我有一个主/详细信息应用程序。
默认情况下，我们将 MasterViewController 附加到 TableViewController，此外，我已将其附加到 Sqlite 数据库，并且所有数据都按应有的方式正确显示。所以我添加了一个 UISearchBar，以便搜索所有项目；
搜索功能工作正常，但唯一的错误是，向下滚动时搜索栏消失。
因此，作为一种解决方案，我删除了 TableViewController 并创建了一个简单的 UIVIewController 并添加了一个 TableView 、 TableViewCell 和一个搜索栏，以便按照许多人的建议将搜索栏固定在 View 的顶部。
现在这两个概念之间的区别在于，一旦应用程序加载，TableViewController（第一种情况）会在单元格中加载整个数据，而当 ViewController（第二种情况，带有 tableView、tableViewCell 和 searchBar）在启动时不加载任何内容时，当用户开始在 searchBar 中写一个单词时，它会加载不同的元素。我如何强制 tableView 在启动时加载所有元素，就像你有一个 TableViewCONtroller 一样？
这是我的代码：
//
// MasterViewController.m
#import "MasterViewController.h"
#import "DetailViewController.h"
#import <sqlite3.h>
#import "Author.h"
@interface MasterViewController ()
- (void)configureCell:(UITableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath;
@end
@implementation MasterViewController
NSString *authorNAme , *authorNAme2;
@synthesize tableView;
@synthesize searchWasActive;
@synthesize detailViewController = _detailViewController;
@synthesize fetchedResultsController = __fetchedResultsController;
@synthesize managedObjectContext = __managedObjectContext;
@synthesize theauthors;
NSString *PathDB;
-(BOOL)canBecomeFirstResponder{
return YES;
}
- (void)awakeFromNib
{
// self.clearsSelectionOnViewWillAppear = NO;
self.contentSizeForViewInPopover = CGSizeMake(320.0, 600.0);
[super awakeFromNib];
}
- (void)viewDidLoad
{
// [self numberOfSectionsInTableView:tableView];
//[self tableView:tableView willDisplayCell:[self.tableView dequeueReusableCellWithIdentifier:@"Cell"] forRowAtIndexPath:0];
//[self.tableView
searchBar.delegate = (id)self;
// [self.tableView reloadData];
// [self configureCell:@"Cell" atIndexPath:0];
[self authorList];
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
self.navigationItem.leftBarButtonItem = self.editButtonItem;
UIBarButtonItem *addButton = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAdd target:self action:@selector(insertNewObject:)];
self.navigationItem.rightBarButtonItem = addButton;
self.detailViewController = (DetailViewController *)[[self.splitViewController.viewControllers lastObject] topViewController];
}
- (void)viewDidUnload
{
[self setTableView:nil];
tableView = nil;
searchBar = nil;
[self setSearchWasActive:nil];
[super viewDidUnload];
// Release any retained subviews of the main view.
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return YES;
}
- (void)insertNewObject:(id)sender
{
NSManagedObjectContext *context = [self.fetchedResultsController managedObjectContext];
NSEntityDescription *entity = [[self.fetchedResultsController fetchRequest] entity];
NSManagedObject *newManagedObject = [NSEntityDescription insertNewObjectForEntityForName:[entity name] inManagedObjectContext:context];
// If appropriate, configure the new managed object.
// Normally you should use accessor methods, but using KVC here avoids the need to add a custom class to the template.
[newManagedObject setValue:[NSDate date] forKey:@"timeStamp"];
// Save the context.
