInsetsZero];
}
然後在重寫willDisplayCell方法
- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell
forRowAtIndexPath:(NSIndexPath *)indexPath{
if ([cell respondsToSelector:@selector(setSeparatorInset:)]) {
[cell setSeparatorInset:UIEdgeInsetsZero];
}
if ([cell respondsToSelector:@selector(setLayoutMargins:)]) {
[cell setLayoutMargins:UIEdgeInsetsZero];
}
}
6. 計算方法耗時時間間隔
// 獲取時間間隔
#define TICK CFAbsoluteTime start = CFAbsoluteTimeGetCurrent();
#define TOCK NSLog(@"Time: %f", CFAbsoluteTimeGetCurrent() - start)
7. Color顏色巨集定義
// 隨機顏色
#define RANDOM_COLOR [UIColor colorWithRed:arc4random_uniform(256) / 255.0 green:arc4random_uniform(256) / 255.0 blue:arc4random_uniform(256) / 255.0 alpha:1]
// 顏色(RGB)
#define RGBCOLOR(r, g, b) [UIColor colorWithRed:(r)/255.0f green:(g)/255.0f blue:(b)/255.0f alpha:1]
// 利用這種方法設定顏色和透明值,可不影響子檢視背景色
#define RGBACOLOR(r, g, b, a) [UIColor colorWithRed:(r)/255.0f green:(g)/255.0f blue:(b)/255.0f alpha:(a)]
8. Alert提示巨集定義
#define Alert(_S_, ...) [[[UIAlertView alloc] initWithTitle:@"提示" message:[NSString stringWithFormat:(_S_), ##__VA_ARGS__] delegate:nil cancelButtonTitle:@"確定" otherButtonTitles:nil] show]
9. 讓iOS應用直接退出
- (void)exitApplication {
AppDelegate *app = [UIApplication sharedApplication].delegate;
UIWindow *window = app.window;
[UIView animateWithDuration:1.0f animations:^{
window.alpha = 0;
} completion:^(BOOL finished) {
exit(0);
}];
}
10. 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);
10. 修改Label中不同文字顏色
- (void)touchesEnded:(NSSet<UITouch> *)touches withEvent:(UIEvent *)event
{
[self editStringColor:self.label.text editStr:@"好" color:[UIColor blueColor]];
}
- (void)editStringColor:(NSString *)string editStr:(NSString *)editStr color:(UIColor *)color {
// string為整體字串, editStr為需要修改的字串
NSRange range = [string rangeOfString:editStr];
NSMutableAttributedString *attribute = [[NSMutableAttributedString alloc] initWithString:string];
// 設定屬性修改字型顏色UIColor與大小UIFont
[attribute addAttributes:@{NSForegroundColorAttributeName:color} range:range];
self.label.attributedText = attribute;
}
11. 播放聲音
#import<AVFoundation>
// 1.獲取音效資源的路徑
NSString *path = [[NSBundle mainBundle]pathForResource:@"pour_milk" ofType:@"wav"];
// 2.將路勁轉化為url
NSURL *tempUrl = [NSURL fileURLWithPath:path];
// 3.用轉化成的url建立一個播放器
NSError *error = nil;
AVAudioPlayer *play = [[AVAudioPlayer alloc]initWithContentsOfURL:tempUrl error:&error];
self.player = play;
// 4.播放
[play play];
12. 檢測是否IPad Pro
- (BOOL)isIpadPro
{
UIScreen *Screen = [UIScreen mainScreen];
CGFloat width = Screen.nativeBounds.size.width/Screen.nativeScale;
CGFloat height = Screen.nativeBounds.size.height/Screen.nativeScale;
BOOL isIpad =[[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPad;
BOOL hasIPadProWidth = fabs(width - 1024.f) < DBL xss=removed xss=removed xss=removed xss=removed xss=removed xss=removed xss=removed xss=removed xss=removed>> ~/.lldbinit
echo target stop-hook add -o \"target stop-hook disable\" >> ~/.lldbinit
下次重新執行專案,然後就不報錯了。
25. Label行間距
-(void)test{
NSMutableAttributedString *attributedString =
[[NSMutableAttributedString alloc] initWithString:self.contentLabel.text];
NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
