Develop Reference

Android- File Directory Doesn't Exist For API 23+

I have an android app that writes files to a directory in internal storage, but it only does that correctly for certain API's. It works fine on my phone which uses Android 5.1 (API 22). And on the Nexus 5 emulator (API 21). However, in most tablets with API >=23 it can't get the directory. It writes the file in a separate activity and puts them in a listView for display in this activity. Whenever this activity loads, it doesn't get any files because the directory 'path' doesn't exist. Yes, I have all the read/write external storage permissions in the manifest. I've included the full code for the activity if anyone really needs to see it, but the part that matters here is only down to the last log tag.
public class ListResults extends Activity {
int data_block = 100;
ArrayList<String> arraylist;
String path_string = Environment.getExternalStorageDirectory().getAbsolutePath()+"/TrafficCounter";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.list_results);
ListView listView1 = (ListView) findViewById(R.id.list);
File path = new File(path_string);
path.mkdirs();
String dir = "" + path;
Log.d("TAG","Path exists: " + path.exists());
Log.d("TAG",String.valueOf(path.mkdirs()));
Log.d("TAG",path.toString());
File f = new File(dir);
String[] fileList = f.list();
Log.d("TAG", Arrays.deepToString(fileList));
//////////////////////////////Rest of Activity (Not Relevant)///////////////////////////////////
arraylist= new ArrayList<String>();
if(fileList!=null){
for(int i=0;i<fileList.length;i++)
{
arraylist.add(fileList[i]);
}}
Collections.sort(arraylist);
ArrayAdapter<String> adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, arraylist);
listView1.setAdapter(adapter);
listView1.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
final String filename = ((TextView) view).getText().toString();
//Creating dialog for choosing what to do with files
final Dialog dialog = new Dialog(ListResults.this);
dialog.setContentView(R.layout.file_options_menu);
dialog.show();
dialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
TextView nameDisplay = (TextView)dialog.findViewById(R.id.file_name);
nameDisplay.setText(filename);
//Defining all buttons within the dialog
Button viewButton = (Button)dialog.findViewById(R.id.view_button);
Button shareButton = (Button)dialog.findViewById(R.id.share_button);
Button deleteButton = (Button)dialog.findViewById(R.id.delete_button);
Button cancelButton = (Button)dialog.findViewById(R.id.cancel_button);
//View option
viewButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
File path = new File(path_string);
File file = new File(path + "/" + filename);
String[] loadText = Load(file);
String finalString = "";
for (int i = 0; i < loadText.length; i++) {
finalString += loadText[i] + System.getProperty("line.separator");
}
// Launching new Activity on selecting single List Item
Intent i = new Intent(getApplicationContext(), SingleListItem.class);
// sending data to new activity
i.putExtra("product", finalString);
i.putExtra("filename export", filename);
dialog.cancel();
startActivity(i);
finish();
}
});
//Upload option from within the dialog
shareButton.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v){
File path = new File(path_string);
File file = new File(path + "/" + filename);
Uri uri = Uri.fromFile(file);
Intent sendIntent = new Intent(Intent.ACTION_SEND);
sendIntent.putExtra(Intent.EXTRA_STREAM, uri);
sendIntent.setType("text/plain");
startActivity(Intent.createChooser(sendIntent,
getResources().getText(R.string.chooser_text)));
dialog.cancel();
}
});
//Delete button function
deleteButton.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v){
File path = new File(path_string);
File file = new File(path,filename);
file.delete();
Toast.makeText(getApplicationContext(), "File Deleted", Toast.LENGTH_SHORT).show();
dialog.cancel();
Intent intent = getIntent();
finish();
startActivity(intent);
}
});
//Cancel option from dialog
cancelButton.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v){
dialog.cancel();
}
});
}
});
}
public static String[] Load(File file)
{
FileInputStream fis = null;
try
{
fis = new FileInputStream(file);
}
catch (FileNotFoundException e) {e.printStackTrace();}
InputStreamReader isr = new InputStreamReader(fis);
BufferedReader br = new BufferedReader(isr);
String test;
int anzahl=0;
try
{
while ((test=br.readLine()) != null)
{
anzahl++;
}
}
catch (IOException e) {e.printStackTrace();}
try
{
fis.getChannel().position(0);
}
catch (IOException e) {e.printStackTrace();}
String[] array = new String[anzahl];
String line;
int i = 0;
try
{
while((line=br.readLine())!=null)
{
array[i] = line;
i++;
}
}
catch (IOException e) {e.printStackTrace();}
return array;
}
public void onRestart(View view) {
Intent restart = new Intent(this, MainActivity.class);
startActivity(restart);
}
}
I included the log tags I get for each of the following tests. First one is whether or not the directory exists, second line is if mkdirs(); was used, third is the actual address, and fourth is the actual array of files in the directory.
For the Nexus 5 Emulator (API 21, works):
D/TAG: Path exists: true
D/TAG: false
D/TAG: /storage/sdcard/TrafficCounter
D/TAG: [test.txt]
For my actual phone (API 22, works):
D/TAG: Path exists: true
D/TAG: false
D/TAG: /storage/emulated/0/TrafficCounter
D/TAG: [Test.txt]
For Nexus 7 and Nexus S Emulators (API 23, doesn't work):
D/TAG: Path exists: false
D/TAG: false
D/TAG: /storage/emulated/0/TrafficCounter
D/TAG: null
Does anyone know how to properly get the directory for the higher API's? Or am I completely missing something else?

