我有一个功能良好的搜索栏。我唯一想要改进的一件事就是 NSTimer。我不知道为什么，但是当我开始打字时，它会在延迟一段时间后搜索我的结果。它运行得很好。但对于每个输入的字母，我都会得到 1 个 API。这意味着如果我输入搜索栏，例如苏丹。我得到 5 个 API，而不是 1 个。有人可以帮助我吗？
TableViewControllerTOP.h
@interface TableViewControllerTOP : UITableViewController<UISearchDisplayDelegate, UISearchBarDelegate,UIScrollViewDelegate,UITableViewDataSource, UITableViewDelegate>
{
NSTimer *myTimer;
}
@property (strong, nonatomic) IBOutlet UITableView *MainTable;
@property (nonatomic, strong) UISearchBar *searchBar;
@property (nonatomic, strong) UISearchDisplayController *searchController;
@property (nonatomic, strong) NSMutableArray *searchResults;
@property (nonatomic, retain) NSTimer *myTimer;
@property (nonatomic, assign) BOOL isAscending;
TableViewControllerTOP.m
@interface TableViewControllerTOP ()
@property (strong,nonatomic) NSMutableArray *itemss;
@end
@implementation TableViewControllerTOP
@synthesize myTimer;
@synthesize searchBar;
@synthesize searchController;
@synthesize searchResults;
- (id)initWithStyle:(UITableViewStyle)style
{
self = [super initWithStyle:style];
if (self) {
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
self.isAscending = YES;
UIRefreshControl *refreshControl = [[UIRefreshControl alloc] init]; [refreshControl addTarget:self action:@selector(pulltorefresh) forControlEvents:UIControlEventValueChanged];
self.refreshControl = refreshControl;
PFQuery *query = [PFQuery queryWithClassName:@"Countries"];
query.cachePolicy = kPFCachePolicyIgnoreCache;
[query addDescendingOrder:@"createdAt"];
[query setLimit:10];
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
if (!error) {
NSMutableArray *items = [NSMutableArray array];
for (id obj in objects)
{
[items addObject:obj];
}
self.itemss = items;
NSLog(@"%@", objects);
NSLog(@"%lu", (unsigned long)[objects count]);
[_MainTable reloadData];
} else {
NSLog(@"Error: %@ %@", error, [error userInfo]);
}
}];
[self searchitems];
}
-(void)searchitems
{
self.searchBar = [[UISearchBar alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, 44)];
self.tableView.tableHeaderView = self.searchBar;
self.searchController = [[UISearchDisplayController alloc] initWithSearchBar:self.searchBar contentsController:self];
self.searchController.searchResultsDataSource = self;
self.searchController.searchResultsDelegate = self;
self.searchController.delegate = self;
self.searchResults = [NSMutableArray array];
self.tableView.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:@"background.png"]];
[self.navigationController.navigationBar setBarTintColor:[UIColor lightGrayColor]];
}
-(void)filterResults:(NSString *)searchTerm {
myTimer = [NSTimer scheduledTimerWithTimeInterval:3.0
target:self
selector:@selector(queryask)
userInfo:_itemss
repeats:NO];
}
-(void)queryask{
PFQuery *queryCapitalizedString = [PFQuery queryWithClassName:@"Countries"];
[queryCapitalizedString whereKey:@"CountryTitle" containsString:[searchBar.text capitalizedString]];
PFQuery *queryLowerCaseString = [PFQuery queryWithClassName:@"Countries"];
[queryLowerCaseString whereKey:@"CountryTitle" containsString:[searchBar.text lowercaseString]];
PFQuery *querySearchBarString = [PFQuery queryWithClassName:@"Countries"];
[querySearchBarString whereKey:@"CountryTitle" containsString:searchBar.text];
PFQuery *finalQuery = [PFQuery orQueryWithSubqueries:[NSArray arrayWithObjects:queryCapitalizedString,queryLowerCaseString, querySearchBarString,nil]];
[finalQuery findObjectsInBackgroundWithTarget:self selector:@selector(callbackWithResult:error:)];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
// Return the number of sections.
