addObject：要數組不工作（數組仍然沒有）

Question

這個應用程序是一個帶有標籤欄控制器的表視圖。我正在記錄數組的數量：arrayOfFavourites，即使我添加一個對象仍然有一個零值，我的相關代碼，顯示的所有對象在代碼中分配和初始化（先前或現在），一些是實例，一些是屬性：

ListViewController.m：

-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { 

NSLog(@"TOUCHED CELL!"); 

// Push the web view controller onto the navigation stack - this implicitly 
// creates the web view controller's view the first time through 
[[self navigationController] pushViewController:webViewController animated:YES]; 

// Grab the selected item 
entry = [[channel items] objectAtIndex:[indexPath row]]; 

if (!entry) { 
    NSLog(@"!entry"); 
} 

// Construct a URL with the link string of the item 
NSURL *url = [NSURL URLWithString:[entry link]]; 

// Construct a request object with that URL 
NSURLRequest *req = [NSURLRequest requestWithURL:url]; 

    // Load the request into the web view 
[[webViewController webView] loadRequest:req]; 

// Take the cell we pressed 
// IMPORTANT PART 
CELL = [tableView cellForRowAtIndexPath:indexPath]; 

[webViewController setItem:entry]; 

webViewController = nil; 
webViewController = [[WebViewController alloc] init]; 
[entry release]; 

    } 

WebViewController.m：

你搖到最喜歡的一個單元

-(void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event { 

cellToPassOn = nil; 

NSLog(@"Favouriting"); // YES I KNOW SPELLING 

// This is pretty simple, what we do is we take the cell we touched and take its title and link 
// then put it inside an array in the Favourites class 

Favourites *fav = [[Favourites alloc] init]; 
ListViewController *list = [[ListViewController alloc] init]; 
[self setCellToPassOn: [list CELL]]; 

if (!item) { 
    NSLog(@"NILLED ITEM"); 

} 

[[fav arrayOfFavourites] addObject:[item autorelease]]; 
[fav setCell: cellToPassOn]; 
[fav release]; 
[list release]; 
item = nil; 

} 

Favourites.m：

-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section 
    { 

arrayOfFavourites = [[NSMutableArray alloc] init]; 


NSLog(@"ROWS NO."); 
NSLog(@"%i", [arrayOfFavourites count]); 

return [arrayOfFavourites count]; 
} 

Answer 1

你爲什麼inializing在tableview:numberOfRowsInSection數組？這將導致陣列在每次重新加載表視圖時被重置。這可能是你的問題。

Answer 2

你分配你的數組中-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section

嘗試到別處分配它。

Answer 3

您可以在tableView:numberOfRowsInSectionMethod中分配arrayOfFavorites，但您首先需要檢查它是否爲零。

if(!arrayOfFavorites) 
    arrayOfFavoriges = [[NSMutableArray alloc] init]; 

你應該釋放它然後在dealloc方法：[arrayOfFavorites release]。

Answer 4

-(void)motionBegan:(UIEventSubtype)motion withEvent:(UIEvent *)event { 
cellToPassOn = nil; 
NSLog(@"Favouriting"); // YES I KNOW SPELLING 
// HERE creation of a Brand NEW empty Favourites instance 
Favourites *fav = [[Favourites alloc] init]; 
// HERE creation of a Brand NEW empty ListViewController instance 
ListViewController *list = [[ListViewController alloc] init]; 
// HERE we hope that the ListViewController as CELL other then nil when it is Brand NEW 
[self setCellToPassOn: [list CELL]]; 

if (!item) { 
    NSLog(@"NILLED ITEM"); 
} 

[[fav arrayOfFavourites] addObject:[item autorelease]]; 
[fav setCell: cellToPassOn]; 
[fav release]; 
// HERE the fav instance get deallocated and don't exist anymore 
[list release]; 
// HERE the list instance get deallocated and don't exist anymore 
item = nil; 
} 

在這段代碼list和fav只有在這種方法的主體存在，試圖讓他們有持有做會失敗，因爲list和fav沒有該方法之外存在的價值。