iOS 9月份问题总结:Xcode 9导航栏UISearchBar /Tableview预加载

9月份问题总结:

主要内容:
(1) 适配iOS11,Xcode 9中出现问题归纳.
(2) Tableview预加载问题测试

一.适配iOS 11; UISearchBar / UISearchBar导航栏显示问题

(1)iOS 11导航栏显示效果改变

标注1: UISearchBar背景高度改为56
标注2: UISearchBar内部TextField高度改为36

背景高度.png

内部TextFileld高度.png

尝试解决方法:

(1) http://www.jianshu.com/p/39a5aee18778 (更改或自定义)
(2) 快速方法:

[[UISearchBar appearance] setSearchFieldBackgroundImage:[self searchFieldBackgroundImage] forState:UIControlStateNormal];
UITextField *txfSearchField = [self.searchBar valueForKey:@"_searchField"];
[txfSearchField setDefaultTextAttributes:@{NSFontAttributeName:[UIFont systemFontOfSize:13.5]}];

self.searchBar.searchTextPositionAdjustment = UIOffsetMake(7, 0)

//调用方法
- (UIImage*)searchFieldBackgroundImage {
    UIColor*color = [UIColor whiteColor];
    CGFloat cornerRadius = 5;
    CGRect rect =CGRectMake(0,0,28,28);

    UIBezierPath*roundedRect = [UIBezierPath bezierPathWithRoundedRect:rect cornerRadius:cornerRadius];
roundedRect.lineWidth=0;

    UIGraphicsBeginImageContextWithOptions(rect.size,NO,0.0f);
    [color setFill];
    [roundedRect fill];
    [roundedRect stroke];
    [roundedRect addClip];

    UIImage *image =UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

快速方法显示效果:

备注::不是放在导航栏上UISearchBar,调用相同方法即可.(背景高度改变-可添加约束/放在父view上等等)

更改后显示效果对比.png

二.适配iOS 11; Safe Area Layout Guide Before IOS 9.0

(1)方法:

http://blog.csdn.net/chmod_r_755/article/details/78052380

三.Tableview滑动预加载测试:

(1)方法:

- (void)scrollViewDidScroll:(UIScrollView *)aScrollView {
    CGPoint offset = aScrollView.contentOffset;
    CGRect bounds = aScrollView.bounds;
    CGSize size = aScrollView.contentSize;
    UIEdgeInsets inset = aScrollView.contentInset;//边缘距离
    float y = offset.y + bounds.size.height - inset.bottom;
    float h = size.height;

    NSLog(@"offset: %f", offset.y);
    NSLog(@"content.height: %f", size.height);
    NSLog(@"bounds.height: %f", bounds.size.height);//603,界面高度6s-667-64,
    NSLog(@"inset.top: %f", inset.top);
    NSLog(@"inset.bottom: %f", inset.bottom);
    NSLog(@"pos: %f of %f", y, h);

   float reload_distance = 80;
   if(y > h - reload_distance) {
      NSLog(@"load more rows");
      self.pageIndex ++;
      [self getServerData];
   }
}

Demo地址:https://github.com/FTC-Chen/TableViewPreload

四.使用UISearchBar实现连续搜索界面,支持/热搜/历史搜索记录.去重/清楚历史搜索/筛选过滤/;整体效果类似京东首页搜索效果

(1)主要代码:

1. 保存搜索记录:

//保存搜索记录
-(void)SearchText :(NSString *)seaTxt{
    NSUserDefaults *userDefaultes = [NSUserDefaults standardUserDefaults];
    //读取数组NSArray类型的数据
    NSArray *myArray = [[NSArray alloc] initWithArray:[userDefaultes arrayForKey:@"searchHistory"]];

    // NSArray --> NSMutableArray
    NSMutableArray *searTXT = [NSMutableArray array];
    searTXT = [myArray mutableCopy];

    BOOL isEqualTo1,isEqualTo2;
    isEqualTo1 = NO;
    isEqualTo2 = NO;

    if (searTXT.count > 0) {
        isEqualTo2 = YES;
        //判断搜索内容是否存在,存在的话放到数组第一位,不存在的话添加。
        for (NSString * str in myArray) {
            if ([seaTxt isEqualToString:str]) {
                //获取指定对象的索引
                NSUInteger index = [myArray indexOfObject:seaTxt];
                [searTXT removeObjectAtIndex:index];
                [searTXT insertObject:seaTxt atIndex:0];
                isEqualTo1 = YES;
                break;
            }
        }
    }
    if (!isEqualTo1 || !isEqualTo2) {
        [searTXT insertObject:seaTxt atIndex:0];
        //[searTXT addObject:seaTxt];
    }
    //大于15去掉最后一个,保存15条记录
    if(searTXT.count > 15){
        [searTXT removeObjectAtIndex:searTXT.count-1];
    }
    //将上述数据全部存储到NSUserDefaults中
    NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
    [userDefaults setObject:searTXT forKey:@"searchHistory"];
}

2. 过滤搜索数据:

 NSString *searchString = [self.searBar text];
 NSPredicate *preicate = [NSPredicate predicateWithFormat:@"SELF CONTAINS[c] %@", searchString];
 if (self.filterResultArray!= nil) {
        [self.filterResultArray removeAllObjects];
  }
 //过滤数据
 self.filterResultArray = [NSMutableArray arrayWithArray:[self.filterArray filteredArrayUsingPredicate:preicate]];

3. 实现效果:

UISearchBar搜索.gif

Demo地址:https://github.com/FTC-Chen/SearchWithHotHistory

五.参考资料
1.http://blog.csdn.net/shengdavolleyball/article/details/50751970
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