Android畫圖demo

如何在圖片上畫畫呢？這裡寫了一個demo，供大家參考

一、先看一眼工程結構

工程結構：

二、自定義view

這個自定義view實現了保留軌跡的功能，代碼如下

package picturegame.view;

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import com.winton.picturegame.R;

public class GameView extends View{
	
	private Paint paint = null; //
	
	private Bitmap originalBitmap = null;//原始圖
	
	private Bitmap new1Bitmap = null;
	
	private Bitmap new2Bitmap = null;
	
	private float clickX =0;
	
	private float clickY=0;
	
	private float startX=0;
	
	private float startY=0;
	
	private boolean isMove = true;
	
	private boolean isClear = false;
	
	private int color =Color.RED;//默認畫筆顏色為紅色
	
	private float strokeWidth =2.0f;//默認畫筆粗度
	
	

	public GameView(Context context) {
		this(context,null);
		// TODO Auto-generated constructor stub
	}
	public GameView(Context context,AttributeSet atts) {
		this(context,atts,0);
		// TODO Auto-generated constructor stub
	}
	public GameView(Context context,AttributeSet atts,int defStyle) {
		super(context,atts,defStyle);
		// TODO Auto-generated constructor stub
		
		originalBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.default_pic).copy(Bitmap.Config.ARGB_8888, true);//加載一張背景
		new1Bitmap=originalBitmap.createBitmap(originalBitmap);
	}

	//清除函數
	public void clear(){
		isClear =true;
		new2Bitmap=originalBitmap.createBitmap(originalBitmap);
		invalidate();//重載
	}
	
	public void setStrokeWidth(float width){
		this.strokeWidth=width;
		initPaint();
	}
	@Override
	protected void onDraw(Canvas canvas) {
		// TODO Auto-generated method stub
		super.onDraw(canvas);
		canvas.drawBitmap(writer(new1Bitmap),0,0, null);
		
	}
	
	@Override
	public boolean onTouchEvent(MotionEvent event) {
		// TODO Auto-generated method stub
		
		
		clickX =event.getX();
		
		clickY=event.getY();
		
		if(event.getAction()==MotionEvent.ACTION_DOWN){
			isMove =false;
			invalidate();
			return true;
		}
		else if(event.getAction()==MotionEvent.ACTION_MOVE){
			isMove =true;
			invalidate();
			return true;
		}
		
		
		return super.onTouchEvent(event);
	}
	
	/** 
	* @Title: writer 
	* @Description: TODO(生成bitmap) 
	* @param @param pic
	* @param @return    設定文件 
	* @return Bitmap    返回類型 
	* @throws 
	*/
	public Bitmap writer(Bitmap pic){
		initPaint();
		
		Canvas canvas =null;
		if(isClear){
			canvas=new Canvas(new2Bitmap);
		}else{
			canvas=new Canvas(pic);
		}
		
		if(isMove){
			canvas.drawLine(startX, startY, clickX, clickY, paint);//劃線
		}
		startX = clickX;
		
		startY =clickY;
		if(isClear){
			return new2Bitmap;
		}
		return pic;
	}
	
	private void initPaint(){
		
		paint = new Paint();//新建畫筆
		
		paint.setStyle(Style.STROKE);//設置為畫線
		
		paint.setAntiAlias(true);//可以讓線條圓滑一些
		
		paint.setColor(color);//設置畫筆顏色
		
		paint.setStrokeWidth(strokeWidth);//設置畫筆線條的粗細
	}
	
	/** 
	* @Title: setColor 
	* @Description: TODO(設置線條顏色的對外接口) 
	* @param @param color    設定文件 
	* @return void    返回類型 
	* @throws 
	*/
	public void setColor(int color){
		
		this.color=color;
		initPaint();
	}
	
	
}

三、主頁面布局文件

主頁面布局文件

四、主Activity代碼

package com.winton.picturegame;

import picturegame.view.GameView;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;

import com.winton.basemodule.BaseActivity;

public class MainActivity extends BaseActivity implements OnClickListener {

	private GameView gameview = null;
	private Button clear = null;
	
	private TextView tv30,tv25,tv20,tv15,tv10,tv5,tv2;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		// TODO Auto-generated method stub
		super.onCreate(savedInstanceState);
	}

	@Override
	public void initView() {
		// TODO Auto-generated method stub
		setContentView(R.layout.activity_main);
		
		gameview=(GameView)findViewById(R.id.gameview);
		clear =(Button)findViewById(R.id.btn_clear);
		tv30=(TextView)findViewById(R.id.tv_30);
		tv25=(TextView)findViewById(R.id.tv_25);
		tv20=(TextView)findViewById(R.id.tv_20);
		tv15=(TextView)findViewById(R.id.tv_15);
		tv10=(TextView)findViewById(R.id.tv_10);
		tv5=(TextView)findViewById(R.id.tv_5);
		tv2=(TextView)findViewById(R.id.tv_2);
	}

	@Override
	public void initListener() {
		// TODO Auto-generated method stub
		clear.setOnClickListener(this);
		tv30.setOnClickListener(this);
		tv25.setOnClickListener(this);
		tv20.setOnClickListener(this);
		tv15.setOnClickListener(this);
		tv10.setOnClickListener(this);
		tv5.setOnClickListener(this);
		tv2.setOnClickListener(this);
		
	}

	@Override
	public void initData() {
		// TODO Auto-generated method stub
		
	}
	@Override
	public void onClick(View v) {
		// TODO Auto-generated method stub
		if(v==clear){
			gameview.clear();
			return;
		}
		if(v==tv30){
			gameview.setStrokeWidth(30f);
			return;
		}
		if(v==tv25){
			gameview.setStrokeWidth(25f);
			return;
		}
		if(v==tv20){
			gameview.setStrokeWidth(20f);
			return;
		}
		if(v==tv15){
			gameview.setStrokeWidth(15f);
			return;
		}
		if(v==tv10){
			gameview.setStrokeWidth(10f);
			return;
		}
		if(v==tv5){
			gameview.setStrokeWidth(5f);
			return;
		}
		if(v==tv2){
			gameview.setStrokeWidth(2f);
			return;
		}
		
	}
	
	



}

五、效果

運行效果圖如下

六、疑問

當線條變粗時，線條會出現如上圖中不連續的問題。請問高手這個怎麼處理呢？我猜測應該要運行算法，但還不知道怎麼運行。