判斷是否是第一次打開應(yīng)用程序

先獲取CFBundleShortVersionString這個(gè)key囊蓝，然后從沙盒中取這個(gè)key饿悬，如果兩個(gè)相等，則表示不是第一次打開該應(yīng)用程序聚霜，不相等的時(shí)候應(yīng)該把沙盒中中的key保存起來(lái)狡恬，下次啟動(dòng)時(shí)候再進(jìn)行判斷

 NSString * key = @"CFBundleShortVersionString";
    
    NSString *currentVersion = [NSBundle mainBundle].infoDictionary[key];
    NSString *sandboxVersion = [[NSUserDefaults standardUserDefaults] stringForKey:key];
    if (![currentVersion isEqualToString:sandboxVersion]) {
        [[NSUserDefaults standardUserDefaults]setObject:currentVersion forKey:key];
        
    }else{
        
    }
    

###修改tabbariterm選中以及未選中顏色

我們可以調(diào)用UIBarItem的這個(gè)`- (void)setTitleTextAttributes:(nullable NSDictionary<NSString *,id> *)attributes forState:(UIControlState)state NS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR;`方法，這個(gè)方法支持在appearance的時(shí)候設(shè)置蝎宇，為什么設(shè)置UIBarItem呢弟劲，因?yàn)閁ITabBarItem繼承自UIBarItem

```objc
  NSMutableDictionary *attrs = [NSMutableDictionary dictionary];
    attrs[NSFontAttributeName] = [UIFont systemFontOfSize:12];
    attrs[NSForegroundColorAttributeName] = [UIColor grayColor];
    
    NSMutableDictionary *selectedAttrs = [NSMutableDictionary dictionary];
    selectedAttrs[NSFontAttributeName] = attrs[NSFontAttributeName];
    selectedAttrs[NSForegroundColorAttributeName] = [UIColor darkGrayColor];
    
    UITabBarItem *item = [UITabBarItem appearance];
    [item setTitleTextAttributes:attrs forState:UIControlStateNormal];
    [item setTitleTextAttributes:selectedAttrs forState:UIControlStateSelected];

替換系統(tǒng)自帶的tabbar

我們可以使用KVC把系統(tǒng)的tabbar替換成我們自己的
在TabBarController的viewDidLoad中進(jìn)行設(shè)置即可

[self setValue:[[RYFTabBar alloc]init] forKey:@"tabBar"];

自定義tabbar

現(xiàn)在很多APP中都要求中間有一個(gè)加號(hào)按鈕或者什么的，這個(gè)時(shí)候就需要我們自定義tabbar了姥芥，當(dāng)然網(wǎng)上有很多自定義tabbar的demo兔乞，不過(guò)這個(gè)方式實(shí)現(xiàn)比較簡(jiǎn)單，我們需要聲明一個(gè)協(xié)議，然后監(jiān)聽按鈕的點(diǎn)擊庸追，我們先在- (instancetype)initWithFrame:(CGRect)frame中創(chuàng)建中間的按鈕霍骄，然后在layoutSubviews中設(shè)置frame，因?yàn)榘砂粹o添加到tabbar上面的時(shí)候會(huì)觸發(fā)layoutSubviews锚国，在這個(gè)方法里面拿到的frame比較準(zhǔn)確腕巡。代碼如下

- (instancetype)initWithFrame:(CGRect)frame
{
    if (self = [super initWithFrame:frame]) {
        _plusButton = [UIButton buttonWithType:UIButtonTypeCustom];
        [_plusButton setBackgroundImage:[UIImage imageNamed:@"tabBar_publish_icon"] forState:UIControlStateNormal];
        [_plusButton setBackgroundImage:[UIImage imageNamed:@"tabBar_publish_click_icon"] forState:UIControlStateSelected];
        [_plusButton addTarget:self action:@selector(plusSignClick) forControlEvents:UIControlEventTouchUpInside];
        [self addSubview:_plusButton];
    }
    return self;
}
- (void)layoutSubviews
{
    [super layoutSubviews];
    
    _plusButton.bounds = CGRectMake(0, 0, _plusButton.currentBackgroundImage.size.width, _plusButton.currentBackgroundImage.size.height);
    _plusButton.center = CGPointMake(self.frame.size.width * 0.5, self.frame.size.height * 0.5);
    
    NSInteger index = 0;

    CGFloat buttonY = 0;
    CGFloat buttonW = self.frame.size.width / 5;
