HelloWorld

package com.example.helloword;import android.os.Bundle;import android.app.Activity;import android.view.Menu;import android.view.View;import android.widget.TextView;public class HelloWordActivity extends Activity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        //使用hellworld.xml 文件定义的界面布局        setContentView(R.layout.hello_word);    }    @Override    public boolean onCreateOptionsMenu(Menu menu) {        // Inflate the menu; this adds items to the action bar if it is present.        getMenuInflater().inflate(R.menu.hello_word, menu);        return true;    }        public void clickHandler(View source){    //获取UI界面中ID为R.id.show的文本框    TextView tv=(TextView)findViewById(R.id.show);    //改变文本框的内容    tv.setText("Hello Android-"+new java.util.Date());            }    }