FileObserver not reacting to CREATE

I'm trying to make an app that will react to screenshots folder and do a toast for beginning,
I'm a new developer and this is my first time using file observer so I can only guess I've made a lot of mistakes.
The problem is there is no toast or log upon taking a screenshot.
Here is the code in my observer class:
public class listeningInit extends FileObserver {
private static final String TAG = "File listener";
public String absolutePath;
public listeningInit(String path) {
super(path, FileObserver.ALL_EVENTS);
absolutePath = path;
}
#Override
public void onEvent(int event, String path) {
if ((FileObserver.CREATE & event)!=0) {
Log.v(TAG, absolutePath + "/" + path + " is created\n");
Context context = getContext();
int duration = Toast.LENGTH_SHORT;
Toast toast = Toast.makeText(context, "Folder action!", duration);
toast.show();
}
}
private Context getContext() {
// TODO Auto-generated method stub
return null;
}
and here's the code on activity that does .startWatching
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listeningInit startObs = new listeningInit("/Pictures/Screenshots/");
startObs.startWatching();
//Checking if this is a first run
Boolean firstRun = false;
SharedPreferences run = getSharedPreferences("MYPREFS", 0);
firstRun = run.getBoolean("fr", true);
//if true launch tutorial activity
if(firstRun == true){
Intent k = new Intent(MainActivity.this, Tutorial.class);
startActivity(k);
}
}
There's no errors thrown by the code, it's just not responding and I don't have a slight clue on why that might be.

Copy file from application Internal memory to external storage in android?

