Android绘图视图非常慢
我从一个问题的答案中得到了这段代码,这个问题是关于如何在Android中绘制的,但是当我在应用程序中使用它并测试它时,我发现它在绘制大对象或多条路径时效率不高。问题来自Android绘图视图非常慢,android,performance,drawing,Android,Performance,Drawing,我从一个问题的答案中得到了这段代码,这个问题是关于如何在Android中绘制的,但是当我在应用程序中使用它并测试它时,我发现它在绘制大对象或多条路径时效率不高。问题来自onDraw内部的代码,因为每次调用invalidate()时,都会调用onDraw,其中包含一个循环,该循环将所有路径再次绘制到画布上,通过向其添加更多路径,速度会非常慢 下面是课堂: public class DrawingView extends View implements OnTouchListener { priva
onDraw
内部的代码,因为每次调用invalidate()
时,都会调用onDraw
,其中包含一个循环,该循环将所有路径再次绘制到画布上,通过向其添加更多路径,速度会非常慢
下面是课堂:
public class DrawingView extends View implements OnTouchListener {
private Canvas m_Canvas;
private Path m_Path;
private Paint m_Paint;
ArrayList<Pair<Path, Paint>> paths = new ArrayList<Pair<Path, Paint>>();
ArrayList<Pair<Path, Paint>> undonePaths = new ArrayList<Pair<Path, Paint>>();
private float mX, mY;
private static final float TOUCH_TOLERANCE = 4;
public static boolean isEraserActive = false;
private int color = Color.BLACK;
private int stroke = 6;
public DrawingView(Context context, AttributeSet attr) {
super(context);
setFocusable(true);
setFocusableInTouchMode(true);
setBackgroundColor(Color.WHITE);
this.setOnTouchListener(this);
onCanvasInitialization();
}
public void onCanvasInitialization() {
m_Paint = new Paint();
m_Paint.setAntiAlias(true);
m_Paint.setDither(true);
m_Paint.setColor(Color.parseColor("#000000"));
m_Paint.setStyle(Paint.Style.STROKE);
m_Paint.setStrokeJoin(Paint.Join.ROUND);
m_Paint.setStrokeCap(Paint.Cap.ROUND);
m_Paint.setStrokeWidth(2);
m_Canvas = new Canvas();
m_Path = new Path();
Paint newPaint = new Paint(m_Paint);
paths.add(new Pair<Path, Paint>(m_Path, newPaint));
}
@Override
public void setBackground(Drawable background) {
mBackground = background;
super.setBackground(background);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
}
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;
}
@Override
protected void onDraw(Canvas canvas) {
for (Pair<Path, Paint> p : paths) {
canvas.drawPath(p.first, p.second);
}
}
private void touch_start(float x, float y) {
if (isEraserActive) {
m_Paint.setColor(Color.WHITE);
m_Paint.setStrokeWidth(50);
Paint newPaint = new Paint(m_Paint); // Clones the mPaint object
paths.add(new Pair<Path, Paint>(m_Path, newPaint));
} else {
m_Paint.setColor(color);
m_Paint.setStrokeWidth(stroke);
Paint newPaint = new Paint(m_Paint); // Clones the mPaint object
paths.add(new Pair<Path, Paint>(m_Path, newPaint));
}
m_Path.reset();
m_Path.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) {
m_Path.quadTo(mX, mY, (x + mX) / 2, (y + mY) / 2);
mX = x;
mY = y;
}
}
private void touch_up() {
m_Path.lineTo(mX, mY);
// commit the path to our offscreen
m_Canvas.drawPath(m_Path, m_Paint);
// kill this so we don't double draw
m_Path = new Path();
Paint newPaint = new Paint(m_Paint); // Clones the mPaint object
paths.add(new Pair<Path, Paint>(m_Path, newPaint));
}
public void onClickUndo() {
if (!paths.isEmpty()) {//paths.size() > 0) {
undonePaths.add(paths.remove(paths.size() - 1));
undo = true;
invalidate();
}
}
public void onClickRedo() {
if (!undonePaths.isEmpty()){//undonePaths.size() > 0) {
paths.add(undonePaths.remove(undonePaths.size() - 1));
undo = true;
invalidate();
}
}}
2覆盖onSizeChanged,代码如下:
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
mBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_4444);
m_Canvas = new Canvas(mBitmap);
}
3.把这个放在onDraw中:
protected void onDraw(Canvas canvas) {
canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
if (!paths.isEmpty())
canvas.drawPath(paths.get(paths.size() - 1).first, paths.get(paths.size() - 1).second);
}
这种方法可以工作,并且不会减慢视图的速度,但是这种方法的问题是我不能使用撤销和重做功能
我尝试了很多方法来使用第二种方法进行撤销和重做,但是我做不到。所以我想问的是三件事之一:
1.使用第二种方法执行撤消和重做的方法
2.另一种使撤消和重做成为可能的方法
3.一个全新的类,它已经完成了所有的工作,比如开源库之类的
如果可以的话,请帮忙。
谢谢
编辑1
好的,所以我把它限制在这个范围内,然后我再也做不了什么了,我已经试了8个多小时了。它一直工作到“撤消”(您可以撤消任意多个路径),然后当再次绘制时,所有剩余的路径都消失了,我不知道是什么使它这样做的
@Override
protected void onDraw(Canvas canvas) {
if (mBitmap != null)
canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
if (!paths.isEmpty() && !undo)
canvas.drawPath(paths.get(paths.size() - 1).first, paths.get(paths.size() - 1).second);
if (undo) {
setBackground(mBackground);
for (Pair<Path, Paint> p : paths)
canvas.drawPath(p.first, p.second);
mBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_4444);
m_Canvas = new Canvas(mBitmap);
undo = false;
}
}
@覆盖
受保护的void onDraw(画布){
如果(mBitmap!=null)
drawBitmap(mBitmap,0,0,mbitMapPoint);
如果(!path.isEmpty()&&!undo)
drawPath(path.get(path.size()-1)。首先,path.get(path.size()-1)。其次);
如果(撤消){
立根背景(mBackground);
用于(对p:路径)
画布绘制路径(第一页,第二页);
mBitmap=Bitmap.createBitmap(w,h,Bitmap.Config.ARGB_4444);
m_Canvas=新画布(mBitmap);
撤销=假;
}
}
所以基本上我所做的是首先使用第一种方法(在调用undo之前),然后如果单击undo,undo
设置为true
,然后执行if(undo)
下的代码,这实际上是第一种方法(再次计算所有路径),然后,我将计算所有路径的结果再次绘制到mBitmap
中,因此每当再次调用onDraw
时,它都会在上面绘制,但该部分仍然需要工作,我希望有人能帮助完成该部分。我不确定这是否是撤消和重做的最佳方式。但是,以下功能在我的设备(三星galaxy s3)上工作正常。抽签似乎很快,撤销效果也很好。我确实认为可以修改以下内容以进一步提高性能
public class MainActivity extends Activity {
MyView mv;
LinearLayout ll;
private ArrayList<Path> undonePaths = new ArrayList<Path>();
private ArrayList<Path> paths = new ArrayList<Path>();
Button b;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mv= new MyView(this);
mv.setDrawingCacheEnabled(true);
ll= (LinearLayout) findViewById(R.id.ll);
ll.addView(mv);
b= (Button) findViewById(R.id.button1);
b.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (paths.size() > 0) {
undonePaths.add(paths
.remove(paths.size()-2));
mv.invalidate();
}
}
});
}
public class MyView extends View implements OnTouchListener {
private Canvas mCanvas;
private Path mPath;
private Paint mPaint;
// private ArrayList<Path> undonePaths = new ArrayList<Path>();
private float xleft, xright, xtop, xbottom;
public MyView(Context context) {
super(context);
setFocusable(true);
setFocusableInTouchMode(true);
this.setOnTouchListener(this);
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setColor(Color.RED);
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);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
}
@Override
protected void onDraw(Canvas canvas) {
for (Path p : paths) {
canvas.drawPath(p, mPaint);
}
}
private float mX, mY;
private static final float TOUCH_TOLERANCE = 0;
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);
}
@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;
}
}
}
公共类MainActivity扩展活动{
MyView mv;
线性布局;
private ArrayList undonePaths=new ArrayList();
私有ArrayList路径=新ArrayList();
按钮b;
@凌驾
创建时受保护的void(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mv=新的MyView(本);
mv.setDrawingCacheEnabled(真);
ll=(线性布局)findViewById(R.id.ll);
ll.addView(mv);
b=(按钮)findViewById(R.id.button1);
b、 setOnClickListener(新的OnClickListener()
{
@凌驾
公共void onClick(视图v){
//TODO自动生成的方法存根
if(path.size()>0){
撤消路径。添加(路径)
.remove(path.size()-2));
mv.invalidate();
}
}
});
}
公共类MyView扩展了视图实现OnTouchListener{
私人帆布mCanvas;
专用路径mPath;
私人油漆;
