Develop Reference

Is there a better way to get this value from compass?

I need to get values from a compass and do it in rxJava.
So I've made this code:
private void goCompass()
{
Observable.create(new Observable.OnSubscribe<SensorEventListener>()
{
SensorEventListener listener = null;
#Override
public void call(final Subscriber<? super SensorEventListener> subscriber)
{
Sensor gsensor;
Sensor msensor;
final float[] mGravity = new float[3];
final float[] mGeomagnetic = new float[3];
listener = new SensorEventListener() {
#Override
public void onSensorChanged(SensorEvent event) {
final float alpha = 0.97f;
Float azimuth = 0f;
synchronized (this) {
if(switchChecked == false) {
subscriber.onNext(listener);
subscriber.onCompleted();
}
if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {
mGravity[0] = alpha * mGravity[0] + (1 - alpha)
* event.values[0];
mGravity[1] = alpha * mGravity[1] + (1 - alpha)
* event.values[1];
mGravity[2] = alpha * mGravity[2] + (1 - alpha)
* event.values[2];
// mGravity = event.values;
// Log.e(TAG, Float.toString(mGravity[0]));
}
if (event.sensor.getType() == Sensor.TYPE_MAGNETIC_FIELD) {
// mGeomagnetic = event.values;
mGeomagnetic[0] = alpha * mGeomagnetic[0] + (1 - alpha)
* event.values[0];
mGeomagnetic[1] = alpha * mGeomagnetic[1] + (1 - alpha)
* event.values[1];
mGeomagnetic[2] = alpha * mGeomagnetic[2] + (1 - alpha)
* event.values[2];
// Log.e(TAG, Float.toString(event.values[0]));
}
float R[] = new float[9];
float I[] = new float[9];
boolean success = SensorManager.getRotationMatrix(R, I, mGravity,
mGeomagnetic);
if (success) {
float orientation[] = new float[3];
SensorManager.getOrientation(R, orientation);
azimuth = (float) Math.toDegrees(orientation[0]); // orientation
azimuth = (azimuth + 360) % 360;
Log.d("obs", "azimuth (rad): " + azimuth);
layout.setRotation(azimuth);
imageView.setRotation(-azimuth);
contlayout.setRotation(azimuth);
}
}
}
#Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
};
sensorManager = (SensorManager) getActivity()
.getSystemService(Context.SENSOR_SERVICE);
gsensor = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
msensor = sensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD);
sensorManager.registerListener(listener, gsensor,
SensorManager.SENSOR_DELAY_FASTEST);
sensorManager.registerListener(listener, msensor,
SensorManager.SENSOR_DELAY_FASTEST);
}
}).observeOn(AndroidSchedulers.mainThread())
.subscribe(new Subscriber<SensorEventListener>() {
#Override
public void onCompleted()
{
}
#Override
public void onError(Throwable e)
{
}
#Override
public void onNext(SensorEventListener listener)
{
sensorManager.unregisterListener(listener);
}
});
}
and it works. However, I'm at the beginning of rxJava and I want to know if there are better ways to do this things:
I've tried to get the azimuth value in onNext() method any times, but it doesn't work
I want to make it asynchronously but I couldn't because registerListener works only in the mainThread() and so if I use Schedulers.io() I need also to do runOnUiThread() method.
There are other ways to do it?
Thank you for help

ImageView still visible after setVisibility(View.INVISIBLE)

I am trying to make a camera app that shows an overlay when a picture is taken.
When this overlay is shown the other UI components (except for the FrameLayout that shows the picture) should go invisible.
But it seems that while my 2 imagebuttons go invisble, my imageview(ivCompass) doesn't.
Here is the code that gets called when a picture is taken
Camera.PictureCallback mPicture = new Camera.PictureCallback() {
#Override
public void onPictureTaken(byte[] data, Camera camera) {
//create a new intent...
String path = createFile(data);
intent = new Intent();
intent.putExtra("path", path);
mBearingProvider.updateBearing();
bearing = mBearingProvider.getBearing();
cardinalDirection = bearingToString(bearing);
//((TextView) findViewById(R.id.tvPicDirection)).setText(cardinalDirection);
Log.e("Direction", cardinalDirection + "," + bearing);
findViewById(R.id.btnFlash).setVisibility(View.INVISIBLE);
findViewById(R.id.btnCapture).setVisibility(View.INVISIBLE);
findViewById(R.id.ivCompass).setVisibility(View.INVISIBLE);
findViewById(R.id.pictureOverlay).setVisibility(View.VISIBLE);
}
};
And here is the layout file
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<FrameLayout
android:id="#+id/camera_preview"
android:layout_width="match_parent"
android:layout_height="match_parent">
</FrameLayout>
<ImageButton
android:id="#+id/btnFlash"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_centerVertical="true"
android:layout_margin="10dp"
android:src="#drawable/camera_flash_on"
android:background="#drawable/circle_flash"
android:onClick="changeFlashMode"/>
<ImageButton
android:id="#+id/btnCapture"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_alignParentRight="true"
android:layout_centerVertical="true"
android:layout_margin="10dp"
android:src="#drawable/icon_camera"
android:background="#drawable/circle_camera"/>
<ImageView
android:id="#+id/ivCompass"
android:layout_width="100dp"
android:layout_height="100dp"
android:layout_alignParentRight="true"
android:src="#drawable/camera_compass"
android:background="#android:color/transparent"/>
<RelativeLayout
android:id="#+id/pictureOverlay"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_margin="20dp"
android:background="#color/alphaBlack"
android:visibility="invisible">
</RelativeLayout>
I think It's just a mistake with naming, syntax or something like that, but I can't seem to find it.
