如何在没有XIB文件的情况下以编程方式更新Xcode中的UILabel？ [英] How to update a UILabel in Xcode programmatically without XIB files?

问题描述

我被卡住了:(

在我的应用程序中，每当它获得新位置的更新时我都需要从CLLocationManager更新。我没有使用XIB / NIB文件，我编写的所有内容我都有以编程方式完成。代码：

.h

I'm stuck :(
In my application I require an update from CLLocationManager every time it gets an update to a new position. I am not using XIB/NIB files, everything I coded I have done programmatically. To the code:
the .h

@interface TestViewController : UIViewController
    UILabel* theLabel;

@property (nonatomic, copy) UILabel* theLabel;

@end

.m

...

-(void)loadView{
    ....
    UILabel* theLabel = [[UILabel alloc] initWithFrame:CGRectMake(0.0,0.0,320.0,20.0)];
    theLabel.text = @"this is some text";

    [self.view addSubView:theLabel];
    [theLabel release]; // even if this gets moved to the dealloc method, it changes nothing...
}

- (void)locationManager:(CLLocationManager *)manager
    didUpdateToLocation:(CLLocation *)newLocation
           fromLocation:(CLLocation *)oldLocation
{
    NSLog(@"Location: %@", [newLocation description]);

    // THIS DOES NOTHING TO CHANGE TEXT FOR ME... HELP??
    [self.view.theLabel setText:[NSString stringWithFormat: @"Your Location is: %@", [newLocation description]]];

    // THIS DOES NOTHING EITHER ?!?!?!?
    self.view.theLabel.text = [NSString stringWithFormat: @"Your Location is: %@", [newLocation description]];

}
...

任何想法或帮助？

（这一切都被卡住了所以请原谅我，如果它看起来有点麻烦）我可以提供更多信息，如果需要。

(this was all hand jammed so please forgive me if it looks kinda gacked) I can provide more info if needed.

推荐答案

您的loadView方法错误。您没有正确设置实例变量，而是生成新的局部变量。通过省略 UILabel * 和不释放将其更改为以下内容，因为您希望保留对标签的引用以设置文本稍后。

Your loadView method is wrong. You do not set the instance variable properly but instead you generate a new local variable. Change it to the following by omitting the UILabel * and do not release it because you want to keep a reference around to the label to set the text later.

-(void)loadView{
    ....
    theLabel = [[UILabel alloc] initWithFrame:CGRectMake(0.0,0.0,320.0,20.0)];
    theLabel.text = @"this is some text";

    [self.view addSubView:theLabel];
}

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

然后直接访问变量，如下所示：

Then later directly access the variable like this:

 - (void)locationManager:(CLLocationManager *)manager
     didUpdateToLocation:(CLLocation *)newLocation
            fromLocation:(CLLocation *)oldLocation
 {
     NSLog(@"Location: %@", [newLocation description]);

     theLabel.text = [NSString stringWithFormat: @"Your Location is: %@", [newLocation description]];

 }

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