    CGFloat buttonH = self.frame.size.height;
    for (UIView *view in self.subviews) {
        if ([view isKindOfClass:NSClassFromString(@"UITabBarButton")]) {
            CGFloat buttonX = buttonW * ((index > 1) ? (index + 1) : index);
            view.frame = CGRectMake(buttonX, buttonY, buttonW, buttonH);
            index ++;
        }
    }
}

- (void)plusSignClick
{
    if ([self.tabBarDelegate respondsToSelector:@selector(plusBtnClick)]) {
        [self.tabBarDelegate plusBtnClick];
    }
}

設(shè)置導(dǎo)航欄UIBarButtonItem顏色以及字體

/**
 *  當(dāng)?shù)谝淮问褂眠@個(gè)類的時(shí)候會(huì)調(diào)用一次
 */
+ (void)initialize
{
    UINavigationBar *navigationBar = [UINavigationBar appearance];
    [navigationBar setBackgroundImage:[UIImage imageNamed:@"navigationbarBackgroundWhite"] forBarMetrics:UIBarMetricsDefault];
    
    //更改title文字可以設(shè)置self.navigationItem.titleView也可以設(shè)置setTitleTextAttributes
    NSMutableDictionary *dict = [NSMutableDictionary dictionary];
    dict[NSFontAttributeName] = [UIFont systemFontOfSize:15];
    dict[NSForegroundColorAttributeName] = [UIColor blackColor];
    [navigationBar setTitleTextAttributes:dict];//UI_APPEARANCE_SELECTOR設(shè)置一次就行了

    //設(shè)置barbuttonitem屬性
    UIBarButtonItem *item = [UIBarButtonItem appearance];
    NSMutableDictionary *itemAttrs= [NSMutableDictionary dictionary];
    itemAttrs[NSForegroundColorAttributeName] = [UIColor blackColor];
    itemAttrs[NSFontAttributeName] = [UIFont systemFontOfSize:14];
    [item setTitleTextAttributes:itemAttrs forState:UIControlStateNormal];
    
    // UIControlStateDisabled
    NSMutableDictionary *itemDisabledAttrs = [NSMutableDictionary dictionary];
    itemDisabledAttrs[NSForegroundColorAttributeName] = [UIColor lightGrayColor];
    [item setTitleTextAttributes:itemDisabledAttrs forState:UIControlStateDisabled];
    
}

設(shè)置導(dǎo)航欄title顏色以及字體

UINavigationBar *bar = self.navigationController.navigationBar；
[bar setTitleTextAttributes:@{NSForegroundColorAttributeName :[UIColor whiteColor]}];

導(dǎo)航欄透明

設(shè)置UINavigationBar全透明, 此處隨便設(shè)置一張圖片即可血筑，重要的是BarMetrics屬性決定了bar的樣式

UINavigationBar *bar = self.navigationController.navigationBar绘沉；
[bar setBackgroundImage:[UIImage imageNamed:@"bg.png"] forBarMetrics:UIBarMetricsCompact];

push到下一個(gè)控制器的時(shí)候隱藏tabbar

這時(shí)候我們可以重寫- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated這個(gè)方法，當(dāng)然我們也可以在這個(gè)方法里面設(shè)置返回按鈕

- (void)pushViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    if (self.viewControllers.count > 0) {
        UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
        [btn setImage:[UIImage imageNamed:@"navigationButtonReturn"] forState:UIControlStateNormal];
        [btn setImage:[UIImage imageNamed:@"navigationButtonReturnClick"] forState:UIControlStateHighlighted];
        [btn setTitle:@"返回" forState:UIControlStateNormal];
        [btn setTitle:@"返回" forState:UIControlStateHighlighted];
        [btn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
        [btn setTitleColor:[UIColor redColor] forState:UIControlStateHighlighted];
        btn.size = CGSizeMake(70, 30);