EDIT:
Here is the entire Activity
public class CameraActivity extends AppCompatActivity implements BearingToNorthProvider.ChangeEventListener {
private Camera mCamera;
private CameraView mCameraView;
private float mDist = 0f;
private String flashMode;
private ImageButton flashButton;
private Intent intent;
private BearingToNorthProvider mBearingProvider;
private double bearing;
private double currentBearing = 0d;
private String cardinalDirection = "?";
private final int REQUEST_CODE_ASK_PERMISSIONS = 2;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera);
mCamera = getCameraInstance();
mCameraView = new CameraView(this, mCamera);
FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
preview.addView(mCameraView);
ImageButton captureButton = (ImageButton) findViewById(R.id.btnCapture);
captureButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Camera.Parameters params = mCamera.getParameters();
params.setFlashMode(flashMode);
mCamera.setParameters(params);
mCamera.takePicture(null, null, mPicture);
}
});
SharedPreferences sharedPref = this.getSharedPreferences(getString(R.string.apiKey), Context.MODE_PRIVATE);
flashMode = sharedPref.getString(getString(R.string.flashMode), Camera.Parameters.FLASH_MODE_OFF);
flashButton = (ImageButton) findViewById(R.id.btnFlash);
setFlashButton();
mBearingProvider = new BearingToNorthProvider(this,this);
mBearingProvider.setChangeEventListener(this);
mBearingProvider.start();
}
#Override
protected void onPause() {
super.onPause();
mBearingProvider.stop();
}
/**
* Helper method to access the camera returns null if it cannot get the
* camera or does not exist
*
* #return the instance of the camera
*/
private Camera getCameraInstance() {
Camera camera = null;
try {
camera = Camera.open();
} catch (Exception e) {
Log.e("CamException", e.toString());
}
return camera;
}
Camera.PictureCallback mPicture = new Camera.PictureCallback() {
#Override
public void onPictureTaken(byte[] data, Camera camera) {
//create a new intent...
String path = createFile(data);
intent = new Intent();
intent.putExtra("path", path);
mBearingProvider.updateBearing();
bearing = mBearingProvider.getBearing();
cardinalDirection = bearingToString(bearing);
//((TextView) findViewById(R.id.tvPicDirection)).setText(cardinalDirection);
Log.e("Direction", cardinalDirection + "," + bearing);
findViewById(R.id.btnFlash).setVisibility(View.INVISIBLE);
findViewById(R.id.btnCapture).setVisibility(View.INVISIBLE);
findViewById(R.id.ivCompass).setVisibility(View.INVISIBLE);
findViewById(R.id.pictureOverlay).setVisibility(View.VISIBLE);
}
};
private void confirmPicture(View v) {
/*String direction = String.valueOf(((TextView) findViewById(R.id.tvPicDirection)).getText());
String description = String.valueOf(((EditText) findViewById(R.id.tvPicDescription)).getText());
intent.putExtra("direction", direction);
intent.putExtra("description", description);*/
//close this Activity...
setResult(Activity.RESULT_OK, intent);
finish();
}
//region File Methods
/**
* Method that creates a file from the given byte array and saves the file in the Pictures Directory
* #param data is the array of bytes that represent the picture taken by the camera
* #return the path of created file
*/
private String createFile(byte[] data){
checkFilePermissions();
File picFile = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES) + File.separator + "tempPic.jpg" + File.separator);
String path = picFile.getPath();
try {
BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(picFile));
bos.write(data);
bos.flush();
bos.close();
return path;
} catch (IOException e) {
e.printStackTrace();
return "";
}
}
/**
* Checks the permission for reading to and writing from the external storage
*/
private void checkFilePermissions() {
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.M) {
int hasWriteExternalStoragePermission = checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE);
if (hasWriteExternalStoragePermission != PackageManager.PERMISSION_GRANTED) {
requestPermissions(new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},
REQUEST_CODE_ASK_PERMISSIONS);
return;
}
}
}
//endregion
//region Zoom Methods
#Override
public boolean onTouchEvent(MotionEvent event) {
// Get the pointer ID
Camera.Parameters params = mCamera.getParameters();
int action = event.getAction();
if (event.getPointerCount() > 1) {
// handle multi-touch events
if (action == MotionEvent.ACTION_POINTER_DOWN) {
mDist = getFingerSpacing(event);
} else if (action == MotionEvent.ACTION_MOVE && params.isZoomSupported()) {
mCamera.cancelAutoFocus();
handleZoom(event, params);
}
} else {
// handle single touch events
if (action == MotionEvent.ACTION_UP) {
handleFocus(event, params);
}
}
return true;
}
private void handleZoom(MotionEvent event, Camera.Parameters params) {
int maxZoom = params.getMaxZoom();
int zoom = params.getZoom();
float newDist = getFingerSpacing(event);
if (newDist > mDist) {
//zoom in
if (zoom < maxZoom)
zoom++;
} else if (newDist < mDist) {
//zoom out
if (zoom > 0)
zoom--;
}
mDist = newDist;
params.setZoom(zoom);
mCamera.setParameters(params);
}
public void handleFocus(MotionEvent event, Camera.Parameters params) {
int pointerId = event.getPointerId(0);
int pointerIndex = event.findPointerIndex(pointerId);
