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iOS开发小技巧总结

iOS开发小技巧总结

作者: 萝卜不花心 | 来源:发表于2017-05-07 10:14 被阅读51次

    1.设置导航栏标题颜色

    UIColor *whiteColor = [UIColor redColor];
        NSDictionary *dic = [NSDictionary dictionaryWithObject:whiteColor forKey:NSForegroundColorAttributeName];
        [self.navigationController.navigationBar setTitleTextAttributes:dic];
    

    2.设置view半透明,subView不跟着变--通过设置背景色

    UIView * backView = [[UIView alloc]initWithFrame:self.view.frame];
        backView.backgroundColor = [[UIColor blackColor] colorWithAlphaComponent:0.5];
        
    //    backView.alpha = 0.3;//错误做法
        [self.view addSubview:backView];
        
        UIButton * button = [[UIButton alloc]init];
        button.backgroundColor = [UIColor redColor];
        button.frame = CGRectMake(200, 200, 200, 200);
        button.center = backView.center;
        [backView addSubview:button];
    

    3.设置VIew的部分圆角

    CGRect rect = button.bounds;
        CGSize radio = CGSizeMake(50, 50);//圆角尺寸
        UIRectCorner corner = UIRectCornerTopLeft|UIRectCornerTopRight;//这只圆角位置
        UIBezierPath *path = [UIBezierPath bezierPathWithRoundedRect:rect byRoundingCorners:corner cornerRadii:radio];
        CAShapeLayer *masklayer = [[CAShapeLayer alloc]init];//创建shapelayer
        masklayer.frame = button.bounds;
        masklayer.path = path.CGPath;//设置路径
        button.layer.mask = masklayer;
    

    4.数组快速求和,平均值,最大值,最小值

     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向下取整%f\n向上取整%f\n%f\n%f\n%f",sum,floor(sum),ceil(sum),avg,max,min);
    

    5.navigationBar根据滑动距离的渐变色实现

    //第一种
    - (void)scrollViewDidScroll:(UIScrollView *)scrollView
    {
        CGFloat offsetToShow = 200.0;//滑动多少就完全显示
        CGFloat alpha = 1 - (offsetToShow - scrollView.contentOffset.y) / offsetToShow;
        [[self.navigationController.navigationBar subviews] objectAtIndex:0].alpha = alpha;
    }
    //第二种
    - (void)scrollViewDidScroll:(UIScrollView *)scrollView
    {
        CGFloat offsetToShow = 200.0;
        CGFloat alpha = 1 - (offsetToShow - scrollView.contentOffset.y) / offsetToShow;
     
        [self.navigationController.navigationBar setShadowImage:[UIImage new]];
        [self.navigationController.navigationBar setBackgroundImage:[self imageWithColor:[[UIColor orangeColor]colorWithAlphaComponent:alpha]] forBarMetrics:UIBarMetricsDefault];
    }
     
    //根据颜色生成图片
    - (UIImage *)imageWithColor:(UIColor *)color
    {
        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();
     
        return theImage;
    }
    

    4.数组快速求和,平均值,最大值,最小值

     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向下取整%f\n向上取整%f\n%f\n%f\n%f",sum,floor(sum),ceil(sum),avg,max,min);
    

    7.获取webView的高度

    CGFloat height = [[self.webView stringByEvaluatingJavaScriptFromString:@"document.body.offsetHeight"] floatValue];
    

    8.图片缓存的清空(包括SD的,可以同时清除session 和 cookie的缓存)

    // 清理内存
    [[SDImageCache sharedImageCache] clearMemory];
     
    // 清理webview 缓存
    NSHTTPCookieStorage *storage = [NSHTTPCookieStorage sharedHTTPCookieStorage];
    for (NSHTTPCookie *cookie in [storage cookies]) {
        [storage deleteCookie:cookie];
    }
     
    NSURLSessionConfiguration *config = [NSURLSessionConfiguration defaultSessionConfiguration];
    [config.URLCache removeAllCachedResponses];
    [[NSURLCache sharedURLCache] removeAllCachedResponses];
     
    // 清理硬盘
    [[SDImageCache sharedImageCache] clearDiskOnCompletion:^{
        [MBProgressHUD hideAllHUDsForView:self.view animated:YES];
     
        [self.tableView reloadData];
    }];
    

    9.UIView 自带动画翻转界面

    
    - (IBAction)changeImages:(id)sender
    {
        CGContextRef context = UIGraphicsGetCurrentContext();
     
        [UIView beginAnimations:nil context:context];
        [UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];
        [UIView setAnimationDuration:1.0];
     
        [UIView setAnimationTransition:UIViewAnimationTransitionCurlDown forView:_parentView cache:YES];
        [UIView setAnimationTransition:UIViewAnimationTransitionCurlUp forView:_parentView cache:YES];
        [UIView setAnimationTransition:UIViewAnimationTransitionFlipFromLeft forView:_parentView cache:YES];
        [UIView setAnimationTransition:UIViewAnimationTransitionFlipFromRight forView:_parentView cache:YES];
     
        NSInteger purple = [[_parentView subviews] indexOfObject:self.image1];
        NSInteger maroon = [[_parentView subviews] indexOfObject:self.image2];
     
        [_parentView exchangeSubviewAtIndex:purple withSubviewAtIndex:maroon];
     
        [UIView setAnimationDelegate:self];
        [UIView commitAnimations];
     
     
    }
    

    10.工程中查看是否使用 IDFA

    打开终端,到工程目录中, 输入:
    
    grep -r advertisingIdentifier .
    
    可以看到那些文件中用到了IDFA,如果用到了就会被显示出来
    

    11.动态计算文本高度

    NSDictionary *attribute = @{NSFontAttributeName: [UIFont systemFontOfSize:13]};
    CGSize size = [@"相关NSString" boundingRectWithSize:CGSizeMake(100, 0) options: NSStringDrawingTruncatesLastVisibleLine | NSStringDrawingUsesLineFragmentOrigin | NSStringDrawingUsesFontLeading attributes:attribute context:nil].size;
    
    

    12.关闭/收起键盘方法

    1、点击Return按扭时收起键盘
    - (BOOL)textFieldShouldReturn:(UITextField *)textField 
    {
        return [textField resignFirstResponder]; 
    }
    2、点击背景View收起键盘
    [self.view endEditing:YES];
    3、你可以在任何地方加上这句话,可以用来统一收起键盘
    [[[UIApplication sharedApplication] keyWindow] endEditing:YES];
    

    13.修改textField的placeholder的字体颜色、大小

    //方法1
    self.textField.placeholder = @"username is in here!";
    [self.textField setValue:[UIColor redColor] forKeyPath:@"_placeholderLabel.textColor"];
    [self.textField setValue:[UIFont boldSystemFontOfSize:16] forKeyPath:@"_placeholderLabel.font"];
    //方法二(实际项目中使用过)
    NSString *string = @"美丽新世界";
        NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:string];
     
        [attributedString addAttribute:NSForegroundColorAttributeName
                                 value:[UIColor redColor]
                                 range:NSMakeRange(0, [string length])];
     
        [attributedString addAttribute:NSFontAttributeName
                                 value:[UIFont systemFontOfSize:16]
                                 range:NSMakeRange(0, [string length])];
     
        self.textField.attributedPlaceholder = attributedString;
    

    14.待发现

    ...
    

    15.待发现

    ...
    

    16.待发现

    ...
    

    ps:第一次写没有什么经验就写一点基础简单的吧,我分享的这些都是经过自己验证过的,大家可以放心使用
    参考文章1
    参考文章2

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