UITableView使用简单进阶(一):搜索栏

UITableView 是开发中使用十分频繁的控件,本系列记录UITableView的进阶使用:UITableView的搜索栏和字母索引表。

不想看我废话的可以直接到gitHub仓库下载源码😏。
UITableView使用进阶gitHub源码

搜索栏有两种实现方式,第一种是通过UISearchBar和UISearchDisplayController实现,第二种是通过UISearchController实现。而在iOS8.0之后,苹果官方推荐使用第二种方式。

使用UISearchController

本文使用的是第二种方式(UISearchController),不过源码中也实现了第一种(UISearchBar+UISearchDisplayController)。关于UISearchBar和UISearchDisplayController的使用,可以参考我的另一篇文章:UISearchBar和UISearchDisplayController实现搜索栏

本文先介绍UITableView的搜索栏(UISearchController),是一个显示美国总统的TableView。

Step1. 创建President类

创建一个名为President的Objective-C类,它继承于NSObject类,用于保存总统的姓氏和名字。定义一个静态方法,用来创建President对象,并且对firstName和lastName赋值。

President.h

#import <Foundation/Foundation.h>

@interface President : NSObject
@property (nonatomic, retain) NSString *firstName;
@property (nonatomic, retain) NSString *lastName;
+ (President *) presidentWithFirstName: (NSString *)firstname lastName: (NSString *)lastname;

@end

President.m

#import "President.h"

@implementation President

+ (President *) presidentWithFirstName:(NSString *)firstname lastName:(NSString *)lastname {
    President *president = [[President alloc] init];
    president.firstName = firstname;
    president.lastName  = lastname;

    return president;
}

@end

Step2. 编写ViewController

viewController.h

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController

@property (nonatomic, strong) UITableView *mTableView;
@property (nonatomic, strong) NSArray *presidents;//所有总统
@property (nonatomic, strong) NSArray *filteredPresidents;//保存搜索结果
@property (nonatomic, retain) UISearchController *searchController;    
@end

viewController.m

#import "ViewController.h"
#import "President.h"

@interface ViewController () <UITableViewDataSource, UITableViewDelegate, UISearchBarDelegate, UISearchResultsUpdating, UISearchDisplayDelegate>

