ios感知设备方向

最新推荐文章于 2018-01-12 18:06:15 发布

原创最新推荐文章于 2018-01-12 18:06:15 发布 · 1k 阅读

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本文介绍了一个iOS应用如何通过监听设备的方向变化来更新UI元素的方法。具体实现包括在viewWillAppear方法中启动方向变化通知监听，定义一个label作为显示方向变化信息的载体，并在收到方向变化通知时更新label内容。

在Viewdidload中新建一个label，并且定义成全局变量，便于下面方法的调用；通过该实例可以感应到设备的方向

- (void)viewWillAppear:(BOOL)animated{

    [super viewWillAppear:animated];
    [[UIDevice currentDevice]beginGeneratingDeviceOrientationNotifications];
    [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(rece:) name:UIDeviceOrientationDidChangeNotification object:nil];
}
- (void)viewWillDisappear:(BOOL)animated{
    [super viewWillDisappear:animated];
    [[NSNotificationCenter defaultCenter]removeObserver:self];
    [[UIDevice currentDevice]endGeneratingDeviceOrientationNotifications];
}
- (void)rece:(NSNotification *)not{
    UIDevice *device = [UIDevice currentDevice];
    switch (device.orientation) {
        case UIDeviceOrientationUnknown: {
           label.text = @"竖直向上";
            break;
        }
        case UIDeviceOrientationPortrait: {
            label.text = @"竖直向下";
            break;
        }
        case UIDeviceOrientationPortraitUpsideDown: {
            label.text = @"水平向左";
            break;
        }
        case UIDeviceOrientationLandscapeLeft: {
            label.text = @"水平向右";
            break;
        }
        case UIDeviceOrientationLandscapeRight: {
            label.text = @"面朝上";
            break;
        }
        case UIDeviceOrientationFaceUp: {
            label.text = @"面朝下";
            break;
        }
        case UIDeviceOrientationFaceDown: {
            label.text = @"未知";
            break;
        }
        default: {
            break;
        }
    }
}