Develop Reference

Speeding up the doinbackground() process

I'm splitting an encrypted video into 4 parts using this code
public class SplitVideoFile {
private static String result;
static ArrayList<String>update=new ArrayList<>();
public static String main(File file) {
try {
// File file = new File("C:/Documents/Despicable Me 2 - Trailer (HD) - YouTube.mp4");//File read from Source folder to Split.
if (file.exists()) {
String videoFileName = file.getName().substring(0, file.getName().lastIndexOf(".")); // Name of the videoFile without extension
// String path = Environment.getDataDirectory().getAbsolutePath().toString() + "/storage/emulated/0/Videointegrity";
String path = "/storage/emulated/0/Videointegrity";
// File myDir = new File(getFile, "folder");
//myDir.mkdir();
File splitFile = new File(path.concat("/").concat(videoFileName));//Destination folder to save.
if (!splitFile.exists()) {
splitFile.mkdirs();
Log.d("Directory Created -> ", splitFile.getAbsolutePath());
}
int i = 01;// Files count starts from 1
InputStream inputStream = new FileInputStream(file);
String videoFile = splitFile.getAbsolutePath() +"/"+ String.format("%02d", i) +"_"+ file.getName();// Location to save the files which are Split from the original file.
OutputStream outputStream = new FileOutputStream(videoFile);
Log.d("File Created Location: ", videoFile);
update.add("File Created Location: ".concat(videoFile));
int totalPartsToSplit =4 ;// Total files to split.
int splitSize = inputStream.available() / totalPartsToSplit;
int streamSize = 0;
int read = 0;
while ((read = inputStream.read()) != -1) {
if (splitSize == streamSize) {
if (i != totalPartsToSplit) {
i++;
String fileCount = String.format("%02d", i); // output will be 1 is 01, 2 is 02
videoFile = splitFile.getAbsolutePath() +"/"+ fileCount +"_"+ file.getName();
outputStream = new FileOutputStream(videoFile);
Log.d("File Created Location: ", videoFile);
streamSize = 0;
}
}
outputStream.write(read);
streamSize++;
}
inputStream.close();
outputStream.close();
Log.d("Total files Split ->", String.valueOf(totalPartsToSplit));
result="success";
} else {
System.err.println(file.getAbsolutePath() +" File Not Found.");
result="failed";
}
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
public ArrayList<String> getUpdate()
{
return update;
}
And in my activity file i call this using async task's doinbackground method like below
protected String doInBackground(Void...arg0) {
Log.d(TAG + " DoINBackGround", "On doInBackground...");
File encvideo=new File(epath.getText().toString());
SplitVideoFile split=new SplitVideoFile();
String result=split.main(encvideo);
publishProgress(1);
return result;
}
Even though it splits the video, it takes too much of time to do the process.
How can I speed them up. As I'm showing a progress bar in preexecute method it looks like the user sees the progress bar for a long time, which I don't want.

OSMdroid : How to render offline map from a local sqlite archive

Programming with Android Studio and the osmdroid library.
I downloaded a portion of a map using the cacheManager.downloadAreaAsync() method. This method stores the map piece in a sqlite file in the data/data/<package>/osmdroid/tiles directory, chosen by me.
Now I want to use this map to load it offline in a mobile application.
I've tried to do it through all kinds of classes (MapTileSqlCacheProvider, XYTileSource, OfflineTileProvider, ...) but I can't get the map to appear.
How should I do it?

To download a portion of the map I do this:
map.setTileSource(TileSourceFactory.OpenTopo);
outputPath = "/data/data/<package>/files" + File.separator + "osmdroid" + File.separator + "tiles" + File.separator;
outputName = outputPath + boxE6.name + ".db";
try {
writer=new SqliteArchiveTileWriter(outputName);
} catch (Exception ex) {
ex.printStackTrace();
}
CacheManager cacheManager = new CacheManager(map,writer);
cacheManager.downloadAreaAsync(this, boxE6, 7, 13, new CacheManager.CacheManagerCallback() {
#Override
public void onTaskComplete() {
Toast.makeText(ctx, "Download complete!", Toast.LENGTH_LONG).show();
if (writer!=null)
writer.onDetach();
} ...
To retrieve the stored map (in this case it is in the usa.db file) I try to do this:
map.setUseDataConnection(false);
map.setTileSource(TileSourceFactory.OpenTopo);
File cache = new File(outputName);
Configuration.getInstance().setOsmdroidTileCache(cache);
mapController.setCenter(new GeoPoint((n+s)/2,(e+w)/2));