NSError *error = nil;
if (![context save:&error]) {
// Replace this implementation with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
abort();
}
}
- (void)searchBarCancelButtonClicked:(UISearchBar *)searchBar {
//[self authorList];
// [filteredTableData release];
//[self.tableView reloadData];
NSLog(@"Cancel Button Clicked");
// Scroll to top
[self.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:0 inSection:0] atScrollPosition:UITableViewScrollPositionTop animated:YES];
self.searchDisplayController.searchBar.text =@" ";
}
- (void) searchBarTextDidBeginEditing:(UISearchBar *)sender
{
[self.tableView reloadData];
searchBar.showsCancelButton=NO;
}
-(void)searchBar:(UISearchBar*)searchBar textDidChange:(NSString*)text
{
searchBar.showsCancelButton=NO;
if(text.length == 0)
{
isFiltered = FALSE;
}
else
{
isFiltered = true;
filteredTableData = [[NSMutableArray alloc] init];
for (Author* author in theauthors)
{ //[NSPredicate predicateWithFormat:@"SELECT * from books where title LIKE %@", searchBar.text];
NSRange nameRange = [author.name rangeOfString:text options:NSAnchoredSearch];
NSRange descriptionRange = [author.genre rangeOfString:text options:NSAnchoredSearch];
if(nameRange.location != NSNotFound || descriptionRange.location != NSNotFound)
{
[filteredTableData addObject:author];
NSLog(@"Item Added is %@" , author.name);
}
}
}
[self.tableView reloadData];
}
#pragma mark - Table View methods
-(NSMutableArray *) authorList{
[self numberOfSectionsInTableView:tableView];
theauthors = [[NSMutableArray alloc] initWithCapacity:1000000];
// NSMutableArray * new2 = [[NSMutableArray alloc ] initWithCapacity:100000];
// authorNAme = theauthors.sortedArrayHint.description;
@try {
NSFileManager *fileMgr = [NSFileManager defaultManager];
NSLog(@"Before the dbpath variable");
NSString *dbPath = [[[NSBundle mainBundle] resourcePath ]stringByAppendingPathComponent:@"dictionary_native.sqlite"];
NSLog(@"After the dbpath variable");
BOOL success = [fileMgr fileExistsAtPath:dbPath];
if(!success)
{
NSLog(@"1");
NSLog(@"Cannot locate database file '%@'.", dbPath);
}
NSLog(@"Database correctly located");
if(!(sqlite3_open([dbPath UTF8String], &db) == SQLITE_OK))
{
NSLog(@"2");
NSLog(@"An error has occured: %@", sqlite3_errmsg(db));
}
NSLog(@"Database correctly opened");
// const char *sql = "SELECT F_Keyword FROM wordss";
const char *sql = "SELECT * FROM wordss";
sqlite3_stmt *sqlStatement;
if(sqlite3_prepare(db, sql, -1, &sqlStatement, NULL) != SQLITE_OK)
{
NSLog(@"Problem with prepare statement: %@", sqlite3_errmsg(db));
}else{
while (sqlite3_step(sqlStatement)==SQLITE_ROW) {
// NSLog(@"entered the while statement");
Author * author = [[Author alloc] init];
// // NSLog(@"Author initialised");
//
author.name = [NSString stringWithUTF8String:(char *) sqlite3_column_text(sqlStatement,1)];
// NSLog(@"this is the author.name %@" , author.name);
author.genre = [NSString stringWithUTF8String:(char *) sqlite3_column_text(sqlStatement, 2)];
//
// authorNAme=author.genre;
//
[theauthors addObject:author];
}
// authorNAme = author.genre;
}
}
@catch (NSException *exception) {
NSLog(@"Problem with prepare statement: %@", sqlite3_errmsg(db));
}
@finally {
// sqlite3_finalize(sqlStatement);.
// authorNAme = nil;
// authorNAme = Nil;
return theauthors;
}
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
// return [[self.fetchedResultsController sections] count];
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
// id <NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:section];
// return [sectionInfo numberOfObjects];
int rowCount;
if(self->isFiltered)
rowCount = filteredTableData.count;
else
rowCount = theauthors.count;
NSLog(@"This is the number of rows accepted %i" , rowCount);
return rowCount;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
// UITableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:@"Cell"];
static NSString *CellIdentifier = @"Cell";
UITableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
}
int rowCount = indexPath.row;
Author *author = [self.theauthors objectAtIndex:rowCount];
if(isFiltered){
author = [filteredTableData objectAtIndex:indexPath.row];
}
else{
author = [theauthors objectAtIndex:indexPath.row];
}
cell.textLabel.text = author.name;
return cell;
}
- (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath
{
// Return NO if you do not want the specified item to be editable.
