android 浅复制和深复制-clone篇

有关java中的 浅复制和深复制

，这里不详细讨论。相关知识请参考以下帖子：

浅复制和深复制http://blog.csdn.net/yang_hui1986527/article/details/7029777
浅析Java中的深拷贝与浅拷贝http://blog.csdn.net/yang_hui1986527/article/details/7012428

android中的 浅复制和深复制，具体可能于java中的有一点不同。下面，我们来探讨下在这个问题。

主要思路：

1、创建TextBox，然后根据TextBox复制出一个对象TextBox2（点击屏幕，进行复制）；

2、改变TextBox2的位置，方便观察比较差异。

3、改变TextBox2内部文本的位置。如果是浅复制，那么TextBox2内部文本改变位置的同时，TextBox内部文本的位置会随着改变。否则，如果是深度复制，TextBox内部文本的位置不会改变。

效果如下：

注：请注意文本“test”在文本框内的位置。

浅复制：

深复制：

源程序：

(点击下载：http://download.csdn.net/detail/yang_hui1986527/3874905)

CloneActivity.java

package com.clone;

import android.app.Activity;
import android.os.Bundle;

public class CloneActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //setContentView(R.layout.main);
        CloneView mCloneView = new CloneView(this);
        setContentView(mCloneView);
    }
}

CloneView.java

package com.clone;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PointF;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

public class CloneView extends View {
	private Document mDocument = null;
	public Paint mPaint= null;
	public TextBox mTextBox = null;
	public TextBox mTextBox2 = null;

	public CloneView(Context context) {
		super(context);
		mDocument = new Document();
		mPaint = new Paint();
		initData();
	}

	public CloneView(Context context, AttributeSet attrs) {
		super(context, attrs);
		mDocument = new Document();
		mPaint = new Paint();
		initData();
	}

	public CloneView(Context context, AttributeSet attrs, int defStyle) {
		super(context, attrs, defStyle);
		mDocument = new Document();
	}

	public void initData()
	{
		PointF textpos = new PointF(30,30);
		String text = new String("test");

		mTextBox = new TextBox(50, 50, 100, 100, textpos, text);

		mDocument.add(mTextBox);
	}

	@Override
	protected void onDraw(Canvas canvas) {
		super.onDraw(canvas);
		canvas.drawColor(Color.WHITE);
		mDocument.draw(canvas, mPaint);
	}

	@Override
	public boolean onTouchEvent(MotionEvent event) {
		switch (event.getAction()) {
		case MotionEvent.ACTION_DOWN:
		{

			try {
				mTextBox2 = (TextBox)mTextBox.clone();
				mTextBox2.moveBound();
				mTextBox2.changeData();
			} catch (CloneNotSupportedException e) {
				e.printStackTrace();
			}
			if(mTextBox2 != null)
				mDocument.add(mTextBox2);
		}
		invalidate();
		break;
		case MotionEvent.ACTION_MOVE:
			break;
		case MotionEvent.ACTION_UP:
			break;
		default:
			break;
		}
		return super.onTouchEvent(event);
	}

}

Document.java

package com.clone;

import java.util.Vector;

import android.graphics.Canvas;
import android.graphics.Paint;

public class Document {

	private Vector<Object> objs = null;

	public Document() {
		objs = new Vector<Object>();
	}

	public void add(Object obj){
		objs.add(obj);
	}

	void draw(Canvas canvas, Paint paint) {
		canvas.save();

		for (int i = 0; i < objs.size(); i++) {
			Object obj = objs.get(i);
			obj.draw(canvas, paint);
		}

		canvas.restore();
	}

}

Object.java

package com.clone;

import android.graphics.Canvas;
import android.graphics.Paint;

public abstract class Object implements Cloneable{
	protected float posx = 0;
	protected float posy =0;
	protected float width = 0;
	protected float height = 0;

	public Object() {
		posx = 0;
		posy =0;
		width = 0;
		height = 0;
	}

	public Object(float posx,float posy,float width,float height){
		this.posx = posx;
		this.posy = posy;
		this.width = width;
		this.height = height;
	}

	public void moveBound() {
		this.posx += 100;
		this.posy += 100;
	}

	abstract  void draw(Canvas canvas,Paint paint);
	abstract  void changeData();

    public Object clone() throws CloneNotSupportedException {
        return (Object) super.clone();
    }
}

TextBox.java

package com.clone;

import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.PointF;

public class TextBox extends Object implements Cloneable{
	private PointF mtextpos = null;
	private String mtextString = null;

	public TextBox() {
		posx = 0;
		posy =0;
		width = 0;
		height = 0;
		mtextpos = new PointF();
		mtextString = new String();
	}

	public TextBox(float posx, float posy, float width, float height,PointF textpos,String text) {
		this.posx = posx;
		this.posy = posy;
		this.width = width;
		this.height = height;
		mtextpos = new PointF(textpos.x,textpos.y);
		mtextString = new String(text);
	}

	@Override
	void draw(Canvas canvas, Paint paint) {
		canvas.save();
		paint.setColor(Color.BLUE);
		paint.setStyle(Style.STROKE);
		canvas.drawRect(posx, posy, posx+width, posy+height, paint);

		canvas.translate(posx, posy);
		paint.setColor(Color.BLACK);
		paint.setTextSize(20);
		canvas.drawText(mtextString, mtextpos.x, mtextpos.y, paint);
		canvas.restore();

	}
//
//	//浅克隆
//    public TextBox clone() throws CloneNotSupportedException {
//        return (TextBox) super.clone();
//    }  

	//深克隆
    public TextBox clone() throws CloneNotSupportedException {
        TextBox o =  (TextBox) super.clone();  

         //对于string，int等基本类型，用上面一句就可以
        //对于复杂类型，例如PointF等还需要手动实现拷贝
        if(mtextpos != null)
        	o.mtextpos = new PointF(mtextpos.x,mtextpos.y);

        return o;
    }

	@Override
	void changeData() {
        if(mtextpos != null)
        	mtextpos.offset(20, 50);
	}
}