自定义View，随机画点

最新推荐文章于 2024-06-19 04:37:24 发布

原创最新推荐文章于 2024-06-19 04:37:24 发布 · 597 阅读

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本文介绍如何在Android中创建自定义View，并实现动态随机绘制点的功能。通过MainActivity.java中的代码设置，结合XML布局activity_main.xml，展示自定义View的绘制过程。

activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent" 
    android:background="#FFFFFF"
    >

    <com.lk.snake_point.Point
        android:id="@+id/point"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        />

</LinearLayout>

Point.java

package com.lk.snake_point;

import java.util.Random;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.drawable.BitmapDrawable;
import android.util.AttributeSet;
import android.view.View;

public class Point extends View{
	
	//图片
	Bitmap point=null;
	//画笔
	private final Paint mpaint=new Paint();
	//随机生成器
	private static final Random RNG=new Random();
	//点的位置
	private Coor[] points=new Coor[5];
	//屏幕的高度和宽度
	public int view_x=0,view_y=0;
	
	public Point(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
	}
	
	public Point(Context context, AttributeSet attrs) {
		super(context, attrs);
	}
	
	//加载图片到内存
	public void LoadImage()
	{
		Resources r=this.getContext().getResources();
		point=((BitmapDrawable)r.getDrawable(R.drawable.hehe)).getBitmap();
		
	}
	
	//设置当前窗口宽度和高度
	public void setview(int height,int width)
	{
		view_x=width;
		view_y=height;
	}
	
	//随机生成点的位置
	public void addRandompoint()
	{
		points[0]=new Coor(RNG.nextInt(view_x),RNG.nextInt(view_y));
		points[1]=new Coor(RNG.nextInt(view_x),RNG.nextInt(view_y));
		points[2]=new Coor(RNG.nextInt(view_x),RNG.nextInt(view_y));
		points[3]=new Coor(RNG.nextInt(view_x),RNG.nextInt(view_y));
		points[4]=new Coor(RNG.nextInt(view_x),RNG.nextInt(view_y));
	}
	
	
	private class Coor
	{
		public int x,y;
		public Coor(int new_x,int new_y)
		{
			x=new_x;
			y=new_y;
		}
		
	}


	@Override
	protected void onDraw(Canvas canvas) {
		super.onDraw(canvas);
		int i;
		for(i=0;i<5;i++)
		{
			canvas.drawBitmap(point, ((float)points[i].x),((float)points[i].y),mpaint);
		}
	}
	
	
	
}

MainActivity.java

package com.lk.snake_point;

import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.app.Activity;
import android.util.DisplayMetrics;

public class MainActivity extends Activity {
	
	Point po=null;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        po=(Point)findViewById(R.id.point);
        po.LoadImage();
        DisplayMetrics ds=new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getMetrics(ds);
        po.setview(ds.heightPixels, ds.widthPixels);  
        update();
    }
    
    private Refrsh Re=new Refrsh();
    
    class Refrsh extends Handler{

		@Override
		public void handleMessage(Message msg) {
			po.addRandompoint();
			po.invalidate();
			sleep(1000);
			
		}
		public void sleep(long t)
		{
			this.removeMessages(0);
			sendMessageDelayed(obtainMessage(0), t);
		}	
    }
    
    public void update()
    {
    	po.addRandompoint();
    	Re.sleep(1000);	
    }

}