Android 更改路径颜色而不更改以前的路径
我想创建一个小的绘画应用程序,我可以使用一些颜色来绘制,我只测试了一个颜色变化,直到现在它还不能正常工作。当我单击按钮并开始使用新颜色绘制时,我之前绘制的所有图形也会更改颜色。有人能帮我吗Android 更改路径颜色而不更改以前的路径,android,colors,touch,Android,Colors,Touch,我想创建一个小的绘画应用程序,我可以使用一些颜色来绘制,我只测试了一个颜色变化,直到现在它还不能正常工作。当我单击按钮并开始使用新颜色绘制时,我之前绘制的所有图形也会更改颜色。有人能帮我吗 public class MyTouchEventView extends View { private Paint paint = new Paint(); private Path path = new Path(); public Button btnChange;
public class MyTouchEventView extends View {
private Paint paint = new Paint();
private Path path = new Path();
public Button btnChange;
public LayoutParams params;
public MyTouchEventView(Context context) {
super(context);
paint.setAntiAlias(true);
paint.setColor(Color.BLACK);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeJoin(Paint.Join.ROUND);
paint.setStrokeWidth(1f);
btnChange = new Button(context);
btnChange.setText("Chaneg color");
params = new LayoutParams(LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT);
btnChange.setLayoutParams(params);
btnChange.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
paint.setColor(Color.GREEN);
}
});
}
@Override
protected void onDraw(Canvas canvas) {
canvas.drawPath(path, paint);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
float pointX = event.getX();
float pointY = event.getY();
// Checks for the event that occurs
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
path.moveTo(pointX, pointY);
return true;
case MotionEvent.ACTION_MOVE:
path.lineTo(pointX, pointY);
break;
default:
return false;
}
postInvalidate();
return true;
}
}
这里的问题是您只使用一条路径 你应该在每一个动作上创建一个新的路径。对于这些路径中的每一条,你也必须存储油漆 例如,可以将两个元素都定义为成员的类:
public class Stroke {
private Path _path;
private Paint _paint;
}// add constructor(Path, Paint) and accessors
以及您上下文中的笔划列表:
List<Stroke> allStrokes = new ArrayList<Stroke>();
请注意,使用这个简单的解决方案,您无法进行多点触控绘图。为此,您还必须存储和处理MotionEvent ID
编辑:以下是一个工作的多点触控绘制示例,该示例创建了使用随机颜色填充的笔划:
DrawArea.java:
import android.content.Context;
import android.graphics.*;
import android.util.SparseArray;
import android.view.MotionEvent;
import android.view.View;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
public class DrawArea extends View {
private List<Stroke> _allStrokes; //all strokes that need to be drawn
private SparseArray<Stroke> _activeStrokes; //use to retrieve the currently drawn strokes
private Random _rdmColor = new Random();
public DrawArea(Context context) {
super(context);
_allStrokes = new ArrayList<Stroke>();
_activeStrokes = new SparseArray<Stroke>();
setFocusable(true);
setFocusableInTouchMode(true);
setBackgroundColor(Color.WHITE);
}
public void onDraw(Canvas canvas) {
if (_allStrokes != null) {
for (Stroke stroke: _allStrokes) {
if (stroke != null) {
Path path = stroke.getPath();
Paint painter = stroke.getPaint();
if ((path != null) && (painter != null)) {
canvas.drawPath(path, painter);
}
}
}
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
final int action = event.getActionMasked();
final int pointerCount = event.getPointerCount();
switch (action) {
case MotionEvent.ACTION_DOWN: {
pointDown((int)event.getX(), (int)event.getY(), event.getPointerId(0));
break;
}
case MotionEvent.ACTION_MOVE: {
for (int pc = 0; pc < pointerCount; pc++) {
pointMove((int) event.getX(pc), (int) event.getY(pc), event.getPointerId(pc));
}
break;
}
case MotionEvent.ACTION_POINTER_DOWN: {
for (int pc = 0; pc < pointerCount; pc++) {
pointDown((int)event.getX(pc), (int)event.getY(pc), event.getPointerId(pc));
}
break;
}
case MotionEvent.ACTION_UP: {
break;
}
case MotionEvent.ACTION_POINTER_UP: {
break;
}
}
invalidate();
return true;
}
private void pointDown(int x, int y, int id) {
//create a paint with random color
Paint paint = new Paint();
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(10);
paint.setColor(_rdmColor.nextInt());
//create the Stroke
Point pt = new Point(x, y);
Stroke stroke = new Stroke(paint);
stroke.addPoint(pt);
_activeStrokes.put(id, stroke);
_allStrokes.add(stroke);
}
private void pointMove(int x, int y, int id) {
//retrieve the stroke and add new point to its path
Stroke stroke = _activeStrokes.get(id);
if (stroke != null) {
Point pt = new Point(x, y);
stroke.addPoint(pt);
}
}
}
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Point;
public class Stroke {
private Path _path;
private Paint _paint;
public Stroke (Paint paint) {
_paint = paint;
}
public Path getPath() {
