Android FileInputStream read() txt file to String

Question

¿Algún experto disponible para ayudarme? En mi actividad principal de Android, intento guardar un String en un archivo y luego recuperarlo si el usuario lo configuró antes. No pude encontrar ningún ejemplo cercano a lo que estoy haciendo. ¡Agradecería cualquier ayuda! Aquí está mi caso de prueba que se estrella:

String testString = "WORKS"; 
String readString; 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.main); 

    FileOutputStream fos; 

    try { 
     fos = openFileOutput("test.txt", Context.MODE_PRIVATE); 
     fos.write(testString.getBytes()); 
     fos.close(); 
    } catch (FileNotFoundException e) { 
     e.printStackTrace(); 

    } catch (IOException e) { 
     e.printStackTrace(); 

    } 

    File file = getBaseContext().getFileStreamPath("test.txt"); 

    if (file.exists()) { 

     FileInputStream fis; 

     try { 
      fis = openFileInput("test.txt"); 
      fis.read(readString.getBytes()); 
      fis.close(); 

     } catch (IOException e) { 
      e.printStackTrace(); 

     } 

     txtDate.setText(String.valueOf(readString)); 

     } else { 
        // more code 
     } 
    } 
} 

Answer 1

Para leer el archivo intente esto:

FileInputStream fis; 
fis = openFileInput("test.txt"); 
StringBuffer fileContent = new StringBuffer(""); 

byte[] buffer = new byte[1024]; 

while ((n = fis.read(buffer)) != -1) 
{ 
    fileContent.append(new String(buffer, 0, n)); 
} 

Answer 2

intentar algo como esto

public void writeData (String data) { 
     try { 
      FileOutputStream fOut = openFileOutput ("settings.dat" , MODE_WORLD_READABLE) ; 
      OutputStreamWriter osw = new OutputStreamWriter (fOut) ; 
      osw.write (data) ; 
      osw.flush () ; 
      osw.close () ; 
     } catch (Exception e) { 
      e.printStackTrace () ; 
     } 
    } 

    public String readSavedData () { 
     StringBuffer datax = new StringBuffer(""); 
     try { 
      FileInputStream fIn = openFileInput ("settings.dat") ; 
      InputStreamReader isr = new InputStreamReader (fIn) ; 
      BufferedReader buffreader = new BufferedReader (isr) ; 

      String readString = buffreader.readLine () ; 
      while (readString != null) { 
       datax.append(readString); 
       readString = buffreader.readLine () ; 
      } 

      isr.close () ; 
     } catch (IOException ioe) { 
      ioe.printStackTrace () ; 
     } 
     return datax.toString() ; 
    } 

Answer 3

menos es más;

public class MainActivity extends AppCompatActivity { 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_main); 

     TextView tvText = (TextView) findViewById(R.id.tvText); 

     try { 
      // Create File and Content 
      String FILE_NAME = "hallo.txt"; 
      String content = "Hallo Welt!"; 

      FileOutputStream fos = openFileOutput(FILE_NAME, MODE_PRIVATE); 
      fos.write(content.getBytes()); 
      fos.close(); 

      // Read File and Content 
      FileInputStream fin = openFileInput(FILE_NAME); 
      int size; 
      String neuText = null; 

      // read inside if it is not null (-1 means empty) 
      while ((size = fin.read()) != -1) { 
       // add & append content 
       neuText += Character.toString((char) size); 
      } 
      // Set text to TextView 
      tvText.setText(neuText); 

     } catch (Exception error) { 
      // Exception 
     } 
    } 
}