18.UISearchBar

UISearchBar

• UISearchBar继承于UIView，可以像创建View那样创建searchBar

初始化

    UISearchBar * bar = [[UISearchBar alloc]initWithFrame:CGRectMake(x, y, w, h)];
    [self.view addSubview:bar];

显示效果

风格设置

    UIBarStyleDefault //默认风格(白色),多出的背景为灰色
    UIBarStyleBlack   //黑色

    //修改搜索框背景
    [_searchBar setBackgroundImage:img];

    //修改搜索输入文本的背景
    [_searchBar setSearchFieldBackgroundImage:[UIImage imageNamed:@"图片"] forState:UIControlStateNormal];

    //修改搜索输入框内左侧的指示图标
    [_searchBar setImage:[UIImage resizedImage:@"图片"] forSearchBarIcon:UISearchBarIconSearch state:UIControlStateNormal];

文字设置

    _searchBar.placeholder = @"test";   //设置占位符 
    bar.prompt = @"搜索框";              //背景文字
    bar.text=@"test"                    //起始搜索内容

功能图标

    UISearchBarIconSearch       //搜索图标
    UISearchBarIconClear        // 清除图标
    UISearchBarIconBookmark     // 书本图标
    UISearchBarIconResultsList  // 结果列表图标

协议函数

• 需要UISearchBarDelegate以及设置代理

//开始编辑先
- (void)searchBarTextDidBeginEditing:(UISearchBar *)searchBar;

//结束编辑调用
- (void)searchBarTextDidEndEditing:(UISearchBar *)searchBar;

//搜索框中的内容发生改变时 回调（即要搜索的内容改变）
- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText{}

//将要开始编辑时调用，设置为NO的话是不允许编辑
- (BOOL)searchBarShouldBeginEditing:(UISearchBar *)searchBar;   

//是否允许放弃响应
- (BOOL)searchBarShouldEndEditing:(UISearchBar *)searchBar;

//文本改变编辑前调用，NO的话，不能再编辑新的内容
- (BOOL)searchBar:(UISearchBar *)searchBar shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text NS_AVAILABLE_IOS(3_0);

//点击键盘搜索按钮时，调用
- (void)searchBarSearchButtonClicked:(UISearchBar *)searchBar; 

//点击书本图标时，调用
- (void)searchBarBookmarkButtonClicked:(UISearchBar *)searchBar __TVOS_PROHIBITED;

//点击取消图标按钮时，调用
- (void)searchBarCancelButtonClicked:(UISearchBar *)searchBar __TVOS_PROHIBITED;

//点击search按钮时，调用
- (void)searchBarResultsListButtonClicked:(UISearchBar *)searchBar NS_AVAILABLE_IOS(3_2) __TVOS_PROHIBITED;

//搜索栏的附加试图中切换按钮触发的回调
- (void)searchBar:(UISearchBar *)searchBar selectedScopeButtonIndexDidChange:(NSInteger)selectedScope 

取消按钮设置

• 注：修改取消按钮文字颜色及背景图片的代码片段，一定要放到取消按钮会显示代理方法中修改，否则遍历找不着呀，那就修改不了了。

#pragma mark 搜索框的代理方法，搜索输入框获得焦点（聚焦）
-(void)searchBarTextDidBeginEditing:(UISearchBar *)searchBar
{
    [searchBar setShowsCancelButton:YES animated:YES];

    // 修改UISearchBar右侧的取消按钮文字颜色及背景图片
    for (UIView *searchbuttons in [searchBar subviews]){
        if ([searchbuttons isKindOfClass:[UIButton class]]) {
            UIButton *cancelButton = (UIButton*)searchbuttons;
            // 修改文字颜色
            [cancelButton setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];
            [cancelButton setTitleColor:[UIColor whiteColor] forState:UIControlStateHighlighted];

            // 修改按钮背景
            [cancelButton setBackgroundImage:[UIImage resizedImage:@"login_btn_login.png"] forState:UIControlStateNormal];
            [cancelButton setBackgroundImage:nil forState:UIControlStateHighlighted];
        }
    }
}