先明確一下空間坐標系的三個方向：
x 方向就是手機的水平方向，右為正；
y 方向就是手機的水平垂直方向，前為正；
z 方向就是手機的空間垂直方向，天空的方向為正，地球的方向為負。
方向角的定義是手機y軸 水平面上的投影 與 正北方向的夾角。 （值得范圍是 0 ~ 359 其中0=North, 90=East, 180=South, 270=West）
傾斜角的定義是手機y軸 與水平面的夾角 （手機z軸向y軸方向移動為正 ,值得范圍是 -180 ~ 180）
旋轉角的定義是手機x軸 與水平面的夾角 （手機x軸離開z軸方向為正， 值得范圍是 -90 ~ 90）
也就是說，當你把手機水平放置在桌面上(屏幕向上)且手機指向正北(Y軸方向)，此時傳感器獲得的xyz三個值應該都為0。
基於Rexsee對於方向傳感器Orientation的擴展，我們可以很快的實現傳感器功能，比如讀取X/Y/Z方向角度值：rexseeOrientation.getLastKnownX()；讀取響應速度：rexseeOrientation.getRate()；設置傳感器檢測周期：rexseeOrientation.setCycle(1000)等。具體的函數介紹可以在Rexsee社區的手冊與源碼中查閱：http://www.rexsee.com/CN/helpReference.php
如下是Rexsee用Java封裝的的方向傳感器功能詳細源碼。感興趣的也可以直接去Rexsee社區查閱：http://www.rexsee.com。
但是首先需要知道，並不是所有的Android手機都支持方向傳感器。。比如說樂Phone，好像就是加速度、重力和光線，方向和磁場貌似都不支持。
[java]
/*
* Copyright (C) 2011 The Rexsee Open Source Project
*
* Licensed under the Rexsee License, Version 1.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.rexsee.com/CN/legal/license.html
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package rexsee.sensor;
import rexsee.core.browser.JavascriptInterface;
import rexsee.core.browser.RexseeBrowser;
import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
public class RexseeSensorOrientation implements JavascriptInterface {
public static final String INTERFACE_NAME = "Orientation";
@Override
public String getInterfaceName() {
return mBrowser.application.resources.prefix + INTERFACE_NAME;
}
@Override
public JavascriptInterface getInheritInterface(RexseeBrowser childBrowser) {
return this;
}
@Override
public JavascriptInterface getNewInterface(RexseeBrowser childBrowser) {
return new RexseeSensorOrientation(childBrowser);
}
public static final String EVENT_ONORIENTATIONCHANGED = "onOrientationChanged";
private final Context mContext;
private final RexseeBrowser mBrowser;
private final SensorManager mSensorManager;
private SensorEventListener mSensorListener;
private final Sensor mSensor;
private int mRate = SensorManager.SENSOR_DELAY_NORMAL;
private int mCycle = 100; //milliseconds
private int mEventCycle = 100; //milliseconds
private float mAccuracyX = 0;
private float mAccuracyY = 0;
private float mAccuracyZ = 0;
private long lastUpdate = -1;
private long lastEvent = -1;
private float x = -999f;
private float y = -999f;
private float z = -999f;
public RexseeSensorOrientation(RexseeBrowser browser) {
mContext = browser.getContext();
mBrowser = browser;
browser.eventList.add(EVENT_ONORIENTATIONCHANGED);
mSensorManager = (SensorManager) mContext.getSystemService(Context.SENSOR_SERVICE);
mSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION);
mSensorListener = new SensorEventListener() {
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
@Override
public void onSensorChanged(SensorEvent event) {
if (event.sensor.getType() != Sensor.TYPE_ORIENTATION) return;
long curTime = System.currentTimeMillis();
if (lastUpdate == -1 || (curTime – lastUpdate) > mCycle) {
lastUpdate = curTime;
float lastX = x;
float lastY = y;
float lastZ = z;
x = event.values[SensorManager.DATA_X];
y = event.values[SensorManager.DATA_Y];
z = event.values[SensorManager.DATA_Z];
if (lastEvent == -1 || (curTime – lastEvent) > mEventCycle) {
if (
(mAccuracyX >= 0 && Math.abs(x – lastX) > mAccuracyX)
|| (mAccuracyY >= 0 && Math.abs(y – lastY) > mAccuracyY)
|| (mAccuracyZ >= 0 && Math.abs(z – lastZ) > mAccuracyZ)
) {
lastEvent = curTime;
mBrowser.eventList.run(EVENT_ONORIENTATIONCHANGED);
}
}
}
}
};
}
public String getLastKnownX() {
return (x == -999) ? "null" : String.valueOf(x);
}
public String getLastKnownY() {
return (y == -999) ? "null" : String.valueOf(y);
}
public String getLastKnownZ() {
return (z == -999) ? "null" : String.valueOf(z);
}
public void setRate(String rate) {
mRate = SensorRate.getInt(rate);
}
public String getRate() {
return SensorRate.getString(mRate);
}
public void setCycle(int milliseconds) {
mCycle = milliseconds;
}
public int getCycle() {
return mCycle;
}
public void setEventCycle(int milliseconds) {
mEventCycle = milliseconds;
}
public int getEventCycle() {
return mEventCycle;
}
public void setAccuracy(float x, float y, float z) {
mAccuracyX = x;
mAccuracyY = y;
mAccuracyZ = z;
}
public float getAccuracyX() {
return mAccuracyX;
}
public float getAccuracyY() {
return mAccuracyY;
}
public float getAccuracyZ() {
return mAccuracyZ;
}
public boolean isReady() {
return (mSensor == null) ? false : true;
