Develop Reference

Output file using FFmpeg in Xamarin Android

I'm building an android app using Xamarin. The requirement of the app is to capture video from the camera and encode the video to send it across to a server.
Initially, I was using an encoder library on the server-side to encode recorded video but it was proving to be extremely unreliable and inefficient especially for large-sized video files. I have posted my issues on another thread here
I then decided to encode the video on the client-side and then send it to the server. I've found encoding to be a bit complicated and there isn't much information available on how this can be done. So, I searched for the only way I knew how to encode a video that is by using FFmpeg codec. I've found some solutions. There's a project on GitHub that demonstrates how FFmpeg is used inside a Xamarin android project. However, running the solution doesn't give any output. The project has a binary FFmpeg file which is installed to the phone directory using the code below:
_ffmpegBin = InstallBinary(XamarinAndroidFFmpeg.Resource.Raw.ffmpeg, "ffmpeg", false);
Below is the example code for encoding video into a different set of outputs:
_workingDirectory = Android.OS.Environment.ExternalStorageDirectory.AbsolutePath;
var sourceMp4 = "cat1.mp4";
var destinationPathAndFilename = System.IO.Path.Combine (_workingDirectory, "cat1_out.mp4");
var destinationPathAndFilename2 = System.IO.Path.Combine (_workingDirectory, "cat1_out2.mp4");
var destinationPathAndFilename4 = System.IO.Path.Combine (_workingDirectory, "cat1_out4.wav");
if (File.Exists (destinationPathAndFilename))
File.Delete (destinationPathAndFilename);
CreateSampleFile(Resource.Raw.cat1, _workingDirectory, sourceMp4);
var ffmpeg = new FFMpeg (this, _workingDirectory);
var sourceClip = new Clip (System.IO.Path.Combine(_workingDirectory, sourceMp4));
var result = ffmpeg.GetInfo (sourceClip);
var br = System.Environment.NewLine;
// There are callbacks based on Standard Output and Standard Error when ffmpeg binary is running as a process:
var onComplete = new MyCommand ((_) => {
RunOnUiThread(() =>_logView.Append("DONE!" + br + br));
});
var onMessage = new MyCommand ((message) => {
RunOnUiThread(() =>_logView.Append(message + br + br));
});
var callbacks = new FFMpegCallbacks (onComplete, onMessage);
// 1. The idea of this first test is to show that video editing is possible via FFmpeg:
// It results in a 150x150 movie that eventually zooms on a cat ear. This is desaturated, and there's a fade-in.
var filters = new List<VideoFilter> ();
filters.Add (new FadeVideoFilter ("in", 0, 100));
filters.Add(new CropVideoFilter("150","150","0","0"));
filters.Add(new ColorVideoFilter(1.0m, 1.0m, 0.0m, 0.5m, 1.0m, 1.0m, 1.0m, 1.0m));
var outputClip = new Clip (destinationPathAndFilename) { videoFilter = VideoFilter.Build (filters) };
outputClip.H264_CRF = "18"; // It's the quality coefficient for H264 - Default is 28. I think 18 is pretty good.
ffmpeg.ProcessVideo(sourceClip, outputClip, true, new FFMpegCallbacks(onComplete, onMessage));
//2. This is a similar version in command line only:
string[] cmds = new string[] {
"-y",
"-i",
sourceClip.path,
"-strict",
"-2",
"-vf",
"mp=eq2=1:1.68:0.3:1.25:1:0.96:1",
destinationPathAndFilename2,
"-acodec",
"copy",
};
ffmpeg.Execute (cmds, callbacks);
// 3. This lists codecs:
string[] cmds3 = new string[] {
"-codecs",
};
ffmpeg.Execute (cmds, callbacks);
// 4. This convers to WAV
// Note that the cat movie just has some silent house noise.
ffmpeg.ConvertToWaveAudio(sourceClip, destinationPathAndFilename4, 44100, 2, callbacks, true);
I have tried different commands but no output file is generated. I have tried to use another project found here but this one has the same issue. I don't get any errors but no output file is generated. I'm really hoping someone can help me find a way I can manage to use FFmpeg in my project or some way to compress video to transport it to the server.
I will really appreciate if someone can point me in the right direction.