// Get the pointer's current position
float x = event.getX(pointerIndex);
float y = event.getY(pointerIndex);
List<String> supportedFocusModes = params.getSupportedFocusModes();
if (supportedFocusModes != null && supportedFocusModes.contains(Camera.Parameters.FOCUS_MODE_AUTO)) {
mCamera.autoFocus(new Camera.AutoFocusCallback() {
#Override
public void onAutoFocus(boolean b, Camera camera) {
// currently set to auto-focus on single touch
}
});
}
}
/** Determine the space between the first two fingers */
private float getFingerSpacing(MotionEvent event) {
double x = event.getX(0) - event.getX(1);
double y = event.getY(0) - event.getY(1);
return (float) Math.sqrt(x * x + y * y);
}
//endregion
//region Flash Methods
public void changeFlashMode(View v) {
switch (flashMode) {
case Camera.Parameters.FLASH_MODE_ON :
flashMode = Camera.Parameters.FLASH_MODE_AUTO;
break;
case Camera.Parameters.FLASH_MODE_AUTO :
flashMode = Camera.Parameters.FLASH_MODE_OFF;
break;
case Camera.Parameters.FLASH_MODE_OFF :
flashMode = Camera.Parameters.FLASH_MODE_ON;;
break;
}
SharedPreferences sharedPref = getSharedPreferences(getString(R.string.flashMode), Context.MODE_PRIVATE);
SharedPreferences.Editor editor = sharedPref.edit();
editor.putString(getString(R.string.flashMode), flashMode);
editor.commit();
setFlashButton();
}
public void setFlashButton() {
switch (flashMode) {
case Camera.Parameters.FLASH_MODE_ON :
flashButton.setImageDrawable(getResources().getDrawable(R.drawable.camera_flash_on));
break;
case Camera.Parameters.FLASH_MODE_AUTO :
flashButton.setImageDrawable(getResources().getDrawable(R.drawable.camera_flash_auto));
break;
case Camera.Parameters.FLASH_MODE_OFF :
flashButton.setImageDrawable(getResources().getDrawable(R.drawable.camera_flash_off));
break;
}
}
//endregion
//region Bearing Methods
/**
* Method that gives a cardinal direction based on the current bearing to the true north
* #param bearing is the bearing to the true north
* #return cardinal direction that belongs to the bearing
*/
private String bearingToString(Double bearing) {
String strHeading = "?";
if (isBetween(bearing,-180.0,-157.5)) { strHeading = "South"; }
else if (isBetween(bearing,-157.5,-112.5)) { strHeading = "SouthWest"; }
else if (isBetween(bearing,-112.5,-67.5)) { strHeading = "West"; }
else if (isBetween(bearing,-67.5,-22.5)) { strHeading = "NorthWest"; }
else if (isBetween(bearing,-22.5,22.5)) { strHeading = "North"; }
else if (isBetween(bearing,22.5,67.5)) { strHeading = "NorthEast"; }
else if (isBetween(bearing,67.5,112.5)) { strHeading = "East"; }
else if (isBetween(bearing,112.5,157.5)) { strHeading = "SouthEast"; }
else if (isBetween(bearing,157.5,180.0)) { strHeading = "South"; }
return strHeading;
}
/**
* Method that checks if a certain number is in a certain range of numbers
* #param x is the number to check
* #param lower is the number that defines the lower boundary of the number range
* #param upper is the number that defines the upper boundary of the number range
* #return true if the number is between the other numbers, false otherwise
*/
private boolean isBetween(double x, double lower, double upper) {
return lower <= x && x <= upper;
}
/*
Method that triggers when the bearing changes, it sets the current bearing and sends an updated context to the provider
*/
#Override
public void onBearingChanged(double bearing) {
this.bearing = bearing;
mBearingProvider.setContext(this);
ImageView image = (ImageView) findViewById(R.id.ivCompass);
// create a rotation animation (reverse turn degree degrees)
if (bearing < 0) {
bearing += 360;
}
RotateAnimation ra = new RotateAnimation((float)currentBearing,(float)-bearing, Animation.RELATIVE_TO_SELF, 0.5f,Animation.RELATIVE_TO_SELF,0.5f);
// how long the animation will take place
ra.setDuration(210);
// set the animation after the end of the reservation status
ra.setFillAfter(true);
// Start the animation
image.startAnimation(ra);
currentBearing = -bearing;
mBearingProvider.setContext(this);
}
//endregion
}
EDIT 2:
I have made a small change to the onBearingChanged Method and now the compass is still visible, but thinks it's invisible and isn't moving because of my new if statement
#Override
public void onBearingChanged(double bearing) {
this.bearing = bearing;
mBearingProvider.setContext(this);
ImageView image = (ImageView) findViewById(R.id.ivCompass);
if (image.getVisibility() == View.VISIBLE) {
// create a rotation animation (reverse turn degree degrees)
if (bearing < 0) {
bearing += 360;
}
RotateAnimation ra = new RotateAnimation((float) currentBearing, (float) -bearing, Animation.RELATIVE_TO_SELF, 0.5f, Animation.RELATIVE_TO_SELF, 0.5f);
// how long the animation will take place
ra.setDuration(210);
// set the animation after the end of the reservation status
ra.setFillAfter(true);
// Start the animation
image.startAnimation(ra);
currentBearing = -bearing;
}
mBearingProvider.setContext(this);
}

If you have some kind of animation, the animation probably intefieres on the calling to invisibility. Try with this just before calling INVISIBLE:
findViewById(R.id.ivCompass).clearAnimation();

Latitude and longitude per pixel Google static maps

I have a static map, i know center coordinates in latitude and longitude, zoom level and image dimensions.
