I'm trying to build a to-do list app in Android Studio that saves the list as a text file and then when you open the app again if there's a text file with stored tasks it will initialize the arraylist in the app with that data.
It was all working well with the arraylist and its adapter until I had to update the arraylist with the stored file. Now it prints but instead of printing the string with the task it prints a weird internal thing like "com.example.todolist.MyData@fe7bcc9"
I've looked around and can't quite find if I can use the same adapter twice (update it?) and generally any info on your experiences using this would be really helpful.
main java code:
package com.example.todolist;
import android.content.Context;
import android.os.Bundle;
import androidx.appcompat.app.ActionBar;
import androidx.appcompat.app.AppCompatActivity;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ListView;
import android.widget.EditText;
import android.view.Menu;
import android.view.MenuItem;
import android.util.Log;
import java.io.*;
import java.io.OutputStreamWriter;
import java.util.ArrayList;
public class MainJava extends AppCompatActivity implements AdapterView.OnItemClickListener {
// 1. Some variables and definitions
ListView listView;
ArrayList<MyData> arrayList = new ArrayList<>();
MyAdapter adapter, adapter2;
private EditText taskEntered;
private int itemPos;
private final String file = "list.txt";
private String line;
private OutputStreamWriter out;
// 2. Method: The classic ON CREATE
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// locate the widgets: edit text (to get string) and list view (to put string)
taskEntered = (EditText) findViewById(R.id.enterTask);
listView = findViewById(R.id.listView);
// attach listener to list view
listView.setOnItemClickListener(this);
taskEntered.setText("");
//hide title and icon in action bar EDIT TO HIDE SAVE AND CLOSE
ActionBar actionBar = getSupportActionBar();
actionBar.setDisplayShowTitleEnabled(false);
actionBar.setDisplayUseLogoEnabled(false);
//open output stream
//try {
// out = new OutputStreamWriter(openFileOutput(file,MODE_PRIVATE)); // also try MODE_APPEND
// } catch (IOException e) {}
readFromFile();
}
// 3. Method: ON CREATE OPTIONS MENU
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu, menu);
return true;
}
// 4. Method: ON OPTIONS SELECTED
@Override
public boolean onOptionsItemSelected(MenuItem item) {
int itemID = item.getItemId(); // get id of menu item picked
switch (itemID) {
case R.id.add :
addNewTask(); // prints entered task in list view
return true;
case R.id.delete :
deleteTask();
return true;
case R.id.update :
updateTask();
return true;
case R.id.save :
saveToFile();
return true;
case R.id.close :
saveToFile();
finish();
default: super.onOptionsItemSelected(item);
}
return false;
}
// 5. Method: PRINT NEW TASK in list view and ADD NEW TASK to arrayList
public void addNewTask() {
// get string from the edit text
String taskString = taskEntered.getText().toString();
// create ArrayList values
arrayList.add(new MyData(arrayList.size() +1, taskString));
// TESTING: arrayList.add(new MyData(2, " Robert"));
//create custom adapter and connect to ListView
adapter = new MyAdapter(this, arrayList);
listView.setAdapter(adapter);
taskEntered.setText(""); // clear edit text bar after adding item
}
// 5. Method:
public void addNewTask(String string) {
// create ArrayList values
arrayList.add(new MyData(arrayList.size() +1, string));
//create custom adapter and connect to ListView
adapter = new MyAdapter(this, arrayList);
listView.setAdapter(adapter);
}
// 6. Method: Listener, when you click on an item in list view it does this:
// listener is passed into the position of the item that was clicked?
