实现简单的写字板

最近在做一个项目，有一个要求就是在手机客户端上记录用户的笔迹，然后发往服务端进行笔记认证。于是就写了一个简单的绘图板，记录用户的笔迹及笔记经过的坐标值。网络连接代码暂时还没加上去。以下是代码：注释很详细的，相信大家能看懂，并希望能提出改进，谢谢！
主来，即要运行的Activity

package snowfox.android;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintStream;
import android.app.Activity;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class SimpleWrite extends Activity implements OnClickListener{
/** Called when the activity is first created. */
Button ok,cancer;
MyView mv;
Bitmap bitmap;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.simple_write);
mv = (MyView)findViewById(R.id.MyView);
mv.setDrawingCacheEnabled(true);
ok = (Button)findViewById(R.id.buttonOk);
cancer = (Button)findViewById(R.id.buttonCancer);
ok.setOnClickListener(this);
cancer.setOnClickListener(this);
}
public void onClick(View v) {
// TODO Auto-generated method stub
switch(v.getId())
{
case R.id.buttonOk:
{
/*
* 将Android的Bitmap对象保存成为一个文件，该类只有compress(Bitmap.CompressFormat format, int quality, OutputStream stream),
* 可以存为png和jpg，png可能还好说，但是jpg是有损压缩会降低图片的质量，其实Google还提供了一个API在Bitmap类，通过
* copyPixelsToBuffer(Buffer dst)这个方法来解决
*/
//此处对图片质量要求不高,可以直接用前一种方法.
bitmap = mv.getDrawingCache(); //获得绘图板上的bitmap资源
//新建文件以保存图片,文件名为系统当前时间
File imageFile = new File("/sdcard",System.currentTimeMillis() + ".png"); //若把文件保存到sdcard,须在配置文件中添加sd卡读写权限
try
{
FileOutputStream fos = new FileOutputStream(imageFile); //获取文件的输出流
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos); //将bitmap的内容输出到文件输出流
fos.flush(); //刷新输出流,将输出流中数据输入文件
fos.close();
}
catch (FileNotFoundException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
mv.destroyDrawingCache(); //关掉缓冲区,以使相关无用的对象内存能被回收
//以下为轨迹记录代码
int array[][][] = mv.cordinate;
//清空画板,并回收内存,在此处清空画板是因为上面已经把坐标信息记录下来了,因此之前画板的相关信息已不需要,可以清除
mv.initBiamap();
System.gc();
File cordinateFile = new File("/sdcard",System.currentTimeMillis() + ".txt");
try
{
PrintStream fps = new PrintStream(cordinateFile);
for(int i = 0; i < 15; i++)
{
for(int j = 0; j < 30; j++)
{
fps.print(array[i][j][0]+" ");
fps.print(array[i][j][1]+" ");
fps.print("\t\t");
fps.flush();
}
fps.print("\r\n");
fps.flush();
}
fps.close();
}
catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
break;
}
case R.id.buttonCancer:
{
//此处将界面返回为初始状
mv.initBiamap(); //重新初始化mv组件,使其成为空白画板
System.gc();
break;
}
default:
break;
}
}
}

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定制组件：MyView:

package snowfox.android;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.CornerPathEffect;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.PathEffect;
import android.util.AttributeSet;
import android.util.Log;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
import android.view.GestureDetector.OnGestureListener;
import android.view.View.OnTouchListener;
import android.widget.Toast;
public class MyView extends View implements OnTouchListener,OnGestureListener
{
int touchNum, pressNum; //笔画坐标数, 笔画数
int[][][] cordinate; //存储坐标的数组
public Paint paint;
public Path path;
private PathEffect effect;
Bitmap myBitmap;
GestureDetector testGestureDetector;
Canvas canvas;
public MyView(Context context, AttributeSet attrs)
{
super(context, attrs);
// TODO Auto-generated constructor stub
this.initBiamap();
this.setOnTouchListener(this);
this.setLongClickable(true); //只有设置了此项,才能监听手势
}
public void initBiamap()
{
touchNum = 0;
pressNum = 0;
cordinate = new int[20][100][2]; //最大笔画数20, 最大笔画坐标数100
canvas = new Canvas();
paint = new Paint();
path = new Path();
paint.setColor(Color.BLUE);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(3);
paint.setAntiAlias(true); //打开抗锯齿
effect = new CornerPathEffect(10); //打开圆角效果
testGestureDetector = new GestureDetector(this);
}
@Override
protected void onDraw(Canvas canvas)
{
super.onDraw(canvas);
paint.setAntiAlias(true);
paint.setPathEffect(effect);
canvas.drawPath(path, paint);
invalidate(); //刷新组件,以显示当前效果
return;
}
public boolean onTouch(View v, MotionEvent event)
{
// TODO Auto-generated method stub
//获取笔画坐标
float x= event.getX();
float y = event.getY();
Log.i("xy===========", x + " " + y+ "==================");
cordinate[pressNum][touchNum][0] = (int)x;
cordinate[pressNum][touchNum][1] = (int)y;
if(touchNum == 0) //当touchNum = 0时，则为一个笔画的起点，因此将path起点移动到此点
path.moveTo(x,y);
else
path.lineTo(x,y);
touchNum++;
//Log.i("touchNum=====", touchNum + " ");
//Log.i("PressNum++++++++++++", pressNum + " ");
if(touchNum == 99) //笔画过长时，停止输入，并要求重新输入
{
Toast.makeText(this.getContext(), "笔画过于复杂,请重新输入", Toast.LENGTH_LONG).show();
this.initBiamap();
}
if(pressNum == 19) //笔画过多时，停止输入，并要求重新输入
{
Toast.makeText(this.getContext(), "笔画过于复杂,请重新输入", Toast.LENGTH_LONG).show();
this.initBiamap();
}
if((event.getAction()) == (MotionEvent.ACTION_UP)) //手指离开屏幕时，则下一笔为新笔画起点，因此相关数据置0
{
touchNum = 0;
pressNum ++;
}
return testGestureDetector.onTouchEvent(event);
}
public boolean onDown(MotionEvent e) {
// TODO Auto-generated method stub
return false;
}
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,float velocityY)
{
// TODO Auto-generated method stub
//n++;
//touchNum = 0;
//onDraw(canvas)
return false;
}
public void onLongPress(MotionEvent e) {
// TODO Auto-generated method stub
}
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX,
float distanceY) {
// TODO Auto-generated method stub
return false;
}
public void onShowPress(MotionEvent e) {
// TODO Auto-generated method stub
}
public boolean onSingleTapUp(MotionEvent e) {
// TODO Auto-generated method stub
return false;
}
}

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布局文件：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background = "#c0c0c0"
>
<snowfox.android.MyView
android:layout_width = "wrap_content"
android:layout_height = "wrap_content"
android:id = "@+id/MyView"
android:layout_weight = "12"
android:background = "#ffffff"
/>
<RelativeLayout
android:layout_width = "fill_parent"
android:layout_height = "wrap_content"
android:layout_gravity="bottom"
android:layout_weight = "1">
<Button
android:id = "@+id/buttonOk"
android:layout_width = "wrap_content"
android:layout_height = "wrap_content"
android:text = "确定"
android:layout_alignParentLeft = "true"
/>
<Button
android:id = "@+id/buttonCancer"
android:layout_width = "wrap_content"
android:layout_height = "wrap_content"
android:text = "取消"
android:layout_alignParentRight = "true"
/>
</RelativeLayout>
</LinearLayout>

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