I don't understood if google static maps are already flattened and latitude and longitude per pixel are the same anywhere. If it's not like that i whant to know how can i calculate latidude and longitude per pixel and then meters per pixel , and how does that values vary with latitude .
P.S. I'm developing an android application that download an static map and computes distance between 2 points , but i've done that asuming the lat and long per pixel are the same ...and doesn't depend on latitude(position on globe)
Here is my mainactivity
package com.mnav.nav;
import android.app.*;
import android.os.*;
import android.view.*;
import android.widget.*;
import android.view.View.*;
import java.net.*;
import org.apache.http.*;
import android.graphics.*;
import java.io.*;
import android.graphics.drawable.*;
public class MainActivity extends Activity
{ Button start, dist;
TextView txt;
EditText lat, longit, zoom;
ImageView img;
Handler mhandler ;
Bitmap bit, original;
Boolean run = false, firstpoint = false, secondpoint = false;
String z, latitude, longitude;
int level;
int[] pointa = new int[2];
int[] pointb = new int[2];
double unit;
int maxx, maxy, minx, miny, distx, disty, distance1;
double distance;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
start=(Button)findViewById(R.id.button);
lat = (EditText)findViewById(R.id.latitude);
longit = (EditText)findViewById(R.id.longitude);
img = (ImageView)findViewById(R.id.img);
zoom =(EditText)findViewById(R.id.zoom);
dist = (Button)findViewById(R.id.dist);
txt = (TextView)findViewById(R.id.txt);
mhandler = new Handler();
start.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View v)
{ z = zoom.getText().toString();
latitude = lat.getText().toString();
longitude = longit.getText().toString();
Thread thr = new Thread(new GetImage());
thr.start();
}
});
img.setOnTouchListener(new OnTouchListener()
{
#Override
public boolean onTouch(View v, MotionEvent event)
{ int i, j;
int x = (int)event.getX();
int vertical = (int)event.getY();
if(secondpoint==true)
{ bit = original.copy(Bitmap.Config.ARGB_4444, true);
img.setImageBitmap(bit);
secondpoint = false;
}
txt.setText(Integer.toString(x)+ " "+Integer.toString(vertical));
for (i = x-2; i < x+3; i++)
{
for(j=vertical-2; j<vertical+3; j++)
{
bit.setPixel(i,j, Color.WHITE);
}
}
bit.setPixel(x,vertical,Color.GREEN);
img.setImageBitmap(bit);
if(firstpoint)
{
pointb[0] = x; pointb[1]=vertical;
secondpoint = true;
firstpoint = false;
}
else
{
pointa[0]=x; pointa[1]=vertical;
firstpoint=true;
}
return false;
}
});
dist.setOnClickListener(new OnClickListener()
{
#Override
public void onClick(View p1)
{
unit = 0.1412/800;
unit = unit*500;
level = Integer.parseInt(z);
if(level == 20)
{
unit = unit;
}
else
if(level == 19)
{
unit = unit*2;
}
else
if(level==18)
{
unit = unit*4;
}
else
if(level == 17)
{
unit =unit*8;
}
else
if(level==16)
{
unit = unit*16;
}
else
if(level==15)
{
unit = unit*32;
}
else
if(level==14)
{
unit = unit*64;
}
else
if(level==13)
{
unit = unit*128;
}
else
if(level == 12)
{
unit = unit*256;
}
else
if(level==11)
{
unit = unit*512;
}
else
if(level==10)
{
unit = unit*1024;
}
distx = Math.abs(pointa[0]-pointb[0]);
disty= Math.abs(pointa[1]-pointb[1]);
distance1 = distx*distx+disty*disty;
distance = Math.sqrt(distance1);
distance = unit*distance;
txt.setText(Double.toString(distance)+" meters");
}
});
}
public class GetImage implements Runnable
{
String Url = "http://maps.google.com/staticmap?center=" + latitude+","+longitude+"&format=png&zoom="+ z +"&size=500x500&scale=1&maptype=hybrid&key=ABQIAAAA-O3c-Om9OcvXMOJXreXHAxRexG7zW5nSjltmIc1ZE-b8yotBWhQYQEU3J87QIBc4nfuySpoW_K6woA";
Bitmap bmp;
#Override
public void run()
{
try
{ mhandler.post(new Runnable()
{
#Override
public void run()
{
txt.setText("Wait...file is downloading...");
}
});
bmp = BitmapFactory.decodeStream((InputStream)new URL(Url).getContent());
}
catch (IOException e)
{ mhandler.post(new Runnable()
{
#Override
public void run()
{
// TODO: Implement this method
Toast.makeText(getApplicationContext(), "Something wrong just happend", Toast.LENGTH_LONG).show();
}
});
e.printStackTrace();
}
mhandler.post(new Runnable()
{
#Override
public void run()
{
if (bmp!=null)
{ txt.setText("Map downloaded..");
img.setImageBitmap(bmp);
bit = ((BitmapDrawable)img.getDrawable()).getBitmap();
bit = bit.copy(Bitmap.Config.ARGB_4444, true);
original = bit.copy(Bitmap.Config.ARGB_4444, true);
}
else
{
mhandler.post(new Runnable()
{
#Override
public void run()
{
Toast.makeText(getApplicationContext(), "null bitmap, sorry", Toast.LENGTH_LONG).show();
}
});
}
}
});
}
}
}

Google Maps android IndexOutOfBoundsException