}
public void start() {
if (isReady()) {
mSensorManager.registerListener(mSensorListener, mSensor, mRate);
} else {
mBrowser.exception(getInterfaceName(), "Orientation sensor is not found.");
}
}
public void stop() {
if (isReady()) {
mSensorManager.unregisterListener(mSensorListener);
}
}
}
/*
* Copyright (C) 2011 The Rexsee Open Source Project
*
* Licensed under the Rexsee License, Version 1.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.rexsee.com/CN/legal/license.html
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package rexsee.sensor;
import rexsee.core.browser.JavascriptInterface;
import rexsee.core.browser.RexseeBrowser;
import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
public class RexseeSensorOrientation implements JavascriptInterface {
public static final String INTERFACE_NAME = "Orientation";
@Override
public String getInterfaceName() {
return mBrowser.application.resources.prefix + INTERFACE_NAME;
}
@Override
public JavascriptInterface getInheritInterface(RexseeBrowser childBrowser) {
return this;
}
@Override
public JavascriptInterface getNewInterface(RexseeBrowser childBrowser) {
return new RexseeSensorOrientation(childBrowser);
}
public static final String EVENT_ONORIENTATIONCHANGED = "onOrientationChanged";
private final Context mContext;
private final RexseeBrowser mBrowser;
private final SensorManager mSensorManager;
private SensorEventListener mSensorListener;
private final Sensor mSensor;
private int mRate = SensorManager.SENSOR_DELAY_NORMAL;
private int mCycle = 100; //milliseconds
private int mEventCycle = 100; //milliseconds
private float mAccuracyX = 0;
private float mAccuracyY = 0;
private float mAccuracyZ = 0;
private long lastUpdate = -1;
private long lastEvent = -1;
private float x = -999f;
private float y = -999f;
private float z = -999f;
public RexseeSensorOrientation(RexseeBrowser browser) {
mContext = browser.getContext();
mBrowser = browser;
browser.eventList.add(EVENT_ONORIENTATIONCHANGED);
mSensorManager = (SensorManager) mContext.getSystemService(Context.SENSOR_SERVICE);
mSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION);
mSensorListener = new SensorEventListener() {
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
@Override
public void onSensorChanged(SensorEvent event) {
if (event.sensor.getType() != Sensor.TYPE_ORIENTATION) return;
long curTime = System.currentTimeMillis();
if (lastUpdate == -1 || (curTime – lastUpdate) > mCycle) {
lastUpdate = curTime;
float lastX = x;
float lastY = y;
float lastZ = z;
x = event.values[SensorManager.DATA_X];
y = event.values[SensorManager.DATA_Y];
z = event.values[SensorManager.DATA_Z];
if (lastEvent == -1 || (curTime – lastEvent) > mEventCycle) {
if (
(mAccuracyX >= 0 && Math.abs(x – lastX) > mAccuracyX)
|| (mAccuracyY >= 0 && Math.abs(y – lastY) > mAccuracyY)
|| (mAccuracyZ >= 0 && Math.abs(z – lastZ) > mAccuracyZ)
) {
lastEvent = curTime;
mBrowser.eventList.run(EVENT_ONORIENTATIONCHANGED);
}
}
}
}
};
}
public String getLastKnownX() {
return (x == -999) ? "null" : String.valueOf(x);
}
public String getLastKnownY() {
return (y == -999) ? "null" : String.valueOf(y);
}
public String getLastKnownZ() {
return (z == -999) ? "null" : String.valueOf(z);
}
public void setRate(String rate) {
mRate = SensorRate.getInt(rate);
}
public String getRate() {
return SensorRate.getString(mRate);
}
public void setCycle(int milliseconds) {
mCycle = milliseconds;
}
public int getCycle() {
return mCycle;
}
public void setEventCycle(int milliseconds) {
mEventCycle = milliseconds;
}
public int getEventCycle() {
return mEventCycle;
}
public void setAccuracy(float x, float y, float z) {
mAccuracyX = x;
mAccuracyY = y;
mAccuracyZ = z;
}
public float getAccuracyX() {
return mAccuracyX;
}
public float getAccuracyY() {
return mAccuracyY;
}
public float getAccuracyZ() {
return mAccuracyZ;
}
public boolean isReady() {
return (mSensor == null) ? false : true;
}
public void start() {
if (isReady()) {
mSensorManager.registerListener(mSensorListener, mSensor, mRate);
} else {
mBrowser.exception(getInterfaceName(), "Orientation sensor is not found.");
}
}
public void stop() {
if (isReady()) {
mSensorManager.unregisterListener(mSensorListener);
}
}
}
僅對Rexsee的源碼和函數事件做瞭整理，相關的demo或源碼解析可以在Rexsee社區瞭解，目前Rexsee已提供瞭近2000個擴展，覆蓋Android原生功能超過90%，且全部開放： http://www.rexsee.com/
摘自 rexsee_dev的專欄
