为什么我没有从加速度计传感器获取数据

Question

问题描述：

我和我的朋友正在自学android开发。我们调试了其他类，比如游戏物理和手动更新值，这些类在我们的棋盘上画出了对角线。当我们把它改回读取加速度计数据时，大理石停止了移动。因此，我们将包括我们认为问题正在发生的类。基本上，我们在android开发中的视图类。

我们正在自学android开发，我们不明白为什么加速度计(我们称之为mSensorX和mSensorY)的数据没有更新。下面包含的是我们的视图类。请注意，我们正在为android 3.1开发。然而，我们在eclipse中使用了android的所有最新功能。

package com.example.marblez;

import com.example.marblez.R;
import android.app.Activity;
import android.content.Context;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.util.Log;
import android.view.Display;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.Surface;
import android.view.View;
import android.view.WindowManager;
public class MarblezView extends View implements SensorEventListener{

//Sensor Stuff
private SensorManager mSensorManager;
private Display mDisplay;

//Accelerometer sensor stuff 
private Sensor mAccelerometer;
private float mSensorX;
private float mSensorY;
//Variables related to time 
private long mCpuTimeStamp;
private long mSensorTimeStamp;
private WindowManager mWindowManager;

//Accelerometer buffer, such that slight movement will roll the marble 
private float sensor_buffer = 0;
//Create the canvas 
private Canvas mCanvas; 
private MarblezBackground background;
//Create the marble
private Marblez ball;
//Constructor for Marblez View 
@SuppressWarnings("deprecation")
public MarblezView(Context context, Activity activity){
super(context);
//Setup sensor stuff
mSensorManager = (SensorManager) context.getSystemService(Context.SENSOR_SERVICE);
mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
mWindowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
mDisplay = mWindowManager.getDefaultDisplay();
//Set up Maze 
background = new MarblezBackground(activity);
//Create our rolling little friend :-) 
ball = new Marblez(activity);
}
@Override
public void onSensorChanged(SensorEvent event) {
if (event.sensor.getType() != Sensor.TYPE_ACCELEROMETER)
return;
/*
* record the accelerometer data, the event's timestamp as well as
* the current time. The latter is needed so we can calculate the
* "present" time during rendering. In this application, we need to
* take into account how the screen is rotated with respect to the
* sensors (which always return data in a coordinate space aligned
* to with the screen in its native orientation).
*/
switch (mDisplay.getRotation()) {
case Surface.ROTATION_0:
mSensorX = event.values[0];
mSensorY = event.values[1];
break;
case Surface.ROTATION_90:
mSensorX = -event.values[1];
mSensorY = event.values[0];
break;
case Surface.ROTATION_180:
mSensorX = -event.values[0];
mSensorY = -event.values[1];
break;
case Surface.ROTATION_270:
mSensorX = event.values[1];
mSensorY = -event.values[0];
break;
}
mSensorTimeStamp = event.timestamp;
mCpuTimeStamp = System.nanoTime();
}

//Automatic call
@Override
public void onDraw(Canvas canvas){
mCanvas = canvas;
//Draw the maze
background.drawMaze(canvas);
//Get the x and y sensor data and other goodies
final long now = mSensorTimeStamp + (System.nanoTime() - mCpuTimeStamp);
//Draw the marble 
ball.drawMarble(canvas, mSensorX, mSensorY, now);
//Invalidate so it draws again 
invalidate();
}
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
}

我们的很多想法和方法都来自一个名为加速度计游戏的开源谷歌项目。然而，熟悉该代码的人可以看到，我们竭尽全力简化命名约定、方法和调用。

基本上，我们会感谢你的帮助。这就像传感器就在"那里"，但出于实际目的，它从未被使用过。例如，当我们向视图添加调试标记时，它从不调用方法onSensorChanged，这很有说服力。因此，我们的加速度计真的不工作是另一种情况。

Answer 1

您需要在传感器管理器中注册您的实例，如下所示：

mSensorManager.registerListener(this, mAccelerometer,
SensorManager.SENSOR_DELAY_NORMAL);