[paragraphStyle setLineSpacing:3];
//調整行間距
[attributedString addAttribute:NSParagraphStyleAttributeName
value:paragraphStyle
range:NSMakeRange(0, [self.contentLabel.text length])];
self.contentLabel.attributedText = attributedString;
}
26. UIImageView填充模式
@"UIViewContentModeScaleToFill", // 拉伸自適應填滿整個檢視
@"UIViewContentModeScaleAspectFit", // 自適應比例大小顯示
@"UIViewContentModeScaleAspectFill", // 原始大小顯示
@"UIViewContentModeRedraw", // 尺寸改變時重繪
@"UIViewContentModeCenter", // 中間
@"UIViewContentModeTop", // 頂部
@"UIViewContentModeBottom", // 底部
@"UIViewContentModeLeft", // 中間貼左
@"UIViewContentModeRight", // 中間貼右
@"UIViewContentModeTopLeft", // 貼左上
@"UIViewContentModeTopRight", // 貼右上
@"UIViewContentModeBottomLeft", // 貼左下
@"UIViewContentModeBottomRight", // 貼右下
27. 巨集定義檢測block是否可用
#define BLOCK_EXEC(block, ...) if (block) { block(__VA_ARGS__); };
// 巨集定義之前的用法
if (completionBlock) {
completionBlock(arg1, arg2);
}
// 巨集定義之後的用法
BLOCK_EXEC(completionBlock, arg1, arg2);
28. Debug欄列印時自動把Unicode編碼轉化成漢字
// 有時候我們在xcode中列印中文,會打印出Unicode編碼,還需要自己去一些線上網站轉換,有了外掛就方便多了。
DXXcodeConsoleUnicodePlugin 外掛
29. 設定狀態列文字樣式顏色
[[UIApplication sharedApplication] setStatusBarHidden:NO];
[[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];
30. 自動生成模型程式碼的外掛
// 可自動生成模型的程式碼,省去寫模型程式碼的時間
ESJsonFormat-for-Xcode
31. iOS中的一些手勢
輕擊手勢(TapGestureRecognizer)
輕掃手勢(SwipeGestureRecognizer)
長按手勢(LongPressGestureRecognizer)
拖動手勢(PanGestureRecognizer)
捏合手勢(PinchGestureRecognizer)
旋轉手勢(RotationGestureRecognizer)
32. iOS 開發中一些相關的路徑
模擬器的位置:
/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs
文件安裝位置:
/Applications/Xcode.app/Contents/Developer/Documentation/DocSets
外掛儲存路徑:
~/Library/ApplicationSupport/Developer/Shared/Xcode/Plug-ins
自定義程式碼段的儲存路徑:
~/Library/Developer/Xcode/UserData/CodeSnippets/
如果找不到CodeSnippets資料夾,可以自己新建一個CodeSnippets資料夾。
證書路徑
~/Library/MobileDevice/Provisioning Profiles
33. 獲取 iOS 路徑的方法
獲取家目錄路徑的函式
NSString *homeDir = NSHomeDirectory();
獲取Documents目錄路徑的方法
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *docDir = [paths objectAtIndex:0];
獲取Documents目錄路徑的方法
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
NSString *cachesDir = [paths objectAtIndex:0];
獲取tmp目錄路徑的方法:
NSString *tmpDir = NSTemporaryDirectory();
34. 字串相關操作
去除所有的空格
[str stringByReplacingOccurrencesOfString:@" " withString:@""]
去除首尾的空格
[str stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
- (NSString *)uppercaseString; 全部字元轉為大寫字母
- (NSString *)lowercaseString 全部字元轉為小寫字母
35. CocoaPods pod install/pod update更新慢的問題
pod install --verbose --no-repo-update
pod update --verbose --no-repo-update
如果不加後面的引數,預設會升級CocoaPods的spec倉庫,加一個引數可以省略這一步,然後速度就會提升不少。
36. MRC和ARC混編設定方式
在XCode中targets的build phases選項下Compile Sources下選擇 不需要arc編譯的檔案
雙擊輸入 -fno-objc-arc 即可
MRC工程中也可以使用ARC的類,方法如下:
在XCode中targets的build phases選項下Compile Sources下選擇要使用arc編譯的檔案
雙擊輸入 -fobjc-arc 即可
37. 把tableview裡cell的小對勾的顏色改成別的顏色
_mTableView.tintColor = [UIColor redColor];
38. 調整tableview的separaLine線的位置
tableView.separatorInset = UIEdgeInsetsMake(0, 100, 0, 0);
39. 設定滑動的時候隱藏navigationbar
navigationController.hidesBarsOnSwipe = Yes
40. 自動處理鍵盤事件,實現輸入框防遮擋的外掛
IQKeyboardManager
https://github.com/hackiftekhar/IQKeyboardManager
41. Quartz2D相關