public void onItemClick(AdapterView<?> parent, View v, int position, long id) {
itemPos = position;
// you click on an item in list view
String task = arrayList.get(position).getName(); // get name of task
int numTask = arrayList.get(position).getNum(); // get number of task
// set edit text field to show the item you just clicked
taskEntered.setText(numTask + " " + task);
}
// 7. Method: Delete a task
public void deleteTask() {
// remove the arrayList item in the position that was clicked
arrayList.remove(itemPos);
// loop through items and reassign numbers
for (int i=0; i < arrayList.size(); i++){
arrayList.get(i).setNum(i+1);
}
//create custom adapter and connect to ListView
adapter = new MyAdapter(this, arrayList);
listView.setAdapter(adapter);
taskEntered.setText(""); // clearing edit text widget
}
// 7. Method: Update a task
public void updateTask() {
// get string from the edit text
String taskString = taskEntered.getText().toString();
String updatedString= taskString.substring(2); // so that the task number is not repeated
arrayList.get(itemPos).setName(updatedString);
//create custom adapter and connect to ListView
adapter = new MyAdapter(this, arrayList);
listView.setAdapter(adapter);
taskEntered.setText(""); // clearing edit text widget
}
// 8. Method: Save contents of app to a file
public void saveToFile() {
try {
// writing!
//open output stream try catch
try {
out = new OutputStreamWriter(openFileOutput(file,MODE_PRIVATE)); // also try MODE_APPEND
} catch (IOException e) {}
// loop through items in ArrayList
for (int i=0; i < arrayList.size(); i++){
line = arrayList.get(i).toString(); // grab each line from the to do list
out.write(line + " \n"); // write each line on TEXT file
}
out.close(); // close output stream
} catch (IOException e) {
Log.e("IOTest", e.getMessage());
}
}
// 9. Method: Read from file
public void readFromFile() {
// check if file already exists, if not - finish, if yes - open stream and update app with that
// A) if file doesn't exist leave method
if ( !fileExists(this, "list.txt") ){
return;
}
// B) if file already exists, open a stream, read it, copy it to ToDoList app
else {
arrayList.clear();
try {
// reading!
InputStream in = openFileInput(file); // open stream for reading from file
InputStreamReader isr = new InputStreamReader(in);
BufferedReader reader = new BufferedReader(isr);
String str = null;
// loop to read lines from file and print in app
while ((str = reader.readLine()) != null) { // str = each line in the text file OR MAYBE THIS STRING IS THE RAW CODE FROM EACH LINE
addNewTask(str);
//str.toString();
//arrayList.add(new MyData(arrayList.size() +1, str)); // create ArrayList value of the string in the text file
// adapter = new MyAdapter(this, arrayList); // create custom adapter and connect to ListView
//listView.setAdapter(adapter);
}
reader.close(); //close input stream
} catch (IOException e) {
Log.e("IOTest", e.getMessage());
}
}
}
// 10. Method: Check if file exists
public boolean fileExists(Context context, String filename) {
File file = context.getFileStreamPath(filename);
if(file == null || !file.exists()) {
return false;
}
return true;
}
}
Adapter.java code:
package com.example.todolist;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;
import java.util.ArrayList;
import androidx.appcompat.app.AppCompatActivity;
/*
ADAPTER
inflate xml file called row.xml
get references (id's) for widgets in row.xml
add each value on arrayList to its widget
*/
public class MyAdapter extends ArrayAdapter {
private Context context;
private ArrayList<MyData> arrayList;
private TextView listNum, name, contactNum;
// calling 3 arg constructor of parent class and storing values stored in
public MyAdapter(Context context, ArrayList<MyData> arrayList) {
super(context, 0, arrayList);
this.context = context;
this.arrayList = arrayList;
}
// all the action is in this getView method
// calls layout inflater class and gives it the layout of the row
@Override
public View getView(int position, View convertView, ViewGroup parent) {
// call inflater to create a View from an xml layout file
convertView = LayoutInflater.from(context).inflate(R.layout.row, parent, false);
// get references for row widgets
listNum = convertView.findViewById(R.id.listNum); // id´s of widgets in MyAdapter.java
name = convertView.findViewById(R.id.task);
// ArrayList provides values that go along in a row when getView is finished it goes through entire ArrayList and
listNum.setText(" " + arrayList.get(position).getNum());
name.setText(arrayList.get(position).getName());
return convertView;
}
}
my data code:
package com.example.todolist;
public class MyData {
private int listNum;
private String name;
//constructors
public MyData(int num, String name) {
this.listNum = num;
this.name = name;
}
//accessors and mutators
public int getNum() {
return listNum;
}
public void setNum(int num) {
this.listNum = num;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
