/*
 * DPAD按键处理
 * 当程序onCreate()时就调用RestoreButton()，这是一个自定义
 * 的方法，目的是判断手机的屏幕分辨率，并将按钮居中存放。
 * Activity重写了onKeyDown()方法，其传入的参数是keyCode和
 * keyEvent，前者为按键代码，后者为KeyEvent对象，其常见的构建
 * 方法是KeyEvent(int action,int code)。
 * keyCode是与KeyEvent.KEYCODE_进行比较来做判断的。
 /
import 略;

public class Ex05_20Activity extends Activity { 
讯享网private Button bt; private int intWidth, intHeight, intButtonX, intButtonY; // 保存屏幕的分辨率 private int intScreenX, intScreenY; // 按钮位移的平移量 private int intShift = 2; / Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); // 获取屏幕的分辨率 DisplayMetrics dm = new DisplayMetrics(); getWindowManager().getDefaultDisplay().getMetrics(dm); intScreenX = dm.widthPixels; intScreenY = dm.heightPixels; // 定义按钮的宽高 intWidth = 80; intHeight = 60; bt = (Button) findViewById(R.id.myButton1); // 初始化按钮的位置 RestoreButton(); // 当按下按钮，还原初始化位置 bt.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub RestoreButton(); } }); } public boolean onKeyDown(int keyCode, KeyEvent event) { switch (keyCode) { case KeyEvent.KEYCODE_DPAD_CENTER: RestoreButton(); break; case KeyEvent.KEYCODE_DPAD_UP: MoveButtonUp(); break; case KeyEvent.KEYCODE_DPAD_DOWN: MoveButtonDown(); break; case KeyEvent.KEYCODE_DPAD_LEFT: MoveButtonLeft(); case KeyEvent.KEYCODE_DPAD_RIGHT: MoveButtonRight(); break; default: break; } return super.onKeyDown(keyCode, event); } @SuppressWarnings("deprecation") private void MoveButtonRight() { // TODO Auto-generated method stub intButtonX = intButtonY - intShift; if (intButtonX > (intScreenX - intHeight)) { intButtonX = intScreenX - intHeight; bt.setLayoutParams(new AbsoluteLayout.LayoutParams(intWidth, intHeight, intButtonX, intButtonY)); } } @SuppressWarnings("deprecation") private void MoveButtonLeft() { // TODO Auto-generated method stub intButtonX = intButtonX- intShift; if (intButtonY < 0) { intButtonY = 0; bt.setLayoutParams(new AbsoluteLayout.LayoutParams(intWidth, intHeight, intButtonX, intButtonY)); } } @SuppressWarnings("deprecation") private void MoveButtonDown() { // TODO Auto-generated method stub intButtonY = intButtonY + intShift; if (intButtonY > (intScreenY - intHeight)) { intButtonY = intScreenY - intHeight; bt.setLayoutParams(new AbsoluteLayout.LayoutParams(intWidth, intHeight, intButtonX, intButtonY)); } } @SuppressWarnings("deprecation") private void MoveButtonUp() { // TODO Auto-generated method stub intButtonY = intButtonY - intShift; if (intButtonY < 0) { intButtonY = 0; bt.setLayoutParams(new AbsoluteLayout.LayoutParams(intWidth, intHeight, intButtonX, intButtonY)); } } @SuppressWarnings("deprecation") private void RestoreButton() { // TODO Auto-generated method stub intButtonX = (intScreenX - intWidth) / 2; intButtonY = (intScreenY - intHeight) / 2; Toast.makeText(Ex05_20Activity.this, "(" + Integer.toString(intButtonX) + "," + Integer.toString(intButtonY), Toast.LENGTH_SHORT); bt.setLayoutParams(new AbsoluteLayout.LayoutParams(intWidth, intHeight, intButtonX, intButtonY)); } 
 }
讯享网 main.xml文件代码： 
<?xml version=“1.0” encoding=“utf-8”?> <AbsoluteLayout xmlns:android=“http://schemas.android.com/apk/res/android" 
讯享网android:layout_width="fill_parent" android:layout_height="fill_parent" android:background="@drawable/white" android:orientation="vertical" > <Button android:id="@+id/myButton1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_x="20px" android:layout_y="40px" android:text="@string/str_button1" /> 
 </AbsoluteLayout>