利用自定义控件绘制小球并完成小球自动下落的功能

1、布局界面

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".GameActivity" >


    <www.csdn.net.tetris.view.GameView 
        android:id="@+id/gameview"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>

    <Button
        android:id="@+id/btn_left"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/gameview"
        android:layout_alignParentBottom="true"
        android:text="@string/btn_text" />

    <Button
        android:id="@+id/btn_right"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignBottom="@+id/gameview"
        android:layout_centerHorizontal="true"
        android:layout_alignParentBottom="true"
        android:text="@string/btn_right" />

    

</RelativeLayout>

 

2、封装的一个绘制的图的类

package www.csdn.net.tetris.domain;

import www.csdn.net.tetris.view.GameView;

public class Block {

	private int x=20,y=20;
	
	
	public GameView gameView;
	public Block(GameView gameView){
		this.gameView=gameView;
	}
	
	

	//向左移动
	public void moveLeft(){
		x-=10;
		gameView.invalidate();
	}
	
	//向右移动
	public void moveRight(){
		x+=10;
		gameView.invalidate();
	}
	
	//下落方法
		public void downLoad(){
			y+=10;
			gameView.invalidate();//重新绘制
		}
	
	public int getX() {
		return x;
	}

	public void setX(int x) {
		this.x = x;
	}

	public int getY() {
		return y;
	}

	public void setY(int y) {
		this.y = y;
	}
	
	
}

3、创建一个画布和线程的操作

package www.csdn.net.tetris.view;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.view.View;
import www.csdn.net.tetris.domain.Block;

public class GameView extends View {

	public static Block block;
	
	public Handler handler;
	//定义方向
	public static  int dir=-1;
	//上下左右
	public static final int DIRUP=1;
	public static final int DIRDOWN=2;
	public static final int DIRLEFT=3;
	public static final int DIRRIGHT=4;
	
	public GameView(Context context,AttributeSet attrs) {
		super(context);
		//创建俄罗斯方块对象
		this.block=new Block(this);
		
		
		handler=new Handler(){
			public void handleMessage(Message msg) {
				super.handleMessage(msg);
				switch (msg.what) {
				case DIRLEFT:
					GameView.block.moveLeft();
					break;
				case DIRRIGHT:
					GameView.block.moveRight();
					break;
				
					
				default:
					GameView.block.downLoad();
					break;
				}

			}
		};
		
		
		
		
		//创建线程
		new Thread (new Runnable(){

			@Override
			public void run() {
				while(true){
					try{
						System.out.println("子线程名称：：："+Thread.currentThread().getName());
						//block.downLoad();
						Thread.sleep(1000);
						handler.sendEmptyMessage(dir);
					}catch(Exception e){
						e.printStackTrace();
					}
				}
				
			}
			
		}).start();
	}

	@Override
	protected void onDraw(Canvas canvas) {
		
		super.onDraw(canvas);
		//设置了画布的颜色
		canvas.drawARGB(255, 0, 0, 255);
		//设置一个画笔
		Paint paint=new Paint();
		paint.setARGB(255, 255, 0, 0);
		canvas.drawCircle(block.getX(), block.getY(), 10, paint);
	}
	
}

4、在MainActivity中的操作

package com.example.tetris;



import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import www.csdn.net.tetris.domain.Block;
import www.csdn.net.tetris.view.GameView;


public class GameActivity extends Activity {
	//声明按钮控件
	public Button btn_start;
	public Button btn_right;
	public Button btn_left;
	

	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_game);
		//获取按钮控件
		btn_start=(Button) findViewById(R.id.btn_start);
		
		
		btn_start.setOnClickListener(new MyOnClickListener());
		System.out.println("主线程：：："+Thread.currentThread().getName());
		
		
	}

	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

	class MyOnClickListener implements View.OnClickListener{

		@Override
		public void onClick(View v) {
			int id=v.getId();
			switch (id) {
			case R.id.btn_start:
				//GameView gameView=new GameView(GameActivity.this,null);
				GameActivity.this.setContentView(R.layout.activity_layout);
				
				//获取控件
				btn_right=(Button) findViewById(R.id.btn_right);
				btn_left=(Button)  findViewById(R.id.btn_left);
				
				btn_left.setOnClickListener(new MyOnClickListener());
				btn_right.setOnClickListener(new MyOnClickListener());
				
				
				break;
			case R.id.btn_left:
				Toast.makeText(GameActivity.this, "向左移动", Toast.LENGTH_LONG).show();
				GameView.block.moveLeft();
				//GameView.dir=GameView.DIRLEFT;
				break;
			case R.id.btn_right:
				Toast.makeText(GameActivity.this, "向右移动", Toast.LENGTH_LONG).show();
				GameView.block.moveRight();
				//GameView.dir=GameView.DIRRIGHT;
				break;
			
			default:
				break;
			}
			
		}
		
	}
}