I am trying to get markers placed on the map and fly to their destination. within a forloop i have an if statement, i wish it to do this:
for(i loop){
If (array(i) == null{ spawn plane code}
else {move plane code}
here is the code:
package com.fly.plane;
import java.sql.Time;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Timer;
import java.util.TimerTask;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import com.fly.plane.R;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.MapView;
import com.google.android.gms.maps.Projection;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
import android.R.array;
import android.app.ListActivity;
import android.app.ProgressDialog;
import android.graphics.Point;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.os.SystemClock;
import android.support.v4.app.FragmentActivity;
import android.text.format.DateFormat;
import android.util.Log;
import android.view.View;
import android.view.animation.Interpolator;
import android.view.animation.LinearInterpolator;
import android.widget.TextView;
public class MyMapActivity extends ListActivity {
private ProgressDialog pDialog;
// URL to get data JSON
private static String url = "http://edmundgentle.com/snippets/flights/api.php";
// JSON Node speeds
private static final String TAG_data = "data";
private static final String TAG_BEARING = "bearing";
private static final String TAG_SPEED = "speed";
private static final String TAG_ARR = "arr";
private static final String TAG_ARR_TIME = "time";
private static final String TAG_ARR_LAT = "lat";
private static final String TAG_ARR_LON = "lon";
private static final String TAG_DEP = "dep";
private static final String TAG_DEP_TIME = "time";
private static final String TAG_DEP_LAT = "lat";
private static final String TAG_DEP_LON = "lon";
// data JSONArray
JSONArray data = null;
// Hashmap for ListView
ArrayList<HashMap<String, Double>> contactList;
// Hashmap for ListView
ArrayList<Double> ct;
List<Marker> markers = new ArrayList<Marker>();
//final Handler handler;
private GoogleMap mMap;
public static final LatLng dest(Double alt,Double aln, int i){
//final double latitude = Double.parseDouble(alt);
//final double longitude = Double.parseDouble(aln);
return new LatLng(alt, aln);
}
public double latt = -15.48169437461;
public double lng = -15.48169437461;
public ArrayList<Integer> dLat;
public String[] markerList;
public String dlat;
public String dlon;
public String alat;
public String alon;
private int count;
public boolean wait = true;
//private Button startB;
public TextView text;
Timer timing;
double time = 600;
double timm = 1;
long timer = 18000000;
long newTime;
TextView tv, test;
Thread t;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my_map);
contactList = new ArrayList<HashMap<String, Double>>();
ct = new ArrayList<Double>();
//ListView lv = getListView();
//create markers
new Getdata().execute();
// timer showing time of day in fast time
t = new Thread() {
#Override
public void run() {
try {
while (!isInterrupted()) {
Thread.sleep(600);
runOnUiThread(new Runnable() {
#Override
public void run() {
timer = timer +60000;
if (timer >= 64000000) timer = 18000000;
newTime = timer;
// update TextView here!
//String time = "HH:mm:ss";
//tv.setText(DateFormat.format(time , timer));
tv.setText(Double.toString(time));
test.setText(Double.toString(timm));
//tv.setText(Double.toString(contactList.get(20).get("time")));
//Timer();
}
});
}
} catch (InterruptedException e) {
}
}
};
tv = new TextView(this);
test = new TextView(this);
tv=(TextView)findViewById(R.id.timer);
test=(TextView)findViewById(R.id.test);
// run the mUpdateUITimerTask's run() method in 10 seconds from now
}
// animate each plane
public void animateMarker(final Marker marker , final LatLng toPosition,
final boolean hideMarker, final double spd) {
float speed = (float) spd;// Float.parseFloat(spd);
final Handler handler = new Handler();
final long start = SystemClock.uptimeMillis();
Projection proj = mMap.getProjection();
Point startPoint = proj.toScreenLocation(marker.getPosition());
final LatLng startLatLng = proj.fromScreenLocation(startPoint);
final float duration = 10 * speed;
final Interpolator interpolator = new LinearInterpolator();
handler.post(new Runnable() {
#Override
public void run() {
long elapsed = SystemClock.uptimeMillis() - start;
float t = interpolator.getInterpolation((float) ((float) elapsed
/ duration));
double lng = t * toPosition.longitude + (1 - t)
* startLatLng.longitude;
double lat = t * toPosition.latitude + (1 - t)
* startLatLng.latitude;
marker.setPosition(new LatLng(lat, lng));
if (t < 1.0) {
// Post again 16ms later.
