我正在构建我的第一个真正的应用程序，你们已经是最有帮助的，但我一直在努力与tableView不更新。我希望这里的某个人可以对此有所了解，并且可能想出任何关于我可能错过或做过不必要的其他事情的想法。
目前，该应用应该执行以下操作：
我经过双重检查的事情：tableview和delegate，datasource和outlet之间的连接; tableView不是nil;数据源本身已经准确更新;
一切都达到了最后一点（7）。似乎myTableView当时不为零。想法？如果您需要查看更多我的代码，请告诉我。
我还看了一下beginUpdates和endUpdates方法，但在我看来，它们一次只关注一些变化和用户交互性。我想根据用户选择重新加载整个表（即希望根据当前用户登录反映整个其他SQL选择字符串）。或者还有另一种更好的方法吗？
提前致谢！
这是一段相当不错的代码：
#import "FirstViewController.h"
@interface FirstViewController ()
@end
@implementation FirstViewController
#import "FirstViewController.h"
@synthesize myTextView, myTableViewDataSource, myFetchedData, resultat, tablesAndChecks, tablesArr, checksArr, tablesToRequest,receivedData, receivedDataString, SQL, sqlStatementsArr, failedSqlStatementsArr, failedSqlStatementsCodeArr, dbloop1;
#pragma mark Table view methods
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 1;
}
// Customize the number of rows in the table view.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
NSLog(@"Konfigurerar tableView"); //swedish for "Configuring tableView"
if(myTableView.dataSource==nil){
NSLog(@"datasource = nil");
}else{
NSLog(@"datasource != nil"); //This prints in log
}
NSLog(@"%d",[myTableViewDataSource count]); //prints "19" in log
return [myTableViewDataSource count];
}
// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
NSLog(@"calling cellForRowAtIndexPath"); //This does NOT print in log
static NSString *CellIdentifier = @"myCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
// Set up the cell...
cell.textLabel.font = [UIFont fontWithName:@"Helvetica" size:15];
cell.textLabel.text = [NSString stringWithFormat:@"Tabell %d: %@", [indexPath row], [myTableViewDataSource objectAtIndex:[indexPath row]]];
return cell;
}
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSLog(@"connection did finish loading");
//...
//script that receives a long SQL-string from the server
//and then updates the database with it goes here
//...
//Ok, so now the database has updated correctly, and it's time
//to update the tableview so that it reflects the new data.
//
//Get data from database...
NSMutableArray * tempArray = [[NSMutableArray alloc] initWithCapacity:0];
if (sqlite3_open(dbpath, &contactDB) == SQLITE_OK)
{
NSLog(@"Databasen öppnad");
NSString *beginSQL = [NSString stringWithFormat: @"SELECT name FROM sqlite_master WHERE type='table' ORDER BY name;"];
const char *begin_stmt = [beginSQL UTF8String];
sqlite3_prepare_v2(contactDB, begin_stmt, -1, &statement, NULL);
while(sqlite3_step(statement) == SQLITE_ROW) {
char *col1 = (char *)sqlite3_column_text(statement, 0);
if (col1 !=NULL){
[tempArray addObject:[NSString stringWithUTF8String: col1]];
}
}
if (sqlite3_step(statement) == SQLITE_DONE)
{
NSLog(@"#####%s; Done: %@", sqlite3_errmsg(nil), beginSQL);
} else {
NSLog(@"#####%s; Error with string: %@; Errcode: %d Errmsg: %s", sqlite3_errmsg(nil), beginSQL, sqlite3_errcode(contactDB), sqlite3_errmsg(nil));
}
NSLog(@"%d", sqlite3_finalize(statement));
sqlite3_close(contactDB);
//update the datasource to the values of tempArray
myTableViewDataSource = tempArray;
//Some logging to see that the updated data is in the array... (which it is)
NSLog(@"myTableViewDataSource count: %d",[myTableViewDataSource count]);
for (i=0; i<[myTableViewDataSource count]; i++) {
NSLog(@"%@",[myTableViewDataSource objectAtIndex:i]);
}
}
//Finally, check so that myTableView isn't nil and can receive messages
if(myTableView == nil){
NSLog(@"NILCHECK mytableview is nil!");
}else{
NSLog(@"NILCHECK mytableview is NOT nil!"); //This is printed out to the log
}
//Reload data -> nothing happens...
