Android 屏幕方向传感器

Question

我想通过设置在点击按钮时强制屏幕方向为横向

 setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);

它工作正常。现在我希望应用程序跟随传感器，以便在倾斜回纵向时将方向恢复为纵向。我知道这可以通过设置 setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_SENSOR); 但不知道在哪里设置。如果方向强制为横向，则无论您向任何方向倾斜，方向都将保持横向。任何人都可以指定如何重置方向标志吗？

Answer 1

当前的 YouTube 应用可以满足您的要求。
我在我的视频播放应用程序中处理过同样的问题。

如果用户在他/她处于纵向时强制将方向设置为横向，请初始化OrientationEventListener，它会通知您来自SensorManager的设备方向。范围从 0 到 360。

观察设备是否倾斜到大约 (orientation >= 60 && orientation <= 120) || (orientation >= 240 && orientation <= 300) 的横向范围。并将此状态保存到枚举或标志中，然后如果设备返回纵向方向范围(orientation <= 40 || orientation >= 320)，检查枚举/标志并调用setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED); ，重置标志/枚举并禁用传感器，直到用户再次强制定向。

下面是演示代码:

private enum SensorStateChangeActions {
        WATCH_FOR_LANDSCAPE_CHANGES, SWITCH_FROM_LANDSCAPE_TO_STANDARD, WATCH_FOR_POTRAIT_CHANGES, SWITCH_FROM_POTRAIT_TO_STANDARD;
}

private SensorStateChangeActions mSensorStateChanges;

public void goFullScreen() {
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_SENSOR_LANDSCAPE);
        mSensorStateChanges = SensorStateChangeActions.WATCH_FOR_LANDSCAPE_CHANGES;
        if (null == sensorEvent)
            initialiseSensor(true);
        else
            sensorEvent.enable();
}

public void shrinkToPotraitMode() {
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
        mSensorStateChanges = SensorStateChangeActions.WATCH_FOR_POTRAIT_CHANGES;
        if (null == sensorEvent)
            initialiseSensor(true);
        else
            sensorEvent.enable();
}
/**
 * Initialises system sensor to detect device orientation for player changes.
 * Don't enable sensor until playback starts on player
 *
 * @param enable if set, sensor will be enabled.
 */
private void initialiseSensor(boolean enable) {
    sensorEvent = new OrientationEventListener(this,
            SensorManager.SENSOR_DELAY_NORMAL) {

        @Override
        public void onOrientationChanged(int orientation) {
            /*
             * This logic is useful when user explicitly changes orientation using player controls, in which case orientation changes gives no callbacks.
             * we use sensor angle to anticipate orientation and make changes accordingly.
             */
            if (null != mSensorStateChanges
                    && mSensorStateChanges == SensorStateChangeActions.WATCH_FOR_LANDSCAPE_CHANGES
                    && ((orientation >= 60 && orientation <= 120) || (orientation >= 240 && orientation <= 300))) {
                mSensorStateChanges = SensorStateChangeActions.SWITCH_FROM_LANDSCAPE_TO_STANDARD;
            } else if (null != mSensorStateChanges
                    && mSensorStateChanges == SensorStateChangeActions.SWITCH_FROM_LANDSCAPE_TO_STANDARD
                    && (orientation <= 40 || orientation >= 320)) {
                setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED);
                mSensorStateChanges = null;
                sensorEvent.disable();
            } else if (null != mSensorStateChanges
                    && mSensorStateChanges == SensorStateChangeActions.WATCH_FOR_POTRAIT_CHANGES
                    && ((orientation >= 300 && orientation <= 359) || (orientation >= 0 && orientation <= 45))) {
                mSensorStateChanges = SensorStateChangeActions.SWITCH_FROM_POTRAIT_TO_STANDARD;
            } else if (null != mSensorStateChanges
                    && mSensorStateChanges == SensorStateChangeActions.SWITCH_FROM_POTRAIT_TO_STANDARD
                    && ((orientation <= 300 && orientation >= 240) || (orientation <= 130 && orientation >= 60))) {
                setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED);
                mSensorStateChanges = null;
                sensorEvent.disable();
            }
        }
    };
    if (enable)
        sensorEvent.enable();
}

这与 YouTube 功能类似，希望对您有所帮助。