ios开发中的常见问题

原文地址：http://shavekevin.com/2016/04/12/iosdeveloptips/

1.取消cell的分割线 

tableview.separatorStyle = UITableViewCellSeparatorStyleNone;  

2.UITabelviewCell 的高亮状态的取消 
用以下方法：

-(void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath{
    //设置cell的背景是透明的。
    cell.backgroundColor = [UIColor clearColor];
    //取消cell的高亮状态
    cell.selectionStyle = UITableViewCellSelectionStyleNone;
}


//使用下面的这个方法会导致cell不能响应点击事件
- (BOOL)tableView:(UITableView *)tableView shouldHighlightRowAtIndexPath:(NSIndexPath *)indexPath {
    return YES;
}

3.设置分割线的左右偏移量 

tableview  setSeparatorInset:inset  

4.推送如何跳转到对应的controller

跳转界面

- (void)push:(NSDictionary *)params
{
    // 类名
    NSString *class =[NSString stringWithFormat:@"%@", params[@"class"]];
    const char *className = [class cStringUsingEncoding:NSASCIIStringEncoding];

    // 从一个字串返回一个类
    Class newClass = objc_getClass(className);
    if (!newClass)
    {
        // 创建一个类
        Class superClass = [NSObject class];
        newClass = objc_allocateClassPair(superClass, className, 0);
        // 注册你创建的这个类
        objc_registerClassPair(newClass);
    }
    // 创建对象
    id instance = [[newClass alloc] init];
 // 对该对象赋值属性
    NSDictionary * propertys = params[@"property"];
    [propertys enumerateKeysAndObjectsUsingBlock:^(id key, id obj, BOOL *stop) {
        // 检测这个对象是否存在该属性
        if ([self checkIsExistPropertyWithInstance:instance verifyPropertyName:key]) {
            // 利用kvc赋值
            [instance setValue:obj forKey:key];
        }
    }];

    // 获取导航控制器
    UITabBarController *tabVC = (UITabBarController *)self.window.rootViewController;
    UINavigationController *pushClassStance = (UINavigationController *)tabVC.viewControllers[tabVC.selectedIndex];
    // 跳转到对应的控制器
    [pushClassStance pushViewController:instance animated:YES];
}

检测对象是否存在该属性

- (BOOL)checkIsExistPropertyWithInstance:(id)instance verifyPropertyName:(NSString *)verifyPropertyName
{
    unsigned int outCount, i;

    // 获取对象里的属性列表
    objc_property_t * properties = class_copyPropertyList([instance
                                                           class], &outCount);

    for (i = 0; i < outCount; i++) {
        objc_property_t property =properties[i];
        //  属性名转成字符串
        NSString *propertyName = [[NSString alloc] initWithCString:property_getName(property) encoding:NSUTF8StringEncoding];
        // 判断该属性是否存在
        if ([propertyName isEqualToString:verifyPropertyName]) {
            free(properties);
            return YES;
        }
    }
    free(properties);

    return NO;
}

来源于简书： iOS 万能跳转界面方法 runtime实用篇一

7.3D效果 还不错哦

https://github.com/nicklockwood/iCarousel

8.xcode7引入xmpp提示module libxmlsimu not found怎么解决？

解决方案如下图：

9.data进行MD5 加密

https://github.com/shaojiankui/iOS-Categories/blob/master/Categories/Foundation/NSData/NSData%2BHash.m

10.UIVisualEffectView 背景是虚化的(类似我们iphone查看通知时的虚化背景)

https://github.com/nicklockwood/FXBlurView

11.NSDate 的坑

Also when using a date format string using the correct format is important.

@"YYYY" is week-based calendar year.

@"yyyy" is ordinary calendar year.

可以看下面这篇博客：NSDateFormatter 'YYYY' 和 'yyyy' 的区别

12.swift 实时滤镜

http://blog.youkuaiyun.com/zhangao0086/article/details/39433519

13.动态加载视频

http://www.jianshu.com/p/3dcebf0493d1

14.swift 闭包

http://www.henishuo.com/closures-of-swift/

15.理解contentsScale

http://joeshang.github.io/2015/01/10/understand-contentsscale/#disqus_thread

16.图文混排

https://github.com/12207480/TYAttributedLabel

19.textField 文字上下居中

textField.contentVerticalAlignment =UIControlContentVerticalAlignmentCenter;


//.全部删除按钮

textField.clearButtonMode =UITextFieldViewModeWhileEditing;

[textFieldsetAutocapitalizationType:UITextAutocapitalizationTypeNone];

26.下面的view或self.view如果小于上面的，上面的view超过下面的部分将无法与用户交互。

27.自定义cell时，最好在cell.contentView上加控件

29.正则 

(?<=src\s*\=\s*\")[\d\D]+?(?=\")

取出html 中的src 图片 

32.dealloc的super dealloc必须放在最后面

33.所有不带星号的和id类型的都只能assign

39.程序崩溃处理方法

- (BOOL)application:(UIApplication*)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions

{

NSSetUncaughtExceptionHandler(&UncaughtExceptionHandler);

}

调用下面的方法，如数组越界，调用不存在的方法等会打出详细的信息。

void UncaughtExceptionHandler(NSException*exception) {

   NSArray *arr = [exception callStackSymbols];

   NSString *reason = [exception reason];

   NSString *name = [exception name];

   NSLog(@"\nname: %@\reason: %@\nuserInfo: %@\ncallStackSymbols:%@\ncallStackReturnAddresses: %@",name,reason,[exceptionuserInfo],arr,[exceptioncallStackReturnAddresses]);

}

开启僵尸模式 Object-C的Enable Zombie Objects勾选，Memory 中的MallocStack勾选，Exceptions里的Log Exceptions勾选

40.NSLog 怎么打印出变量类型的？

NSStringFromSelector(SEL aSelector);

NSSelectorFromString(NSString *aSelectorName);

NSStringFromClass(Class aClass);

NSClassFromString(NSString *aClassName);

NSStringFromProtocol(Protocol *proto)

NSProtocolFromString(NSString *namestr) 

NSStringFromCGPoint(CGPoint point);

NSStringFromCGVector(CGVector vector);

NSStringFromCGSize(CGSize size);

NSStringFromCGRect(CGRect rect);

NSStringFromCGAffineTransform(CGAffineTransform transform);

NSStringFromUIEdgeInsets(UIEdgeInsets insets);

NSStringFromUIOffset(UIOffset offset);

CGPointFromString(NSString *string);

CGVectorFromString(NSString *string);

CGSizeFromString(NSString *string);

CGRectFromString(NSString *string);

CGAffineTransformFromString(NSString *string);

UIEdgeInsetsFromString(NSString *string);

UIOffsetFromString(NSString *string);