待办任务事项应用程序

模仿书上的例子，用代码来写，主要代码如下：

package com.todolist;

import java.util.ArrayList;

import android.os.Bundle;
import android.app.Activity;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnKeyListener;
import android.view.ViewGroup.LayoutParams;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.ListView;

public class MainActivity extends Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);

		LinearLayout layout = new LinearLayout(this);
		layout.setOrientation(LinearLayout.VERTICAL);
		layout.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,
				LayoutParams.MATCH_PARENT));

		
		final ArrayList<String> todoItems = new ArrayList<String>();
		final EditText editText = new EditText(this);
		final ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,todoItems);
		
		ListView listView = new ListView(this);
		listView.setAdapter(arrayAdapter);
		
		editText.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,
				LayoutParams.WRAP_CONTENT));
		editText.setSingleLine(true);
		editText.setOnKeyListener(new OnKeyListener() {
			@Override
			public boolean onKey(View view, int keyCode, KeyEvent keyEvent) {
				if (keyEvent.getAction() == KeyEvent.ACTION_DOWN) {
					if (keyCode == KeyEvent.KEYCODE_DPAD_CENTER
							|| keyCode == KeyEvent.KEYCODE_ENTER) {
						todoItems.add(0, editText.getText().toString());
						arrayAdapter.notifyDataSetChanged();
						editText.setText("");
						return true;
					}
				}
				return false;
			}
		});
		layout.addView(editText);
		
		layout.addView(listView);

		
		setContentView(layout);

	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

}