iOS 常用公共方法（四）

原文链接：点击这里

1、navigationBar变为纯透明

//第一种方法
//导航栏纯透明
[self.navigationBar setBackgroundImage:[UIImage new] forBarMetrics:UIBarMetricsDefault];
//去掉导航栏底部的黑线
self.navigationBar.shadowImage = [UIImage new];

//第二种方法
[[self.navigationBar subviews] objectAtIndex:].alpha = ;
           

tabBar同理

[self.tabBar setBackgroundImage:[UIImage new]];
self.tabBar.shadowImage = [UIImage new];
           

2、navigationBar根据滑动距离的渐变色实现

//第一种
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    CGFloat offsetToShow = ;//滑动多少就完全显示
    CGFloat alpha =  - (offsetToShow - scrollView.contentOffset.y) / offsetToShow;
    [[self.navigationController.navigationBar subviews] objectAtIndex:].alpha = alpha;
}
           

//第二种
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
    CGFloat offsetToShow = ;
    CGFloat alpha =  - (offsetToShow - scrollView.contentOffset.y) / offsetToShow;

    [self.navigationController.navigationBar setShadowImage:[UIImage new]];
    [self.navigationController.navigationBar setBackgroundImage:[self imageWithColor:[[UIColor orangeColor]colorWithAlphaComponent:alpha]] forBarMetrics:UIBarMetricsDefault];
}
           

3、生成一张纯色的图片

- (UIImage *)imageWithColor:(UIColor *)color
{
    CGRect rect = CGRectMake(f, f, f, f);
    UIGraphicsBeginImageContext(rect.size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextSetFillColorWithColor(context, [color CGColor]);
    CGContextFillRect(context, rect);
    UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return theImage;
}
           

4、iOS 开发中一些相关的路径

模拟器的位置:
/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform/Developer/SDKs 

文档安装位置:
/Applications/Xcode.app/Contents/Developer/Documentation/DocSets

插件保存路径:
~/Library/ApplicationSupport/Developer/Shared/Xcode/Plug-ins

自定义代码段的保存路径:
~/Library/Developer/Xcode/UserData/CodeSnippets/ 
如果找不到CodeSnippets文件夹，可以自己新建一个CodeSnippets文件夹。

描述文件路径
~/Library/MobileDevice/Provisioning Profiles