ZDMQueson

开发中遇到的一些问题

1）输出时加该的方法类和名称行数

NSLog(@"%@__%s,%d",[NSString stringWithUTF8String:object_getClassName(self)],__FUNCTION__, __LINE__);

2）怎么把tableview里cell的小对勾的颜色改成别的颜色？

tableView.tintColor = [UIColor redColor];

3）iOS8中UITableVIew分割线短的问题

在iOS8中会发现分割线默认是没有全部显示的，在iOS7中适用的代码
if ([self.myCardTableView respondsToSelector:@selector(separatorInset)]) {
    self.myCardTableView.separatorInset = UIEdgeInsetsZero;
}

已经不管用了。而要在viewDidLoad中加入已下代码

 if ([self.myCardTableView respondsToSelector:@selector(setLayoutMargins:)]) {
    [self.myCardTableView setLayoutMargins:UIEdgeInsetsZero];
 }

并且加入UITableView的代理方法

  - (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath   *)indexPath
 {
     if ([cell respondsToSelector:@selector(setSeparatorInset:)]) {
         [cell setSeparatorInset:UIEdgeInsetsZero];
     }
     if ([cell respondsToSelector:@selector(setLayoutMargins:)]) {
         [cell setLayoutMargins:UIEdgeInsetsZero];
     }
 }

4）判断设备类型

CGSize iOSDeviceScreenSize = [[UIScreen mainScreen] bounds].size;
if ([UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomPhone)
{
    if (iOSDeviceScreenSize.width > 568 || // for iOS devices
        iOSDeviceScreenSize.height > 568) // for iOS simulator
    {   // iPhone 6 and iPhone 6+
        // Instantiate a new storyboard object using the storyboard file named Storyboard_iPhone6
        NSLog(@"loaded iPhone6 Storyboard");
    }
    else if (iOSDeviceScreenSize.width == 568 || // for iOS devices
             iOSDeviceScreenSize.height == 568) // for iOS simulator
    {   // iPhone 5 and iPod Touch 5th generation: 4 inch screen (diagonally measured)
        // Instantiate a new storyboard object using the storyboard file named Storyboard_iPhone5
        NSLog(@"loaded iPhone5 Storyboard");
    }
    else
    {   // iPhone 3GS, 4, and 4S and iPod Touch 3rd and 4th generation: 3.5 inch screen (diagonally measured)
            // Instantiate a new storyboard object using the storyboard file named Storyboard_iPhone4
            NSLog(@"loaded iPhone4 Storyboard");
    }
}
else if ([UIDevice currentDevice].userInterfaceIdiom == UIUserInterfaceIdiomPad)
{  
// The iOS device = iPad
    NSLog(@"loaded iPad Storyboard");
}

5）base64

 http://stackoverflow.com/questions/392464/how-do-i-do-base64-encoding-on-iphone-sdk

6）系统版本号

if (floor(NSFoundationVersionNumber) > NSFoundationVersionNumber_iOS_6_1) {
    // here you go with iOS 7
}
NSString *versionString = [[UIDevice currentDevice] systemVersion];

http://stackoverflow.com/questions/448162/determine-device-iphone-ipod-touch-with-iphone-sdk

7）获取当前手机号

 extern NSString* CTSettingCopyMyPhoneNumber();
+(NSString *) phoneNumber {
   NSString *phone = CTSettingCopyMyPhoneNumber();
   return phone;
}
或
NSString *num = [[NSUserDefaults standardUserDefaults] stringForKey:@"SBFormattedPhoneNumber"];

8）在block里用到成员变量或self的，请主动使用__weak

 __weak Class *weakSelf = self;
 但很多时候你不能避免在 Block 中使用 self,在 ARC 以前,你可以使用以下 技巧:
 __block DetailViewController *blockSelf = self;
 self.animatedView.block = ^(CGContextRef context, CGRect rect, CFTimeInterval totalTime, CFTimeInterval deltaTime)
 {
 }
 __block 关键字表示 Block 不 retain 这个变量,因此可以使用 blockSelf.artistName 来访问 artistName 属性,而 Block 也不会捕获 self 对 象。
 
 不过 ARC 中不能使用这个方法,因为变量默认是 strong 引用,即使标记为 __block 也仍然是 strong 类型的引用。这时候__block 的唯一功能是允许你修改 已捕获的变量(没有__block 则变量是只读的)。
 ARC 的解决办法是使用 __weak 变量:
 
