对于初入Android开发的网友可以很好的了解代码规范，同时很多成熟的可复用代码希望对大家有帮助。PhoneGap内部数据传递使用了JSON，比如PhoneGap中指南针部分源码如下:
public class CompassListener extends Plugin implements SensorEventListener {
public static int STOPPED = 0;
public static int STARTING = 1;
public static int RUNNING = 2;
public static int ERROR_FAILED_TO_START = 3;
public long TIMEOUT = 30000;// Timeout in msec to shut off listener
int status;// status of listener
float heading;// most recent heading value
long timeStamp;// time of most recent value
long lastAccessTime;// time the value was last retrieved
private SensorManager sensorManager;// Sensor manager
Sensor mSensor;// Compass sensor returned by sensor manager
/**
* Constructor.
*/
public CompassListener() {
this.timeStamp = 0;
this.setStatus(CompassListener.STOPPED);
}
/**
* Sets the context of the Command. This can then be used to do things like
* get file paths associated with the Activity.
*
* @param ctx The context of the main Activity.
*/
public void setContext(PhonegapActivity ctx) {
super.setContext(ctx);
this.sensorManager = (SensorManager) ctx.getSystemService(Context.SENSOR_SERVICE);
}
/**
* Executes the request and returns PluginResult.
*
* @param actionThe action to execute.
* @param argsJSONArry of arguments for the plugin.
* @param callbackId The callback id used when calling back into JavaScript.
* @returnA PluginResult object with a status and message.
*/
public PluginResult execute(String action, JSONArray args, String callbackId) {
PluginResult.Status status = PluginResult.Status.OK;
String result = "";
try {
if (action.equals("start")) {
this.start();
}
else if (action.equals("stop")) {
this.stop();
}
else if (action.equals("getStatus")) {
int i = this.getStatus();
return new PluginResult(status, i);
}
else if (action.equals("getHeading")) {
// If not running, then this is an async call, so don't worry about waiting
if (this.status != RUNNING) {
int r = this.start();
if (r == ERROR_FAILED_TO_START) {
return new PluginResult(PluginResult.Status.IO_EXCEPTION, ERROR_FAILED_TO_START);
}
// Wait until running
long timeout = 2000;
while ((this.status == STARTING) && (timeout > 0)) {
timeout = timeout - 100;
try {
Thread.sleep(100);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
if (timeout == 0) {
return new PluginResult(PluginResult.Status.IO_EXCEPTION, AccelListener.ERROR_FAILED_TO_START);
}
}
float f = this.getHeading();
return new PluginResult(status, f);
}
else if (action.equals("setTimeout")) {
this.setTimeout(args.getLong(0));
}
else if (action.equals("getTimeout")) {
long l = this.getTimeout();
return new PluginResult(status, l);
}
return new PluginResult(status, result);
} catch (JSONException e) {
e.printStackTrace();
return new PluginResult(PluginResult.Status.JSON_EXCEPTION);
}
}
/**
* Identifies if action to be executed returns a value and should be run synchronously.
*
* @param action The action to execute
* @returnT=returns value
*/
public boolean isSynch(String action) {
if (action.equals("getStatus")) {
return true;
}
else if (action.equals("getHeading")) {
// Can only return value if RUNNING
if (this.status == RUNNING) {
return true;
}
}
else if (action.equals("getTimeout")) {
return true;
}
return false;
}
/**
* Called when listener is to be shut down and object is being destroyed.
*/
public void onDestroy() {
this.stop();
}
//--------------------------------------------------------------------------
// LOCAL METHODS
//--------------------------------------------------------------------------
/**
* Start listening for compass sensor.
*
* @returnstatus of listener
*/
public int start() {
// If already starting or running, then just return
if ((this.status == CompassListener.RUNNING) || (this.status == CompassListener.STARTING)) {
return this.status;
}
// Get accelerometer from sensor manager
List<Sensor> list = this.sensorManager.getSensorList(Sensor.TYPE_ORIENTATION);
// If found, then register as listener
if (list.size() > 0) {
this.mSensor = list.get(0);
this.sensorManager.registerListener(this, this.mSensor, SensorManager.SENSOR_DELAY_NORMAL);
this.lastAccessTime = System.currentTimeMillis();
this.setStatus(CompassListener.STARTING);
}
// If error, then set status to error
else {
this.setStatus(CompassListener.ERROR_FAILED_TO_START);
}
return this.status;
}
/**
* Stop listening to compass sensor.
*/
public void stop() {
if (this.status != CompassListener.STOPPED) {
this.sensorManager.unregisterListener(this);
}
this.setStatus(CompassListener.STOPPED);
}
public void onAccuracyChanged(Sensor sensor, int accuracy) {
// TODO Auto-generated method stub
}
/**
* Sensor listener event.
*
* @param SensorEvent event
*/
public void onSensorChanged(SensorEvent event) {
// We only care about the orientation as far as it refers to Magnetic North
float heading = event.values[0];
// Save heading
this.timeStamp = System.currentTimeMillis();
this.heading = heading;
this.setStatus(CompassListener.RUNNING);
// If heading hasn't been read for TIMEOUT time, then turn off compass sensor to save power
if ((this.timeStamp - this.lastAccessTime) > this.TIMEOUT) {
this.stop();
}
}
/**
* Get status of compass sensor.
*
* @returnstatus
*/
public int getStatus() {
return this.status;
}
/**
* Get the most recent compass heading.
*
* @returnheading
*/
public float getHeading() {
this.lastAccessTime = System.currentTimeMillis();
return this.heading;
}
/**
* Set the timeout to turn off compass sensor if getHeading() hasn't been called.
*
* @param timeoutTimeout in msec.
*/
public void setTimeout(long timeout) {
this.TIMEOUT = timeout;
}
/**
* Get the timeout to turn off compass sensor if getHeading() hasn't been called.
*
* @return timeout in msec
*/
public long getTimeout() {
return this.TIMEOUT;
}
/**
* Set the status and send it to JavaScript.
* @param status
*/
private void setStatus(int status) {
this.status = status;
}
}