圖形上下是一個CGContextRef型別的資料。
圖形上下文包含:
1,繪圖路徑(各種各樣圖形)
2,繪圖狀態(顏色,線寬,樣式,旋轉,縮放,平移)
3,輸出目標(繪製到什麼地方去?UIView、圖片)
1,獲取當前圖形上下文
CGContextRef ctx = UIGraphicsGetCurrentContext();
2,新增線條
CGContextMoveToPoint(ctx, 20, 20);
3,渲染
CGContextStrokePath(ctx);
CGContextFillPath(ctx);
4,關閉路徑
CGContextClosePath(ctx);
5,畫矩形
CGContextAddRect(ctx, CGRectMake(20, 20, 100, 120));
6,設定線條顏色
[[UIColor redColor] setStroke];
7, 設定線條寬度
CGContextSetLineWidth(ctx, 20);
8,設定頭尾樣式
CGContextSetLineCap(ctx, kCGLineCapSquare);
9,設定轉折點樣式
CGContextSetLineJoin(ctx, kCGLineJoinBevel);
10,畫圓
CGContextAddEllipseInRect(ctx, CGRectMake(30, 50, 100, 100));
11,指定圓心
CGContextAddArc(ctx, 100, 100, 50, 0, M_PI * 2, 1);
12,獲取圖片上下文
UIGraphicsGetImageFromCurrentImageContext();
13,儲存圖形上下文
CGContextSaveGState(ctx)
14,恢復圖形上下文
CGContextRestoreGState(ctx)
42. 螢幕截圖
// 1. 開啟一個與圖片相關的圖形上下文
UIGraphicsBeginImageContextWithOptions(self.view.bounds.size,NO,0.0);
// 2. 獲取當前圖形上下文
CGContextRef ctx = UIGraphicsGetCurrentContext();
// 3. 獲取需要擷取的view的layer
[self.view.layer renderInContext:ctx];
// 4. 從當前上下文中獲取圖片
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
// 5. 關閉圖形上下文
UIGraphicsEndImageContext();
// 6. 把圖片儲存到相簿
UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
43. 隱藏導航欄上的返回字型
//Swift
UIBarButtonItem.appearance().setBackButtonTitlePositionAdjustment(UIOffsetMake(0, -60), forBarMetrics: .Default)
//OC
[[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60) forBarMetrics:UIBarMetricsDefault];
44. 解決tableview的分割線短一截
-(void)viewDidLayoutSubviews{
if ([self.tableView respondsToSelector:@selector(setSeparatorInset:)])
{
[self.tableView setSeparatorInset:UIEdgeInsetsMake(0,0,0,0)];
}
if ([self.tableView respondsToSelector:@selector(setLayoutMargins:)])
{
[self.tableView setLayoutMargins:UIEdgeInsetsMake(0,0,0,0)];
}
}
-(void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath{
if ([cell respondsToSelector:@selector(setSeparatorInset:)])
{
[cell setSeparatorInset:UIEdgeInsetsZero];
}
if ([cell respondsToSelector:@selector(setLayoutMargins:)])
{
[cell setLayoutMargins:UIEdgeInsetsZero];
}
}
45. 動態隱藏NavigationBar
//1.當我們的手離開螢幕時候隱藏
- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)targetContentOffset
{
if(velocity.y > 0)
{
[self.navigationController setNavigationBarHidden:YES animated:YES];
} else {
[self.navigationController setNavigationBarHidden:NO animated:YES];
}
}
velocity.y這個量,在上滑和下滑時,變化極小(小數),但是因為方向不同,有正負之分,這就很好處理了。
//2.在滑動過程中隱藏
//像safari
(1)
self.navigationController.hidesBarsOnSwipe = YES;
(2)
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
CGFloat offsetY = scrollView.contentOffset.y + __tableView.contentInset.top;
CGFloat panTranslationY = [scrollView.panGestureRecognizer translationInView:self.tableView].y;
if (offsetY > 64) {
if (panTranslationY > 0)
{
//下滑趨勢,顯示
[self.navigationController setNavigationBarHidden:NO animated:YES];
} else {
//上滑趨勢,隱藏
[self.navigationController setNavigationBarHidden:YES animated:YES];
}
} else {
[self.navigationController setNavigationBarHidden:NO animated:YES];
}
}
這裡的offsetY > 64只是為了在檢視滑過navigationBar的高度之後才開始處理,防止影響展示效果。panTranslationY是scrollView的pan手勢的手指位置的y值,可能不是太好,因為panTranslationY這個值在較小幅度上下滑動時,可能都為正或都為負,這就使得這一方式不太靈敏.
