Android 视图和传感器

Question

我有一个使用方向传感器的指南针应用程序，每次传感器更改时，我的指南针视图都会失效，以便向北旋转。我的指南针是 444 像素 x 444 像素的位图。我面临的问题是，每当传感器发生变化并且你看到指南针旋转时，它就会滞后，基本上每秒帧数很差。我尝试改用表面视图并更改 SENSOR_DELAY，但没有任何更改。如果有人能帮助我找出这个问题的答案，我会很高兴。

注册传感器

    orientation = sm.getDefaultSensor(Sensor.TYPE_ORIENTATION);
    sm.registerListener(this, orientation, SensorManager.SENSOR_DELAY_UI);

每当传感器发生变化时

public void onSensorChanged(SensorEvent event) {
    // TODO Auto-generated method stub
    if (compass != null) {
        float[] v = event.values;
        north = v[0];
        compass.setNorth(-north);
    }
} 

罗盘视图

public void setNorth(float n) {
    north_changed = true;
    north = n;
    invalidate();
}

private void drawBackground(Canvas canvas) {
    canvas.save();
    if (north_changed == true) {
        canvas.rotate(north);
    }
    float maxwidth = (float) (backgroundTexture.getWidth() * Math.sqrt(2));
    float maxheight = (float) (backgroundTexture.getHeight() * Math.sqrt(2));
    float ratio = Math.min(w / maxwidth, h / maxheight);
    int width = (int) (backgroundTexture.getWidth() * ratio);
    int height = (int) (backgroundTexture.getHeight() * ratio);
    canvas.drawBitmap(
            backgroundTexture,
            new Rect(0, 0, backgroundTexture.getWidth(), backgroundTexture
                    .getHeight()), new RectF(-width / 1.5f, -height / 1.5f,
                    width / 1.5f, height / 1.5f), facePaint);
    canvas.restore();
}

onDraw中的方法

protected void onDraw(Canvas canvas) {
    // TODO Auto-generated method stub
    super.onDraw(canvas);
    if (showCompass) {
        w = getWidth();
        h = getHeight();
        cx = w / 2;
        cy = h / 2;
        canvas.translate(cx, cy);
        loadImages();
        drawBackground(canvas);
    }
}

Answer 1

您可以尝试这个

替换：

sm.registerListener(this,orientation, SensorManager.SENSOR_DELAY_UI);

用这个：

sm.registerListener(this,orientation, SensorManager.SENSOR_DELAY_FASTEST);

如果你想要一些额外的平滑度

替换：

if (compass != null) {
    float[] v = event.values;
    north = v[0];
    compass.setNorth(-north);
}

用这个：

if (compass != null) {
    float[] v = event.values;
    north =north*0.1f + v[0]*0.9f;
    compass.setNorth(-north);
}