Just figure how to get the output by adding the permission in AndroidManifest file.
android.permission.WRITE_EXTERNAL_STORAG

Please read the update on the repository, it says that there is a second package, Xamarin.Android.MP4Transcoder for Android 6.0 onwards.
Install NuGet https://www.nuget.org/packages/Xamarin.Android.MP4Transcoder/
await Xamarin.MP4Transcoder.Transcoder
.For720pFormat()
.ConvertAsync(inputFile, ouputFile, f => {
onProgress?.Invoke((int)(f * (double)100), 100);
});
return ouputFile;
For Previous Android versions
Soruce Code https://github.com/neurospeech/xamarin-android-ffmpeg
Install-Package Xamarin.Android.FFmpeg
Use this as template, this lets you log output as well as calculates progress.
You can take a look at source, this one downloads ffmpeg and verifies sha1 hash on first use.
public class VideoConverter
{
public VideoConverter()
{
}
public File ConvertFile(Context contex,
File inputFile,
Action<string> logger = null,
Action<int,int> onProgress = null)
{
File ouputFile = new File(inputFile.CanonicalPath + ".mpg");
ouputFile.DeleteOnExit();
List<string> cmd = new List<string>();
cmd.Add("-y");
cmd.Add("-i");
cmd.Add(inputFile.CanonicalPath);
MediaMetadataRetriever m = new MediaMetadataRetriever();
m.SetDataSource(inputFile.CanonicalPath);
string rotate = m.ExtractMetadata(Android.Media.MetadataKey.VideoRotation);
int r = 0;
if (!string.IsNullOrWhiteSpace(rotate)) {
r = int.Parse(rotate);
}
cmd.Add("-b:v");
cmd.Add("1M");
cmd.Add("-b:a");
cmd.Add("128k");
switch (r)
{
case 270:
cmd.Add("-vf scale=-1:480,transpose=cclock");
break;
case 180:
cmd.Add("-vf scale=-1:480,transpose=cclock,transpose=cclock");
break;
case 90:
cmd.Add("-vf scale=480:-1,transpose=clock");
break;
case 0:
cmd.Add("-vf scale=-1:480");
break;
default:
break;
}
cmd.Add("-f");
cmd.Add("mpeg");
cmd.Add(ouputFile.CanonicalPath);
string cmdParams = string.Join(" ", cmd);
int total = 0;
int current = 0;
await FFMpeg.Xamarin.FFMpegLibrary.Run(
context,
cmdParams
, (s) => {
logger?.Invoke(s);
int n = Extract(s, "Duration:", ",");
if (n != -1) {
total = n;
}
n = Extract(s, "time=", " bitrate=");
if (n != -1) {
current = n;
onProgress?.Invoke(current, total);
}
});
return ouputFile;
}
int Extract(String text, String start, String end)
{
int i = text.IndexOf(start);
if (i != -1)
{
text = text.Substring(i + start.Length);
i = text.IndexOf(end);
if (i != -1)
{
text = text.Substring(0, i);
return parseTime(text);
}
}
return -1;
}
public static int parseTime(String time)
{
time = time.Trim();
String[] tokens = time.Split(':');
int hours = int.Parse(tokens[0]);
int minutes = int.Parse(tokens[1]);
float seconds = float.Parse(tokens[2]);
int s = (int)seconds * 100;
return hours * 360000 + minutes * 60100 + s;
}
}

Read random files from assets on Android

Hello I'm having problem reading random files on Eclipse, Android programming...
At assets folders I have a folder called "fytyra" and there are jpg pictures with mumbers like 1.jpg 2.jpg...
I tried to debug the app, list was null always.. ???
//Gets a random number from 0 to 431,.. I think it is !
private int nasiqim (){
int i = 0;
Random nasiqimi = new Random();
i=nasiqimi.nextInt(431);
return i;
}
//This need to fill list with integers and to not repeat the same number...
private void listaEFotove(){
int nse=-1,i=0,numriRandom;
while (nse<0){
numriRandom = nasiqim();
nse = Arrays.binarySearch(numrat, numriRandom);
if (nse <0 ){
numrat[i] = numriRandom;
i++;
}
if (i == 11)break;
}
}
This is to fill imageView with photos...
private void merrFytyrat(){
int fotoNr=0;
String emri;
listaEFotove();
for (int i=0; i<11;i++){
fotoNr=numrat[i];
if (i==0){
try
{
emri = Integer.toString(fotoNr);
// get input stream
InputStream ims = getAssets().open( "fytyra/" + emri +".jpg");
// load image as Drawable
Drawable d = Drawable.createFromStream(ims, null);
// set image to ImageView
i11.setImageDrawable(d);
}
catch(IOException ex)
{
return;
};
}
else if (i==1){ ... Continues until 12...

I got the answer, thank you greenapps, for trying to help mee...
My mistake was on declaration of array... so my new code is this :
int[] numrat = new int[12];
it was like this :
int[] numrat = null;
another mistake was on the getAssets, like greenapps told me
getAssets().open( "/fytyra/" + emri +".jpg");
now thanks to him i changed that code to :
getAssets().open( "fytyra/" + emri +".jpg");
No everything works perfect,.,
This site is the best, Thank you...

Cordova plugin Android Activity - accessing resources

I am developing a Cordova plugin for Android and I am having difficulty overcoming accessing project resources from within an activity - the plugin should be project independent, but accessing the resources (e.g. R.java) is proving tricky.
My plugin, for now, is made up of two very simple classes: RedLaser.java and RedLaserScanner.java.
RedLaser.java
Inherits from CordovaPlugin and so contains the execute method and looks similar to the following.
public class RedLaser extends CordovaPlugin {
private static final string SCAN_ACTION = "scan";
public boolean execute(String action, final JSONArray args, final CallbackContext callbackContext) throws JSONException {
if (action.equals(SCAN_ACTION)) {
this.cordova.getActivity().runOnUiThread(new Runnable() {
#Override
public void run() {
scan(args, callbackContext);
}
});
return true;
}
return false;
}
private void scan(JSONArray args, CallbackContext callbackContext) {
Intent intent = new Intent(this.cordova.getActivity().getApplicationContext(), RedLaserScanner.class);
this.cordova.startActivityForResult((CordovaPlugin) this, intent, 1);
}
#Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
// Do something with the result
}
}
RedLaserScanner.java
The RedLaserScanner contains the Android Activity logic and inherits from BarcodeScanActivity (which is a RedLaser SDK class, presumably itself inherits from Activity);
A very simple structure is as follows:
public class RedLaserScanner extends BarcodeScanActivity {
#Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.preview_overlay_new_portrait);
}
}
I am having trouble because I need to access the project's resources to access R.layout.preview_overlay_new_portrait (which are scatted in the Eclipse project) - but I cannot do this unless I import com.myProject.myApp.R - which makes my plugin have a dependency on the project itself.
I did some investigation and found cordova.getActivity().getResources() which seems useful, but this is not accessible from within my RedLaserScanner - because it does not inherit from CordovaPlugin.
Can somebody please help me with some pointers?
Thanks

I just ran into the same issue and it turns out to be pretty easy to solve. RedLaserScanner extends an activity, so you can just call getResources() like this:
setContentView(getResources("preview_overlay_new_portrait", "layout", getPackageName()));

Hooks can be used to replace source file contents to remove wrong imports and/or add the right imports of resources.
I created a script that do it without needing to specify the files. It tries to find source files (with .java extension), removes any resource import already in it and then put the right resources import (if needed), using the Cordova application package name.
This is the script:
#!/usr/bin/env node
/*
* A hook to add resources class (R.java) import to Android classes which uses it.
*/
function getRegexGroupMatches(string, regex, index) {
index || (index = 1)
var matches = [];
var match;
if (regex.global) {
while (match = regex.exec(string)) {
matches.push(match[index]);
console.log('Match:', match);
}
}
else {
if (match = regex.exec(string)) {
matches.push(match[index]);
}
}
return matches;
}
module.exports = function (ctx) {
// If Android platform is not installed, don't even execute
if (ctx.opts.cordova.platforms.indexOf('android') < 0)
return;
var fs = ctx.requireCordovaModule('fs'),
path = ctx.requireCordovaModule('path'),
Q = ctx.requireCordovaModule('q');
var deferral = Q.defer();
var platformSourcesRoot = path.join(ctx.opts.projectRoot, 'platforms/android/src');
var pluginSourcesRoot = path.join(ctx.opts.plugin.dir, 'src/android');
var androidPluginsData = JSON.parse(fs.readFileSync(path.join(ctx.opts.projectRoot, 'plugins', 'android.json'), 'utf8'));
var appPackage = androidPluginsData.installed_plugins[ctx.opts.plugin.id]['PACKAGE_NAME'];
fs.readdir(pluginSourcesRoot, function (err, files) {
if (err) {
console.error('Error when reading file:', err)
deferral.reject();
return
}
var deferrals = [];
files.filter(function (file) { return path.extname(file) === '.java'; })
.forEach(function (file) {
var deferral = Q.defer();
var filename = path.basename(file);
var file = path.join(pluginSourcesRoot, filename);
fs.readFile(file, 'utf-8', function (err, contents) {
if (err) {
console.error('Error when reading file:', err)
deferral.reject();
return
}
if (contents.match(/[^\.\w]R\./)) {
console.log('Trying to get packages from file:', filename);
var packages = getRegexGroupMatches(contents, /package ([^;]+);/);
for (var p = 0; p < packages.length; p++) {
try {
var package = packages[p];
var sourceFile = path.join(platformSourcesRoot, package.replace(/\./g, '/'), filename)
if (!fs.existsSync(sourceFile))
throw 'Can\'t find file in installed platform directory: "' + sourceFile + '".';
var sourceFileContents = fs.readFileSync(sourceFile, 'utf8');
if (!sourceFileContents)
throw 'Can\'t read file contents.';
var newContents = sourceFileContents
.replace(/(import ([^;]+).R;)/g, '')
.replace(/(package ([^;]+);)/g, '$1 import ' + appPackage + '.R;');
fs.writeFileSync(sourceFile, newContents, 'utf8');
break;
}
catch (ex) {
console.log('Could not add import to "' + filename + '" using package "' + package + '". ' + ex);
}
}
}
});
deferrals.push(deferral.promise);
});
Q.all(deferrals)
.then(function() {
console.log('Done with the hook!');
deferral.resolve();
})
});
return deferral.promise;
}
Just add as an after_plugin_install hook (for Android platform) in your plugin.xml:
<hook type="after_plugin_install" src="scripts/android/addResourcesClassImport.js" />
Hope it helps someone!

I implemented a helper for this to keep things clean. It also helps when you create a plugin which takes config.xml arguments which you store in a string resource file in the plugin.
private int getAppResource(String name, String type) {
return cordova.getActivity().getResources().getIdentifier(name, type, cordova.getActivity().getPackageName());
}
You can use it as follows:
getAppResource("app_name", "string");
That would return the string resource ID for app_name, the actually value still needs to be retrieved by calling:
this.activity.getString(getAppResource("app_name", "string"))
Or for the situation in the original question:
setContentView(getAppResource("preview_overlay_new_portrait", "layout"));
These days I just create a helper which returns the value immediately from the the helper:
private String getStringResource(String name) {
return this.activity.getString(
this.activity.getResources().getIdentifier(
name, "string", this.activity.getPackageName()));
}
which in turn you'd call like this:
this.getStringResource("app_name");
I think it's important to point out that when you have the resource ID you're not always there yet.

try using android.R.layout.preview_overlay_new_portrait

Create a fast file search function in android

I'm new to android and I'm trying to develop file explorer which includes search function. I'm using a recursive search function that works fine in folders with a few subfolders and files, but for some reason it's EXTREMELY SLOW and could "Force Close" in folders with lots of subfolders and files, because there's not enough memory. I do the search by creating ArrayList where the results will be placed, and then calling the recursive function that will fill the list. The "path" argument is the file where the search will start from, and "query" is the search query.
ArrayList<File> result = new ArrayList<File>();
fileSearch(path, query, result);
this is what the recursive function looks like:
private void fileSearch(File dir, String query, ArrayList<File> res) {
if (dir.getName().toLowerCase().contains(query.toLowerCase()))
res.add(dir);
if (dir.isDirectory() && !dir.isHidden()) {
if (dir.list() != null) {
for (File item : dir.listFiles()) {
fileSearch(item, query, res);
}
}
}
}
If someone could point me to a way of performing a faster and/or more efficient file search, I would really appreciate that.
EDIT:
This is how I tried to do the job with AsyncTask:
private class Search extends AsyncTask<File, Integer, Void> {
String query;
ArrayList<File> result = new ArrayList<File>();
public Search(String query){
this.query = query;
setTitle("Searching");
}
#Override
protected Void doInBackground(File... item) {
int count = item.length;
for (int i = 0; i < count; i++) {
fileSearch(item[i], query, result);
publishProgress((int) ((i / (float) count) * 100));
// Escape early if cancel() is called
if (isCancelled()) break;
}
return null;
}
protected void onProgressUpdate(Integer... progress) {
setProgress(progress[0]);
}
protected void onPostExecute() {
searchResults = new ListItemDetails[result.size()];
for (int i = 0; i < result.size(); i++) {
File temp = result.get(i);
if (temp.isDirectory())
searchResults[i] = new ListItemDetails(temp.getAbsolutePath(),
R.drawable.folder, temp.lastModified(), temp.length());
else {
String ext;
if (temp.getName().lastIndexOf('.') == -1)
ext = "";
else
ext = temp.getName().substring(
temp.getName().lastIndexOf('.'));
searchResults[i] = new ListItemDetails(temp.getAbsolutePath(),
getIcon(ext), temp.lastModified(), temp.length());
}
}
finishSearch();
}
}
public void finishSearch() {
Intent intent = new Intent(this, SearchResults.class);
startActivity(intent);
}
The call to finishSearch() is just so I can create the Intent to show the results in other Activity. Any ideas, suggestions, tips? Thanks in advance

It is possible that you are hitting symbolic links and going into an infinitive loop with your search function and depleting available memory to your application.
I would suggest you to keep a separate list containing canonical paths (File.getCanonicalPath()) of directories you've visited and avoid visiting them over and over again.

Why don't you use Apache Commons IO? It has some functions to deal with searching.
I also suggest using the method FileUtils.listFiles, which takes a folder, a search query and a directory filter as parameters.
The following example returns you a list of all file's paths that matched according to a regex. Try adding it in doInBackground of your AsyncTask:
Collection files = FileUtils.listFiles(new File(yourRootPath),
new RegexFileFilter(searchQuery),
DirectoryFileFilter.DIRECTORY);

Have you looked into Lucene?
It is especially designed to index and query large numbers of free-text documents, so many of the I/O streaming and indexing tasks have already been solved for you. If you remove the recursion and do the document indexing using a Lucene index in a purely iterative fashion, memory issues may be mitigated.
Look into this thread:
Lucene in Android

Do it in the background, and starting from Android O (API 26) , you can use Files.find API. Exmaple:
Files.find(
Paths.get(startPath), Integer.MAX_VALUE,
{ path, _ -> path.fileName.toString() == file.name }
).forEach { foundPath ->
Log.d("AppLog", "found file on:${foundPath.toFile().absolutePath}")
}

Android app uses static method to transfer and plot data

I've been asking questions regarding my Android project that continually plots Bluetooth data in real-time.
Basically what I've already done is create a first version of my app by cobbling together some open source code Blueterm and OrientationSensorExample
It's been suggested that I add a thread, a handler, a Service, or use Async Task, or AIDL, etc. But I don't know how to use any of these and would appreciate an explanation.
Here's a description of the Blueterm open source code I started with (see link above). Blueterm is basically a terminal emulator program that communicates over Bluetooth. It consists of several activities with Blueterm being the most important. It discovers, pairs, and connects with a remote Bluetooth device that supports SPP/RfComm. When connected I can use Blueterm to configure the remote device by sending it commands to turn on sampling, change the number of channels to sample (to one channel), change to format of the incoming data (I like comma separated data), etc
Here's a description of the OrientationSensorExample open source code I started with (see link above). It's basically an example application of the AnroidPlot library. The OrientationSensor activity implements SensorEventListener. This includes overriding onSenorChanged() which is called whenever new orientation sensor data is taken, and it redraws the graph.
Having cobbled together these two open source projects (Blueterm and OrientationSensorExample) into one application (Blueterm) here's a description of how the overall application (Blueterm) works. When I start Blueterm the whole screen emulates a nice blue terminal. From the Options Menu I discover, pair with, connect to, and configure a remote bluetooth device as described above. Once I have configured the remote device, I go again to the Options Menu and select "Plot data" which launches the Plot activity. The terminal emulator goes away, and a nice scrolling real-time plot from the Plot activity shows up.
As far as I can tell there is a background thread that calls an update() method as follows:
/**
* Look for new input from the ptty, send it to the terminal emulator.
*/
private void update() {
int bytesAvailable = mByteQueue.getBytesAvailable();
int bytesToRead = Math.min(bytesAvailable, mReceiveBuffer.length);
try {
int bytesRead = mByteQueue.read(mReceiveBuffer, 0, bytesToRead);
append(mReceiveBuffer, 0, bytesRead);
//VTR use existing handler that calls update() to get data into plotting activity
Plot.plotData(mReceiveBuffer, 0, bytesRead);
} catch (InterruptedException e) {
//VTR OMG their swallowing this exception
}
}
In the update() method I found it convenient to call my Plot.plotData() method and pass it the same date that is passed to the append() method to plot the data. NOTE: This only works if plotData() is a static method. No one has been able to explain why.
Anyway plotData() is a static method and here's how it and it's helper methods look now:
private static StringBuffer strData = new StringBuffer("");
public static void plotData(byte[] buffer, int base, int length) {
Log.i("Entering: ", "plotData()");
/*
byte[] buffer = (byte[]) msg.obj;
int base = msg.arg1;
int length = msg.arg2;
*/
for (int i = 0; i < length; i++) {
byte b = buffer[base + i];
try {
if (true) {
char printableB = (char) b;
if (b < 32 || b > 126) {
printableB = ' ';
}
Log.w("Log_plotData", "'" + Character.toString(printableB)
+ "' (" + Integer.toString(b) + ")");
strData.append(Character.toString(printableB));
if (b == 10)
{
Log.i("End of line: ", "processBlueData()");
Log.i("strData", strData.toString());
splitData(strData);
strData = new StringBuffer("");
}
}
} catch (Exception e) {
Log.e("Log_plotData_exception", "Exception while processing character "
+ Integer.toString(i) + " code "
+ Integer.toString(b), e);
}
}
Log.i("Leaving: ", "plotData()");
}
private static void splitData(StringBuffer strBuf) {
String strDash = strBuf.toString().trim();
String[] strDashSplit = strDash.split("-");
for (int ndx = 0; ndx < strDashSplit.length; ndx++)
{
if (strDashSplit[ndx].length() > 0)
Log.i("strDashSplit", ndx + ":" + strDashSplit[ndx]);
String strComma = strDashSplit[ndx].trim();
String[] strCommaSplit = strComma.split(",");
for (int mdx = 0; mdx < strCommaSplit.length; mdx++)
{
if (strCommaSplit[mdx].length() > 0)
Log.i("strCommaSplit", mdx + ":" + strCommaSplit[mdx]);
if (mdx == 1)
{
int raw = Integer.parseInt(strCommaSplit[1],16);
Log.i("raw", Integer.toString(raw));
float rawFloat = raw;
Log.i("rawFloat", Float.toString(rawFloat));
float ratio = (float) (rawFloat/65535.0);
Log.i("ratio", Float.toString(ratio));
float voltage = (float) (5.0*ratio);
Log.i("voltage", Float.toString(voltage));
nowPlotData(voltage);
}
}
}
}
public static void nowPlotData(float data) {
// get rid the oldest sample in history:
if (plotHistory.size() > HISTORY_SIZE) {
plotHistory.removeFirst();
}
// add the latest history sample:
plotHistory.addLast(data);
// update the plot with the updated history Lists:
plotHistorySeries.setModel(plotHistory, SimpleXYSeries.ArrayFormat.Y_VALS_ONLY);
//VTR null pointer exception?
if (plotHistoryPlot == null)
Log.i("aprHistoryPlot", "null pointer exception");
// redraw the Plots:
plotHistoryPlot.redraw();
}
If it is strongly recommended that plotData() not be a static method and that I should do something else please explain here and how. Thanks!

This might be a question much better suited for Code Review, rather than here. Perhaps you can reformulate to post it there, or trim it a lot to repost it here.
Furthermore, to answer: "It's been suggested that I add a thread, a handler, a Service, or use Async Task, or AIDL, etc. But I don't know how to use any of these and would appreciate an explanation.", the best advise would be to link you to a book about android, such as: http://commonsware.com/Android/ . Chapters 35 and 36 deal with services, while chapter 20 is about threads. You will never get an answer as complete as those chapters here.