iOS編程經常使用方法和常見bug修復

時間 2019-11-17

原文原文鏈接

1.去除NSString字符串裏面的特殊符號

-(NSString*)deleteSpecificSymbolForString:(NSString*)text{
    //先建立NSCharacterSet，把須要去除的字符串放在裏面
    NSCharacterSet *set = [NSCharacterSet characterSetWithCharactersInString:@"@／:：；;¥「」＂、[]{}#%-*+=_\\|~＜＞$€^•'@#$%^&*()（）_+'\""];
    //該方法返回的就是去除特殊符號後的字符串
    NSString *trimmedString = [text stringByTrimmingCharactersInSet:set];
    return trimmedString;
}
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2.判斷NSString字符串裏面有沒有漢字

-(BOOL)estimateStringContainChinese:(NSString*)text{
    if(text){
        for (int i=0; i<text.length; i++) {
            NSRange range = NSMakeRange(i,1);
            NSString *subString = [text substringWithRange:range];
            const char *cString = [subString UTF8String];
            if (strlen(cString) == 3){ //表明有漢字
                return YES;  
            }
        }
    }
    return NO;
}
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3.判斷NSString字符串裏面有沒有英文字母

-(BOOL)estimateStringContainEnglish:(NSString*)text{
    if(text){
        for (int i=0; i<text.length; i++) {
            NSRange range = NSMakeRange(i,1);
            NSString *subString = [text substringWithRange:range];
            const char *cString = [subString UTF8String];
            if (strlen(cString) == 1){ //表明有英文
                return YES;
            }
        }
    }
    return NO;
}
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4.在指定控制器裏面更改狀態欄文字顏色

每個應用程序，應該都會有統一的導航欄和狀態欄風格。可是有時候，也有須要在指定控制器裏面修改
狀態欄的風格，如：播放視頻。
-(void)viewWillAppear:(BOOL)animated{
    [super viewWillAppear:animated];
    [[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleDefault animated:YES];
}

-(void)viewWillDisappear:(BOOL)animated{
    [super viewWillDisappear:animated];
    [[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent animated:YES];
}

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5.點擊進入搜索控制器時，自動彈出鍵盤，讓搜索框進入編輯狀態

當點擊搜索時，進入搜索控制器，使用系統自帶的搜索框，searchController.searchBar，進入時，自動實現以下圖的效果 git

找了不少方法，下面這個是有效方法：

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    [self performSelector:@selector(showKeyboard) withObject:nil afterDelay:0];
}

- (void)showKeyboard {
    [self.searchController.searchBar becomeFirstResponder];
}
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6.修改系統自帶搜索框的UI

系統自帶的搜索框，使用方便快捷，可是有時候它的外觀與要求不符，這時候就須要咱們來對系統搜索框
進行一些修改
for (UIView* subview in [[self.searchController.searchBar.subviews lastObject] subviews]) {
        //至關於UITextField，輸入框，能夠修改背景顏色等
        if ([subview isKindOfClass:NSClassFromString(@"UISearchBarTextField")]) {
            UITextField *textField = (UITextField*)subview;
            [textField setBackgroundColor:COLOR_RGB(238, 238, 238)];
        }
        //至關於UIButton，搜索框右側的Cancle按鈕，能夠修改默認文字等
        if ([subview isKindOfClass:NSClassFromString(@"UINavigationButton")]) {
            UIButton* cancle = (UIButton*)subview;
            [cancle setTitle:@"取消" forState:UIControlStateNormal];
            [cancle setTitleColor:COLOR_RGB(82, 184, 255) forState:UIControlStateNormal];
        }
        //至關於UIView，搜索框的背景view，通常將它去掉，而後本身添加一層背景view
        if ([subview isKindOfClass:NSClassFromString(@"UISearchBarBackground")]) {
            [subview removeFromSuperview];
            UIView* back = [[UIView alloc]initWithFrame:self.searchController.searchBar.bounds];
            back .backgroundColor = [UIColor whiteColor];
            [self.searchController.searchBar insertSubview:back atIndex:0];
        }
    }
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7.在指定控制器中隱藏導航欄

有時候，須要在指定控制器中隱藏導航欄，試過好幾個方法，或多或少有些坑，下面這個是我認爲比較好的：
  首先讓該控制器成爲導航欄的代理：
  self.navigationController.delegate = self;
  而後，實現指定的代理方法：
  -(void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated{
    // 判斷要顯示的控制器是不是本身
    BOOL isShowHomePage = [viewController isKindOfClass:[self class]];
    [self.navigationController setNavigationBarHidden:isShowHomePage animated:YES];
  }
  
