To read a file from internal storage:
Call openFileInput() and pass it the name of the file to read. This returns a FileInputStream. Read bytes from the file with read(). Then close the stream with close().
code::
StringBuilder sb = new StringBuilder();
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(is, "UTF-8"));
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line).append("\n");
}
is.close();
} catch(OutOfMemoryError om){
om.printStackTrace();
} catch(Exception ex){
ex.printStackTrace();
}
String result = sb.toString();
Read a file as a string full version (handling exceptions, using UTF-8, handling new line):
// Calling:
/*
Context context = getApplicationContext();
String filename = "log.txt";
String str = read_file(context, filename);
*/
public String read_file(Context context, String filename) {
try {
FileInputStream fis = context.openFileInput(filename);
InputStreamReader isr = new InputStreamReader(fis, "UTF-8");
BufferedReader bufferedReader = new BufferedReader(isr);
StringBuilder sb = new StringBuilder();
String line;
while ((line = bufferedReader.readLine()) != null) {
sb.append(line).append("\n");
}
return sb.toString();
} catch (FileNotFoundException e) {
return "";
} catch (UnsupportedEncodingException e) {
return "";
} catch (IOException e) {
return "";
}
}
Note: you don't need to bother about file path only with file name.
Call To the following function with argument as you file path:
private String getFileContent(String targetFilePath){
File file = new File(targetFilePath);
try {
fileInputStream = new FileInputStream(file);
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
Log.e("",""+e.printStackTrace());
}
StringBuilder sb;
while(fileInputStream.available() > 0) {
if(null== sb) sb = new StringBuilder();
sb.append((char)fileInputStream.read());
}
String fileContent;
if(null!=sb){
fileContent= sb.toString();
// This is your fileContent in String.
}
try {
fileInputStream.close();
}
catch(Exception e){
// TODO Auto-generated catch block
Log.e("",""+e.printStackTrace());
}
return fileContent;
}
I prefer to use java.util.Scanner
:
try {
Scanner scanner = new Scanner(context.openFileInput(filename)).useDelimiter("\\Z");
StringBuilder sb = new StringBuilder();
while (scanner.hasNext()) {
sb.append(scanner.next());
}
scanner.close();
String result = sb.toString();
} catch (IOException e) {}
String path = Environment.getExternalStorageDirectory().toString();
Log.d("Files", "Path: " + path);
File f = new File(path);
File file[] = f.listFiles();
Log.d("Files", "Size: " + file.length);
for (int i = 0; i < file.length; i++) {
//here populate your listview
Log.d("Files", "FileName:" + file[i].getName());
}
For others looking for an answer to why a file is not readable especially on a sdcard, write the file like this first.. Notice the MODE_WORLD_READABLE
try {
FileOutputStream fos = Main.this.openFileOutput("exported_data.csv", MODE_WORLD_READABLE);
fos.write(csv.getBytes());
fos.close();
File file = Main.this.getFileStreamPath("exported_data.csv");
return file.getAbsolutePath();
} catch (Exception e) {
e.printStackTrace();
return null;
}
Source: Stackoverflow.com