效果圖
46. 設定導航欄透明
//方法一:設定透明度
[[[self.navigationController.navigationBar subviews]objectAtIndex:0] setAlpha:0.1];
//方法二:設定背景圖片
/**
* 設定導航欄,使其透明
*
*/
- (void)setNavigationBarColor:(UIColor *)color targetController:(UIViewController *)targetViewController{
//導航條的顏色 以及隱藏導航條的顏色targetViewController.navigationController.navigationBar.shadowImage = [[UIImage alloc]init];
CGRect rect=CGRectMake(0.0f, 0.0f, 1.0f, 1.0f); UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext(); CGContextSetFillColorWithColor(context, [color CGColor]); CGContextFillRect(context, rect);
UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); [targetViewController.navigationController.navigationBar setBackgroundImage:theImage forBarMetrics:UIBarMetricsDefault];
}
47. 設定字型和行間距
//設定字型和行間距
UILabel * lable = [[UILabel alloc]initWithFrame:CGRectMake(50, 100, 300, 200)];
lable.text = @"大家好,我是Frank_chun,在這裡我們一起學習新的知識,總結我們遇到的那些坑,共同的學習,共同的進步,共同的努力,只為美好的明天!!!有問題一起相互的探討--438637472!!!";
lable.numberOfLines = 0;
lable.font = [UIFont systemFontOfSize:12];
lable.backgroundColor = [UIColor grayColor];
[self.view addSubview:lable];
//設定每個字型之間的間距
//NSKernAttributeName 這個物件所對應的值是一個NSNumber物件(包含小數),作用是修改預設字型之間的距離調整,值為0的話表示字距調整是禁用的; NSMutableAttributedString * str = [[NSMutableAttributedString alloc]initWithString:lable.text attributes:@{NSKernAttributeName:@(5.0)}];
//設定某寫字型的顏色
//NSForegroundColorAttributeName 設定字型顏色
NSRange blueRange = NSMakeRange([[str string] rangeOfString:@"Frank_chun"].location, [[str string] rangeOfString:@"Frank_chun"].length);
[str addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:blueRange];
NSRange blueRange1 = NSMakeRange([[str string] rangeOfString:@"438637472"].location, [[str string] rangeOfString:@"438637472"].length);
[str addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:blueRange1];
//設定每行之間的間距
//NSParagraphStyleAttributeName 設定段落的樣式
NSMutableParagraphStyle * par = [[NSMutableParagraphStyle alloc]init];
[par setLineSpacing:20];
//為某一範圍內文字新增某個屬性
//NSMakeRange表示所要的範圍,從0到整個文字的長度
[str addAttribute:NSParagraphStyleAttributeName value:par range:NSMakeRange(0, lable.text.length)]; [lable setAttributedText:str];
效果圖
48. 點選button倒計時
//第一種方法
//點選button倒計時
#import "ViewController.h"
@interface ViewController ()
@property (nonatomic, strong) UIButton * timeButton;
@property (nonatomic, strong) NSTimer * timer;
@property (nonatomic, strong)UIButton * btn;
@[email protected] ViewController
{
NSInteger _time;
}
- (void)viewDidLoad {
[super viewDidLoad];
_time = 5;
self.btn = [UIButton buttonWithType:UIButtonTypeCustom]; _btn.backgroundColor = [UIColor orangeColor];
[_btn setTitle:@"獲取驗證碼" forState:UIControlStateNormal]; _btn.titleLabel.font = [UIFont systemFontOfSize:15];
[_timeButton setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
[_btn addTarget:self action:@selector(btnAction:) forControlEvents:UIControlEventTouchUpInside];
[self refreshButtonWidth];
[self.view addSubview:self.btn];
}
- (void)refreshButtonWidth{
CGFloat width = 0;
if (_btn.enabled){
width = 100;
} else {
width = 200;
}
_btn.center = CGPointMake(self.view.frame.size.width/2, 200);
_btn.bounds = CGRectMake(0, 0, width, 40);
//每次重新整理,保證區域正確
[_btn setBackgroundImage:[self imageWithColor:[UIColor orangeColor] andSize:_btn.frame.size] forState:UIControlStateNormal];
