小编obj*_*jlv的帖子

这是我的代码

 UILabel *label = [[UILabel alloc]initWithFrame:CGRectMake(10, 50, 300, 50)];
    label.textAlignment = UITextAlignmentCenter;
    label.backgroundColor = [UIColor clearColor];
    label.textColor = [UIColor whiteColor];
    label.textColor.font = [UIFont fontWithName:@"Verdana" size:30];
    label.text = @"A very long string";
     etc...

问题是字体很大,无法放入标签中.它只显示"非常"

怎么做才能显示整个文本.我试过了

label.lineBreakMode = UILineBreakModeWordWrap;
label.numberOfLines = 0;

但它对我不起作用.我想以编程方式做到这一点.

//编辑

CGRect frame = CGRectMake(10, 50, 300, 50);
    NSString *labelString = @"Players.";

    UILabel *howManyUsersLabel = [[UILabel alloc]initWithFrame:frame];
    howManyUsersLabel.textAlignment = UITextAlignmentCenter;
    howManyUsersLabel.backgroundColor = [UIColor clearColor];
    howManyUsersLabel.textColor = [UIColor whiteColor];
    howManyUsersLabel.adjustsFontSizeToFitWidth = NO;
    howManyUsersLabel.numberOfLines = 0;

    CGFloat fontSize = 30;
    while …

我正在学习ObjC和iOS开发.我在应用程序中使用的每个组件都是以编程方式创建的(视图,按钮,标签等).

这是我的代码

...
UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
[self.btn addTarget:self 
                  action:@selector(someAction:) 
        forControlEvents:UIControlEventTouchDown];
....


-(void)someAction
{
 logic
}

我注意到我可以使用void而不是IBAction作为返回类型的选择器.这是正确的方法吗？可能有任何陷阱吗？

将变量初始化为nil？是一种好习惯吗？

我问的是因为当我在我的项目上运行分析器时,我收到了警告.

 NSString *q;

    if(sqlite3_prepare_v2(database, [query UTF8String], -1, &statement, nil) == SQLITE_OK)
    {
        sqlite3_step(statement);
        selectedQuestion =[NSString stringWithFormat: @"%s",(char *)sqlite3_column_text(statement, 0)];
        sqlite3_finalize(statement);
    }

    sqlite3_close(database);

    return q; //Undefined or garbage value returned to caller

当我更改代码时,警告消失了:

NSString *q = nil;

我知道viewWillAppear没有在pop/push视图上调用,但我真的需要这个方法.这是我尝试的

我添加了UINavigationControllerDelegate并采用了

- (void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated {
       [viewController viewWillAppear:animated];
}

-(void)viewWillAppear
{
    NSLog(@"Log");
}

但仍未调用viewWillAppear

编辑

AppDelegate.m

    self.navigationController = [[UINavigationController alloc]init];
    [self.window setRootViewController:self.navigationController];

    FirstView *fview = [FirstView]alloc]init];
    [self.viewController pushViewController:fview animated:YES];

FirstView.m
....
-(void)viewWillAppear
{
  NSLog(@"Logged");
}

....