问题杂烩

判断字符串是不是纯数字

/// 判断字符串是不是纯数字
- (BOOL)isPureNumandCharacters:(NSString *)string
{
    string = [string stringByTrimmingCharactersInSet:[NSCharacterSet decimalDigitCharacterSet]];
    if(string.length > 0)
    {
        return NO;
    }
    return YES;
}

Attempt to present XX on XX whose view is not in the window hierarchy

Attempt to present <LoginVC: 0x9358770> on <ViewController: 0x9529380> whose view is not in the window hierarchy

也就是你在呈现一个LoginVC时，但ViewController的view并不在window上，可能是因为ViewController还没被显示出来。
所以不要在某个viewController的viewDidLoad或者viewWillAppear方法中去呈现其他的viewController，你如果想要的是ViewController显示之后马上呈现LoginVC的话，可以在viewDidAppear中写方法。

指定颜色生成图片

//指定颜色生成图片：
+ (UIImage *)imageWithColor:(UIColor *)color
{
    CGRect rect = CGRectMake(0, 0, 1, 1);
    UIGraphicsBeginImageContext(rect.size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    
    CGContextSetFillColorWithColor(context, [color CGColor]);
    CGContextFillRect(context, rect);
    
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    return image;
}

获取系统版本、型号等信息

获取基本信息

//  IOS-获取Model（设备型号）、Version（设备版本号）、app（程序版本号）等  
    NSLog(@"name: %@", [[UIDevice currentDevice] name]);  
    NSLog(@"systemName: %@", [[UIDevice currentDevice] systemName]);  
    NSLog(@"systemVersion: %@", [[UIDevice currentDevice] systemVersion]);  
    NSLog(@"model: %@", [[UIDevice currentDevice] model]);  
    NSLog(@"localizedModel: %@", [[UIDevice currentDevice] localizedModel]);  
      
      
      
    NSDictionary *infoDictionary = [[NSBundle mainBundle] infoDictionary];  
      
    CFShow((__bridge CFTypeRef)(infoDictionary));  
      
    // app名称  
    NSString *app_Name = [infoDictionary objectForKey:@"CFBundleDisplayName"];  
    // app版本  
    NSString *app_Version = [infoDictionary objectForKey:@"CFBundleShortVersionString"];  
    // app build版本  
    NSString *app_build = [infoDictionary objectForKey:@"CFBundleVersion”];

获取具体型号，如5s，6P等

#import "sys/utsname.h"


//获得设备型号
+ (NSString *)getCurrentDeviceModel
{
    struct utsname systemInfo;
    uname(&systemInfo);
    NSString *platform = [NSString stringWithCString:systemInfo.machine encoding:NSUTF8StringEncoding];
    
    if ([platform isEqualToString:@"iPhone1,1"]) return @"iPhone 2G (A1203)";
    if ([platform isEqualToString:@"iPhone1,2"]) return @"iPhone 3G (A1241/A1324)";
    if ([platform isEqualToString:@"iPhone2,1"]) return @"iPhone 3GS (A1303/A1325)";
    if ([platform isEqualToString:@"iPhone3,1"]) return @"iPhone 4 (A1332)";
    if ([platform isEqualToString:@"iPhone3,2"]) return @"iPhone 4 (A1332)";
    if ([platform isEqualToString:@"iPhone3,3"]) return @"iPhone 4 (A1349)";
    if ([platform isEqualToString:@"iPhone4,1"]) return @"iPhone 4S (A1387/A1431)";
    if ([platform isEqualToString:@"iPhone5,1"]) return @"iPhone 5 (A1428)";
    if ([platform isEqualToString:@"iPhone5,2"]) return @"iPhone 5 (A1429/A1442)";
    if ([platform isEqualToString:@"iPhone5,3"]) return @"iPhone 5c (A1456/A1532)";
    if ([platform isEqualToString:@"iPhone5,4"]) return @"iPhone 5c (A1507/A1516/A1526/A1529)";
    if ([platform isEqualToString:@"iPhone6,1"]) return @"iPhone 5s (A1453/A1533)";
    if ([platform isEqualToString:@"iPhone6,2"]) return @"iPhone 5s (A1457/A1518/A1528/A1530)";
    if ([platform isEqualToString:@"iPhone7,1"]) return @"iPhone 6 Plus (A1522/A1524)";
    if ([platform isEqualToString:@"iPhone7,2"]) return @"iPhone 6 (A1549/A1586)";
    