I will show how I store and load multiple sqlite Tiles, not just one.
The above answer from José Espejo Roig worked only partly for me. It worked almost fine for caching the tiles, but not for reading them. Writing down cache files though is also not complete. I have created my own code using as example: Make a tile archive from OSMDroid Github.
So to store potentially more than 1 tiles in a specific directory I use a code like below. It creates sequentially my_mapX.sqlite, where X are just stepped consecutive integers. So I get my_map1.sqlite, my_map2.sqlite and so on.
private final String MAP_FILE_NAME = "my_map";
private final String MAP_FILE_EXTENSION = ".sqlite";
// ...
Context ctx = getActivity();
mMapView = new MapView(ctx);
((ConstraintLayout) view.findViewById(R.id.osm_fragment)).addView(mMapView);
mMapView.setTileSource(TileSourceFactory.OpenTopo);
ContextWrapper contextWrapper = new ContextWrapper(ctx);
File root_directory = contextWrapper.getDir(ctx.getFilesDir().getName(), Context.MODE_PRIVATE);
File directory_osm = new File(root_directory, "osmdroid");
directory_osm.mkdir();
File directory = new File(directory_osm, "tiles");
directory.mkdir();
File[] nrFiles = directory.listFiles(new FilenameFilter() {
#Override
public boolean accept(File dir, String name) {
if (name.endsWith(MAP_FILE_EXTENSION))
return true;
return false;
}
});
String osmdroidTile = directory.getAbsolutePath() + File.separator + MAP_FILE_NAME + (nrFiles.length + 1) + MAP_FILE_EXTENSION;
BoundingBox boxE6 = mMapView.getBoundingBox();
SqliteArchiveTileWriter writer = null;
try {
writer = new SqliteArchiveTileWriter(osmdroidTile);
} catch (Exception ex) {
ex.printStackTrace();
}
CacheManager cacheManager = new CacheManager(mMapView, writer);
SqliteArchiveTileWriter finalWriter = writer;
int currZoom = (int)mMapView.getZoomLevelDouble();
cacheManager.downloadAreaAsync(ctx, boxE6, currZoom, currZoom + 1, new CacheManager.CacheManagerCallback() {
#Override
public void onTaskComplete() {
Toast.makeText(ctx, "Download complete!", Toast.LENGTH_LONG).show();
if (finalWriter != null)
finalWriter.onDetach();
}
#Override
public void updateProgress(int progress, int currentZoomLevel, int zoomMin, int zoomMax) {
}
#Override
public void downloadStarted() {
}
#Override
public void setPossibleTilesInArea(int total) {
}
#Override
public void onTaskFailed(int errors) {
Toast.makeText(getActivity(), "Download complete with " + errors + " errors", Toast.LENGTH_LONG).show();
if (finalWriter != null)
finalWriter.onDetach();
}
});
}
});
This way I can create as many tile files as I want. Important is that they have ".sqlite" extension. ".db" extension didn't work for me.
Now to read these tiles I used again example from OSMDroid Github: Sample SQLITE example. In OSMDroid Github example TileSource is being determined with IArchiveFile. I skipped that, as I assume I know what TileSource I used (in my case it is OpenTopo, as you can see). Then to read multiple offline tiles from the same TileSource (basing on example from OSMDroid) my code looks like this:
//first we'll look at the default location for tiles that we support
Context ctx = getActivity();
mMapView = new MapView(ctx);
((ConstraintLayout) view.findViewById(R.id.osm_fragment)).addView(mMapView);
mMapView.setUseDataConnection(false);
ContextWrapper contextWrapper = new ContextWrapper(ctx);
File root_directory = contextWrapper.getDir(ctx.getFilesDir().getName(), Context.MODE_PRIVATE);
String osmDir = root_directory.getAbsolutePath() + File.separator + "osmdroid" + File.separator + "tiles";
File f = new File(osmDir);
if (f.exists()) {
File[] list = f.listFiles();
ArrayList<File> sqliteArray = new ArrayList<>();
if (list != null) {
for (int i = 0; i < list.length; i++) {
if (list[i].isDirectory()) {
continue;
}
String name = list[i].getName().toLowerCase();
if (!name.contains(".")) {
continue; //skip files without an extension
}
name = name.substring(name.lastIndexOf(".") + 1);
if (name.length() == 0) {
continue;
}
//narrow it down to only sqlite tiles
if (ArchiveFileFactory.isFileExtensionRegistered(name) && name.equals("sqlite")) {
sqliteArray.add(list[i]);
}
}
}
OfflineTileProvider tileProvider;
if (sqliteArray.size() > 0) {
try {
tileProvider = new OfflineTileProvider(new SimpleRegisterReceiver(getActivity()), sqliteArray.toArray(new File[0]));
mMapView.setTileProvider(tileProvider);
mMapView.setTileSource(TileSourceFactory.OpenTopo);
mMapView.invalidate();
} catch (Exception e) {
e.printStackTrace();
}
}
} else {
Toast.makeText(getActivity(), f.getAbsolutePath() + " dir not found!", Toast.LENGTH_SHORT).show();
}

