Question

我有Java和Android开发经验，现在正在尝试学习Objective-C和iPhone / iPad开发。为了帮助自学，我正在将我为Android制作的应用程序重新编写到iPhone上。

我正在尝试创建一个tableView，它将包含成员的名称，然后在按下时在不同的视图中显示联系人信息。具体来说，我无法从我的NSMutableArray“currentMembers”设置我的单元格标签，该标签填充了NSObjects“member”，它有五个属性，即NSStrings。其中两个变量包括名字和姓氏。我想将单元格标签设置为全名，因此是firstName + lastName的串联字符串。以下是我的tableview类中的一些代码。

**只是为了澄清，我的数组确实填充了正确定义但不是nil的对象

的.m

@implementation CurrentMemberViewController

@synthesize currentMembers = _currentMembers;
@synthesize alumniMembers = _alumniMembers;
@synthesize currentMembersLoadCheck = _currentMembersLoadCheck;


- (void)viewDidLoad
{
    [super viewDidLoad];

    if(self.currentMembersLoadCheck == NO)
    {
        NSString *currentFilePath = [[NSBundle mainBundle] pathForResource:@"akpsi_contact_list"                                                                ofType:@"txt"];
       // NSString *alumniFilePath = [[NSBundle mainBundle] pathForResource:@"akpsi_alumni_list"                                                           ofType:@"txt"];

        [self readFileString:currentFilePath];
        //[self readFileString:alumniFilePath];

        self.currentMembersLoadCheck = YES;
    }
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return [self.currentMembers count];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Current Member Name";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];

    //if you dont have string, make default cell
    if(cell == nil)
    {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    }

    // Configure the cell...
    cell.textLabel.text = [self.currentMembers objectAtIndex:indexPath.row];
    //rest of implementation for creating cell label.. above is not correct

    return cell;
}

#pragma mark - Table view delegate

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    // Navigation logic may go here. Create and push another view controller.
    /*
     <#DetailViewController#> *detailViewController = [[<#DetailViewController#> alloc] initWithNibName:@"<#Nib name#>" bundle:nil];
     // ...
     // Pass the selected object to the new view controller.
     [self.navigationController pushViewController:detailViewController animated:YES];
     */
}

- (NSString *)loadFileToString:(NSString *)filePath
{
    NSError *error = nil;
    NSString *fileContent = [NSString stringWithContentsOfFile:filePath
                                                      encoding:NSUTF8StringEncoding
                                                         error:&error];
    if(error)
    {
        NSLog(@"ERROR while loading from file: %@", error);
    }
    return fileContent;
}

-(void)readFileString:(NSString *)filePath
{
    NSScanner *scanner = [NSScanner scannerWithString: [self loadFileToString:filePath]];
    //temporary variables
    NSString *thisFirstName;
    NSString *thisLastName;
    NSString *thisPhoneNum;
    NSString *thisEmail;
    NSString *thisPledge;
    NSString *thisMajor;

    NSMutableArray *memberArray = [[NSMutableArray alloc]initWithCapacity:40];

    //begin scanning string until end
    while ([scanner isAtEnd] == NO)
    {
        //scan one line, set variables, begin at next line
        NSCharacterSet *whitespace = [NSCharacterSet whitespaceCharacterSet];
        [scanner scanUpToCharactersFromSet:whitespace intoString:&thisFirstName];
        [scanner scanCharactersFromSet:whitespace intoString:nil];
        [scanner scanUpToCharactersFromSet:whitespace intoString:&thisLastName];
        [scanner scanCharactersFromSet:whitespace intoString:nil];
        [scanner scanUpToCharactersFromSet:whitespace intoString:&thisPhoneNum];
        [scanner scanCharactersFromSet:whitespace intoString:nil];
        [scanner scanUpToCharactersFromSet:whitespace intoString:&thisEmail];
        [scanner scanCharactersFromSet:whitespace intoString:nil];
        [scanner scanUpToCharactersFromSet:whitespace intoString:&thisPledge];
        [scanner scanCharactersFromSet:whitespace intoString:nil];
        NSCharacterSet *newLineCharacterSet = [NSCharacterSet newlineCharacterSet];
        [scanner scanUpToCharactersFromSet:newLineCharacterSet intoString:&thisMajor];
        [scanner scanCharactersFromSet:newLineCharacterSet intoString:nil];

        //create member object
        AKPsiMember *member = [[AKPsiMember alloc] init];
        member.firstName = thisFirstName;
        member.lastName = thisLastName;
        member.phoneNum = thisPhoneNum;
        member.emailAddress = thisEmail;
        member.pledgeClass = thisPledge;
        member.major = thisMajor;
        //add to array depending on file being read
        //broken?//
        [memberArray addObject:member];
    }
    self.currentMembers = memberArray;
}


@end

Answer 1

你所谈论的逻辑应该在cellForRowAtIndexPath:中，应该符合以下几行：

AKPsiMember *member = [self.currentMembers objectAtIndex:indexPath.row];
NSString *fullName = [NSString stringWithFormat:@"%@ %@", member.firstName, member.lastName];

cell.textLabel.text = fullName;

如果名字或姓氏可能为零，则上述内容不会产生漂亮的全名字符串......

objectAtIndex:与细胞无关。它是一个数组方法，用于获取指定索引处的值。在这种情况下，索引被指定为indexPath.row，它只是表的当前行（作为索引路径提供，因为可能还有相关部分）。

您似乎没有使用任何原型单元格。你只是重用细胞实例。表视图为您管理，您需要做的就是尝试从池中获取实例（使用dequeueReusableCellWithIdentifier:），然后再自己创建一个实例。

从对象数组中设置UITextView单元格标签

1 个答案: