Develop Reference

CSV File not opening for reading in Android

I am trying to open a CSV file downloaded into internal storage for reading purpose alone. This is the code I have used:
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Toast;
import java.io.FileInputStream;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void onClick(View v) {
try {
String FileName = "/storage/emulated/0/Download/MyDocument.csv";
FileInputStream fis = openFileInput(FileName);
fis.read();
fis.close();
Toast.makeText(getBaseContext(),"File Access Permitted",Toast.LENGTH_SHORT).show();
}
catch (Exception e) {
Toast.makeText(getBaseContext(),"File Access Denied",Toast.LENGTH_SHORT).show();
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
While the file is downloaded and I am able to open it in File Manager, the above code does not work. How do I achieve the required functionality?

As per this stackoverflow question's accepted answer, you could try this:
public String readFileFromDownloads(String fileName) {
File downloadsDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
if (!downloadsDir.exists()) return null;
File file = new File(downloadsDir, fileName);
if (!file.exists()) return null;
try {
StringBuilder fileContent = new StringBuilder();
BufferedReader br = new BufferedReader(new FileReader(file));
String line;
while ((line = br.readLine()) != null) {
fileContent.append(line);
fileContent.append('\n');
}
br.close();
return fileContent.toString();
} catch (IOException ex) {
//Handle error
return null;
}
}
And then call readFileFromDownloads("MyDocument.csv"); from inside your onClick(); method.
Also, you might need to add android.permission.READ_EXTERNAL_STORAGE to your Manifest and handle Android 6.0 new permission system as per Android Docs.

How can I access(read/write) file in the external sdcard in Android Kitkat?

Here is my source code;
I've installed microsdsvc app on the external_SD.
szSDCardFileName = "/storage/external_SD/Android/data/com.tmnt.microsdsvc/files/AAA.DAT";
if ((fp = open(szSDCardFileName, O_RDWR|O_DIRECT|O_SYNC, S_IRWXU)) == -1) {
if ((fp = open(szSDCardFileName, O_RDWR|O_DIRECT|O_SYNC|O_CREAT, S_IRWXU)) == -1) {
return -1;
}
}
memset(g_buf, 0x00, BLOCK_LENGTH);
if (read(fp, (char *)g_buf, BLOCK_LENGTH) == ERROR) {
__android_log_print(ANDROID_LOG_INFO, "JNI", "<Err>file read error[errno=%d, handle=%d]", errno, fp);
return -1;
}
when running the code on the Lg G2 Kitkat version, open() is OK, but next read() is failed with errorno 22.
I don't know that what I mistake!!

Maybe this is the reason why...
KitKat, applications will no longer be able to create, modify, or remove files and folders on 'secondary external storage device' respectively dual-storage devices with internal flash AND a removable / external SD card.
"The WRITE_EXTERNAL_STORAGE permission must only grant write access to the primary external storage on a device. Apps must not be allowed to write to secondary external storage devices, except in their package-specific directories as allowed by synthesized permissions."
http://source.android.com/devices/tech/storage/index.html

package com.example.readfilefromexternalresource;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import android.app.Activity;
import android.app.ActionBar;
import android.app.Fragment;
import android.os.Bundle;
import android.os.Environment;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;
import android.os.Build;
public class MainActivity extends Activity {
private TextView textView;
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
textView = (TextView)findViewById(R.id.textView);
String state = Environment.getExternalStorageState();
if (!(state.equals(Environment.MEDIA_MOUNTED))) {
Toast.makeText(this, "There is no any sd card", Toast.LENGTH_LONG).show();
} else {
BufferedReader reader = null;
try {
Toast.makeText(this, "Sd card available", Toast.LENGTH_LONG).show();
File file = Environment.getExternalStorageDirectory();
File file2 = new File(file.getAbsolutePath()+File.separator + "myText.txt");
reader = new BufferedReader(new FileReader(file2));
StringBuilder textBuilder = new StringBuilder();
String line;
while((line = reader.readLine()) != null) {
textBuilder.append(line);
textBuilder.append("\n");
}
textView.setText(textBuilder);
} catch (FileNotFoundException e) {
// TODO: handle exception
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally{
if(reader != null){
try {
reader.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
}

First you need to get the state of your external sd card
then you check if there is a mounted sd card, if no sd card its found, it will do nothing(you can put error msgs here)
get its absolute path and add a separator then put the file name of the file you want to read
use a BufferedReader to read your textFile.
Use a StringBuilder to build your string, it is more efficient than simple concatinating strings
after appending your strings, always close the reader to save memory, smartphones are known to have less memory than desktop
call to toString() method of the StringBuiler to create your String which you can use
String state = Environment.getExternalStorageState();
if(!state.equals(Environment.MEDIA_MOUNTED)) {
} else {
File externalDir = Environment.getExternalStorageDirectory();
File textFile = new File(externalDir.getAbsolutePath()
+ File.separator + fileName);
BufferedReader reader
= new BufferedReader(new FileReader(textFile));
StringBuilder textBuilder = new StringBuilder();
String line;
while((line = reader.readLine()) != null) {
textBuilder.append(line);
textBuilder.append("\n");
}
reader.close();
String yourString = textBuilder.toString();
}
it throws a FileNotFound exception btw. You can do the same in writing a file.

Blank Screen and only pop up "Not Responding" dialog.

I am unable to figure out why I am stuck at this point although there is no error is my coding. My problem is actually, it doesn't print out my epub, as well as it just hangs there, till the not responding dialog comes up.
My code is as below:
package com.epub;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.List;
import nl.siegmann.epublib.domain.Book;
import nl.siegmann.epublib.domain.Resource;
import nl.siegmann.epublib.domain.Spine;
import nl.siegmann.epublib.domain.SpineReference;
import nl.siegmann.epublib.epub.EpubReader;
import android.app.Activity;
import android.content.res.AssetManager;
import android.os.Bundle;
import android.util.Log;
import android.webkit.WebView;
import android.widget.TextView;
public class EpubReaderActivity extends Activity {
WebView webView;
Book book;
TextView tv;
String line;
String linez;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
tv = new TextView(this);
webView = (WebView)findViewById(R.id.webView);
webView.getSettings().setJavaScriptEnabled(true);
AssetManager am = getAssets();
try {
InputStream epubInputStream = am.open("testbook.epub");
book = (new EpubReader()).readEpub(epubInputStream);
} catch (IOException e) {
Log.e("epublib", e.getMessage());
}
Spine spine = book.getSpine();
List<SpineReference> spineList = spine.getSpineReferences() ;
int count = spineList.size();
tv.setText(Integer.toString(count));
StringBuilder string = new StringBuilder();
for (int i = 0; count > i; i++) {
Resource res = spine.getResource(i);
try {
InputStream is = res.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
try {
while ((line = reader.readLine()) != null) {
linez = string.append(line + "\n").toString();
}
} catch (IOException e) {e.printStackTrace();}
//do something with stream
} catch (IOException e) {
e.printStackTrace();
}
}
webView.loadData(linez, "text/html", "utf-8");
}
}
Mind helping me out on this point?

An ANR(Application Not Responding) happens generally when you do a heavy job. In Android, if the OS can't execute one code line within about 5 seconds, the ANR dialog wil pop up. From your codes, it seems that you are reading and parsing an .epub file from your asset folder. I am not familiar with epub files, but I suspect this is a heavy task which blocks your app.
How about start a Thread or AsyncTask to read the file so the main thread would not be blocked?

Pu this code inside a thread as this takes time to write the data and load a web view
Thread is a different part of execution and you will have to wait for few sconds if yor file is large
you can also put a progress dialog to show loading of webview
new Thread(){
public void run() {
for (int i = 0; count > i; i++) {
Resource res = spine.getResource(i);
try {
InputStream is = res.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
try {
while ((line = reader.readLine()) != null) {
linez = string.append(line + "\n").toString();
}
} catch (IOException e) {e.printStackTrace();}
//do something with stream
} catch (IOException e) {
e.printStackTrace();
}
}
};
}.start();

More your file reading code form onCreaate() to onResume(). As data will be read once the UI show to user

how do i load remote text from a text file into android textview?

I have gone through all the examples and I can not seem to get this to work.
This is my current code:
package hello.android;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class HelloAndroidActivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
TextView tv = (TextView) findViewById(R.id.textView1);
try {
// Create a URL for the desired page
URL url = new URL("http://xlradioaustin.com/song/CurrentSong.txt");
// Read all the text returned by the server
BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream()));
String str;
while ((str = in.readLine()) != null) {
// str is one line of text; readLine() strips the newline character(s)
}
in.close();
tv.setText(str);
} catch (MalformedURLException e) {
tv.setText("mal");
} catch (IOException e) {
tv.setText("io");
}
}
}

Assuming your Android device is online and you've granted your app the INTERNET permission, try this:
try {
// Create a URL for the desired page
URL url = new URL("http://xlradioaustin.com/song/CurrentSong.txt");
// Read all the text returned by the server
BufferedReader in = new BufferedReader(new InputStreamReader(url.openStream()));
String str;
StringBuilder sb = new StringBuilder(100);
while ((str = in.readLine()) != null) {
sb.append(str);
// str is one line of text; readLine() strips the newline character(s)
}
in.close();
tv.setText(sb.toString());
} catch (MalformedURLException e) {
tv.setText("mal");
} catch (IOException e) {
tv.setText("io");
}
Let me know if that works: you are currently looping until str is null, then using that null value.

A follow up on the answer, it worked after adding
if (android.os.Build.VERSION.SDK_INT > 9) {
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
}

How can I read a text file from the SD card in Android?

I am new to Android development.
I need to read a text file from the SD card and display that text file.
Is there any way to view a text file directly in Android or else how can I read and display the contents of a text file?

In your layout you'll need something to display the text. A TextView is the obvious choice. So you'll have something like this:
<TextView
android:id="#+id/text_view"
android:layout_width="fill_parent"
android:layout_height="fill_parent"/>
And your code will look like this:
//Find the directory for the SD Card using the API
//*Don't* hardcode "/sdcard"
File sdcard = Environment.getExternalStorageDirectory();
//Get the text file
File file = new File(sdcard,"file.txt");
//Read text from file
StringBuilder text = new StringBuilder();
try {
BufferedReader br = new BufferedReader(new FileReader(file));
String line;
while ((line = br.readLine()) != null) {
text.append(line);
text.append('\n');
}
br.close();
}
catch (IOException e) {
//You'll need to add proper error handling here
}
//Find the view by its id
TextView tv = (TextView)findViewById(R.id.text_view);
//Set the text
tv.setText(text);
This could go in the onCreate() method of your Activity, or somewhere else depending on just what it is you want to do.

In response to
Don't hardcode /sdcard/
Sometimes we HAVE TO hardcode it as in some phone models the API method returns the internal phone memory.
Known types: HTC One X and Samsung S3.
Environment.getExternalStorageDirectory().getAbsolutePath() gives a different path - Android

You should have READ_EXTERNAL_STORAGE permission for reading sdcard.
Add permission in manifest.xml
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
From android 6.0 or higher, your app must ask user to grant the dangerous permissions at runtime. Please refer this link
Permissions overview
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (checkSelfPermission(Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, 0);
}
}

package com.example.readfilefromexternalresource;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import android.app.Activity;
import android.app.ActionBar;
import android.app.Fragment;
import android.os.Bundle;
import android.os.Environment;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;
import android.os.Build;
public class MainActivity extends Activity {
private TextView textView;
#Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
textView = (TextView)findViewById(R.id.textView);
String state = Environment.getExternalStorageState();
if (!(state.equals(Environment.MEDIA_MOUNTED))) {
Toast.makeText(this, "There is no any sd card", Toast.LENGTH_LONG).show();
} else {
BufferedReader reader = null;
try {
Toast.makeText(this, "Sd card available", Toast.LENGTH_LONG).show();
File file = Environment.getExternalStorageDirectory();
File textFile = new File(file.getAbsolutePath()+File.separator + "chapter.xml");
reader = new BufferedReader(new FileReader(textFile));
StringBuilder textBuilder = new StringBuilder();
String line;
while((line = reader.readLine()) != null) {
textBuilder.append(line);
textBuilder.append("\n");
}
textView.setText(textBuilder);
} catch (FileNotFoundException e) {
// TODO: handle exception
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
finally{
if(reader != null){
try {
reader.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
}

BufferedReader br = null;
try {
String fpath = Environment.getExternalStorageDirectory() + <your file name>;
try {
br = new BufferedReader(new FileReader(fpath));
} catch (FileNotFoundException e1) {
e1.printStackTrace();
}
String line = "";
while ((line = br.readLine()) != null) {
//Do something here
}

Beware: some phones have 2 sdcards , an internal fixed one and a removable card.
You can find the name of the last one via a standard app:"Mijn Bestanden" ( in English: "MyFiles" ? )
When I open this app (item:all files) the path of the open folder is "/sdcard" ,scrolling down there is an entry "external-sd" , clicking this opens the folder "/sdcard/external_sd/" .
Suppose I want to open a text-file "MyBooks.txt" I would use something as :
String Filename = "/mnt/sdcard/external_sd/MyBooks.txt" ;
File file = new File(fname);...etc...