        btn.contentHorizontalAlignment = UIControlContentHorizontalAlignmentLeft;
        btn.contentEdgeInsets = UIEdgeInsetsMake(0, -10, 0, 0);
        [btn addTarget:self action:@selector(back) forControlEvents:UIControlEventTouchUpInside];
        viewController.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc]initWithCustomView:btn];
        viewController.hidesBottomBarWhenPushed = YES;
    }
    [super pushViewController:viewController animated:animated];
}

解決重寫返回按鈕的時(shí)候可能會(huì)導(dǎo)致系統(tǒng)自帶的左側(cè)滑動(dòng)返回實(shí)現(xiàn)

可以使用孫源大神寫的那個(gè)FDFullscreenPopGesture豺总，也可以設(shè)置self.interactivePopGestureRecognizer.delegate = nil;车伞，在導(dǎo)航控制器中設(shè)置即可

自定義UIBarButtonItem

我們可以給UIBarButtonItem添加一個(gè)分類，這樣用起來(lái)也比較方便

+ (instancetype)itemWithimage:(NSString *)image heighlitImage:(NSString *)heighlitImage target:(id)target ation:(SEL)action
{
    UIButton *btn = [UIButton buttonWithType:UIButtonTypeCustom];
    [btn setBackgroundImage:[UIImage imageNamed:image] forState:UIControlStateNormal];
    [btn setBackgroundImage:[UIImage imageNamed:heighlitImage] forState:UIControlStateHighlighted];
    [btn addTarget:target action:action forControlEvents:UIControlEventTouchUpInside];
    btn.size = btn.currentBackgroundImage.size;
    return [[self alloc]initWithCustomView:btn];
}

狀態(tài)欄的設(shè)置

//iOS7以后狀態(tài)欄由controller進(jìn)行控制喻喳，如果不需要控制器控制的話需要在info.plist設(shè)置View controller-based status bar appearancer然后通過(guò)[UIApplication sharedApplication].statusBarStyle = UIStatusBarStyleDefault;設(shè)置
如果不想設(shè)置plist另玖，我們可以重寫- (UIStatusBarStyle)preferredStatusBarStyle

- (UIStatusBarStyle)preferredStatusBarStyle
{
    return UIStatusBarStyleLightContent;
}

修改UITextField的placeholder顏色

1. 修改Placeholder的方法有好幾種，可以設(shè)置textField的attributedPlaceholder屬性表伦，這是一個(gè)富文本屬性谦去，
2. 也可以自定義一個(gè)TextField，重寫- (void)drawPlaceholderInRect:(CGRect)rect這個(gè)方法[self.placeholder drawInRect:rect withAttributes:@{NSForegroundColorAttributeName:[UIColor whiteColor]}];
3. 就是通過(guò)Runtime運(yùn)行時(shí)進(jìn)行修改

• 使用屬性

@property(nonatomic,copy)   NSAttributedString     *attributedPlaceholder;

// 文字屬性
NSMutableDictionary *attrs = [NSMutableDictionary dictionary];
attrs[NSForegroundColorAttributeName] = [UIColor grayColor];

// NSAttributedString : 帶有屬性的文字(富文本技術(shù))
NSAttributedString *placeholder = [[NSAttributedString alloc] initWithString:@"手機(jī)號(hào)" attributes:attrs];
self.phoneField.attributedPlaceholder = placeholder;

NSMutableAttributedString *placehoder = [[NSMutableAttributedString alloc] initWithString:@"手機(jī)號(hào)"];
[placehoder setAttributes:@{NSForegroundColorAttributeName : [UIColor whiteColor]} range:NSMakeRange(0, 1)];
[placehoder setAttributes:@{
                            NSForegroundColorAttributeName : [UIColor yellowColor],
                            NSFontAttributeName : [UIFont systemFontOfSize:30]
                            } range:NSMakeRange(1, 1)];
[placehoder setAttributes:@{NSForegroundColorAttributeName : [UIColor redColor]} range:NSMakeRange(2, 1)];
self.phoneField.attributedPlaceholder = placehoder;