Why does WorkManager tasks hang sometimes in my OneTimeWorkRequest?

I'm aware that that
All background work is given a maximum of ten minutes to finish its execution
and that it may take it's time depending on certain things
My code belows creates 8 OneTimeWorkRequests then puts them what im hoping is a chain then is enqueued;
workManager.beginWith(deleteCurrent)
.then(deleteCurrentImages)
.then(insertData)
.then(insertImage)
.then(insertAutoNames)
.then(insertAutoCondition)
.then(checkComplete)
.enqueue();
The last request is to finish the current activity (if it reaches this request, it's assumed all tasks ran successfully) see below.
public class CheckComplete extends Worker {
#NonNull
#Override
public Result doWork() {
MyApplication myApplication = null;
boolean run = true;
Context context = getActivity();
myApplication = (MyApplication) context.getApplicationContext();
SQLiteConnection mybdc = myApplication.getData();
String jobNo = getInputData().getString("jobNo", "");
String section = getInputData().getString("section", "");
int viewSize = getInputData().getInt("viewSize", 0);
int result = checkLastEntry(jobNo, section,viewSize, mybdc);
if (1 == result) {
getActivity().finish();
return Result.SUCCESS;
} else {
Message.message(context, "Error occurred, please try and save again");
return Result.FAILURE;
}
}
public int checkLastEntry(String jobNo, String section, int viewSize, SQLiteConnection mydbc) {
ArrayList<String> values = new ArrayList<>();
try {
SQLiteStatement mystatement = null;
mystatement = mydbc.prepareStatement("SELECT value FROM documentTable WHERE jobNo = '" + jobNo + "' AND section = '" + section + "'");
while (mystatement.step()) {
values.add(mystatement.getColumnTextNativeString(0));
}
} catch (SQLException ex) {
try {
File path = new File("/sdcard/exports/logs");
SimpleDateFormat dateFormat = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss");
String currentDateTime = dateFormat.format(new Date()) + " ";
File myFile = new File(path, "DBCrashes.txt");
FileOutputStream fOut = new FileOutputStream(myFile, true);
OutputStreamWriter myOutWriter = new OutputStreamWriter(fOut);
myOutWriter.append("\n" +
"\r");
myOutWriter.append(currentDateTime + " Error reading values: " + ex);
myOutWriter.close();
fOut.close();
return 0;
} catch (java.io.IOException e) {
return 0;
}
}
if(values.size()==viewSize) {
return 1;
}else{
return 0;
}
}
}
There is a class for each OneTimeWorkRequests (besides insertAutoNames/Condition)
I put a break point on each return line in doWork().
For some reason when I run it sometimes it just hangs and would not reach the next tasks return line what could be causing this?
Edit: The workers begin when a "save" button is pressed, if it hangs this should allow the user to push save again, this will run the line below then run the commands above, however it doesn't seem to cancel the threads at work.
workManager.cancelAllWork();
Should I even be using WorkManager to query the database?
Previously I had it on a main thread but had some problems.

You cannot assume that there will be an Activity running when your Worker is being run. This is because JobScheduler may run your Worker alone in the background. You should be using getWorkInfoById() instead.

need to plot graph from internal storage file

I am storing my data which is coming from hardware device (i.e console), 1st i am creating the file in my device as follows -->>
final String folderName = LOGGING_ROOT_FOLDER;
File folder = new File(folderName);
if (!folder.isDirectory()) {
boolean ret = folder.mkdirs();
if (ret != true) {
return null; // return empty string if fail.
}
}
final SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd_HHmmss_SSS", Locale.US);
final String fileName = folderName + File.separator + firstName + "-" + patientId + "-" + procedureId + "-"
+ sdf.format(new Date(System.currentTimeMillis())) + ".log";
File f = new File(fileName);
if (!f.exists()) {
try {
f.createNewFile();
} catch (IOException e) {
e.printStackTrace();
}
}
try {
customLogFile = new BufferedWriter(new FileWriter(f, true));
} catch (IOException e) {
e.printStackTrace();
}
After creating the file i am storing the data in my device as .log with flag (below i have given the code )-->>
if (customLogFile != null) {
StringBuilder sb = new StringBuilder(500);
final String d = mFormatter.format(new Date(System.currentTimeMillis()));
if (pdMeanValue != -1) {
sb.append(pdMeanValue);
}
sb.append("|");
if (aoMean != -1) {
sb.append(aoMean);
}
sb.append("|");
if (aoMap != -1) {
sb.append(aoMap);
}
sb.append("|");
if (ffrValue != -1) {
sb.append(ffrValue);
}
sb.append("|");
if (ffrLowestValue != -1) {
sb.append(ffrLowestValue);
}
sb.append("|");
sb.append(d);
if (mIsRecording) {
sb.append("|1"); // this is the flag
}
if (!canLogFile(sb.toString().getBytes().length)) {
return false;
}
customLogFile.write(sb.toString());
customLogFile.newLine();
So i am getting the data from console continuously and plotting the graph, but now after this i want to fetch the stored file data and wants to plot again in graph but segment wise like one interval of time to another interval (i.e like if flag is 1,then that data i want to fetch from the device and plot the graph, by taking pdMeanValue, aoMean value which will be there in side file as string format). (stored data structure is like [20|30|45|10|12|time will place here|flag])
Please help me to plot the graph by taking the value where the flag is 1.

How to read a CSV file?

