In this tutorial I have shared a very simple notepad app android example. I have used file handling to read and write data. The notepad consists of three options to create new file, save and open a file. When you click on save or open button an alert dialog opens where you have to enter the file name. Internal memory is used to save the text file. At the end I have shared a link to download the apk for this example so that you can directly install and run it in your phone.
Simple Notepad App Android Example
MainActivity.java
It contains the actual source code responsible for all the working.
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package com.thecrazyprogrammer.www.notepadapp; import android.app.Activity; import android.app.AlertDialog; import android.content.DialogInterface; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.Toast; import java.io.FileInputStream; import java.io.FileOutputStream; public class MainActivity extends Activity { Button newButton,saveButton,openButton; EditText text; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); newButton=(Button)findViewById(R.id.newButton); saveButton=(Button)findViewById(R.id.saveButton); openButton=(Button)findViewById(R.id.openButton); text=(EditText)findViewById(R.id.text); } public void buttonAction(View v) { final EditText fileName=new EditText(this); AlertDialog.Builder ad=new AlertDialog.Builder(this); ad.setView(fileName); if (v.getId() == R.id.saveButton) { ad.setMessage("Save File"); ad.setPositiveButton("Save",new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { try { FileOutputStream fout=openFileOutput(fileName.getText().toString()+".txt",MODE_WORLD_READABLE); fout.write(text.getText().toString().getBytes()); } catch (Exception e) { Toast.makeText(getApplicationContext(), "Error Occured: "+e,Toast.LENGTH_LONG).show(); } } }); ad.setNegativeButton("Cancel",new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.cancel(); } }); ad.show(); } if(v.getId()==R.id.openButton) { ad.setMessage("Open File"); ad.setPositiveButton("Open",new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { int c; text.setText(""); try { FileInputStream fin = openFileInput(fileName.getText().toString()+".txt"); while ((c = fin.read()) != -1) { text.setText((text.getText().toString() + Character.toString((char) c))); } }catch (Exception e) { Toast.makeText(getApplicationContext(), "Error Occured: "+e,Toast.LENGTH_LONG).show(); } } }); ad.setNegativeButton("Cancel",new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.cancel(); } }); ad.show(); } if(v.getId()==R.id.newButton) { text.setText(""); } } } |
activity_main.xml
This xml file contains the code for the design of notepad app.
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<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" android:paddingBottom="@dimen/activity_vertical_margin" tools:context="in.co.makeiton.notepadapp" android:orientation="vertical" android:weightSum="10"> <LinearLayout android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="9" android:orientation="vertical"> <EditText android:layout_width="match_parent" android:layout_height="match_parent" android:inputType="textMultiLine" android:gravity="top" android:id="@+id/text" android:scrollbars = "vertical"/> </LinearLayout> <LinearLayout android:layout_width="match_parent" android:layout_height="0dp" android:layout_weight="1"> <Button android:layout_width="match_parent" android:layout_height="wrap_content" android:text="New" android:id="@+id/newButton" android:layout_weight="1" android:onClick="buttonAction"/> <Button android:layout_width="match_parent" android:layout_height="wrap_content" android:text="Save" android:id="@+id/saveButton" android:onClick="buttonAction" android:layout_weight="1"/> <Button android:layout_width="match_parent" android:layout_height="wrap_content" android:text="Open" android:id="@+id/openButton" android:onClick="buttonAction" android:layout_weight="1"/> </LinearLayout> </LinearLayout> |