Android的帆布重做和撤消操作 [英] Android Canvas Redo and Undo Operation
本文介绍了Android的帆布重做和撤消操作的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我的工作在绘制project.my code明智的工作完美，但是，帆布重做和撤消操作不灵perfectly.undo操作不灵完善和重做操作不灵perfectly.my撤销操作移除路径从路径ArrayList和保存到undopaths ArrayList和重做操作删除最后一个元素，从undopaths ArrayList和保存路径数组列表。
i am working in drawing project.my code wise working perfectly but, canvas redo and undo operation not working perfectly.undo operation not working perfect and redo operations not working perfectly.my undo operation remove paths from paths arraylist and save to undopaths arraylist and redo operation remove last element from undopaths arraylist and save to paths arraylist.
下面是我的code：
import java.util.ArrayList;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Path;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
public class DrawView extends View implements OnTouchListener {
private Canvas mCanvas;
private Path mPath;
private Paint mPaint;
private ArrayList<Path> paths = new ArrayList<Path>();
private ArrayList<Path> undonePaths = new ArrayList<Path>();
private Bitmap im;
public DrawView(Context context)
{
super(context);
setFocusable(true);
setFocusableInTouchMode(true);
this.setOnTouchListener(this);
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setColor(0xFFFFFFFF);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setStrokeWidth(6);
mCanvas = new Canvas();
mPath = new Path();
paths.add(mPath);
im=BitmapFactory.decodeResource(context.getResources(),R.drawable.ic_launcher);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
}
@Override
protected void onDraw(Canvas canvas) {
//mPath = new Path();
//canvas.drawPath(mPath, mPaint);
for (Path p : paths){
canvas.drawPath(p, mPaint);
}
}
private float mX, mY;
private static final float TOUCH_TOLERANCE = 4;
private void touch_start(float x, float y) {
mPath.reset();
mPath.moveTo(x, y);
mX = x;
mY = y;
}
private void touch_move(float x, float y) {
float dx = Math.abs(x - mX);
float dy = Math.abs(y - mY);
if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) {
mPath.quadTo(mX, mY, (x + mX)/2, (y + mY)/2);
mX = x;
mY = y;
}
}
private void touch_up() {
mPath.lineTo(mX, mY);
// commit the path to our offscreen
mCanvas.drawPath(mPath, mPaint);
// kill this so we don't double draw
mPath = new Path();
paths.add(mPath);
}
public void onClickUndo () {
if (paths.size()>0)
{
undonePaths.add(paths.remove(paths.size()-1));
invalidate();
}
else
{
}
//toast the user
}
public void onClickRedo (){
if (undonePaths.size()>0)
{
paths.add(undonePaths.remove(undonePaths.size()-1));
invalidate();
}
else
{
}
//toast the user
}
@Override
public boolean onTouch(View arg0, MotionEvent event) {
float x = event.getX();
float y = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
touch_start(x, y);
invalidate();
break;
case MotionEvent.ACTION_MOVE:
touch_move(x, y);
invalidate();
break;
case MotionEvent.ACTION_UP:
touch_up();
invalidate();
break;
}
return true;
}
}
这code绘制工作完全不正常使用撤消和重做操作。
this code drawing is working perfectly and not working perfectly undo and redo operation.
什么是错在我的code！
what's wrong in my code!
如何解决这个问题，任何一个可以帮助我大大AP preciated。
How to Solve this issue can any one help me with greatly appreciated.
下面是我的源$ C $ C
Here's my Source Code
<一个href="http://www.4shared.com/rar/8PQQEZdH/test_draw.html">http://www.4shared.com/rar/8PQQEZdH/test_draw.html
谢谢...
终于我的问题是在这里解决的是我的绘画课：
import java.util.ArrayList;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Path;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
public class DrawView extends View implements OnTouchListener {
private Canvas mCanvas;
private Path mPath;
private Paint mPaint;
private ArrayList<Path> paths = new ArrayList<Path>();
private ArrayList<Path> undonePaths = new ArrayList<Path>();
private Bitmap im;
public DrawView(Context context)
{
super(context);
setFocusable(true);
setFocusableInTouchMode(true);
this.setOnTouchListener(this);
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setColor(0xFFFFFFFF);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setStrokeWidth(6);
mCanvas = new Canvas();
mPath = new Path();
im=BitmapFactory.decodeResource(context.getResources(),R.drawable.ic_launcher);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
}
@Override
protected void onDraw(Canvas canvas) {
//mPath = new Path();
//canvas.drawPath(mPath, mPaint);
for (Path p : paths){
canvas.drawPath(p, mPaint);
}
canvas.drawPath(mPath, mPaint);
}
private float mX, mY;
private static final float TOUCH_TOLERANCE = 4;
private void touch_start(float x, float y) {
undonePaths.clear();
mPath.reset();
mPath.moveTo(x, y);
mX = x;
mY = y;
}
private void touch_move(float x, float y) {
float dx = Math.abs(x - mX);
float dy = Math.abs(y - mY);
if (dx >= TOUCH_TOLERANCE || dy >= TOUCH_TOLERANCE) {
mPath.quadTo(mX, mY, (x + mX)/2, (y + mY)/2);
mX = x;
mY = y;
}
}
private void touch_up() {
mPath.lineTo(mX, mY);
// commit the path to our offscreen
mCanvas.drawPath(mPath, mPaint);
// kill this so we don't double draw
paths.add(mPath);
mPath = new Path();
}
public void onClickUndo () {
if (paths.size()>0)
{
undonePaths.add(paths.remove(paths.size()-1));
invalidate();
}
else
{
}
//toast the user
}
public void onClickRedo (){
if (undonePaths.size()>0)
{
paths.add(undonePaths.remove(undonePaths.size()-1));
invalidate();
}
else
{
}
//toast the user
}
@Override
public boolean onTouch(View arg0, MotionEvent event) {
float x = event.getX();
float y = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
touch_start(x, y);
invalidate();
break;
case MotionEvent.ACTION_MOVE:
touch_move(x, y);
invalidate();
break;
case MotionEvent.ACTION_UP:
touch_up();
invalidate();
break;
}
return true;
}
}
这是code的工作完美...！
推荐答案
我一眼就看到以下问题：
At first glance I see the following problems:
- 将只要你让它加入你的空
路径到路径，你将有一个问题只要你撤消：你大跌眼镜的空路径首先，使第一撤消似乎不工作。然后，如果你画成路径，它不会被添加到路径。解决的方法是创建一个新的前添加结束路径来的路径在touch_up（）。
- By adding your empty
Pathtopathsas soon as you make it, you're going to have a problem as soon as you undo: you're popping that emptyPathfirst, making the first undo not seem to work. Then if you draw into thatPath, it's not added topaths. The solution is to add the completedPathto paths intouch_up()before creating a new one.
也就是说，删除
paths.add(mPath);
从构造，并在 touch_up（），将
mPath = new Path();
paths.add(mPath);
到
paths.add(mPath);
mPath = new Path();
您还需要添加
You'll also want to add
canvas.drawPath(mPath, mPaint);
你的为循环后的OnDraw（），以吸引正在进行中的路径。
after your for loop in onDraw() in order to draw the in-progress Path.
- 您不是在排空
undonePaths当用户再次开始绘制。
- You're not emptying
undonePathswhen the user starts drawing again.
这篇关于Android的帆布重做和撤消操作的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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