  可是，若是須要在連續的兩個控制器裏面隱藏導航欄，上述方法就行不通了，建議寫一個導航欄的基類，在基類中設置代理：
  self.delegate = self;
  而後，實現代理方法：
  - (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
    // 判斷若是是須要隱藏導航控制器的類，則隱藏
    BOOL isHideNav = ([viewController isKindOfClass:NSClassFromString(@"EXBusinessCardVC")] ||
                      [viewController isKindOfClass:NSClassFromString(@"EXSearchCardVC")] ||
                      [viewController isKindOfClass:NSClassFromString(@"EXExhibitDataVC")] ||
                      [viewController isKindOfClass:NSClassFromString(@"EXNoticeVC")] ||
                      [viewController isKindOfClass:NSClassFromString(@"EXBusinessCenterVC")] ||
                      [viewController isKindOfClass:NSClassFromString(@"EXMeVC")]);
    
    [self setNavigationBarHidden:isHideNav animated:YES];
  }
  
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8.根據指定文本，字體，固定寬度或高度，求尺寸

// 根據指定文本,字體和最大高度計算尺寸
- (CGSize)sizeWithText:(NSString *)text font:(UIFont *)font maxHeight:(CGFloat)height
{
    NSMutableDictionary *attrDict = [NSMutableDictionary dictionary];
    attrDict[NSFontAttributeName] = font;
    CGSize size = [text boundingRectWithSize:CGSizeMake(MAXFLOAT, height) options:NSStringDrawingUsesLineFragmentOrigin attributes:attrDict context:nil].size;
    return size;
}
// 根據指定文本,字體和最大寬度計算尺寸
- (CGSize)sizeWithText:(NSString *)text font:(UIFont *)font maxWidth:(CGFloat)width
{
    NSMutableDictionary *attrDict = [NSMutableDictionary dictionary];
    attrDict[NSFontAttributeName] = font;
    CGSize size = [text boundingRectWithSize:CGSizeMake(width, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin attributes:attrDict context:nil].size;
    return size;
}
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9.給UILabel設置行間距，字間距等富文本屬性，並計算高度

//給UILabel設置行間距和字間距
-(void)setLabelSpace:(UILabel*)label withValue:(NSString*)str withFont:(UIFont*)font {
    NSMutableParagraphStyle *paraStyle = [[NSMutableParagraphStyle alloc] init];
    paraStyle.lineBreakMode = NSLineBreakByCharWrapping; //結尾部分的文字省略方式
    paraStyle.alignment = NSTextAlignmentLeft; //文本對齊方式
    paraStyle.lineSpacing = 7; //設置行間距
    paraStyle.hyphenationFactor = 1.0; //連字屬性 在iOS，惟一支持的值分別爲0和1
    paraStyle.firstLineHeadIndent = 0.0; //首行縮進
    paraStyle.paragraphSpacingBefore = 0.0; //段首行空白空間
    paraStyle.headIndent = 0; //總體縮進(首行除外)
    paraStyle.paragraphSpacing = 15; //段與段之間的間距
    
    //設置字間距 NSKernAttributeName:@1.5f
    NSDictionary *dic = @{NSFontAttributeName:font, NSParagraphStyleAttributeName:paraStyle, NSKernAttributeName:@1.5f};
    NSAttributedString *attributeStr = [[NSAttributedString alloc] initWithString:str attributes:dic];
    label.attributedText = attributeStr;
}

//計算UILabel的高度(帶有行間距的狀況)
-(CGFloat)getSpaceLabelHeight:(NSString*)str withFont:(UIFont*)font withWidth:(CGFloat)width {
    NSMutableParagraphStyle *paraStyle = [[NSMutableParagraphStyle alloc] init];
    paraStyle.lineBreakMode = NSLineBreakByCharWrapping;
    paraStyle.alignment = NSTextAlignmentLeft;
    paraStyle.lineSpacing = 7;
    paraStyle.hyphenationFactor = 1.0;
    paraStyle.firstLineHeadIndent = 0.0;
    paraStyle.paragraphSpacingBefore = 0.0;
    paraStyle.headIndent = 0;
    paraStyle.paragraphSpacing = 15;
    
    NSDictionary *dic = @{NSFontAttributeName:font, NSParagraphStyleAttributeName:paraStyle, NSKernAttributeName:@1.5f};
    CGSize size = [str boundingRectWithSize:CGSizeMake(width, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin attributes:dic context:nil].size;
    
    return size.height;
}
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