handler.postDelayed(this, 16);
} else {
handler.postDelayed(this, 16);
if (hideMarker) {
marker.setVisible(false);
} else {
marker.setVisible(true);
}
}
}
});
}
public void Timer(){
//TimerTask tasknew = new TimerTask();
timing = new Timer();
timing.schedule(new CreateMarker(), 1000, 1000);
}
public String calcCurPos(double curlat, double curlon, double deslat, double deslon, double avgSpd, double bearing){
double distance = avgSpd * 0.0167;
// check if degrees or radians
//deslat = distance * Math.cosh(bearing);
//double retLat = curlat + deslat;
//double dPhi = Math.log(Math.tan(retLat/2+Math.PI/4)/Math.tan(curlat/2+Math.PI/4));
//double q = deslat/dPhi deslat/dPhi : Math.cos(curlat);
bearing = bearing * Math.PI / 180;
int radius = 6371;
double nextLat = Math.asin(Math.sin(curlat)* Math.cos(distance/radius)
+ Math.cos(curlat)*Math.sin(distance/radius)*Math.cos(bearing));
double nextLon = curlon + Math.atan2(Math.sin(bearing)* Math.sin(distance/ radius)
* Math.cos(curlat), Math.cos(distance/radius)-Math.sin(curlat) * Math.sin(nextLat));
nextLat = (nextLat * 180) / Math.PI;
nextLon = (nextLon * 180) / Math.PI;
/**
* Warning might want to convert them to string prior to return.
*/
return nextLat + ";" + nextLon;
}
public class CreateMarker extends TimerTask{
#Override
public void run() {
// TODO Auto-generated method stub
// print test
//tv.setText(Double.toString(time));
//tv.setText(Double.toString(time));
if (time >= 2400){
time=0;
}
time += 1;
//mMap = ((MapFragment) getFragmentManager().findFragmentById(R.id.map)).getMap();
for (int i =0; i < 100;i++){
// get data from array list
final double depLat = contactList.get(i).get("dlat");
final double depLon = contactList.get(i).get("dlon");
final double arLat = contactList.get(i).get("alat");
final double arLon = contactList.get(i).get("alon");
final double spd = contactList.get(i).get("speed");
final double dTime = contactList.get(i).get("time");
double curLat = contactList.get(i).get("clat");
double curLon = contactList.get(i).get("clon");
final double bearing = contactList.get(i).get("bearing");
final int j = i;
//int dTime = Integer.parseInt(dtime);
double oldLat = curLat;
if (time >= dTime)
{
if (curLat < arLat || curLat > 0){
String latlng = calcCurPos(curLat, curLon, arLat, arLon ,spd, bearing );
String[] values = latlng.split(";");
curLat = Double.parseDouble(values[0]);
curLon = Double.parseDouble(values[1]);
final double crLat = curLat;
final double crLon = curLon;
final LatLng position = new LatLng(crLat,crLon);
/*Marker mo = mMap.addMarker(new MarkerOptions()
.position(new LatLng(depLat, depLon))
.icon(BitmapDescriptorFactory.fromResource(R.drawable.planemarker)));*/
//DrawMarker();
//animateMarker(markers.get(i), position , true, spd);
try{
if (markers.get(i) == null){
//timm += 1;
timm += 1;
runOnUiThread(new Runnable() {
#Override
public void run() {
final Marker marker = mMap.addMarker(new MarkerOptions()
.position(new LatLng(depLat, depLon))
.title("Hello world")
.icon(BitmapDescriptorFactory.fromResource(R.drawable.planemarker)));
markers.add(marker);
//marker.setVisible(false);
//animateMarker(markers.get(j), new LatLng(arLat,arLon) , true, spd);
//Marker marker = markers.get(i);
//marker.setPosition(position);
}
});
}
else //(markers.get(i) != null){
{
Marker marker = markers.get(i);
marker.setPosition(position);
marker.setVisible(false);
//animateMarker(markers.get(i), position , true, spd);
}
}
catch(NullPointerException npe)
{
//do something else
}
}
}
}
//return null;
}
}
/**
* Async task class to get json by making HTTP call
* */
private class Getdata extends AsyncTask<Void, Void, Void> {
#Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
pDialog = new ProgressDialog(MyMapActivity.this);
pDialog.setMessage("Please wait...");
pDialog.setCancelable(false);
pDialog.show();
}
#Override
protected Void doInBackground(Void... arg0) {
// Creating service handler class instance
HTTPHandler sh = new HTTPHandler();
// Making a request to url and getting response
String jsonStr = sh.makeServiceCall(url, HTTPHandler.GET);
Log.d("Response: ", "> " + jsonStr);
boolean limit = false;
if (jsonStr != null || limit == false) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
// Getting JSON Array node
data = jsonObj.getJSONArray(TAG_data);
// looping through All data
for (int i = 0; i < data.length(); i++) {
JSONObject c = data.getJSONObject(i);
String bearing = c.getString(TAG_BEARING);
String spd = c.getString(TAG_SPEED);
// departure node is JSON Object
JSONObject dep = c.getJSONObject(TAG_DEP);
String dtime = dep.getString(TAG_DEP_TIME);
//String dlat = dep.getString(TAG_DEP_LAT);
//String dlon = dep.getString(TAG_DEP_LON);
dlat = dep.getString(TAG_DEP_LAT);
dlon = dep.getString(TAG_DEP_LON);
// replace : and last 2 0's from departure time
dtime = dtime.replaceAll(":","");
//dtime.replaceAll(";","");
dtime = dtime.substring(0,dtime.length()-2);
// arrival node is JSON Object
JSONObject arr = c.getJSONObject(TAG_ARR);
String alt = arr.getString(TAG_ARR_LAT);
String aln = arr.getString(TAG_ARR_LON);
// convert data positions to doubles for Google Maps + stuff
double brng = Double.parseDouble(bearing);
brng = brng * Math.PI / 180;
double speed = Double.parseDouble(spd);
//double brng = Double.parseDouble(bearing);
double dLatitude = Double.parseDouble(dlat);
double dLongitude = Double.parseDouble(dlon);
double aLatitude = Double.parseDouble(alt);
double aLongitude = Double.parseDouble(aln);
double cLatitude = Double.parseDouble(dlat);
double cLongitude = Double.parseDouble(dlon);
double dtme = Double.parseDouble(dtime);
// tmp hashmap for single contact
HashMap<String, Double> contact = new HashMap<String, Double>();
contact.put("bearing", brng);
contact.put("speed", speed);
contact.put("time", dtme);
contact.put("alat", aLatitude);
contact.put("alon", aLongitude);
contact.put("dlat", dLatitude);
contact.put("dlon", dLongitude);
contact.put("clat", cLatitude);
contact.put("clon", cLongitude);
// adding contact to contact list
contactList.add(contact);
if (i== data.length()){
wait = false;
}
}
} catch (JSONException e) {
e.printStackTrace();
}
} else {
Log.e("ServiceHandler", "Couldn't get any data from the url");
}
return null;
}
// spawns planes when json loaded
#Override
protected void onPostExecute(Void result) {
Timer();
t.start();
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
// use plane api for latlon
mMap = ((MapFragment) getFragmentManager().findFragmentById(R.id.map)).getMap();
//for (int i = 0; i < contactList.size() ; i++)
}}
}
and here is the error message:
02-26 21:53:42.031: E/AndroidRuntime(14970): FATAL EXCEPTION: Timer-0
02-26 21:53:42.031: E/AndroidRuntime(14970): java.lang.IndexOutOfBoundsException: Invalid index 0, size is 0
02-26 21:53:42.031: E/AndroidRuntime(14970): at java.util.ArrayList.throwIndexOutOfBoundsException(ArrayList.java:255)
02-26 21:53:42.031: E/AndroidRuntime(14970): at java.util.ArrayList.get(ArrayList.java:308)
02-26 21:53:42.031: E/AndroidRuntime(14970): at com.fly.plane.MyMapActivity$CreateMarker.run(MyMapActivity.java:395)
02-26 21:53:42.031: E/AndroidRuntime(14970): at java.util.Timer$TimerImpl.run(Timer.java:284)
i understand that the markers.get(i) is causing the problem, but i dont know how to check if the markers array is null without it throwing this error.
Any help would be appreciated.

You can use Map<Integer, Marker> (Integer are keys and Marker are values). Then you can leverage Map.get() which don't throws Exception if key is Integer and not null (your i will not be null in your code).
Declare markers as Map:
Map<Integer, Marker> markers = new HashMap<Integer, Marker>();
Inside CreateMarker.run() after final LatLng position = new LatLng(crLat,crLon); change as follows:
//implicit boxing to use int in Map
Integer ii = Integer.valueOf(i);
//try to get marker by index from map (index is the key)
Marker markerByIndex = markers.get(ii);
//Map.get() returns null if object by specified key is not in map
if (markerByIndex == null){
//marker doesn't exists - create it, add to Google Map and to Map by key
timm += 1;
runOnUiThread(new Runnable() {
#Override
public void run() {
final Marker marker = mMap.addMarker(new MarkerOptions()
.position(new LatLng(depLat, depLon))
.title("Hello world")
.icon(BitmapDescriptorFactory.fromResource(R.drawable.planemarker)));
//put marker to map using i as a key
markers.put(ii, marker);
}
});
} else {
//marker exists, mutate it
markerByIndex.setPosition(position);
markerByIndex.setVisible(false);
//...replace the marker in map
markers.put(ii, markerByIndex);
//animate the marker
animateMarker(markerByIndex, position , true, spd);
}

You wrote:
i understand that the markers.get(i) is causing the problem, but i dont know how to check if the markers array is null without it throwing this error.
==> you can check it this way:
if (markers != null && markers.size() > 0) {
//there are actually markers. Calling markers.get(i) should work!
//...as long as i is smaller than markers.size()
} else {
//sorry, no markers! Don't call markers.get(i) here...
}

Android - Calculate Distance Using Haversine Formula (Using GPS , Lat and Long)

I need some help :) I am assign with a project to come out with the distance / speed and time. I have already come out with the Timer. However, the distance is giving me some problem. The distance does not changed at all from I travel from one place to another.
//GPS
private static Double EARTH_RADIUS = 6371.00; // Radius in Kilometers default
private static final String DEBUG_TAG = "GPS";
private String[] location;
private double[] coordinates;
private double[] gpsOrg;
private double[] gpsEnd;
private LocationManager lm;
private LocationListener locationListener;
private double totalDistanceTravel;
private boolean mPreviewRunning;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.waterspill);
/*getWindow().setFormat(PixelFormat.TRANSLUCENT);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN,
WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN);*/
mSurfaceView = (SurfaceView) findViewById(R.id.surface_camera);
mSurfaceHolder = mSurfaceView.getHolder();
mSurfaceHolder.addCallback(this);
mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
distanceCal=new LocationUtil(EARTH_RADIUS);
totalDistanceTravel=0;
// ---Additional---
//mapView = (MapView) findViewById(R.id.mapview1);
//mc = mapView.getController();
// ----------------
txtTimer = (TextView) findViewById(R.id.Timer);
gpsOnOff = (TextView) findViewById(R.id.gpsOnOff);
disTrav = (TextView) findViewById(R.id.disTrav);
startButton = (Button) findViewById(R.id.startButton);
startButton.setOnClickListener(startButtonClickListener);
stopButton = (Button) findViewById(R.id.stopButton);
stopButton.setOnClickListener(stopButtonClickListener);
testButton = (Button) findViewById(R.id.testButton);
testButton.setOnClickListener(testButtonClickListener);
startButton.setEnabled(false);
stopButton.setEnabled(false);
getLocation();
}
public void getLocation()
{
lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
locationListener = new MyLocationListener();
lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 3000, 0,locationListener);
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER,3000,0,locationListener);
}
private OnClickListener startButtonClickListener = new OnClickListener()
{
public void onClick(View v) {
// TODO Auto-generated method stub
gpsOrg=coordinates;
totalDistanceTravel=0;
Toast.makeText(getBaseContext(),
"Start Location locked : Lat: " + gpsOrg[0] +
" Lng: " + gpsOrg[1],
Toast.LENGTH_SHORT).show();
if (!isTimerStarted)
{
startTimer();
isTimerStarted = true;
}
stopButton.setEnabled(true);
}
};
private OnClickListener stopButtonClickListener = new OnClickListener()
{
public void onClick(View v) {
// TODO Auto-generated method stub
gpsEnd=coordinates;
//gpsEnd = new double[2];
//gpsEnd[0]=1.457899;
//gpsEnd[1]=103.828659;
Toast.makeText(getBaseContext(),
"End Location locked : Lat: " + gpsEnd[0] +
" Lng: " + gpsEnd[1],
Toast.LENGTH_SHORT).show();
double d = distFrom(gpsOrg[0],gpsOrg[1],gpsEnd[0],gpsEnd[1]);
totalDistanceTravel+=d;
disTrav.setText(Double.toString(d));
}
};
public static double distFrom(double lat1, double lng1, double lat2, double lng2) {
double earthRadius = EARTH_RADIUS;
double dLat = Math.toRadians(lat2-lat1);
double dLng = Math.toRadians(lng2-lng1);
double a = Math.sin(dLat/2) * Math.sin(dLat/2) +
Math.cos(Math.toRadians(lat1)) * Math.cos(Math.toRadians(lat2)) *
Math.sin(dLng/2) * Math.sin(dLng/2);
double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
double dist = earthRadius * c;
return new Float(dist).floatValue();
}
public class MyLocationListener implements LocationListener
{
public void onLocationChanged(Location loc) {
if(coordinates!=null)
{
double[] coordinatesPrev=coordinates;
double d = distFrom(coordinatesPrev[0],coordinatesPrev[1],coordinates[0],coordinates[1]);
totalDistanceTravel+=d;
}
else
{
coordinates = getGPS();
}
startButton.setEnabled(true);
}
private double[] getGPS() {
List<String> providers = lm.getProviders(true);
double[] gps = new double[2];
//Loop over the array backwards, and if you get an accurate location, then break out the loop
Location l = null;
for (int i=providers.size()-1; i>=0; i--) {
String s = providers.get(i);
Log.d("LocServ",String.format("provider (%d) is %s",i,s));
l = lm.getLastKnownLocation(providers.get(i));
if (l != null) {
gps[0] = l.getLatitude();
gps[1] = l.getLongitude();
Log.d("LocServ",String.format("Lat %f, Long %f accuracy=%f",gps[0],gps[1],l.getAccuracy()));
gpsOnOff.setText("On");
}
}
return gps;
}
Is there anything wrong with my codes. Please advice and Thanks a lot for your help :)

Test your formula with this: The distance between {-73.995008, 40.752842}, and {-73.994905, 40.752798} should be 0.011532248670891638 km.