iOS開發經驗總結（三）
101、將tableView滾動到頂部
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[tableView setContentOffset:CGPointZero animated:YES];
或者
[tableView scrollRectToVisible:CGRectMake(0, 0, 1, 1) animated:YES];
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102、如果用addTarget:action:forControlEvents:方法爲一個button添加了很多點擊事件，在某個時刻想一次刪除怎麼辦？只需要調用下邊這句代碼
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[youButton removeTarget:nil action:nil forControlEvents:UIControlEventAllEvents];
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103、某個字體的高度
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font.lineHeight;
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104、刪除某個view所有的子視圖
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[[someView subviews]
makeObjectsPerformSelector:@selector(removeFromSuperview)];
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105、刪除NSUserDefaults所有記錄
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//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];
}
// 方法三
[[NSUserDefaults standardUserDefaults] setPersistentDomain:[NSDictionary dictionary] forName:[[NSBundle mainBundle] bundleIdentifier]];
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106、禁用系統滑動返回功能
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- (void)viewDidAppear:(BOOL)animated
{
[
super
viewDidAppear:animated];
if
([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {self.navigationController.interactivePopGestureRecognizer.delegate = self;
}
}
- (void)viewWillDisappear:(BOOL)animated {
[
super
viewWillDisappear:animated];
if
([self.navigationController respondsToSelector:@selector(interactivePopGestureRecognizer)]) {self.navigationController.interactivePopGestureRecognizer.delegate = nil;
}
}
- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer
{
return
NO;
}
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107、模擬器報錯
模擬器報錯
解決辦法：
打開模擬器->Simulator->Reset Content and Settings...
如果不行，就重啓試試！
108、自定義cell選中背景顏色
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UIView *bgColorView = [[UIView alloc] init];
bgColorView.backgroundColor = [UIColor redColor];
[cell setSelectedBackgroundView:bgColorView];
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109、UILabel設置內邊距
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子類化UILabel，重寫drawTextInRect方法
- (void)drawTextInRect:(CGRect)rect {
// 邊距，上左下右
UIEdgeInsets insets = {0, 5, 0, 5};
[
super
drawTextInRect:UIEdgeInsetsInsetRect(rect, insets)];
}
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110、UILabel設置文字描邊
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子類化UILabel，重寫drawTextInRect方法
- (void)drawTextInRect:(CGRect)rect
{
CGContextRef c = UIGraphicsGetCurrentContext();
// 設置描邊寬度
CGContextSetLineWidth(c, 1);
CGContextSetLineJoin(c, kCGLineJoinRound);
CGContextSetTextDrawingMode(c, kCGTextStroke);
// 描邊顏色
self.textColor = [UIColor redColor];
[
super
drawTextInRect:rect];
// 文本顏色
self.textColor = [UIColor yellowColor];
CGContextSetTextDrawingMode(c, kCGTextFill);
[
super
drawTextInRect:rect];
}
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111、使用模擬器截圖
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快捷鍵command + s
或者File->Save Screen Shot
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112、scrollView滾動到最下邊
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CGPoint bottomOffset = CGPointMake(0, scrollView.contentSize.height - scrollView.bounds.size.height);
[scrollView setContentOffset:bottomOffset animated:YES];
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113、UIView背景顏色漸變
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UIView *view = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 100)];
[self.view addSubview:view];
CAGradientLayer *gradient = [CAGradientLayer layer];
gradient.frame = view.bounds;
gradient.colors = [NSArray arrayWithObjects:(id)[[UIColor blackColor] CGColor], (id)[[UIColor whiteColor] CGColor], nil];
[view.layer insertSublayer:gradient atIndex:0];
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114、停止UIView動畫
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[yourView.layer removeAllAnimations]
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115、爲UIView某個角添加圓角
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// 左上角和右下角添加圓角
UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:view.bounds byRoundingCorners:(UIRectCornerTopLeft | UIRectCornerBottomRight) cornerRadii:CGSizeMake(20, 20)];
CAShapeLayer *maskLayer = [CAShapeLayer layer];
maskLayer.frame = view.bounds;
maskLayer.path = maskPath.CGPath;
view.layer.mask = maskLayer;
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116、刪除Xcode Derived data緩存數據
依次點擊Xcode -> Preferences -> location，然後點擊 Derived data路徑後到小箭頭，刪除這個文件夾下的數據就可以了，如圖
Xcode Derived data
117、將一個view放置在其兄弟視圖的最上面
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[parentView bringSubviewToFront:yourView]
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118、將一個view放置在其兄弟視圖的最下面
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[parentView sendSubviewToBack:yourView]
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119、讓手機震動一下
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倒入框架
#import
AudioServicesPlayAlertSound(kSystemSoundID_Vibrate);
或者
AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);
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120、layoutSubviews方法什麼時候調用？
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1、init方法不會調用
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2、addSubview方法等時候會調用
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3、bounds改變的時候調用
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4、scrollView滾動的時候會調用scrollView的layoutSubviews方法(所以不建議在scrollView的layoutSubviews方法中做複雜邏輯)
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5、旋轉設備的時候調用
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6、子視圖被移除的時候調用
參考請看：http://blog.logichigh.com/2011/03/16/when-does-layoutsubviews-get-called/
121、讓UILabel在指定的地方換行
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// 換行符爲\n,在需要換行的地方加上這個符號即可，如
label.numberOfLines = 0;
label.text = @
"此處\n換行"
;
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122、搖一搖功能
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1、打開搖一搖功能
[UIApplication sharedApplication].applicationSupportsShakeToEdit = YES;
2、讓需要搖動的控制器成爲第一響應者
[self becomeFirstResponder];
3、實現以下方法
// 開始搖動
- (void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event
// 取消搖動
- (void)motionCancelled:(UIEventSubtype)motion withEvent:(UIEvent *)event
// 搖動結束
- (void)motionEnded:(UIEventSubtype)motion withEvent:(UIEvent *)event
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123、獲取圖片大小
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CGFloat imageWidth = image.size.width;
CGFloat imageHeight = imageWidth * image.scale;
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124、獲取view的座標在整個window上的位置
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// v上的(0, 0)點在toView上的位置
CGPoint point = [v convertPoint:CGPointMake(0, 0) toView:[UIApplication sharedApplication].windows.lastObject];
或者
CGPoint point = [v.superview convertPoint:v.frame.origin toView:[UIApplication sharedApplication].windows.lastObject];
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125、提交App Store審覈程序限制
您的應用程序的未壓縮大小必須小於4GB。每個Mach-O可執行文件（例如app_name.app/app_name）不能超過這些限制：
對於MinimumOSVersion小於7.0的應用程序：TEXT二進制文件中所有部分的總數最多爲80 MB 。
對於MinimumOSVersion7.x到8.x的應用程序：TEXT對於二進制文件中每個體系結構片段的每個片段，最大爲60 MB 。
對於MinimumOSVersion9.0或更高版本的應用程序：__TEXT二進制文件中所有部分的總數最多爲500 MB 。參閱：iTunes Connect開發者指南
126、修改UISegmentedControl的字體大小
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[segment setTitleTextAttributes:@{NSFontAttributeName : [UIFont systemFontOfSize:15.0f]} forState:UIControlStateNormal];
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127、在非ViewController的地方彈出UIAlertController對話框
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// 最好抽成一個分類
UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@
"Title"
message:@
"message"
preferredStyle:UIAlertControllerStyleAlert];
//...
id rootViewController = [UIApplication sharedApplication].delegate.window.rootViewController;
if
([rootViewController isKindOfClass:[UINavigationController class]])
{
rootViewController = ((UINavigationController *)rootViewController).viewControllers.firstObject;
}
if
([rootViewController isKindOfClass:[UITabBarController class]])
{
rootViewController = ((UITabBarController *)rootViewController).selectedViewController;
}
[rootViewController presentViewController:alertController animated:YES completion:nil];
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128、獲取一個view所屬的控制器
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// view分類方法
- (UIViewController *)belongViewController {
for
(UIView *next = [self superview]; next; next = next.superview) {
UIResponder* nextResponder = [next nextResponder];
if
([nextResponder isKindOfClass:[UIViewController class]]) {
return
(UIViewController *)nextResponder;
}
}
return
nil;
}
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129、UIImage和base64互轉
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// view分類方法
- (NSString *)encodeToBase64String:(UIImage *)image {
return
[UIImagePNGRepresentation(image) base64EncodedStringWithOptions:NSDataBase64Encoding64CharacterLineLength];
}
- (UIImage *)decodeBase64ToImage:(NSString *)strEncodeData {
NSData *data = [[NSData alloc]initWithBase64EncodedString:strEncodeData options:NSDataBase64DecodingIgnoreUnknownCharacters];
return
[UIImage imageWithData:data];
}
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130、UIWebView設置背景透明
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[webView setBackgroundColor:[UIColor clearColor]];
[webView setOpaque:NO];
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131、判斷NSDate是不是今天
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NSDateComponents *otherDay = [[NSCalendar currentCalendar] components:NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay fromDate:aDate];
NSDateComponents *today = [[NSCalendar currentCalendar] components:NSCalendarUnitEra | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay fromDate:[NSDate date]];
if
([today day] == [otherDay day] &&
[today month] == [otherDay month] &&
[today year] == [otherDay year] &&
[today era] == [otherDay era]) {
// 是今天
}
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132、設置tableView分割線顏色
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[self.tableView setSeparatorColor:[UIColor myColor]];