return 1;
}
- (BOOL)searchDisplayController:(UISearchDisplayController *)controller shouldReloadTableForSearchString:(NSString *)searchString {
[self filterResults:searchString];
return YES;
}
- (void)callbackWithResult:(NSArray *)items error:(NSError *)error
{
if(!error) {
[self.searchResults removeAllObjects];
[self.searchResults addObjectsFromArray:items];
[self.searchDisplayController.searchResultsTableView reloadData];
}
}
-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
if (tableView == self.tableView) {
return self.itemss.count;
} else {
return self.searchResults.count;
}
}
- (void)searchDisplayController:(UISearchDisplayController *)controller didLoadSearchResultsTableView:(UITableView *)tableView
{
tableView.rowHeight = 70.0f;
}
- ( UITableViewCell * ) tableView : ( UITableView * ) tableView cellForRowAtIndexPath : ( NSIndexPath * ) indexPath
{
static NSString *uniqueIdentifier = @"MainCell";
CustomCell3 *cell = nil;
cell = (CustomCell3 *) [self.tableView dequeueReusableCellWithIdentifier:uniqueIdentifier];
if (!cell) {
NSArray *topLevelObjects = [[NSBundle mainBundle] loadNibNamed:@"MainCell" owner:nil options:nil];
for (id currentObject in topLevelObjects)
{
if([currentObject isKindOfClass:[CustomCell3 class]])
{
cell = (CustomCell3 *)currentObject;
break;
}
}
}
if (tableView == self.tableView) {
cell.MainTitle.text = [[self.itemss objectAtIndex:indexPath.row] objectForKey:@"CountryTitle"];
cell.DescriptTitle.text = [[self.itemss objectAtIndex:indexPath.row] objectForKey:@"DescriptTitle"];
[cell.FlagTitle setImageWithURL:[NSURL URLWithString:[[self.itemss objectAtIndex:indexPath.row] objectForKey:@"ImaURL"]]
placeholderImage:[UIImage imageNamed:@"placeholder.png"]];
cell.backgroundView = [[UIImageView alloc] initWithImage:[ [UIImage imageNamed:@"background.png"] stretchableImageWithLeftCapWidth:0.0 topCapHeight:5.0] ];
cell.selectedBackgroundView = [[UIImageView alloc] initWithImage:[ [UIImage imageNamed:@"background.png"] stretchableImageWithLeftCapWidth:0.0 topCapHeight:5.0] ];
}
if(tableView == self.searchDisplayController.searchResultsTableView) {
PFObject *searchedUser = [self.searchResults objectAtIndex:indexPath.row];
NSString *content = [searchedUser objectForKey:@"CountryTitle"];
NSString *desco = [searchedUser objectForKey:@"DescriptTitle"];
cell.DescriptTitle.text = desco;
cell.MainTitle.text = content;
NSString *image = [searchedUser objectForKey:@"ImaURL"];
[cell.FlagTitle setImageWithURL:[NSURL URLWithString:image]
placeholderImage:[UIImage imageNamed:@"placeholder.png"]];
cell.backgroundView = [[UIImageView alloc] initWithImage:[ [UIImage imageNamed:@"background.png"] stretchableImageWithLeftCapWidth:0.0 topCapHeight:5.0] ];
cell.selectedBackgroundView = [[UIImageView alloc] initWithImage:[ [UIImage imageNamed:@"background.png"] stretchableImageWithLeftCapWidth:0.0 topCapHeight:5.0] ];
}
return cell;
}
@end
有关延迟搜索的方法，请看一下这个问题： 延迟UISearchbar解析
将其与洛根的建议结合起来可能是一个好主意。通常在输入最少字符之前不应执行搜索，以避免搜索范围过大（在许多情况下，对包含“s”的任何内容进行搜索没有多大意义，具体取决于您要搜索的内容）。
也许您可以实现一个搜索栏委托来代替计时器，以在一些自定义逻辑之后（也许每 3 个字母）运行一个查询？
- (void) searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText {
if ((searchBar.text.length % 3) == 0) {
[self queryAsk];
}
}
注意：这种逻辑不是最好的，您可能想探索何时搜索的各种参数，但我认为这个概念比计时器有所改进，因为它更多地基于输入。 我认为这会给你更多的控制权。