• 重寫方法

- (void)drawPlaceholderInRect:(CGRect)rect
{
    [self.placeholder drawInRect:CGRectMake(0, 10, rect.size.width, 25) withAttributes:@{
                                                       NSForegroundColorAttributeName : [UIColor grayColor],
                                                       NSFontAttributeName : self.font}];
}

• 使用KVC

[self setValue:[UIColor grayColor] forKeyPath:@"_placeholderLabel.textColor"];

圖片在上面文字在下面的UIButton

我們可以自定義一個(gè)UIButton
我們?cè)?code>awakeFromNib以及initWithFrame設(shè)置文字的居中蹦哼，在layoutSubviews設(shè)置UIButton的圖片位置大小以及l(fā)able的位置大小

- (void)awakeFromNib
{
    [self setup];
}

- (instancetype)initWithFrame:(CGRect)frame
{
    if (self = [super initWithFrame:frame]) {
        [self setup];
    }
    return self;
}

- (void)setup
{
    self.titleLabel.textAlignment = NSTextAlignmentCenter;
}

- (void)layoutSubviews
{
    [super layoutSubviews];
    
    self.imageView.x = 0;
    self.imageView.y = 0;
    self.imageView.width = self.imageView.width;
    self.imageView.height = self.imageView.width;
    
    self.titleLabel.x = 0;
    self.titleLabel.y = self.imageView.height + 10;
    self.titleLabel.width = self.imageView.width;
    self.titleLabel.height = self.titleLabel.height;
    
}

SDWebImage獲取緩存圖片大小

SDWebImage已經(jīng)提供了方法獲取圖片占據(jù)內(nèi)存大小了鳄哭，我們調(diào)用即可

[[SDImageCache sharedImageCache]getSize]

• 清空緩存

[[SDImageCache sharedImageCache]cleanDisk];

帶有placeholder的UITextView

一個(gè)好的自定義控件最好有提供一些其他屬性供其他人用，這里提供了一個(gè)設(shè)置placeholder顏色以及字體的屬性纲熏，使用懶加載先設(shè)置一下placeholder的基本屬性以及x妆丘，y以及設(shè)置默認(rèn)的顏色，然后在initWithFrame方法里面監(jiān)聽UITextViewTextDidChangeNotification這個(gè)通知局劲，通過(guò)UITextView是否有文字輸入從而判斷placeholder是否隱藏勺拣，重寫setfont，settext以及setAttributedText方法鱼填，代碼如下

- (UILabel *)placeholerLabel
{
    if (!_placeholerLabel) {
        _placeholerLabel = [[UILabel alloc]init];
        [self addSubview:_placeholerLabel];
        _placeholerLabel.numberOfLines = 0;
        _placeholerLabel.x = 5;
        _placeholerLabel.y = 5;
        _placeholerLabel.textColor = [UIColor lightGrayColor];
    }
    return _placeholerLabel;
}

- (instancetype)initWithFrame:(CGRect)frame
{
    if (self = [super initWithFrame:frame]) {
        self.alwaysBounceVertical = YES;
        self.font = [UIFont systemFontOfSize:15];
        
        [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(textChange) name:UITextViewTextDidChangeNotification object:nil];
    }
    return self;
}

- (void)textChange
{
    self.placeholerLabel.hidden = self.hasText;
}

- (void)setPlaceholer:(NSString *)placeholer
{
    _placeholer = placeholer;
    self.placeholerLabel.text = placeholer;
    [self setNeedsLayout];
}

- (void)setPlaceholerColor:(UIColor *)placeholerColor
{
    _placeholerColor = placeholerColor;
    self.placeholerLabel.textColor = placeholerColor;
    
}

- (void)setFont:(UIFont *)font
{
    [super setFont:font];
    self.placeholerLabel.font = font;
    [self setNeedsLayout];
}

- (void)setText:(NSString *)text
{
    [super setText:text];
    [self textChange];
}

- (void)setAttributedText:(NSAttributedString *)attributedText