[_btn setBackgroundImage:[self imageWithColor:[UIColor lightGrayColor] andSize:_btn.frame.size] forState:UIControlStateDisabled];
}
- (UIImage *)imageWithColor:(UIColor *)color andSize:(CGSize)aSize{
CGRect rect = CGRectMake(0.0f, 0.0f, aSize.width, aSize.height); UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext(); CGContextSetFillColorWithColor(context, [color CGColor]); CGContextFillRect(context, rect);
UIImage *image = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext();
return image;
}
- (void)btnAction:(UIButton *)sender{
sender.enabled = NO;
[self refreshButtonWidth];
[sender setTitle:[NSString stringWithFormat:@"獲取驗證碼(%zi)", _time] forState:UIControlStateNormal];
_timer = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(timeDown) userInfo:nil repeats:YES];
}
- (void)timeDown{
_time --;
if (_time == 0) {
[_btn setTitle:@"重新獲取" forState:UIControlStateNormal]; _btn.enabled = YES;
[self refreshButtonWidth];
[_timer invalidate];
_timer = nil;
_time = 5 ;
return;
}
[_btn setTitle:[NSString stringWithFormat:@"獲取驗證碼(%zi)", _time] forState:UIControlStateNormal];
}
//第二種方法
#pragma mark -點擊發送驗證碼
- (void)sendMessage:(UIButton *)btn{
if (self.phoneField.text.length == 0) {
[self remindMessage:@"請輸入正確的手機號"];
}else{
__block int timeout=60;
//倒計時時間
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),1.0*NSEC_PER_SEC, 0);
//每秒執行
dispatch_source_set_event_handler(_timer, ^{
if(timeout<=0){
//倒計時結束,關閉
dispatch_source_cancel(_timer); dispatch_async(dispatch_get_main_queue(), ^{
// 設定介面的按鈕顯示 根據自己需求設定
[btn setTitle:@"傳送驗證碼" forState:UIControlStateNormal]; btn.userInteractionEnabled = YES;
});
}else{
int seconds = timeout % 60;
NSString *strTime = [NSString stringWithFormat:@"%d", seconds];
if ([strTime isEqualToString:@"0"]) {
strTime = [NSString stringWithFormat:@"%d",60];
}
dispatch_async(dispatch_get_main_queue(), ^{
//設定介面的按鈕顯示 根據自己需求設定
//NSLog(@"____%@",strTime);
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:1];
[btn setTitle:[NSString stringWithFormat:@"%@秒後重新發送",strTime] forState:UIControlStateNormal];
[UIView commitAnimations];
btn.userInteractionEnabled = NO;
});
timeout--;
}
});
dispatch_resume(_timer);
}
效果圖
49. UITextField預設佔位符是居中顯示,讓其居上顯示
textField.contentVerticalAlignment = UIControlContentVerticalAlignmentTop;
50. 解決同時按兩個按鈕進兩個view的問題
[button setExclusiveTouch:YES];
51. 圖片拉伸
UIImage* img=[UIImage imageNamed:@"2.png"];//原圖
UIEdgeInsets edge=UIEdgeInsetsMake(0, 10, 0,10);
//UIImageResizingModeStretch:拉伸模式,通過拉伸UIEdgeInsets指定的矩形區域來填充圖片
//UIImageResizingModeTile:平鋪模式,通過重複顯示UIEdgeInsets指定的矩形區域來填充圖
img= [img resizableImageWithCapInsets:edge resizingMode:UIImageResizingModeStretch];
self.imageView.image=img;
52. 修改textFieldplaceholder字型顏色和大小
textField.placeholder = @"username is in here!";
[textField setValue:[UIColor redColor] forKeyPath:@"_placeholderLabel.textColor"];
[textField setValue:[UIFont boldSystemFontOfSize:16] forKeyPath:@"_placeholderLabel.font"];
53. 修改狀態列字型顏色
只能設定兩種顏色,黑色和白色,系統預設黑色
設定為白色方法:
(1)在plist裡面新增Status bar style,值為UIStatusBarStyleLightContent(白色)或UIStatusBarStyleDefault(黑 色)
(2)在Info.plist中設定UIViewControllerBasedStatusBarAppearance 為NO
54. 去掉導航欄下邊的黑線
[self.navigationController.navigationBar setBackgroundImage:[[UIImage alloc] init] forBarMetrics:UIBarMetricsDefault];
self.navigationC