 __weak DetailViewController *weakSelf = self;
 self.animatedView.block = ^(CGContextRef context, CGRect rect, CFTimeInterval totalTime, CFTimeInterval deltaTime)
 {
     DetailViewController *strongSelf = weakSelf;
     if (strongSelf != nil)
     {
     };
}
weakSelf 变量引用了 self,但不会进行 retain。我们让 Block 捕获 weakSelf 而不是 self,因此不存在所有权回环。但是我们在 Block 中不能直接使用 weakSelf,因为这是一个 weak 指针,当 DetailViewController 释放时它会自动 变成 nil。虽然向 nil 发送 message 是合法的,我们在 Block 中仍然检查了对象 是否存在。这里还有一个技巧,我们临时把 weakSelf 转换为 strong 类型的引 用 strongSelf,这样我们在使用 strongSelf 的时候,可以确保 DetailViewController 不会被其它人释放掉!

9）屏幕亮度

 [[UIApplication sharedApplication] setIdleTimerDisabled:YES ] ;
 设置为YES保持屏幕常亮.
 [[UIScreen mainScreen]setBrightness:0.5f];       
 取值范围从0.0到1.0

10）更改图片尺寸

 + (UIImage *)imageWithImage:(UIImage *)image scaledToSize:(CGSize)newSize {
    //UIGraphicsBeginImageContext(newSize);
    // In next line, pass 0.0 to use the current device's pixel scaling factor (and thus account for Retina resolution).
    // Pass 1.0 to force exact pixel size.
    UIGraphicsBeginImageContextWithOptions(newSize, NO, 0.0);
    [image drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();    
    UIGraphicsEndImageContext();
    return newImage;
 }

11）获取UIView的相关UIViewController

 @implementation UIView (AppNameAdditions)
 - (UIViewController *)appName_viewController {
    // Finds the view's view controller.
    // Take the view controller class object here and avoid sending the same message iteratively unnecessarily.
    // Traverse responder chain. Return first found view controller, which will be the view's view controller.
     UIResponder *responder = self;
     while ((responder = [responder nextResponder]))
         if ([responder isKindOfClass: [UIViewController class]])
         return (UIViewController *)responder;
         // If the view controller isn't found, return nil.
     return nil;
 }
 @end

12）GCD的用法

  //  后台执行：
  dispatch_async(dispatch_get_global_queue(0, 0), ^{
      // something
 });
  
 // 主线程执行：
 dispatch_async(dispatch_get_main_queue(), ^{
      // something
 });
    
 // 一次性执行：
 static dispatch_once_t onceToken;
 dispatch_once(&onceToken, ^{
     // code to be executed once
 });
     
 // 延迟2秒执行：
 double delayInSeconds = 2.0;
 dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
 dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
     // code to be executed on the main queue after delay
 });
  
 // 自定义dispatch_queue_t
 dispatch_queue_t urls_queue = dispatch_queue_create("blog.devtang.com", NULL);
 dispatch_async(urls_queue, ^{  
   // your code 
 });
 dispatch_release(urls_queue);
 
 // 合并汇总结果
 dispatch_group_t group = dispatch_group_create();
 dispatch_group_async(group, dispatch_get_global_queue(0,0), ^{
      // 并行执行的线程一
 });
 dispatch_group_async(group, dispatch_get_global_queue(0,0), ^{
      // 并行执行的线程二
 });
 dispatch_group_notify(group, dispatch_get_global_queue(0,0), ^{
      // 汇总结果
 });

13）UIWebView更改背景颜色

  _webview.backgroundColor = self.view.backgroundColor;
  _webview.opaque = NO;

14）NSInterger适配bit64

 NSInteger i = ...;
 NSLog(@"%ld", (long)i);
 #if __LP64__
 #define NSI "ld"
 #define NSU "lu"
 #else
 #define NSI "d"
 #define NSU "u"
 #endif

15）RAC指南

https://www.jianshu.com/p/87ef6720a096

16）契合设计提供的行高

NSMutableParagraphStyle *paragraphStyle = [NSMutableParagraphStyle new];
paragraphStyle.lineSpacing = 10 - (label.font.lineHeight - label.font.pointSize);
NSMutableDictionary *attributes = [NSMutableDictionary dictionary];
[attributes setObject:paragraphStyle forKey:NSParagraphStyleAttributeName];
label.attributedText = [[NSAttributedString alloc] initWithString:label.text attributes:attributes];

MING10/ZDMQueson

ZDMQueson