[myTableView reloadData];
}
- (void)fetchData
{
//function that gets current checksums for all db tables on the server, compares them to the local database
//and then requests an SQL-string from the server to update the tables that needs it.
//I don't think this is relevant for my problem, and it runs fine anyways.
//The last thing it does is setting up a NSURLConnection to communicate with
//the server (sending which tables to request via POST and then getting the SQL-string as the server response)
NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:request delegate:self];
if (theConnection) {
//receivedData = [NSMutableData data];
NSLog(@"ReceivedData är: %d", [receivedData length]);
} else {
NSLog(@"Connection Failed!");
}
//All done here, now the ReceivedData method takes over
}
}
更新
这是我的viewDidLoad方法：
- (void)viewDidLoad
{
//creates database and fills "tempArray" with data
NSLog(@"%d", sqlite3_finalize(statement));
sqlite3_close(contactDB);
myTableViewDataSource = tempArray;
NSLog(@"myTableViewDataSource count: %d",[myTableViewDataSource count]);
for (i=0; i<[myTableViewDataSource count]; i++) {
NSLog(@"%@",[myTableViewDataSource objectAtIndex:i]);
}
}
myTableView = [[UITableView alloc] initWithFrame:self.view.frame style:UITableViewStylePlain];
myTableView.delegate = self; //Added this after comment (1)
myTableView.dataSource = self; //Added this after comment (2)
}
更新： 添加后：
myTableView.delegate = self;
myTableView.dataSource = self;
到viewDidLoad，调用了tableView:numberOfRowsInSection:，并且dataSource不是nil，但是没有调用tableView:cellForRowAtIndexPath:，并且表没有更新。
更新2： 这是我的头文件：
//
// FirstViewController.h
// OHBSYS Storyboards
//
// Created by David Forsberg on 2012-09-25.
// Copyright (c) 2012 David Forsberg. All rights reserved.
//
#import <UIKit/UIKit.h>
#import <sqlite3.h>
@interface FirstViewController : UIViewController <UITableViewDataSource, UITableViewDelegate>{
NSString *databasePath;
sqlite3 *contactDB;
UITextView *myTextView;
UITableView *myTableView;
NSMutableArray *myTableViewDataSource;
NSMutableString * tableRowCount;
NSMutableArray * dbloop1;
//And a bunch of other variables here
}
@property (retain, nonatomic) IBOutlet UITextView *myTextView;
@property (nonatomic, retain) IBOutlet UITableView *myTableView;
@property (nonatomic, retain) IBOutlet NSMutableArray *myTableViewDataSource;
- (IBAction) fetchData;
@property (nonatomic) NSString * tableRowCount;
@property (nonatomic, retain) NSMutableArray * dbloop1;
//A bunch of other properties here as well
@end
更新3：
我尝试使用断点检查值。
tableview中的断点：numberofrowsinsection：
(lldb) po self.myTableView
(UITableView *) $0 = 0x0d13ca00 <UITableView: 0xd13ca00; frame = (0 20; 768 1004); clipsToBounds = YES; layer = <CALayer: 0x2a3d30>; contentOffset: {0, 0}>
(lldb) po self.myTableView.delegate
(objc_object *) $1 = 0x0ce99500 <FirstViewController: 0xce99500>
(lldb) po self.myTableView.dataSource
(objc_object *) $2 = 0x0ce99500 <FirstViewController: 0xce99500>
(lldb) po self.myTableViewDataSource
(NSMutableArray *) $3 = 0x0029fb20 <__NSArrayM 0x29fb20>(
CONTACTS,
sqlite_sequence
)
(lldb)
更新db之后的断点，就在调用reloadData之前：
(lldb) po self.myTableView
