android 按键控制飞机

演示一个很好的的效果，类似雷电，但功能上差很多，现在就实现了飞机的移动功能，不过，看上去还是挺漂亮的。

首先新建一个布局main.xml文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/root"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<ImageView  
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    android:src="@drawable/back"
    android:scaleType="fitXY"
    />
</LinearLayout>

第二步：建一个飞机类，这样就可以在主程序里new出飞机来了。

package cn.edu.zwu.tel;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.view.View;

public class PlaneView extends View
{
    public float currentX;
    public float currentY;
    Bitmap plane;

    public PlaneView(Context context)
    {
        super(context);
        // TODO Auto-generated constructor stub
//定义飞机图片
        plane = BitmapFactory.decodeResource(context.getResources()
            , R.drawable.plane);
        setFocusable(true);
    }
    @Override
    public void onDraw (Canvas canvas)
    {
        super.onDraw(canvas);
        //创建画笔
        Paint p = new Paint();
        //绘制飞机
        canvas.drawBitmap(plane , currentX , currentY , p);    
    }
}

第三，修改LayoutKeyEvent01.java文件，可以控制飞机上下移动

package cn.edu.zwu.tel;

import android.app.Activity;
import android.os.Bundle;
import android.view.Display;
import android.view.KeyEvent;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.view.View.OnKeyListener;

public class LayoutKeyEvent01Activity extends Activity {
    /** Called when the activity is first created. */
    private int speed = 12;

    @Override
    public void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        // 去掉窗口标题
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        // 全屏显示
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
            WindowManager.LayoutParams.FLAG_FULLSCREEN);
        // 创建PlaneView组件
        final PlaneView planeView = new PlaneView(this);
        setContentView(planeView);
        planeView.setBackgroundResource(R.drawable.back);
        // 获取窗口管理器
        WindowManager windowManager = getWindowManager();
        Display display = windowManager.getDefaultDisplay();
        // 获得屏幕宽和高
        int screenWidth = display.getWidth();
        int screenHeight = display.getHeight();
        // 设置飞机的初始位置
        planeView.currentX = screenWidth / 2;
        planeView.currentY = screenHeight - 40;
        // 为draw组件键盘事件绑定监听器
        planeView.setOnKeyListener(new OnKeyListener()
        {
            @Override
            public boolean onKey(View source, int keyCode, KeyEvent event)
            {
                // 获取由哪个键触发的事件
                switch (event.getKeyCode())
                {
                    // 控制飞机下移
                    case KeyEvent.KEYCODE_DPAD_DOWN:
                        planeView.currentY += speed;
                        break;
                    // 控制飞机上移
                    case KeyEvent.KEYCODE_DPAD_UP:
                        planeView.currentY -= speed;
                        break;
                    // 控制飞机左移
                    case KeyEvent.KEYCODE_DPAD_LEFT:
                        planeView.currentX -= speed;
                        break;
                    // 控制飞机右移
                    case KeyEvent.KEYCODE_DPAD_RIGHT:
                        planeView.currentX += speed;
                        break;
                }
                // 通知planeView组件重绘
                planeView.invalidate();
                return true;
            }
        });
    }
}

下面是效果图：