I have an application that saves data to a file called 'sensorLog.txt'. I am not sure where exactly this is stored but I know this is only accessible by the applicationand it is in the internal memory.
I want to be able to write a copy the current file to an external storage when I click on a button "export". I have pasted a small bit of my program, But i am not sure how to copy sensorLog.txt file to the external storage.
public class MainActivity extends Activity {
private static final String DEBUG_TAG = "MainActivity";
private Button buttonStartService;
private Button buttonStopService;
private Button buttonSettings;
private Button buttonExport;
private TextView textStatus;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Context context = getApplicationContext();
setContentView(R.layout.activity_main);
buttonStartService = (Button) findViewById(R.id.button_start_service);
buttonStopService = (Button) findViewById(R.id.button_stop_service);
buttonSettings = (Button) findViewById(R.id.button_settings);
buttonExport = (Button) findViewById(R.id.button_export);
textStatus = (TextView) findViewById(R.id.text_status);
buttonStartService.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
startSensorService();
}
});
buttonStopService.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
stopSensorService();
}
});
//export button listener
buttonExport.setOnClickListener(export_handler);
}
public void startSensorService() {
// Schedule
AlarmManager scheduler = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent(getApplicationContext(), SensorService.class);
PendingIntent scheduledIntent = PendingIntent.getService(getApplicationContext(), 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
// 30 seconds
long interval = 30 * 1000;
scheduler.setInexactRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), interval, scheduledIntent);
Log.d(DEBUG_TAG, "Service started");
}
public void stopSensorService() {
// Cancel
AlarmManager scheduler = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
Intent intent = new Intent(this, SensorService.class);
PendingIntent scheduledIntent = PendingIntent.getService(getApplicationContext(), 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
scheduler.cancel(scheduledIntent);
Log.d(DEBUG_TAG, "Service stopped");
}
View.OnClickListener export_handler = new View.OnClickListener() {
public void onClick(View v)
{
// Here is the part I am not sure what to do. I want to copy a file sensorLog.txt that has all my sensor information to sd card
String state = Environment.getExternalStorageState();
if (Environment.MEDIA_MOUNTED.equals(state))
{
Log.d(DEBUG_TAG, "SD card detected");
stopSensorService();
File file = new File(Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_DOCUMENTS),"SensorLog.txt");
// delete file from the internal storage once exported
context.deleteFile("SensorLog.txt");
startSensorService();
}
else
{
Log.d(DEBUG_TAG, "No external storage detected(cannot copy file)");
}
}
};
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
Part where I create sensorLog.txt***(I dont think it is necessary to read for this question but just in case someone needs it)*:
private class SensorServiceLoggerTask extends AsyncTask<SensorFrame, Void, Void> {
#Override
protected Void doInBackground(SensorFrame... frames) {
SensorFrame frame = frames[0];
BufferedWriter bufWr = null;
try {
File file = new File(getApplicationContext().getFilesDir(), "SensorLog.txt");
if (file.exists()) {
// Write to new file
bufWr = new BufferedWriter(new FileWriter(file, true));
} else {
file.createNewFile();
Log.d(DEBUG_TAG, "New log file created");
// Append to existing file
bufWr = new BufferedWriter(new FileWriter(file, false));
// Write header
bufWr.append(sensorHeader.toString());
}
// Write frame
bufWr.append(sensorFrame.toString());
bufWr.flush();
Log.d(DEBUG_TAG, "Added frame to log");
} catch (IOException ex) {
// TODO: useful error handling
} finally {
// Cleanup
if (bufWr != null) {
try {
bufWr.close();
} catch (IOException ex) {
// TODO: useful error handling
}
}
}
return null;
}
}
I also have 2 more queries:
Lets say I want to append some information at the top of the file just before moving it how can I do that?
My aim is to transfer the sensorLog.txt file from internal to external storage when the export button is pressed. delete or empty the internal sensorLog.txt file and then the same thing happens again if i press export again, then I would have to rename my file when I export it right? would there not be a name clash? How do I handle that? could I give a name dynamically?
Thank you.
EDIT: Some corrections
View.OnClickListener export_handler = new View.OnClickListener() {
public void onClick(View v)
{
String state = Environment.getExternalStorageState();
if (Environment.MEDIA_MOUNTED.equals(state))
{
Log.d(DEBUG_TAG, "SD card detected");
stopSensorService();
Log.d(DEBUG_TAG, "stopSensorService for file transfer");
//make the timestamp the file name
long TS = System.currentTimeMillis();
StringBuilder stringBuilder = new StringBuilder();
stringBuilder.append(TS);
stringBuilder.append(".txt");
String file_name = stringBuilder.toString();
//file name stored in file_name
File file_ext = new File(Environment.getExternalStoragePublicDirectory(
Environment.DIRECTORY_DOCUMENTS),file_name);
// attempt to create this new directory
//read from sensorLog.txt file
try
{
file_ext.createNewFile();
File file = getBaseContext().getFileStreamPath("sensorLog.txt");
if(file.exists())
{
FileInputStream read_file = openFileInput("sensorLog.txt");
//read contents of internal file
InputStreamReader inputStreamReader = new InputStreamReader(read_file);
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
StringBuilder sb = new StringBuilder();
sb.append("Timestamp of export to SD"+TS+"/n");
String line;
while ((line = bufferedReader.readLine()) != null) {
sb.append(line);
}
BufferedWriter bufWr = null;
bufWr = new BufferedWriter(new FileWriter(file_ext, false));
// Write header
bufWr.append(sb.toString());
inputStreamReader.close();
bufWr.close();
read_file.close();
//delete sensor file once exported
getApplicationContext().deleteFile("sensorLog.txt");
}
}
catch(Exception e){}
But for some reason my file is not getting stored in the SD card.