{
    [super setAttributedText:attributedText];
    [self textChange];
}

- (void)layoutSubviews
{
    [super layoutSubviews];
    self.placeholerLabel.width = SCREENWIDTH - 2 * self.placeholerLabel.x;
    [self.placeholerLabel sizeToFit];
}
/**
 * 更新占位文字的尺寸
 */
- (void)updatePlaceholderLabelSize
{
    CGSize maxSize = CGSizeMake(SCREENWIDTH - 2 * self.placeholerLabel.x, MAXFLOAT);
    self.placeholerLabel.size = [self.placeholer boundingRectWithSize:maxSize options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName : self.font} context:nil].size;
//    self.placeholerLabel.backgroundColor = [UIColor redColor];
}

- (void)dealloc
{
    [[NSNotificationCenter defaultCenter]removeObserver:self];
}

另一種是使用drawRect方法實(shí)現(xiàn)的

- (instancetype)initWithFrame:(CGRect)frame
{
    if (self = [super initWithFrame:frame]) {
        self.alwaysBounceVertical = YES;
        self.font = [UIFont systemFontOfSize:15];
        self.placeholerColor = [UIColor lightGrayColor];
        [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(textChange) name:UITextViewTextDidChangeNotification object:nil];
    }
    return self;
}

- (void)textChange
{
    [self setNeedsDisplay];
}

- (void)drawRect:(CGRect)rect {
    
    //可以使用這種方式判斷
//    if (self.text.length || self.attributedText.length) return;
    //或者是這種
    if (self.hasText) return;
    rect.origin.x = 5;
    rect.origin.y = 5;
    rect.size.width -= 2 * rect.origin.x;
    NSMutableDictionary *att = [NSMutableDictionary dictionary];
    att[NSFontAttributeName] = self.font;
    att[NSForegroundColorAttributeName] = self.placeholerColor;
    [self.placeholer drawInRect:rect withAttributes:att];
}

- (void)setPlaceholer:(NSString *)placeholer
{
    _placeholer = placeholer;
    [self setNeedsDisplay];
}

- (void)setPlaceholerColor:(UIColor *)placeholerColor
{
    _placeholerColor = placeholerColor;
    [self setNeedsDisplay];
}

- (void)setFont:(UIFont *)font
{
    [super setFont:font];
    [self setNeedsDisplay];
}

- (void)setText:(NSString *)text
{
    [super setText:text];
    [self setNeedsDisplay];
}

- (void)setAttributedText:(NSAttributedString *)attributedText
{
    [super setAttributedText:attributedText];
    [self setNeedsDisplay];
}

當(dāng)點(diǎn)擊一個(gè)按鈕就發(fā)送一次請(qǐng)求的時(shí)候药有，如果不想連著點(diǎn)兩下發(fā)兩次網(wǎng)絡(luò)請(qǐng)求，這時(shí)候我們可以把請(qǐng)求參數(shù)弄一個(gè)property苹丸，然后比較兩次是否相同塑猖，相同就不發(fā)請(qǐng)求

當(dāng)網(wǎng)絡(luò)比較慢的時(shí)候，我們從當(dāng)前頁(yè)面返回到了上一個(gè)頁(yè)面谈跛，這時(shí)候可能后來(lái)返回?cái)?shù)據(jù)的時(shí)候造成崩潰，我們可以重寫dealloc方法塑陵，在dealloc方法中把這次請(qǐng)求給取消掉

cell選中顏色

//highlightedTextColor可以設(shè)置選中時(shí)候字體的顏色
self.textLabel.highlightedTextColor = RGBCOLOR(215, 27, 26);

改變cell的大小

我們可以在layoutSubviews中設(shè)置

- (void)layoutSubviews
{
    [super layoutSubviews];
    
    //如果想改變系統(tǒng)中某一個(gè)控件的位置可以在layoutSubviews重新設(shè)置控件的位置
    self.textLabel.height = self.height - 2;
}

cell選擇一個(gè)標(biāo)記視圖

我們可以在- (void)setSelected:(BOOL)selected animated:(BOOL)animated 這個(gè)方法中設(shè)置
