Write and Read Data from SD Card in Android Studio - Tutorial

Write and Read Data from SD Card in Android Studio

1. Create new Project with Basic Settings

it will take some time...

2. Drag and Drop Text-Plain Text and Buttons-Button from Design view
- align the units by attaching circles to corner as shown in vdo

3. Make Changes in XMl File to adjust
- size - keep same for all
- id ---- button1 , button2 , button3... check the parents id too.
- text - i left blank text in EditText

4. Give SD Card Permission in Manifest.xml !! Important !!

5. Write the java code inside

app/java/yourapp/MainActivity.java -- onCreate Function

Write the code below the super.onCreate call Important!!!!

6. To Auto Import Libraries use Altr + Enter

make sure all reds are gone!

7. Build , click on the hammer on top right corner

no errors


8. Connect your phone with file storage on and USB debugging enabled

9. You will see your mobile name in run button, Run



CODE Tutorial

1. Call the text box and button by id using findViewById(R.id.*****)
- **** is id you defined in XML file

2. Assign OnClickListner to each button with new View.OnClickListner

3. Importan notes:
- File is used to access file
- FileOutputStream for writing file
- FileInputStream and BufferedReader for reading the file
- Toast is just to notify ( can we ignore if not remebering )


after installation

// Give SD Card Permission to App before RUNNING!!!!! important



Java Code:

final EditText text = findViewById(R.id.editText);
Button write = findViewById(R.id.button1);
Button read = findViewById(R.id.button2);
Button clear = findViewById(R.id.button3);

write.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {

String data = text.getText().toString();

try{

File file = new File("/sdcard/myfile.txt");
file.createNewFile();

FileOutputStream fout = new FileOutputStream(file , true);
fout.write( data.getBytes() );
fout.close();

Toast.makeText(getBaseContext() , "DATA IS WRITTEN", Toast.LENGTH_LONG ).show();

}
catch ( Exception e ){
Toast.makeText(getBaseContext() , e.getMessage() , Toast.LENGTH_LONG).show();
}


}
});

read.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {

String data , buff = "";

try{

File file = new File("/sdcard/myfile.txt");

FileInputStream fin = new FileInputStream(file);
BufferedReader br = new BufferedReader( new InputStreamReader(fin));

while ( ( data = br.readLine() ) != null ){
buff += data;
}

text.setText(buff);
br.close();
fin.close();

Toast.makeText(getBaseContext() , "DATA IS READ", Toast.LENGTH_LONG ).show();

}
catch ( Exception e ){
Toast.makeText(getBaseContext() , e.getMessage() , Toast.LENGTH_LONG).show();
}



}
});

clear.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
text.setText("");
}
});