Tạo ứng dụng lên lịch làm việc

package at.exam;

import java.util.ArrayList;

import android.app.Activity;

import android.os.Bundle;

import android.app.AlertDialog;

import android.content.DialogInterface;

import android.os.Bundle;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.ArrayAdapter;

import android.widget.Button;

import android.widget.EditText;

import android.widget.ListView;

public class Example extends Activity {

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);

    setContentView(R.layout.main);

    //Tao mang de chua String noi dung cong viec va gio

    final ArrayList<String> arrayWork = new    ArrayList<String>();

    //Adapter dung de ket noi mang voi List View

    final ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,arrayWork);

    //Cac EditText de vao noi dung cong viec duoc lay ve tu XML

    final EditText workEnter = (EditText)findViewById(R.id.work_enter);

    final EditText hourEdit = (EditText)findViewById(R.id.hour_edit);

    final EditText minuteEdit = (EditText)findViewById(R.id.minute_edit);

    //Button khi nhan se them cong viec vao ListView

    final Button button = (Button)findViewById(R.id.button);

    //ListView chua danh sach cong viec

    final ListView list = (ListView)findViewById(R.id.list);

    //Can set Adapter cho list de biet se lay noi dung tu mang arrayWork

    list.setAdapter(arrayAdapter);

    //Ðinh nghia Listener xu ly su kien nhan vào button

    OnClickListener add = new OnClickListener() {

        @Override

        public void onClick(View v) {

            //Neu 1 trong 3 Edit Text khong co noi dung thi hien len thong bao

            if(workEnter.getText().toString().equals("") || hourEdit.getText().toString().equals("") || minuteEdit.getText().toString().equals("")) {

            AlertDialog.Builder builder = new AlertDialog.Builder(Example.this);

            builder.setTitle("Info missing");

            builder.setMessage("Please enter all information of the work");

            builder.setPositiveButton("Continue", new DialogInterface.OnClickListener() {

                public void onClick(DialogInterface dialog, int which) {

                // TODO Auto-generated method stub

                }

            });

            builder.show();

            }

            //Lay noi dung cong viec va thoi gian ra tu Edit Text va dua vao list

            else {

            String str = workEnter.getText().toString() + " - " + hourEdit.getText().toString() + ":" + minuteEdit.getText().toString();

            arrayWork.add(0,str);

            arrayAdapter.notifyDataSetChanged();

            workEnter.setText("");

            hourEdit.setText("");

            minuteEdit.setText("");

            }

        }

    };

    //set Listener cho button

    button.setOnClickListener(add);

    }

}