<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" //1.5以后默認(rèn)的是LinearLayout布局  android:orientation="vertical"  android:layout_width="fill_parent"  android:layout_height="fill_parent"  ><TextView  android:id="@+id/textview1" //定義Id方便Java類找到它,并且控制它  android:layout_width="fill_parent"  android:layout_height="wrap_content"  android:text="@string/hello"  /><Button  android:id="@+id/button1"  android:layout_width="60px"  android:layout_height="wrap_content"  android:layout_gravity="right" //讓Button放在右面  android:text="確定"/></LinearLayout>

package com.android.test;import android.app.Activity;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.TextView;import android.widget.Toast;public class ButtonDemo extends Activity {  private TextView textview1;  private Button button1;  public void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.main);    //通過(guò)ID在找到定義在main.xml里的TextView和Button控件    textview1 = (TextView)findViewById(R.id.textview1);    button1 = (Button)findViewById(R.id.button1);    //增加事件響應(yīng)    button1.setOnClickListener(new Button.OnClickListener(){      public void onClick(View v)      {        //Toast提示控件        Toast.makeText(ButtonDemo.this,            "TextView里的文字發(fā)生了改變,你注意到了嗎?",            Toast.LENGTH_LONG).show();        //將TextView的文字發(fā)生改變        textview1.setText("歡迎來(lái)到魏祝林的博客!");      }    });  }}