根据加速度感应器判断手机方向

//手机顶部朝上
public static final int UP = 0;
//手机底部朝上
public static final int DOWN = 1;
//手机左边朝上
public static final int LEFT = 2;
//手机右边朝上
public static final int RIGHT = 3;
public int orientation = 0;

@Override
public void onResume() {
    SensorManager sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
    Sensor sensor_gravity=sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
     sensorManager.registerListener(new SensorEventListener() {
            
            @Override
            public void onSensorChanged(SensorEvent event) {
                if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {
                    float x = event.values[0];
                    float y = event.values[1];
                    //y的绝对值大于x时，顶部或者底部朝上
                    if (Math.abs(y) > Math.abs(x)) {
                        if (y > 0) {
                            orientation = UP;
                        }else{
                            orientation = DOWN;
                        }
                    }else{
                        if (x > 0) {
                            orientation = LEFT;
                        }else{
                            orientation = RIGHT;
                        }
                    }
                }
            }
            
            @Override
            public void onAccuracyChanged(Sensor arg0, int arg1) {
                // TODO Auto-generated method stub
                
            }
        }, sensor_gravity, SensorManager.SENSOR_DELAY_UI);
        super.onResume();