iOS - 如何从要在 AppleDelegate.m 中使用的类访问变量

Question

我有一个名为 AddAlarmViewController 的类并声明了两个变量。

声明变量

@interface AddAlarmViewController ()
{
    NSString *soundName;
    NSString *soundName2;
}

我有这个方法可以从选择器 View 中获取警报音的名称

-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row
      inComponent:(NSInteger)component
{
    soundName = _alarmNames[row];
    soundName2 = [soundName stringByAppendingString:@".caf"];
}

现在，我想在另一个类 AppleDelegate.m 中使用 soundName2。这是 AppleDelegate.m 中我想要执行的代码行。

notification.soundName = soundName2;

我该怎么做？

Answer 1

在您的 AddAlarmViewController 上

-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row
      inComponent:(NSInteger)component
{
    soundName = _alarmNames[row];
    soundName2 = [soundName stringByAppendingString:@".caf"];

    NSDictionary *payload = [NSDictionary dictionaryWithObject:soundName2 forKey:@"NewSound"]];

    [[NSNotificationCenter defaultCenter] postNotificationName:@"NewSoundSelected" object:self withUserInfo:payload];

}

在你的 AppDelegate 的某个地方，可能在 didFinishLaunchingWithOptions 里面:

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(doSomethingWithNewSound:) name:@"NewSoundSelected" object:nil];

然后将以下方法添加到您的 AppDelegate

-(void) doSomethingWithNewSound:(NSNotification *) notification {
   NSDictionary *payload = [notification userInfo];

   //Here is what you are looking for
   NSString *sound = [payload objectForKey:@"NewSound"];

}