當(dāng)選中cell的時(shí)候如果設(shè)置了selectionStyle為none的話會(huì)造成self.textLabel.highlightedTextColor這個(gè)顏色無(wú)法正常顯示感憾，解決這個(gè)問題的方法就是在- (void)setSelected:(BOOL)selected animated:(BOOL)animated這個(gè)方法中設(shè)置選中時(shí)字體顏色以及普通狀態(tài)下的文字顏色,cell被選中時(shí)內(nèi)部子控件不會(huì)進(jìn)入高亮狀態(tài)

- (void)setSelected:(BOOL)selected animated:(BOOL)animated {
    [super setSelected:selected animated:animated];

    /**
     *  當(dāng)選中cell的時(shí)候如果設(shè)置了selectionStyle為none的話會(huì)造成self.textLabel.highlightedTextColor這個(gè)顏色無(wú)法正常顯示，解決這個(gè)問題的方法就是在- (void)setSelected:(BOOL)selected animated:(BOOL)animated這個(gè)方法中設(shè)置選中時(shí)字體顏色以及普通狀態(tài)下的文字顏色,cell被選中時(shí)內(nèi)部子控件不會(huì)進(jìn)入高亮狀態(tài)
     *
     *
     */
    _selectView.hidden = !selected;
    self.textLabel.textColor = !selected ? RGBCOLOR(74, 74, 74) : RGBCOLOR(215, 27, 26);
}

改變UITextField提示文字顏色

static NSString * const PlacerholderColorKeyPath = @"_placeholderLabel.textColor";

- (void)drawPlaceholderInRect:(CGRect)rect
{
    [super drawPlaceholderInRect:rect];
    //需要設(shè)置位置
    [self.placeholder drawInRect:CGRectMake(0, 5, 0, 0) withAttributes:@{NSForegroundColorAttributeName:[UIColor whiteColor]}];
}

- (void)awakeFromNib
{
    //設(shè)置光標(biāo)顏色和文字顏色一樣
    self.tintColor = self.textColor;
    
    [self resignFirstResponder];
}

- (BOOL)becomeFirstResponder
{
    [self setValue:[UIColor whiteColor] forKeyPath:PlacerholderColorKeyPath];
    return [super becomeFirstResponder];
}

- (BOOL)resignFirstResponder
{
    [self setValue:[UIColor grayColor] forKeyPath:PlacerholderColorKeyPath];
    return [super resignFirstResponder];
}

判斷一個(gè)控件是否在主窗口上面

首先把當(dāng)前控件坐標(biāo)轉(zhuǎn)換成其父控件所在坐標(biāo)系的rect，然后判斷轉(zhuǎn)換后的rect是否在主窗口的bounds之內(nèi)阻桅，然后只有當(dāng)前控件顯示以及透明度大于0.01 以及當(dāng)前控件所在的窗口為主窗口以及轉(zhuǎn)換后的rect是否在主窗口的bounds之內(nèi)凉倚，只有這些條件都成立的時(shí)候這個(gè)控件才在主窗口上面顯示，代碼如下

- (BOOL)isShowOnWindow
{
    //主窗口
    UIWindow *keyWindow = [UIApplication sharedApplication].keyWindow;
    
    //相對(duì)于父控件轉(zhuǎn)換之后的rect
    CGRect newRect = [keyWindow convertRect:self.frame fromView:self.superview];
    //主窗口的bounds
    CGRect winBounds = keyWindow.bounds;
    //判斷兩個(gè)坐標(biāo)系是否有交匯的地方嫂沉，返回bool值
    BOOL isIntersects =  CGRectIntersectsRect(newRect, winBounds);
    if (self.hidden != YES && self.alpha >0.01 && self.window == keyWindow && isIntersects) {
        return YES;
    }else{
        return NO;
    }
}

在XIB或者SB中設(shè)置控件圓角或者邊框

我們可以寫一個(gè)UIView的分類稽寒，然后在分類中加入IB_DESIGNABLE，以及property(borderWidth,borderColor,cornerRadius)這些property前面需要使用IBInspectable修飾才會(huì)有效果趟章，然后重寫set方法即可

IB_DESIGNABLE

@interface UIView (RYF)
@property (nonatomic, assign)CGFloat x;
@property (nonatomic, assign)CGFloat y;
@property (nonatomic, assign)CGFloat width;
@property (nonatomic, assign)CGFloat height;
@property (nonatomic, assign)CGFloat centerX;
@property (nonatomic, assign)CGFloat centerY;
@property (nonatomic, assign)CGSize size;
@property(nonatomic, assign) IBInspectable CGFloat borderWidth;
@property(nonatomic, assign) IBInspectable UIColor *borderColor;
@property(nonatomic, assign) IBInspectable CGFloat cornerRadius;

- (void)setBorderWidth:(CGFloat)borderWidth