return YES;
}
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
if (editingStyle == UITableViewCellEditingStyleDelete) {
NSManagedObjectContext *context = [self.fetchedResultsController managedObjectContext];
[context deleteObject:[self.fetchedResultsController objectAtIndexPath:indexPath]];
NSError *error = nil;
if (![context save:&error]) {
// Replace this implementation with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
abort();
}
}
}
- (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath
{
// The table view should not be re-orderable.
return NO;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
// NSManagedObject *object = [[self fetchedResultsController] objectAtIndexPath:indexPath];
// self.detailViewController.detailItem = object;
// DetailViewController* vc ;
MasterViewController *author;
NSLog(@"This is the showDetailsForIndexPath");
[self->searchBar resignFirstResponder];
// Details* vc = [self.storyboard instantiateViewControllerWithIdentifier:@"Details"];
// AuthorVC* author;
if(isFiltered)
{
author = [filteredTableData objectAtIndex:indexPath.row];
}
else
{
author = [theauthors objectAtIndex:indexPath.row];
}
//vc.author = author;
authorNAme = author.genre;
authorNAme2 = author.name ;
// author = [theauthors objectAtIndex:indexPath.row];
NSLog(@"This is the author.genre %@" , author.genre);
//vc.author.genre = author.genre;
authorNAme = author.genre;
authorNAme2 = author.name;
//NSLog(@"This is the details %@",vc.author.genre);
NSLog(@"This is the authorNAme Variable %@" , authorNAme);
self.detailViewController.detailItem = authorNAme;
self.detailViewController.detailItem2 = authorNAme2;
}
#pragma mark - Fetched results controller
- (NSFetchedResultsController *)fetchedResultsController
{
if (__fetchedResultsController != nil) {
return __fetchedResultsController;
}
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
// Edit the entity name as appropriate.
NSEntityDescription *entity = [NSEntityDescription entityForName:@"Event" inManagedObjectContext:self.managedObjectContext];
[fetchRequest setEntity:entity];
// Set the batch size to a suitable number.
[fetchRequest setFetchBatchSize:20];
// Edit the sort key as appropriate.
NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"timeStamp" ascending:NO];
NSArray *sortDescriptors = [NSArray arrayWithObjects:sortDescriptor, nil];
[fetchRequest setSortDescriptors:sortDescriptors];
// Edit the section name key path and cache name if appropriate.
// nil for section name key path means "no sections".
NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:@"Master"];
aFetchedResultsController.delegate = self;
self.fetchedResultsController = aFetchedResultsController;
NSError *error = nil;
if (![self.fetchedResultsController performFetch:&error]) {
// Replace this implementation with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
abort();
}
return __fetchedResultsController;
}
- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller
{
[self.tableView beginUpdates];
}
- (void)controller:(NSFetchedResultsController *)controller didChangeSection:(id <NSFetchedResultsSectionInfo>)sectionInfo
atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type
{
switch(type) {
case NSFetchedResultsChangeInsert:
[self.tableView insertSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeDelete:
[self.tableView deleteSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];
break;
}
}
- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject
atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type
newIndexPath:(NSIndexPath *)newIndexPath
{
// UITableView *tableView = self.tableView;
switch(type) {
case NSFetchedResultsChangeInsert:
[tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeDelete:
[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
break;
case NSFetchedResultsChangeUpdate:
[self configureCell:[tableView cellForRowAtIndexPath:indexPath] atIndexPath:indexPath];
break;
case NSFetchedResultsChangeMove:
[tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];
[tableView insertRowsAtIndexPaths:[NSArray arrayWithObject:newIndexPath]withRowAnimation:UITableViewRowAnimationFade];
break;
}
}
- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller
{
[self.tableView endUpdates];
}
/*
// Implementing the above methods to update the table view in response to individual changes may have performance implications if a large number of changes are made simultaneously. If this proves to be an issue, you can instead just implement controllerDidChangeContent: which notifies the delegate that all section and object changes have been processed.
- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller
{
// In the simplest, most efficient, case, reload the table view.
[self.tableView reloadData];
}
*/
- (void)configureCell:(UITableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath
{
// NSManagedObject *object = [self.fetchedResultsController objectAtIndexPath:indexPath];
// cell.textLabel.text = [[object valueForKey:@"timeStamp"] description];
}
@end
任何帮助将不胜感激......感谢您抽出宝贵的时间。