1

I am implementing my own camera Activity. To rotate the captured image I need to know the orientation at the time of shooting. Is there a higher level API for the sensor values pitch and roll that tells me my device is oriented in:

top-down - holding the phone normal, portrait
down-top
right-left - landscape the top of the phone is on the right side
left-right - landscape the top of the phone is on the left side

Or is there any other way to geht it directly from the system?

4

2 回答 2

1

可悲的是，当相机不处于横向模式时（这是 android 上相机的“自然”方向），相机在 android 上以一种奇怪的方式工作。

最好的办法是将活动设置为横向模式，并添加 onConfigurationChanged 事件（并将 android:configChanges="orientation" 添加到清单中）以获得当前方向。

捕获图像时，请检查方向并根据您希望拥有的任何逻辑进行操作。

于 2012-04-28T23:01:39.863 回答
1

好的解决了我的问题到一定程度，所以它对我有用，我忽略了自下而上的识别。

public class DeviceOrientation {

public static final int ORIENTATION_PORTRAIT = 0;
public static final int ORIENTATION_LANDSCAPE_REVERSE = 1;
public static final int ORIENTATION_LANDSCAPE = 2;
public static final int ORIENTATION_PORTRAIT_REVERSE = 3;

int smoothness = 1;
public float averagePitch = 0;
public float averageRoll = 0;
public int orientation = ORIENTATION_PORTRAIT;

private float[] pitches;
private float[] rolls;

public DeviceOrientation(int smoothness) {
    this.smoothness = smoothness;

    pitches = new float[smoothness];
    rolls = new float[smoothness];
}

public void addSensorEvent(SensorEvent event) {
    azimuth = event.values[0];

    averagePitch = addValue(event.values[1], pitches);
    averageRoll = addValue(event.values[2], rolls);

    orientation = calculateOrientation();
}

private float addValue(float value, float[] values) {
    float average = 0;

    for(int i=1; i<smoothness; i++) {
        values[i-1] = values[i];
        average += values[i];
    }
    values[smoothness-1] = value;
    average = (average + value)/smoothness;

    return average;
}

/** handles all 4 possible positions perfectly */
private int calculateOrientation() {
    // finding local orientation dip
    if (((orientation == ORIENTATION_PORTRAIT || orientation == ORIENTATION_PORTRAIT_REVERSE)
            && (averageRoll > -30 && averageRoll < 30))) {
        if (averagePitch > 0)
            return ORIENTATION_PORTRAIT_REVERSE;
        else
            return ORIENTATION_PORTRAIT;
    } else {
        // divides between all orientations
        if (Math.abs(averagePitch) >= 30) {
            if (averagePitch > 0)
                return ORIENTATION_PORTRAIT_REVERSE;
            else
                return ORIENTATION_PORTRAIT;
        } else {
                if (averageRoll > 0) {
                    return ORIENTATION_LANDSCAPE_REVERSE;
                } else {
                    return ORIENTATION_LANDSCAPE;
                }
        }
    }
}

说明：如果我处于纵向模式并将移动设备向前倾斜直到它处于水平位置，由于其余代码，它将切换到横向。因此，我检查它是否是纵向的，并使条件难以离开此模式。这就是我对局部倾角的看法。其余的只是分为所有 3 个方向。

一件事是坏的。如果设备在 Landscape_x 中并向后倾斜一些度数，则 pich 从 ~2 跳到 ~175。那时我的代码在横向和纵向之间翻转。

平滑度将通过组合最后 n 个值并计算平均值来平滑传感器数据的值。这不是真的必要。

我希望这对其他人有帮助。如果您可以进一步改进代码，请告诉我。

于 2012-04-29T09:13:27.170 回答