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    //初始化数据
    self.presidents = [[NSArray alloc] initWithObjects:
                       [President presidentWithFirstName:@"George" lastName:@"Washington"],
                       [President presidentWithFirstName:@"John" lastName:@"Adams"],
                       [President presidentWithFirstName:@"Thomas" lastName:@"Jeffeson"],
                       [President presidentWithFirstName:@"James" lastName:@"Madison"],
                       [President presidentWithFirstName:@"James" lastName:@"Monroe"],
                       [President presidentWithFirstName:@"John Quincy" lastName:@"Adams"],
                       [President presidentWithFirstName:@"Andrew" lastName:@"Jackson"],
                       [President presidentWithFirstName:@"Martin" lastName:@"van Buren"],
                       [President presidentWithFirstName:@"William Henry" lastName:@"Harrison"],
                       [President presidentWithFirstName:@"John" lastName:@"Tyler"],
                       [President presidentWithFirstName:@"James K" lastName:@"Polk"],
                       [President presidentWithFirstName:@"Zachary" lastName:@"Taylor"],
                       [President presidentWithFirstName:@"Millard" lastName:@"Fillmore"],
                       [President presidentWithFirstName:@"Franklin" lastName:@"Pierce"],
                       [President presidentWithFirstName:@"James" lastName:@"Buchanan"],
                       [President presidentWithFirstName:@"Abraham" lastName:@"Lincoln"],
                       [President presidentWithFirstName:@"Andrew" lastName:@"Johnson"],
                       [President presidentWithFirstName:@"Ulysses S" lastName:@"Grant"],
                       [President presidentWithFirstName:@"Rutherford B" lastName:@"Hayes"],
                       [President presidentWithFirstName:@"James A" lastName:@"Garfield"],
                       [President presidentWithFirstName:@"Chester A" lastName:@"Arthur"],
                       [President presidentWithFirstName:@"Grover" lastName:@"Cleveland"],
                       [President presidentWithFirstName:@"Bejamin" lastName:@"Harrison"],
                       [President presidentWithFirstName:@"Grover" lastName:@"Cleveland"],
                       [President presidentWithFirstName:@"William" lastName:@"McKinley"],
                       [President presidentWithFirstName:@"Theodore" lastName:@"Roosevelt"],
                       [President presidentWithFirstName:@"William Howard" lastName:@"Taft"],
                       [President presidentWithFirstName:@"Woodrow" lastName:@"Wilson"],
                       [President presidentWithFirstName:@"Warren G" lastName:@"Harding"],
                       [President presidentWithFirstName:@"Calvin" lastName:@"Coolidge"],
                       [President presidentWithFirstName:@"Herbert" lastName:@"Hoover"],
                       [President presidentWithFirstName:@"Franklin D" lastName:@"Roosevelt"],
                       [President presidentWithFirstName:@"Harry S" lastName:@"Truman"],
                       [President presidentWithFirstName:@"Dwight D" lastName:@"Eisenhower"],
                       [President presidentWithFirstName:@"John F" lastName:@"Kennedy"],
                       [President presidentWithFirstName:@"Lyndon B" lastName:@"Johnson"],
                       [President presidentWithFirstName:@"Richard" lastName:@"Nixon"],
                       [President presidentWithFirstName:@"Gerald" lastName:@"Ford"],
                       [President presidentWithFirstName:@"Jimmy" lastName:@"Carter"],
                       [President presidentWithFirstName:@"Ronald" lastName:@"Reagan"],
                       [President presidentWithFirstName:@"George H W" lastName:@"Bush"],
                       [President presidentWithFirstName:@"Bill" lastName:@"Clinton"],
                       [President presidentWithFirstName:@"George W" lastName:@"Bush"],
                       [President presidentWithFirstName:@"Barack" lastName:@"Obama"],
                       nil];

    CGRect appFrame = [[UIScreen mainScreen] bounds];
    //创建tableview
    self.mTableView = [[UITableView alloc] initWithFrame:CGRectMake(0, 20, appFrame.size.width, appFrame.size.height - 20) style:UITableViewStylePlain];
    self.mTableView.delegate = self;
    self.mTableView.dataSource = self;
    [self.view addSubview:self.mTableView];

    //创建searchController
    self.searchController = [[UISearchController alloc] initWithSearchResultsController:nil];
    self.searchController.searchResultsUpdater = self;
    self.searchController.dimsBackgroundDuringPresentation = NO;
    self.searchController.hidesNavigationBarDuringPresentation = NO;
    //设置tableview的搜索栏
    self.mTableView.tableHeaderView = self.searchController.searchBar;

}

#pragma mark - tableView Delegate

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    if (self.searchController.active) {
        return [self.filteredPresidents count];
    } else {
        return [self.presidents count];
    }
}

#pragma mark - tableView Datasource
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *cellId = @"cellId";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellId];

    if (!cell) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellId];
    }

    President *president;
    if (self.searchController.active) {
        president = [self.filteredPresidents objectAtIndex:indexPath.row];
    } else {
        president = [self.presidents objectAtIndex:indexPath.row];
    }
    cell.textLabel.text = [NSString stringWithFormat:@"%@ %@", president.firstName, president.lastName];

    return cell;

}

#pragma mark - SearchController delegate
- (void)updateSearchResultsForSearchController:(UISearchController *)searchController {
    NSString *searchString = [self.searchController.searchBar text];
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"firstName CONTAINS[cd] %@ OR lastName CONTAINS[cd] %@", searchString, searchString];
    self.filteredPresidents = [self.presidents filteredArrayUsingPredicate:predicate];

    //刷新表格
    [self.mTableView reloadData];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

实现效果

实现效果

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