    if ([platform isEqualToString:@"iPod1,1"])   return @"iPod Touch 1G (A1213)";
    if ([platform isEqualToString:@"iPod2,1"])   return @"iPod Touch 2G (A1288)";
    if ([platform isEqualToString:@"iPod3,1"])   return @"iPod Touch 3G (A1318)";
    if ([platform isEqualToString:@"iPod4,1"])   return @"iPod Touch 4G (A1367)";
    if ([platform isEqualToString:@"iPod5,1"])   return @"iPod Touch 5G (A1421/A1509)";
    
    if ([platform isEqualToString:@"iPad1,1"])   return @"iPad 1G (A1219/A1337)";
    
    if ([platform isEqualToString:@"iPad2,1"])   return @"iPad 2 (A1395)";
    if ([platform isEqualToString:@"iPad2,2"])   return @"iPad 2 (A1396)";
    if ([platform isEqualToString:@"iPad2,3"])   return @"iPad 2 (A1397)";
    if ([platform isEqualToString:@"iPad2,4"])   return @"iPad 2 (A1395+New Chip)";
    if ([platform isEqualToString:@"iPad2,5"])   return @"iPad Mini 1G (A1432)";
    if ([platform isEqualToString:@"iPad2,6"])   return @"iPad Mini 1G (A1454)";
    if ([platform isEqualToString:@"iPad2,7"])   return @"iPad Mini 1G (A1455)";
    
    if ([platform isEqualToString:@"iPad3,1"])   return @"iPad 3 (A1416)";
    if ([platform isEqualToString:@"iPad3,2"])   return @"iPad 3 (A1403)";
    if ([platform isEqualToString:@"iPad3,3"])   return @"iPad 3 (A1430)";
    if ([platform isEqualToString:@"iPad3,4"])   return @"iPad 4 (A1458)";
    if ([platform isEqualToString:@"iPad3,5"])   return @"iPad 4 (A1459)";
    if ([platform isEqualToString:@"iPad3,6"])   return @"iPad 4 (A1460)";
    
    if ([platform isEqualToString:@"iPad4,1"])   return @"iPad Air (A1474)";
    if ([platform isEqualToString:@"iPad4,2"])   return @"iPad Air (A1475)";
    if ([platform isEqualToString:@"iPad4,3"])   return @"iPad Air (A1476)";
    if ([platform isEqualToString:@"iPad4,4"])   return @"iPad Mini 2G (A1489)";
    if ([platform isEqualToString:@"iPad4,5"])   return @"iPad Mini 2G (A1490)";
    if ([platform isEqualToString:@"iPad4,6"])   return @"iPad Mini 2G (A1491)";
    
    if ([platform isEqualToString:@"i386"])      return @"iPhone Simulator";
    if ([platform isEqualToString:@"x86_64"])    return @"iPhone Simulator";
    return platform;
}

读写plist文件

问题，我有一个plist文件，表示56个民族的，但是里面保存的字典，我想转换成一个数组
好的，那么就先遍历这个plist，然后将结果保存到一个数组中，这里出现的一个问题就是C语言字符串转换成NSString的问题，一开始使用- (nullable id)initWithCString:(const char *)bytes,一直出问题，转换后有问题。
然后我就换了一个方法- (nullable id)initWithCString:(const char *)bytes length:(NSUInteger)length 这个方法转换后没有问题了。
第一个plist是按照26个英文字母为key的字典。
结果，按照数组保存。

// 读取56个民族
NSString *filePath = [[NSBundle mainBundle] pathForResource:@"nation.plist" ofType:nil];
NSDictionary *dict2 = [NSDictionary dictionaryWithContentsOfFile:filePath];

