com.wx.iseeweather.GetPressurePlugin.GetPressure.java Source code

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Here is the source code for com.wx.iseeweather.GetPressurePlugin.GetPressure.java

Source

/*
   See:
   http://www.apache.org/licenses/LICENSE-2.0
   for license information.
*/

package com.wx.iseeweather.GetPressurePlugin;

import org.apache.cordova.CordovaPlugin;
import org.apache.cordova.CallbackContext;
import org.apache.cordova.PluginResult;

import org.json.JSONArray;
import org.json.JSONException;

import android.content.Context;

import android.hardware.Sensor;
import android.hardware.SensorManager;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;

import java.util.concurrent.Semaphore;
import java.util.Arrays;

public class GetPressure extends CordovaPlugin implements SensorEventListener {

    /*
       -The idea is to take an odd number of readings, store them into an array, 
       sort the array, and then take the middle of the array. 
       -This is the median result so that an initial 'bad' reading doesn't cause any issues.
    */
    private final int NUMBER_OF_READINGS = 13;
    private final double NUMBER_OF_READINGS_D = NUMBER_OF_READINGS;

    private SensorManager mSensorManager;
    private Sensor mPressure;

    private CallbackContext callbackContext;

    private final Semaphore pressureMux = new Semaphore(1);
    private float[] pressures = new float[NUMBER_OF_READINGS];
    private int currentNumberOfReadings;

    @Override
    public boolean execute(String action, JSONArray args, CallbackContext callbackContext) throws JSONException {
        this.callbackContext = callbackContext;

        mSensorManager = (SensorManager) this.cordova.getActivity().getSystemService(Context.SENSOR_SERVICE);
        mPressure = mSensorManager.getDefaultSensor(Sensor.TYPE_PRESSURE);

        if (mPressure != null) {
            currentNumberOfReadings = 0;
            mSensorManager.registerListener(this, mPressure, SensorManager.SENSOR_DELAY_NORMAL);

            PluginResult result = new PluginResult(PluginResult.Status.NO_RESULT);
            result.setKeepCallback(true);
            callbackContext.sendPluginResult(result);
            return true;
        } else {
            callbackContext.error("No pressure sensor found.");
            return false;
        }
    }

    @Override
    public final void onAccuracyChanged(Sensor sensor, int accuracy) {
        // Do something here if sensor accuracy changes. Do what exactly?
    }

    @Override
    public final void onSensorChanged(SensorEvent event) {
        try {
            pressureMux.acquire();
        } catch (InterruptedException e) {

        }
        pressures[currentNumberOfReadings] = event.values[0];
        currentNumberOfReadings++;
        pressureMux.release();
        if (currentNumberOfReadings >= NUMBER_OF_READINGS - 1) {
            sendFinalResult();
        }
    }

    private void sendFinalResult() {
        mSensorManager.unregisterListener(this);
        Arrays.sort(pressures);
        PluginResult result = new PluginResult(PluginResult.Status.OK, pressures[(NUMBER_OF_READINGS - 1) / 2]);
        result.setKeepCallback(false);
        callbackContext.sendPluginResult(result);
    }
}