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133、設置屏幕方向
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[[UIDevice currentDevice] setValue:@(UIInterfaceOrientationLandscapeLeft) forKey:@
"orientation"
];
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134、比較兩個顏色是否相等
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- (BOOL)isEqualToColor:(UIColor *)otherColor {
CGColorSpaceRef colorSpaceRGB = CGColorSpaceCreateDeviceRGB();
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UIColor *(^convertColorToRGBSpace)(UIColor*) = ^(UIColor *color) {
if
(CGColorSpaceGetModel(CGColorGetColorSpace(color.CGColor)) == kCGColorSpaceModelMonochrome) {
const CGFloat *oldComponents = CGColorGetComponents(color.CGColor);
CGFloat components[4] = {oldComponents[0], oldComponents[0], oldComponents[0], oldComponents[1]};
CGColorRef colorRef = CGColorCreate( colorSpaceRGB, components );
6
UIColor *color = [UIColor colorWithCGColor:colorRef];
CGColorRelease(colorRef);
return
color;
}
else
return
color;
};
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UIColor *selfColor = convertColorToRGBSpace(self);
otherColor = convertColorToRGBSpace(otherColor);
CGColorSpaceRelease(colorSpaceRGB);
return
[selfColor isEqual:otherColor];
}
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135、tableViewCell分割線頂到頭
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- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
[cell setSeparatorInset:UIEdgeInsetsZero];
[cell setLayoutMargins:UIEdgeInsetsZero];
cell.preservesSuperviewLayoutMargins = NO;
}
- (void)viewDidLayoutSubviews {
[self.tableView setSeparatorInset:UIEdgeInsetsZero];
[self.tableView setLayoutMargins:UIEdgeInsetsZero];
}
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136、不讓控制器的view隨着控制器的xib拉伸或壓縮
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self.view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
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137、cocoaPods報錯 : [!] Unable to add a source with url https://github.com/CocoaPods/Specs.git named master-1.
You can try adding it manually in ~/.cocoapods/repos or via pod repo add.
解決方法：這是因爲電腦裏安裝了另外一個Xcode導致cocoapods找不到路徑了
在終端執行 sudo xcode-select -switch /Applications/Xcode.app 即可
138、安裝cocoapods的時候出現 ERROR: While executing gem ... (Errno::EPERM)
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Operation not permitted - /usr/bin/pod
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解決辦法：直接在終端執行 sudo gem install -n /usr/local/bin cocoapods
139、在狀態欄增加網絡請求的菊花，類似safari加載網頁的時候狀態欄菊花
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[UIApplication sharedApplication].networkActivityIndicatorVisible = YES;
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140、檢查一個rect是否包含一個point
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// point是否在rect內
BOOL isContains = CGRectContainsPoint(rect, point);
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141、在指定的寬度下，讓UILabel自動設置最佳font
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label.adjustsFontSizeToFitWidth = YES;
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142、將一個image保存在相冊中
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UIImageWriteToSavedPhotosAlbum(image, nil, nil, nil);
或者
#import
[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
PHAssetChangeRequest *changeRequest = [PHAssetChangeRequest creationRequestForAssetFromImage:image];
changeRequest.creationDate = [NSDate date];
} completionHandler:^(BOOL success, NSError *error) {
if
(success) {
NSLog(@
"successfully saved"
);
}
else
{
NSLog(@
"error saving to photos: %@"
, error);
}
}];
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143、修改cell.imageView的大小
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UIImage *icon = [UIImage imageNamed:@
""
];
CGSize itemSize = CGSizeMake(30, 30);
UIGraphicsBeginImageContextWithOptions(itemSize, NO ,0.0);
CGRect imageRect = CGRectMake(0.0, 0.0, itemSize.width, itemSize.height);
[icon drawInRect:imageRect];
cell.imageView.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
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144、爲一個view添加虛線邊框
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CAShapeLayer *border = [CAShapeLayer layer];
border.strokeColor = [UIColor colorWithRed:67/255.0f green:37/255.0f blue:83/255.0f alpha:1].CGColor;
border.fillColor = nil;
border.lineDashPattern = @[@4, @2];
border.path = [UIBezierPath bezierPathWithRect:view.bounds].CGPath;
border.frame = view.bounds;
[view.layer addSublayer:border];
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145、UITextView中打開或禁用複製，剪切，選擇，全選等功能
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// 繼承UITextView重寫這個方法
- (BOOL)canPerformAction:(SEL)action withSender:(id)sender
{
// 返回NO爲禁用，YES爲開啓
// 粘貼
if
(action == @selector(paste:))
return
NO;
// 剪切
if
(action == @selector(cut:))
return
NO;
// 複製
if
(action == @selector(copy:))
return
NO;
// 選擇
if
(action == @selector(select:))
return
NO;
// 選中全部
if
(action == @selector(selectAll:))
return
NO;
// 刪除
if
(action == @selector(
delete
:))
return
NO;
// 分享
if
(action == @selector(share))
return
NO;
return
[
super
canPerformAction:action withSender:sender];
}
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