{
    if (borderWidth < 0) {
        return;
    }
    self.layer.borderWidth = borderWidth;
}

- (void)setBorderColor:(UIColor *)borderColor
{
    self.layer.borderColor = borderColor.CGColor;
}

- (void)setCornerRadius:(CGFloat)cornerRadius
{
    self.layer.cornerRadius = cornerRadius;
    self.layer.masksToBounds = YES;
}

判斷當(dāng)前view所屬的控制器

UIView的分類里面寫的一個(gè)對(duì)象方法

- (UIViewController *)parentController
{
    UIResponder *responder = [self nextResponder];
    while (responder) {
        if ([responder isKindOfClass:[UIViewController class]]) {
            return (UIViewController *)responder;
        }
        responder = [responder nextResponder];
    }
    return nil;
}

當(dāng)設(shè)置某一個(gè)控件為tableview的tableHeaderView時(shí)候杏糙，當(dāng)滑動(dòng)tableview的時(shí)候會(huì)一直調(diào)用找個(gè)控件的setframe方法

連續(xù)點(diǎn)擊tabbar刷新tableView或者返回至最上面

首先我們現(xiàn)在AppDelegate當(dāng)中監(jiān)聽tabbar的點(diǎn)擊，通過(guò)- (void)tabBarController:(UITabBarController *)tabBarController didSelectViewController:(UIViewController *)viewController,然后發(fā)出通知蚓土，在需要的地方監(jiān)聽宏侍，然后判斷當(dāng)前view是否在主窗口上面以及設(shè)置一個(gè)index記錄上次selectedIndex，只有顯示在主窗口以及不等于上次的selectedIndex的時(shí)候進(jìn)入刷新

- (void)tabbarClick
{
    /**
     *  先判斷是否顯示在窗口上了蜀漆，如果沒有顯示在窗口就不刷新谅河，然后判斷當(dāng)前選中的和上次是否一致，如果不一致的話才會(huì)刷新
     */
    if ([self.view isShowOnWindow] && self.tabSelectIndex != self.tabBarController.selectedIndex) {
        [self.tableView.mj_header beginRefreshing];
    }
    self.tabSelectIndex =  self.tabBarController.selectedIndex;
    
}

當(dāng)UITableView是plain的樣式時(shí)候确丢，兩個(gè)cell之間需要有一定的間隙绷耍，這時(shí)候我們可以重寫cell的setFramefangfa

/**
 *  修改父類中的東西可以在這個(gè)方法中進(jìn)行設(shè)置，這個(gè)方法會(huì)覆蓋之前所有的frame
 *
 *  @param frame <#frame description#>
 */
- (void)setFrame:(CGRect)frame
{
    frame.origin.x = 10;
    frame.size.width -= 2 * frame.origin.x;
    frame.size.height -= 1;
    
    [super setFrame:frame];
}

當(dāng)一個(gè)控件從XIB創(chuàng)建的時(shí)候鲜侥，如果顯示出來(lái)的效果和你設(shè)置的不一樣褂始，建議你把a(bǔ)utoresizingMask設(shè)置為UIViewAutoresizingNone

當(dāng)一個(gè)很長(zhǎng)的圖片在一個(gè)固定大小的區(qū)域內(nèi)我們想顯示圖片的最上方內(nèi)容

我們可以裁剪圖片然后再顯示到UIImageView上面

 //在這里設(shè)置長(zhǎng)圖片顯示最上方的一部分
        UIGraphicsBeginImageContextWithOptions(jokesModel.picF.size, YES, 0.0);
        
        CGFloat width = jokesModel.picF.size.width;
        CGFloat height = width * image.size.height / image.size.width;
        
        [image drawInRect:CGRectMake(0, 0, width, height)];
        
        _imageView.image = UIGraphicsGetImageFromCurrentImageContext();
        
        UIGraphicsEndImageContext();

UIImage裁剪

- (UIImage *)circleImage
{
    //NO代表透明
    UIGraphicsBeginImageContextWithOptions(self.size, NO, 0.0);
    
    CGContextRef ref = UIGraphicsGetCurrentContext();
    
    CGRect rect = CGRectMake(0, 0, self.size.width, self.size.height);
    CGContextAddEllipseInRect(ref, rect);
    
    CGContextClip(ref);
    //把圓畫上去
    [self drawInRect:rect];
    
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    return image;
}

iOS開發(fā)當(dāng)中開發(fā)技巧總結(jié)

自定義了leftBarbuttonItem左滑返回手勢(shì)失效了怎么辦?