(UITableView *) $4 = 0x0d13ca00 <UITableView: 0xd13ca00; frame = (0 20; 768 1004); clipsToBounds = YES; layer = <CALayer: 0x2a3d30>; contentOffset: {0, 0}>
(lldb) po self.myTableView.delegate
(objc_object *) $5 = 0x0ce99500 <FirstViewController: 0xce99500>
(lldb) po self.myTableView.dataSource
(objc_object *) $6 = 0x0ce99500 <FirstViewController: 0xce99500>
(lldb) po self.myTableView.dataSource //(accidentally hit that twice)
(objc_object *) $7 = 0x0ce99500 <FirstViewController: 0xce99500>
(lldb) po self.myTableViewDataSource
(NSMutableArray *) $8 = 0x0ce6baa0 <__NSArrayM 0xce6baa0>(
CONTACTS,
meta_tablechecksums,
prot_multicoltest,
prot_multicoltest_4,
prot_multicoltest_4_desc,
prot_multicoltest_desc,
sqlite_sequence,
superadmin_filefolders,
superadmin_files,
superadmin_imagefolders,
superadmin_images,
sys_customers,
sys_fieldlooks,
sys_fieldtypes,
sys_formtables,
sys_pages,
sys_subpages,
sys_userroles,
sys_users
)
(lldb)
断点AT reloadData line：
(lldb) po self.myTableView
(UITableView *) $9 = 0x0d13ca00 <UITableView: 0xd13ca00; frame = (0 20; 768 1004); clipsToBounds = YES; layer = <CALayer: 0x2a3d30>; contentOffset: {0, 0}>
(lldb) po self.myTableView.delegate
(objc_object *) $10 = 0x0ce99500 <FirstViewController: 0xce99500>
(lldb) po self.myTableView.dataSource
(objc_object *) $11 = 0x0ce99500 <FirstViewController: 0xce99500>
(lldb) po self.myTableViewDataSource
(NSMutableArray *) $12 = 0x0ce6baa0 <__NSArrayM 0xce6baa0>(
CONTACTS,
meta_tablechecksums,
prot_multicoltest,
prot_multicoltest_4,
prot_multicoltest_4_desc,
prot_multicoltest_desc,
sqlite_sequence,
superadmin_filefolders,
superadmin_files,
superadmin_imagefolders,
superadmin_images,
sys_customers,
sys_fieldlooks,
sys_fieldtypes,
sys_formtables,
sys_pages,
sys_subpages,
sys_userroles,
sys_users
)
(lldb)
tableview中的断点：numberofrowsinsection：在更新db并运行reloadData命令之后：
(lldb) po self.myTableView
(UITableView *) $13 = 0x0d13ca00 <UITableView: 0xd13ca00; frame = (0 20; 768 1004); clipsToBounds = YES; layer = <CALayer: 0x2a3d30>; contentOffset: {0, 0}>
(lldb) po self.myTableView.delegate
(objc_object *) $14 = 0x0ce99500 <FirstViewController: 0xce99500>
(lldb) po self.myTableView.dataSource
(objc_object *) $15 = 0x0ce99500 <FirstViewController: 0xce99500>
(lldb) po self.myTableViewDataSource
(NSMutableArray *) $16 = 0x0ce6baa0 <__NSArrayM 0xce6baa0>(
CONTACTS,
meta_tablechecksums,
prot_multicoltest,
prot_multicoltest_4,
prot_multicoltest_4_desc,
prot_multicoltest_desc,
sqlite_sequence,
superadmin_filefolders,
superadmin_files,
superadmin_imagefolders,
superadmin_images,
sys_customers,
sys_fieldlooks,
sys_fieldtypes,
sys_formtables,
sys_pages,
sys_subpages,
sys_userroles,
sys_users
)
(lldb)
答案 0 :(得分：2)
我没有看到myTableView被合成。 在执行reloadData？
时，还调用了tableView数据源方法如果没有，请仔细检查并验证myTableView委托是否设置正确。 如果您已正确将表连接到笔尖并且有插座，则可以在代码中设置它，即在viewDidLoad方法中，通过设置：
myTableView.delegate = self;
答案 1 :(得分：2)
@Lefteris是对的。您可能已经拥有此功能，但我看不到您的头文件。在视图控制器的头文件中，添加一个属性以维护对tableview的引用：
@property (nonatomic, strong) UITableView *myTableView;
然后在您的实施文件中：
@synthesize myTableView = myTableView_;
最后，在实现文件中，将对tableview的所有引用从myTableView更改为self.myTableView，并查看是否突然开始获取委托回调。
答案 2 :(得分：0)
这个问题的基本问题是MVC应用程序中缺少Controller。我阅读了基本概念并从头开始重新构建 - 这一次，正确的方式。