iOS UI 知识点

懒加载数据模型

1. if语句判断是否为空
2. 然后取路径
3. 从路径中取出数组（数组内容为字典）
4. 把字典转换成模型

5. 返回模型
   例子：

   - (NSMutableArray *)tgModels
   {
   if (_tgModels == nil) {
       NSString *path = [[NSBundle mainBundle] pathForResource:@"tgs" ofType:@"plist"];
       NSArray *models = [NSArray arrayWithContentsOfFile:path];
       _tgModels = [NSMutableArray array];
       for (NSDictionary *dict in models) {
           QYTGModel *model = [QYTGModel tgModelWithDcitionary:dict];
           [_tgModels addObject:model];
       }
   }
   return _tgModels;
   }

自定义单元格

1. contentView
2. 创建xib中设置
3. storyboard中设置
4. layoutSubView(子视图化)

重写set方法的时候一定要先把set方法本身的任务写上

区分 section 和 tableView 的 头视图

1. section 的头视图只需要设置行高
2. tableView 的头视图要设置 frame

创建模型

1. 模型属于一个类
2. .h 文件中声明数模型中需要的属性和初始化方法(两个初始化方法—类初始化方法和对象初始化方法)

3. 先写对象初始化初始化方法

   -(instancetype)initWithDictionary:(NSDictionary *)dict
   {
   if (self = [super init]) {
           //第一种方法：
               _buycount = dict[@"buycount"];
              _icon = dict[@"icon"];
              _price = dict[@"price"];
              _title = dict[@"title"];
       // 第二种方法：灌入字典
       //[self setValuesForKeysWithDictionary:dict];
   }
   return self;
   }

4. 再写类初始化方法

   + (instancetype)tgModelWithDcitionary:(NSDictionary *)dict{     
       return [[self alloc] initWithDictionary:dict];
   }

设置导航栏的编辑按钮并实现编辑

移动的实现和编辑相似，先返回是否允许移动，然后移动方法：先从原处取出要移动的，删除原处内容，再把内容插入到目的处(移动的界面实现系统已经做好，我们只需要做数据源的处理)
在viewDidLoad中调用下两个方法：

//设置导航栏上右边的编辑
-(void)setRightBarButtonItem{
    UIBarButtonItem *rightBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"编辑" style:UIBarButtonItemStylePlain target:self action:@selector(edit:)];
    self.navigationItem.rightBarButtonItem = rightBarButtonItem;
}
//编辑  完成  切换
- (void)edit:(UIBarButtonItem *)sender {
    if ([sender.title isEqualToString:@"编辑"]) {
        sender.title = @"完成";
        [self.tableView setEditing:YES animated:YES];
    } else {
        sender.title = @"编辑";
        [self.tableView setEditing:NO animated:YES];
    }
}

实现代理方法：

//是否可以编辑
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath {
    return YES;
}
//编辑风格(插入和删除)
- (UITableViewCellEditingStyle)tableView:(UITableView *)tableView editingStyleForRowAtIndexPath:(NSIndexPath *)indexPath{
    if (indexPath.row % 2) {//奇数行
        return UITableViewCellEditingStyleInsert;
    }else{//偶数
        return UITableViewCellEditingStyleDelete;
    }
}
//编辑的实现方法(注意必须把数据源删除)
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
    if (editingStyle == UITableViewCellEditingStyleInsert) {
        //更改数据源
        [array insertObject:@"青云iOS" atIndex:indexPath.row + 1];
        //更改界面
        NSIndexPath *addIndexPath = [NSIndexPath indexPathForRow:indexPath.row + 1 inSection:indexPath.section];
        [tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:addIndexPath] withRowAnimation:UITableViewRowAnimationLeft];
    }else if (editingStyle == UITableViewCellEditingStyleDelete){
        //更改数据源
        [array removeObjectAtIndex:indexPath.row];
        //更改界面
        [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationMiddle];
    }
}

代码设置tabbar

-(void)awakeFromNib{
    self.tabBarController.tabBar.tintColor = [UIColor brownColor];
    UIImage *image = [[UIImage imageNamed:@"tabbar_contacts"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
    UIImage *selectedImage = [[UIImage imageNamed:@"tabbar_contactsHL"] imageWithRenderingMode:UIImageRenderingModeAlwaysOriginal];
    self.tabBarItem = [[UITabBarItem alloc] initWithTitle:@"通讯录" image:image selectedImage:selectedImage];
}

下拉刷新

UIRefreshControl *refresh = [[UIRefreshControl alloc] init];
    [self.tableView addSubview:refresh];
    [refresh addTarget:self action:@selector(refresh:) forControlEvents:UIControlEventValueChanged];
--------------------------------    
-(void)refresh:(UIRefreshControl *)refresh{
    [refresh performSelector:@selector(endRefreshing) withObject:nil afterDelay:2];
}

根据TextField输入的网址来访问对应的网页

注意要遵循UIWebViewDelegate,UITextFieldDelegate协议，并设置代理

NSURL *url = [NSURL URLWithString:_textField.text];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
[_webView loadRequest:request];
//设置状态栏的风火轮
-(void)webViewDidStartLoad:(UIWebView *)webView{
    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES];
}
-(void)webViewDidFinishLoad:(UIWebView *)webView{
    [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO];
}

索引条

NSString *path = [[NSBundle mainBundle] pathForResource:@"sortednames" ofType:@"plist"];
_dict = [NSDictionary dictionaryWithContentsOfFile:path];
NSArray *keys = _dict.allKeys;
_keys = [keys sortedArrayUsingSelector:@selector(compare:)];
//设置索引
-(NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView{
    return _keys;
}
//点击索引
-(NSInteger)tableView:(UITableView *)tableView sectionForSectionIndexTitle:(NSString *)title atIndex:(NSInteger)index{
    return index;
}

搜索栏

必须遵循协议 UISearchResultsUpdating

- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText{
    if ([searchText isEqualToString:@""] || searchText == nil) {//clear
        _isSearching = NO;
        [_tableView reloadData];
        return;
    }
    _isSearching = YES;
    //搜索关键字(谓词过滤，谓词是针对于数组的)
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"SELF CONTAINS[CD] %@",searchText];
    NSMutableArray *resultArr = [NSMutableArray array];
    for (NSString *key in _keys) {
        NSArray *array = _dict[key];
        NSArray * resultArray = [array filteredArrayUsingPredicate:predicate];
        [resultArr addObjectsFromArray:resultArray];
    }
    _results = resultArr;
    [_tableView reloadData];
}