// 拼接路径
NSArray *paths=NSSearchPathForDirectoriesInDomains(NSCachesDirectory,NSUserDomainMask,YES);
NSString *plistPath1 = [paths objectAtIndex:0];
NSString *filename = [plistPath1 stringByAppendingPathComponent:@"nation2.plist"];

NSMutableArray *mutab = [NSMutableArray array];

for (int i = 0 ; i < 26; i ++) {
    char x = 65 + i;
    NSString *str=  [[NSString alloc] initWithCString:&x length:1];
    NSArray *arr = dict2[str];
    for (NSInteger j = 0; j < arr.count; j ++) {
        [mutab addObject:arr[j]];
    }
}
// 保存成数组
[mutab writeToFile:filename atomically:NO];
NSLog(@"%@",mutab);

XCode快捷键

command + option +J 快速定位到当前打开的类所在位置目录结构
command + 1…..7 切换工程选项卡左边的那个
ESC 代码自动补全
command + shift +k clean 工程
command + k 清空console 输出
command + f 搜索当前文件
command + shift + f 搜索整个工程
command + l 跳转到某一行
command + control + 左右方向键前进或者后退已打开过的文件
command + control + 上下方向键切换.h 和 .m文件
command + 0 隐藏/显示导航栏

pragma使用

组织代码

组织N个方法为一个section的依据是什么呢？这个就见仁见智了。一般来说：
- 将一个protocol的方法组织成一个section；
- 将target-action类型方法组织成一个section；
- 将notification相关方法组织成一个section；
- 将需要override的父类方法组成成一个section；

屏蔽警告

#pragma clang diagnostic push
#pragma clang diagnostic i![](屏蔽编译警告.png)gnored "-Wundeclared-selector"
    if ([self.selectedViewController respondsToSelector:@selector(isReadyForEditing)]) {
        boolNumber = [self.selectedViewController performSelector:@selector(isReadyForEditing)];
    }
#pragma clang diagnostic pop

其他方式

某些时候如果我们的源码在编译过程中出现大量的编译警告时，看起来是挺不爽的；但又确实没办法解决警告问题的时候，我们可以使用下面的方法来屏蔽指定的某个文件的所有警告信息。
- 1、在Xcode中选中工程文件。
- 2、在右边面板中选中“Build Phases”。
- 3、展开“Compile Sources”
- 4、在需要屏蔽警告的源文件一行中双击“Compiler F lags”。
- 5、在弹出窗口中输入-w

图片旋转问题

ios 照片旋转问题
http://feihu.me/blog/2015/how-to-handle-image-orientation-on-iOS
添加一个分类在上传之前进行处理即可

- (UIImage *)fixOrientation {
    
    // No-op if the orientation is already correct
    if (self.imageOrientation == UIImageOrientationUp) return self;
    
    // We need to calculate the proper transformation to make the image upright.
    // We do it in 2 steps: Rotate if Left/Right/Down, and then flip if Mirrored.
    CGAffineTransform transform = CGAffineTransformIdentity;
    
    switch (self.imageOrientation) {
        case UIImageOrientationDown:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, self.size.height);
            transform = CGAffineTransformRotate(transform, M_PI);
            break;
            
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, 0);
            transform = CGAffineTransformRotate(transform, M_PI_2);
            break;
            
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, 0, self.size.height);
            transform = CGAffineTransformRotate(transform, -M_PI_2);
            break;
        case UIImageOrientationUp:
        case UIImageOrientationUpMirrored:
            break;
    }
    
    switch (self.imageOrientation) {
        case UIImageOrientationUpMirrored:
        case UIImageOrientationDownMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.width, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
            
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRightMirrored:
            transform = CGAffineTransformTranslate(transform, self.size.height, 0);
            transform = CGAffineTransformScale(transform, -1, 1);
            break;
        case UIImageOrientationUp:
        case UIImageOrientationDown:
        case UIImageOrientationLeft:
        case UIImageOrientationRight:
            break;
    }
    
