今天折腾了半天的问题,百尺竿头更进一步.

bug现象-在iOS8 系统上出现

1.追根溯源

UIalertcontroller里面添加的textfield旁边会有两个黑色的框，自己拆视图(Debug View 就是xcode的功能)发现里面有一个tableview.里面cell的背景色是黑色

2.找它

2.1>通过runtime 找不到这个tableView

   unsigned int numIvars; //成员变量个数
             
   Ivar *vars = class_copyIvarList(NSClassFromString(@"UIAlertController"), &numIvars);
             
           //Ivar *vars = class_copyIvarList([UIView class], &numIvars);   
          NSString *key=nil;
             
                 for(int i = 0; i < numIvars; i++) {

                 Ivar thisIvar = vars[i];
                 
                         key = [NSString stringWithUTF8String:ivar_getName(thisIvar)];  //获取成员变量的名字
                 
                         NSLog(@"variable name :%@", key);
                 
                         key = [NSString stringWithUTF8String:ivar_getTypeEncoding(thisIvar)]; //获取成员变量的数据类型
                 
                         NSLog(@"variable type :%@", key);
                 
                     }
                 free(vars);

2.2>循环遍历子视图

首先判断是不是8的系统

     if (SYSTEM_VERSION_LESS_THAN(@"9.0"))
             {//循环遍历方法
                 [self wipeOutBlackColorInIOS8WithView:alert.view];
             }

-(void)wipeOutBlackColorInIOS8WithView:(UIView *)fatherview
{
    for (UIView *view in fatherview.subviews)
    {
        NSLog(@"view_class:%@",NSStringFromClass([view class]));
        
        if ([NSStringFromClass([view class]) isEqualToString:@"_UIAlertControllerShadowedScrollView"])
        {
            
        }
        if ([view isKindOfClass:[UITableView class]])
        {
            UITableView *tableView =(UITableView *)view;
            NSInteger sections = tableView.numberOfSections;
            for (int section = 0; section < sections; section++)
            {
                NSInteger rows =[tableView numberOfRowsInSection:section];
                for (int row = 0; row < rows; row++)
                {//找到tableView 改变cell背景色
                    NSIndexPath *indexPath = [NSIndexPath indexPathForRow:row inSection:section];
                    UITableViewCell *cell =[tableView cellForRowAtIndexPath:indexPath];
                    [cell setBackgroundColor:kClearColor];
                }
            }
        }
        else
        {
            if (view.subviews.count)
            {
                [self wipeOutBlackColorInIOS8WithView:view];
            }
        }
    }
}

坚持就是胜利