I am creating an application where i do some real-time image analysis and store them into a csv file. The csv has 2 columns time and y-value of each frame.
I want to read this file and store the values from 2 columns into to double array. I want this because i want to perform an fast Fourier transformation on the data.
public class MainActivity extends AppCompatActivity implements CameraView.PreviewReadyCallback {
private static Camera camera = null;
private CameraView image = null;
private LineChart bp_graph;
private int img_Y_Avg, img_U_Avg, img_V_Avg;
private long end = 0, begin = 0;
double valueY, valueU, valueV;
Handler handler;
private int readingRemaining = 1200;
private static long time1, time2, timeDifference;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
getWindow().addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
bp_graph = (LineChart)findViewById(R.id.graph);
graph_features();
//open camera
try {
camera = Camera.open();
handler = new Handler();
final Runnable runnable = new Runnable() {
#Override
public void run() {
camera.stopPreview();
camera.release();
}
};
handler.postDelayed(runnable, 30000);
} catch (Exception e) {
Log.d("ERROR", "Failed to get camera: " + e.getMessage());
}
if (camera != null) {
image = new CameraView(this, camera);
FrameLayout camera_view = (FrameLayout) findViewById(R.id.camera_view);
camera_view.addView(image);
image.setOnPreviewReady(this);
}
}
#Override
protected void onResume(){
super.onResume();
}
#Override
protected void onPause() {
super.onPause();
}
#Override
public void onPreviewFrame(long startTime, int ySum, int uSum, int vSum, long endTime) {
begin = startTime;
img_Y_Avg = ySum;
img_U_Avg = uSum;
img_V_Avg = vSum;
end = endTime;
showResults(begin, img_Y_Avg, img_U_Avg, img_V_Avg, end);
}
private void showResults(long startTime, int ySum, int uSum, int vSum, long endTime){
//set value of Y on the text view
TextView valueOfY = (TextView)findViewById(R.id.valueY);
//valueY = img_Y_Avg;
valueOfY.setText(String.valueOf(img_Y_Avg));
//start time in milliseconds
long StartDurationInMs = TimeUnit.MILLISECONDS.convert(begin, TimeUnit.MILLISECONDS);
ArrayList<Long> startOfTime = new ArrayList<>();
startOfTime.add(StartDurationInMs);
//store value to array list
ArrayList<Integer> yAverage = new ArrayList<>();
yAverage.add(img_Y_Avg);
//convert to readable format
String readableDate = new SimpleDateFormat("MMM dd,yyyy, HH:mm:ss.SSS").format(EndDurationInMs);
Log.d("Date ", readableDate);
Log.d("time ", String.valueOf(String.valueOf(yAverage.size())));
//store when all array are generated
Log.d("time ", String.valueOf(StartDurationInMs));
ArrayList<Long> getValues = new ArrayList<>();
for(int i = 0; i < yAverage.size(); i++) {
getValues.add(startOfTime.get(i));
getValues.add((long)(yAverage.get(i)));
}
//store the yAverage and start time to csv file
storeCsv(yAverage, getValues);
Log.d("MyEntryData", String.valueOf(getValues));
}
public void storeCsv(ArrayList<Integer>yAverage, ArrayList<Long>getValues){
String filename = "temporary.csv";
//File directoryDownload = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
String path = Environment.getExternalStorageDirectory().getAbsolutePath() + "/bpReader";
//File logDir = new File (directoryDownload, "bpReader"); //Creates a new folder in DOWNLOAD directory
File logDir = new File(path);
logDir.mkdirs();
File file = new File(logDir, filename);
FileOutputStream outputStream = null;
try {
file.createNewFile();
outputStream = new FileOutputStream(file, true);
//outputStream = openFileOutput(filename, Context.MODE_PRIVATE);
for (int i = 0; i < yAverage.size(); i += 2) {
outputStream.write((getValues.get(i) + ",").getBytes());
outputStream.write((getValues.get(i + 1) + "\n").getBytes());
//outputStream.write((getValues.get(i + 2) + ",").getBytes());
//outputStream.write((getValues.get(i + 3) + "\n").getBytes());
}
outputStream.flush();
outputStream.close();
} catch (Exception e) {
e.printStackTrace();
}
}
public void readCsv(){
}
}
This is my MainActivity. What I am doing here is getting the data from CameraView class for each frame with the help of an interface that I created. After that im storing the values into a CSV file called temporary.csv.
Issues
I want to read this csv and store the first column(the time) into one double array and the second column(yAverage) into another double array.
I also want to delete the file once i have all the data stored into the into the double array.
How can I do that?

I would suggest youto use an open source library like OpenCSV to get the datafrom the CSV file. When you have the library implemented it's only a matter of iterating through the x and y columns and assign them to an array. With OpenCSV it would look like that. But i would also suggest you an more object orientec approach if the x and y with the same index coords are related to each other.
String csvFile = "/Users/mkyong/csv/country3.csv";
int length = 100; //If you dont know how many entries the csv file has i would suggest to use ArrayList
double[] xCoords = new double[length];
double[] yCoords = new double[length];
CSVReader reader = null;
try {
reader = new CSVReader(new FileReader(csvFile));
String[] line;
int i = 0;
while ((line = reader.readNext()) != null) {
xCoords[i] = Double.parseDouble(line[0]);
yCoords[i] = Double.parseDouble(line[1]);
}
} catch (IOException e) {
e.printStackTrace();
}

From the answer given by Lucas, I got the direction to my solution
public void readCsv(){
//set the path to the file
String getPath = Environment.getExternalStorageDirectory() + "/bpReader";
String csvFile = "temporary.csv";
String path = getPath+ "/" + csvFile;
//File file = new File(path, csvFile);
int length = 500;
double[] xCoords = new double[length];
double[] yCoords = new double[length];
CSVReader reader = null;
try {
File myFile = new File (path);
reader = new CSVReader(new FileReader(myFile));
String[] line;
int i = 0;
while ((line = reader.readNext()) != null) {
xCoords[i] = Double.parseDouble(line[0]) ;
yCoords[i] = Double.parseDouble(line[1]);
Log.d("read:: ", "Time: "+String.valueOf(xCoords[i])+" Y: "+String.valueOf(yCoords[i]));
}
myFile.delete();
} catch (IOException e) {
e.printStackTrace();
}
}
And then i had to add
// https://mvnrepository.com/artifact/org.apache.commons/commons-lang3
compile group: 'org.apache.commons', name: 'commons-lang3', version: '3.6'
to my gradle,, which can be found at MVN repository