Check out the Android documentation. If you can read your sensorLog.txt file, then you can save it in a String and then save the string to a file in the external storage.

How open choose directory dialog on Android java?

My app downloads files from the internet and I need the user to select where to save them. How to make a choice directory on the Android Java? Please give example code

You just need to override onCreateDialog in an activity like this:
//In an Activity
private String[] mFileList;
private File mPath = new File(Environment.getExternalStorageDirectory() + "//yourdir//");
private String mChosenFile;
private static final String FTYPE = ".txt";
private static final int DIALOG_LOAD_FILE = 1000;
private void loadFileList() {
try {
mPath.mkdirs();
}
catch(SecurityException e) {
Log.e(TAG, "unable to write on the sd card " + e.toString());
}
if(mPath.exists()) {
FilenameFilter filter = new FilenameFilter() {
#Override
public boolean accept(File dir, String filename) {
File sel = new File(dir, filename);
return filename.contains(FTYPE) || sel.isDirectory();
}
};
mFileList = mPath.list(filter);
}
else {
mFileList= new String[0];
}
}
protected Dialog onCreateDialog(int id) {
Dialog dialog = null;
AlertDialog.Builder builder = new Builder(this);
switch(id) {
case DIALOG_LOAD_FILE:
builder.setTitle("Choose your file");
if(mFileList == null) {
Log.e(TAG, "Showing file picker before loading the file list");
dialog = builder.create();
return dialog;
}
builder.setItems(mFileList, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
mChosenFile = mFileList[which];
//you can do stuff with the file here too
}
});
break;
}
dialog = builder.show();
return dialog;
}

Check this out :
small open source Android Library Project that streamlines this process, while also providing a built-in file explorer (in case the user does not have one present). It's extremely simple to use, requiring only a few lines of code.
You can find it at GitHub: https://github.com/iPaulPro/aFileChooser
For More Details:
Android file chooser

Display SD Card path to select for storing a download file

I'm writting an app, which lets user to input URL then select the location to put the downloaded file. But I'm get stuck in the 2nd step.
All I want to do is display the location like this:
And return the path to location.
Anyone has the solution? Thanks in advance!
PS: Display the external storage.

Create activity
public class ... extend activity
{
string path = "/";
public void onResume()
{
...
setContentView(..);
if (getIntent().hasExtra("path"))
{
path = getIntent().getStringExtra("path");
}
listview = findviewbyid(R.id.listview);
listview.setAdapter(new adapter(path));
listview.setOnItemClickListener(this);
}
public void onActivityResult(result)
{
if (resultOK) ...
}
public void onclicklisteneer(view,pos,id)
{
if (dir)
{
Intent intent = new Intent(this, this.class);
intent.put("path",path+" "+view.getAdapter().getItem(pos))
intent.setFlag(FLAG_NEW_TASK)
startActivityForResult(intent)
}
else if (file)
{
setResult(Result_OK);
finish();
}
}
}

This is how I do, and it works for me:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_tree_view);
File dir = new File("/sdcard");
ArrayList<String> folders = new ArrayList<String>();
final File[] fileList = dir.listFiles();
if (fileList == null){
Toast msg = Toast.makeText(this, "No files", 3000);
msg.show();
}else{
for (File f:fileList){
if (f.isDirectory()){
folders.add(f.getName());
}
}
final ListView lvFolder = (ListView)findViewById(R.id.lvTree);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_selectable_list_item, folders);
lvFolder.setAdapter(adapter);
lvFolder.setOnItemClickListener(new OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> arg0, View v,
int position, long id) {
// TODO Auto-generated method stub
Object o = lvFolder.getItemAtPosition(position);
String fullObject = (String)o;
Toast.makeText(getApplicationContext(), "You have chosen: " + " " + fullObject.toString(), Toast.LENGTH_LONG).show();
}
});
}
}