self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc]
initWithImage:img
style:UIBarButtonItemStylePlain
target:self
action:@selector(onBack:)];
self.navigationController.interactivePopGestureRecognizer.delegate = (id<UIGestureRecognizerDelegate>)self;

ScrollView莫名其妙不能在viewController劃到頂怎么辦?

self.automaticallyAdjustsScrollViewInsets = NO;

想在代碼里改在xib里添加的layoutAttributes,但是怎么用代碼找啊?

像拉button一樣的拉你的約束.nslayoutattribute也是可以拉線的.

怎么像safari一樣滑動(dòng)的時(shí)候隱藏navigationbar?

navigationController.hidesBarsOnSwipe = Yes

導(dǎo)航條返回鍵帶的title太討厭了,怎么讓它消失!

[[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60)
forBarMetrics:UIBarMetricsDefault];

本來(lái)我的statusbar是lightcontent的，結(jié)果用UIImagePickerController會(huì)導(dǎo)致我的statusbar的樣式變成黑色剃毒，怎么辦病袄？

• (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated
  {
  [[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];
  }

怎么把我的navigationbar弄成透明的而不是帶模糊的效果？

[self.navigationBar setBackgroundImage:[UIImage new]
forBarMetrics:UIBarMetricsDefault];
self.navigationBar.shadowImage = [UIImage new];
self.navigationBar.translucent = YES;

怎么改變uitextfield placeholder的顏色和位置赘阀？

1. 重寫方法

• (void) drawPlaceholderInRect:(CGRect)rect
  {
  [[UIColor blueColor] setFill];
  [self.placeholder drawInRect:rect withFont:self.font lineBreakMode:UILineBreakModeTailTruncation alignment:self.textAlignment];
  }

2. KVC

UIColor *color = [UIColor whiteColor];
_userName.attributedPlaceholder = [[NSAttributedString alloc] initWithString:@"用戶名" attributes:@{NSForegroundColorAttributeName: color}];

[_userName setValue:[UIColor whiteColor] forKeyPath:@"_placeholderLabel.textColor"];

應(yīng)該使用FOUNDATION_EXPORT還是#define來(lái)定義常量?

一般iOS我們定義常量的方法有兩種,來(lái)看下面例子
我的.h文件

FOUNDATION_EXPORT NSString * const kMyConstantString;
FOUNDATION_EXPORT NSString * const kMyConstantString2;
.m文件是這樣定義的

NSString * const kMyConstantString = @"Hello";
NSString * const kMyConstantString2 = @"World";
還有一種是常用的#define方法了

define kMyConstantString @"Hello"

有什么區(qū)別呢?
使用第一種方法在檢測(cè)字符串的值是否相等的時(shí)候更快.對(duì)于第一種你可以直接使用(stringInstance == MyFirstConstant)來(lái)比較,而define則使用的是這種.([stringInstance isEqualToString:MyFirstConstant])
哪個(gè)效率高,顯而易見了.第一種直接比較的是指針地址,而第二個(gè)則是一一比較字符串的每一個(gè)字符是否相等.

static inline function是干嘛的?

如果你的.m文件需要頻繁調(diào)用一個(gè)函數(shù),可以用static inline來(lái)聲明,這相當(dāng)于把函數(shù)體當(dāng)做一個(gè)大號(hào)的宏定義.不過(guò)這也不是百分之百有效,到底能不能把函數(shù)體轉(zhuǎn)換為大號(hào)宏定義來(lái)用要看編譯器心情,它要是覺得你的方法太復(fù)雜,他就不轉(zhuǎn)了.他直接調(diào)用函數(shù).
類似這種簡(jiǎn)單函數(shù)他肯定是樂意的.

static inline CGRect ScaleRect(CGRect rect, float n)