//搜索框
UISearchBar *searchBar = [[UISearchBar alloc] init];
// searchBar.delegate = self;
searchBar.frame = CGRectMake(10, 0, screenW-80, titleView.bounds.size.height);
searchBar.layer.cornerRadius = 17;
searchBar.layer.masksToBounds = YES;
[searchBar.layer setBorderWidth:8];
[searchBar.layer setBorderColor:[UIColor whiteColor].CGColor]; //设置边框为白色
searchBar.placeholder = @"请输入目的地";
searchBar.translucent = YES;
searchBar.searchBarStyle = UISearchBarStyleProminent;
//改变占位符的字体大小颜色
UITextField * searchField = [searchBar valueForKey:@"_searchField"];
[searchField setValue:[UIColor lightGrayColor] forKeyPath:@"_placeholderLabel.textColor"];
[searchField setValue:[UIFont boldSystemFontOfSize:16] forKeyPath:@"_placeholderLabel.font"];
//改变左边搜索图标坐标位置。后面的占位符苹果已经做好约束总是跟随在搜索🔍图标后面。
[searchBar setPositionAdjustment:UIOffsetMake(60, 0) forSearchBarIcon:UISearchBarIconSearch];
设置搜索栏中图片的位置偏移，图片的枚举如下：
typedef NS_ENUM(NSInteger, UISearchBarIcon) {
UISearchBarIconSearch, //搜索图标
UISearchBarIconClear, // 清除图标
UISearchBarIconBookmark, // 书本图标
UISearchBarIconResultsList, // 结果列表图标
};
下面是搜索框控件的一些代理方法：
- (BOOL)searchBarShouldBeginEditing:(UISearchBar *)searchBar;
将要开始编辑时的回调，返回为NO，则不能编辑
- (void)searchBarTextDidBeginEditing:(UISearchBar *)searchBar;
已经开始编辑时的回调
- (BOOL)searchBarShouldEndEditing:(UISearchBar *)searchBar;
将要结束编辑时的回调
- (void)searchBarTextDidEndEditing:(UISearchBar *)searchBar;
已经结束编辑的回调
- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText; 编辑文字改变的回调
- (BOOL)searchBar:(UISearchBar *)searchBar shouldChangeTextInRange:(NSRange)range replacementText:(NSString *)text ;
编辑文字改变前的回调，返回NO则不能加入新的编辑文字
- (void)searchBarSearchButtonClicked:(UISearchBar *)searchBar;
搜索按钮点击的回调
- (void)searchBarBookmarkButtonClicked:(UISearchBar *)searchBar;
书本按钮点击的回调
- (void)searchBarCancelButtonClicked:(UISearchBar *)searchBar;
取消按钮点击的回调
- (void)searchBarResultsListButtonClicked:(UISearchBar *)searchBar;
搜索结果按钮点击的回调
- (void)searchBar:(UISearchBar *)searchBar selectedScopeButtonIndexDidChange:(NSInteger)selectedScope;
搜索栏的附加试图中切换按钮触发的回调
D7C05039-1BCD-40EA-801F-F3BD6C8CDE41.png
