将数据从 .plist 加载到 iPhone 的 TableView

Question

我正在练习《开始 iPhone 4 开发：探索 iOS SDK》中的示例。第 8 章展示了如何将数据从 plist 加载到 tableview 中。该示例是使用 Interface Builder 完成的。我想通过代码实现但遇到问题。屏幕上没有显示任何内容...

这是 .h

#import <UIKit/UIKit.h>
@interface FifthViewController : UIViewController <UITableViewDataSource, UITableViewDelegate>
{
    NSDictionary *names;
    NSArray      *keys;
}
@property (nonatomic, retain) NSDictionary *names;
@property (nonatomic, retain) NSArray *keys;
@end

这是 .m

#import "FifthViewController.h"
@implementation FifthViewController
@synthesize names;
@synthesize keys;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
    }
    return self;
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
}

#pragma mark - View lifecycle

- (void)viewDidLoad
{
    [super viewDidLoad];

    UITableView *table = [[UITableView alloc]initWithFrame:CGRectMake(0, 0, 320, 367) style:UITableViewStyleGrouped];
    [table setDataSource:self];
    [table setDelegate:self];


    NSString *path = [[NSBundle mainBundle] pathForResource:@"sortednames"
                                                 ofType:@"plist"];
    NSDictionary *dict = [[NSDictionary alloc]
                      initWithContentsOfFile:path];
    self.names = dict;
    [dict release];

    NSArray *array = [[names allKeys] sortedArrayUsingSelector:
                  @selector(compare:)];
    self.keys = array;
    [self.view addSubview:table];
    [table release];
}

- (void)dealloc 
{
    [names release];
    [keys release];
    [super dealloc];    
}

- (void)viewDidUnload
{
    self.names = nil;
    self.keys = nil;
    [super viewDidUnload];
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}

#pragma mark -
#pragma mark Table View Data Source Methods
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView 
{
    return [keys count];
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section 
{
    NSString *key = [keys objectAtIndex:section];
    NSArray *nameSection = [names objectForKey:key];
    return [nameSection count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView
     cellForRowAtIndexPath:(NSIndexPath *)indexPath 
{
    NSUInteger section = [indexPath section];
    NSUInteger row = [indexPath row];

    NSString *key = [keys objectAtIndex:section];
    NSArray *nameSection = [names objectForKey:key];

    static NSString *SectionsTableIdentifier = @"SectionsTableIdentifier";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:
                         SectionsTableIdentifier];
    if (cell == nil) 
    {
        cell = [[[UITableViewCell alloc]
             initWithStyle:UITableViewCellStyleDefault
             reuseIdentifier:SectionsTableIdentifier] autorelease];
    }

    cell.textLabel.text = [nameSection objectAtIndex:row];
    return cell;
}

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section 
{
    NSString *key = [keys objectAtIndex:section];
    return key;
}

- (NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView 
{
    return keys;
}

@end

Answer 1

您的代码存在一些问题，但根本问题是您永远不会将 UITableView 添加为 UIViewController 中的视图/子视图：

UITableView *table = [[UITableView alloc]initWithFrame:CGRectMake(0, 0, 320, 367) style:UITableViewStyleGrouped];
[table setDataSource:self];
[table setDelegate:self];
[table release];

// These two lines are what you're missing:
self.view = table;
[table release];

或者，您可以在 Interface Builder 中创建界面并避免必须以编程方式创建这些东西。

此外您不应该在您所在的位置创建 UITableView。 viewDidLoad 应用于在创建所有界面组件后执行任何其他操作。

您应该将 UITableView 的创建移至 loadView 方法：

查看 UIViewController 类参考以了解更多详细信息