    // Now we draw the underlying CGImage into a new context, applying the transform
    // calculated above.
    CGContextRef ctx = CGBitmapContextCreate(NULL, self.size.width, self.size.height,
                                             CGImageGetBitsPerComponent(self.CGImage), 0,
                                             CGImageGetColorSpace(self.CGImage),
                                             CGImageGetBitmapInfo(self.CGImage));
    CGContextConcatCTM(ctx, transform);
    switch (self.imageOrientation) {
        case UIImageOrientationLeft:
        case UIImageOrientationLeftMirrored:
        case UIImageOrientationRight:
        case UIImageOrientationRightMirrored:
            // Grr...
            CGContextDrawImage(ctx, CGRectMake(0,0,self.size.height,self.size.width), self.CGImage);
            break;
            
        default:
            CGContextDrawImage(ctx, CGRectMake(0,0,self.size.width,self.size.height), self.CGImage);
            break;
    }
    
    // And now we just create a new UIImage from the drawing context
    CGImageRef cgimg = CGBitmapContextCreateImage(ctx);
    UIImage *img = [UIImage imageWithCGImage:cgimg];
    CGContextRelease(ctx);
    CGImageRelease(cgimg);
    return img;
}

判断用户短时间内发送消息太多

看到这个问题时，我想到了定时器，首先定义一个变量numberOfSend保存发送次数，然后在第一次输入时开启定时器timer1，5s之内如果numberOfSend没有超过8条，就在5s后重置numberOfSend，如果5s内发送次数超过8条，就开启另一个定时器timer2，来延迟执行发送操作，在timer2中要先取消之前的timer1，然后就return


 NSInteger _numberOfSendMessagesInFiveSecond;


- (void)sendMessages
{
    _numberOfSendMessagesInFiveSecond = 0;
}

- (void)sendText:(NSString *)contentString
{
   // 喝杯茶休息一下吧！
    _numberOfSendMessagesInFiveSecond ++ ;
    if ( 1 == _numberOfSendMessagesInFiveSecond){
        
        [self performSelector:@selector(sendMessages) withObject:nil afterDelay:5];
    }
    else if (_numberOfSendMessagesInFiveSecond >= 9) {
        
        [chatInputView insertTextAfterCursor:contentString];
        [self presentSuccessTips:NSLocalizedString(@"CHATPANEL_TAKE_A_CUP_OF_TEA" ,@"喝杯茶休息一下吧！")];
        
        if(_numberOfSendMessagesInFiveSecond == 9) {
            [[self class] cancelPreviousPerformRequestsWithTarget:self selector:@selector(sendMessages) object:nil];
            dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(5.0f * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
                _numberOfSendMessagesInFiveSecond = 0;
            });
        }
        return;
    }
}

另外一种方式

@interface P2PSendMsgFrequencyStrategy ()
{
    NSInteger _iMaxCount;
    long long _iMaxMillisecond; //1秒
    NSInteger _iCount;
    NSTimeInterval _lastSendTime;
}

@end

@implementation P2PSendMsgFrequencyStrategy

- (instancetype)init
{
    self = [super init];
    if (self)
    {
        _iMaxCount = 8;
        _iMaxMillisecond = 1*1000; //1秒
        _iCount = 0;
        _lastSendTime = 0;
    }
    return self;
}

- (BOOL)sendMessageTooOften
{//规则是：5秒内发送超过8条就不能发送，然后再过5秒才能发送。
    NSTimeInterval nowSendTime = [[NSDate date]timeIntervalSince1970]*1000;

    long long time = (nowSendTime - _lastSendTime);
    if ((time > _iMaxMillisecond*5 && _iCount < _iMaxCount)
        || (time > _iMaxMillisecond*10 && _iCount >= _iMaxCount)
        )
    {
        _lastSendTime = [[NSDate date]timeIntervalSince1970]*1000;
        _iCount = 0;

        YJLog(@"sendMessage time:%lld", time);
        return NO;
    }
    else
    {
        if (++_iCount < _iMaxCount)
        {
            YJLog(@"sendMessage count: %ld, time:%lld",  (long)_iCount, time);
            return NO;
        }

    }

    YJLog(@"sendMessage Too Many: %ld, time:%lld",  (long)_iCount, time);
    return YES;
}

@end