//private ArrayList undonePaths=new ArrayList();
私人浮动xleft、xright、xtop、xbottom;
公共MyView(上下文){
超级(上下文);
设置聚焦(真);
setFocusableInTouchMode(真);
this.setOnTouchListener(this);
mPaint=新油漆();
mPaint.setAntiAlias(true);
mPaint.setColor(Color.RED);
mPaint.setStyle(油漆、样式、笔划);
mPaint.setStrokeJoin(油漆.连接.圆形);
mPaint.setStrokeCap(油漆盖圆形);
mPaint.设定行程宽度(6);
mCanvas=新画布();
mPath=新路径();
路径。添加(mPath);
}
@凌驾
已更改尺寸的受保护空心(整数w、整数h、整数oldw、整数oldh){
super.onSizeChanged(w,h,oldw,oldh);
}
@凌驾
受保护的void onDraw(画布){
用于(路径p:路径){
画布绘制路径(p,mPaint);
}
}
私人浮动mX,我的;
专用静态最终浮动接触公差=0;
专用无效触摸启动(浮动x、浮动y){
mPath.reset();
移动到(x,y)的速度;
mX=x;
mY=y;
}
私有无效触摸移动(浮动x、浮动y){
float dx=Math.abs(x-mX);
float dy=Math.abs(y-mY);
如果(dx>=接触公差| | dy>=接触公差){
兆帕四分之一秒(mX,mY,(x+mX)/2,(y+mY)/2);
mX=x;
mY=y;
}
}
私人空间修补(){
mPath.lineTo(mX,mY);
//将路径提交到我们的屏幕外
mCanvas.drawPath(mPath,mPaint);
//杀死
public class MainActivity extends Activity {
MyView mv;
LinearLayout ll;
private ArrayList<Path> undonePaths = new ArrayList<Path>();
private ArrayList<Path> paths = new ArrayList<Path>();
Button b;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mv= new MyView(this);
mv.setDrawingCacheEnabled(true);
ll= (LinearLayout) findViewById(R.id.ll);
ll.addView(mv);
b= (Button) findViewById(R.id.button1);
b.setOnClickListener(new OnClickListener()
{
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (paths.size() > 0) {
undonePaths.add(paths
.remove(paths.size()-2));
mv.invalidate();
}
}
});
}
public class MyView extends View implements OnTouchListener {
private Canvas mCanvas;
private Path mPath;
private Paint mPaint;
// private ArrayList<Path> undonePaths = new ArrayList<Path>();
private float xleft, xright, xtop, xbottom;
public MyView(Context context) {
super(context);
setFocusable(true);
setFocusableInTouchMode(true);
this.setOnTouchListener(this);
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setColor(Color.RED);
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);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
}
@Override
protected void onDraw(Canvas canvas) {
for (Path p : paths) {
canvas.drawPath(p, mPaint);
}
}
private float mX, mY;
private static final float TOUCH_TOLERANCE = 0;
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);
}
@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;
}
}
}
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<LinearLayout
android:id="@+id/ll"
android:layout_width="match_parent"
android:layout_height="fill_parent"
android:layout_weight="1"
android:orientation="vertical" >
</LinearLayout>
<Button
android:id="@+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="Undo" />
</LinearLayout>
@Override
protected void onDraw(Canvas canvas) {
if (mBitmap != null)
canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
if (!paths.isEmpty()) {
canvas.drawPath(paths.get(paths.size() - 1).first, paths.get(paths.size() - 1).second);
}
}
public void onClickUndo() {
if (paths.size() >= 2) {
undonePaths.add(paths.remove(paths.size() - 2));
mBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
m_Canvas = new Canvas(mBitmap);
for (Pair<Path, Paint> p : paths)
m_Canvas.drawPath(p.first, p.second);
invalidate();
}
}
public void onClickRedo() {
if (undonePaths.size() >= 2){
paths.add(undonePaths.remove(undonePaths.size() - 2));
mBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
m_Canvas = new Canvas(mBitmap);
for (Pair<Path, Paint> p : paths)
m_Canvas.drawPath(p.first, p.second);
invalidate();
}
}