return _path;
}
public Paint getPaint() {
return _paint;
}
public void addPoint(Point pt) {
if (_path == null) {
_path = new Path();
_path.moveTo(pt.x, pt.y);
} else {
_path.lineTo(pt.x, pt.y);
}
}
}
import android.app.Activity;
import android.os.Bundle;
public class MyActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
DrawArea da = new DrawArea(this);
setContentView(da);
}
}
MyActivity.java:
import android.content.Context;
import android.graphics.*;
import android.util.SparseArray;
import android.view.MotionEvent;
import android.view.View;
import java.util.ArrayList;
import java.util.List;
import java.util.Random;
public class DrawArea extends View {
private List<Stroke> _allStrokes; //all strokes that need to be drawn
private SparseArray<Stroke> _activeStrokes; //use to retrieve the currently drawn strokes
private Random _rdmColor = new Random();
public DrawArea(Context context) {
super(context);
_allStrokes = new ArrayList<Stroke>();
_activeStrokes = new SparseArray<Stroke>();
setFocusable(true);
setFocusableInTouchMode(true);
setBackgroundColor(Color.WHITE);
}
public void onDraw(Canvas canvas) {
if (_allStrokes != null) {
for (Stroke stroke: _allStrokes) {
if (stroke != null) {
Path path = stroke.getPath();
Paint painter = stroke.getPaint();
if ((path != null) && (painter != null)) {
canvas.drawPath(path, painter);
}
}
}
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
final int action = event.getActionMasked();
final int pointerCount = event.getPointerCount();
switch (action) {
case MotionEvent.ACTION_DOWN: {
pointDown((int)event.getX(), (int)event.getY(), event.getPointerId(0));
break;
}
case MotionEvent.ACTION_MOVE: {
for (int pc = 0; pc < pointerCount; pc++) {
pointMove((int) event.getX(pc), (int) event.getY(pc), event.getPointerId(pc));
}
break;
}
case MotionEvent.ACTION_POINTER_DOWN: {
for (int pc = 0; pc < pointerCount; pc++) {
pointDown((int)event.getX(pc), (int)event.getY(pc), event.getPointerId(pc));
}
break;
}
case MotionEvent.ACTION_UP: {
break;
}
case MotionEvent.ACTION_POINTER_UP: {
break;
}
}
invalidate();
return true;
}
private void pointDown(int x, int y, int id) {
//create a paint with random color
Paint paint = new Paint();
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(10);
paint.setColor(_rdmColor.nextInt());
//create the Stroke
Point pt = new Point(x, y);
Stroke stroke = new Stroke(paint);
stroke.addPoint(pt);
_activeStrokes.put(id, stroke);
_allStrokes.add(stroke);
}
private void pointMove(int x, int y, int id) {
//retrieve the stroke and add new point to its path
Stroke stroke = _activeStrokes.get(id);
if (stroke != null) {
Point pt = new Point(x, y);
stroke.addPoint(pt);
}
}
}
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Point;
public class Stroke {
private Path _path;
private Paint _paint;
public Stroke (Paint paint) {
_paint = paint;
}
public Path getPath() {
return _path;
}
public Paint getPaint() {
return _paint;
}
public void addPoint(Point pt) {
if (_path == null) {
_path = new Path();
_path.moveTo(pt.x, pt.y);
} else {
_path.lineTo(pt.x, pt.y);
}
}
}
import android.app.Activity;
import android.os.Bundle;
public class MyActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
DrawArea da = new DrawArea(this);
setContentView(da);
}
}
我的解决方案:
public class PaintView extends ImageView {
private class Holder {
Path path;
Paint paint;
Holder(int color) {
path = new Path();
paint = new Paint();
paint.setAntiAlias(true);
paint.setStrokeWidth(4f);
paint.setColor(color);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeJoin(Paint.Join.ROUND);
paint.setStrokeCap(Paint.Cap.ROUND);
}
}
private int color = Color.WHITE;
private List<Holder> holderList = new ArrayList<Holder>();
public PaintView(Context context) {
super(context);
init();
}
public PaintView(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public PaintView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
init();
}
private void init() {
holderList.add(new Holder(color));
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
for (Holder holder : holderList) {
canvas.drawPath(holder.path, holder.paint);
}
}
@Override
public boolean onTouchEvent(MotionEvent event) {
float eventX = event.getX();
float eventY = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
holderList.add(new Holder(color));
holderList.get(holderList.size() - 1).path.moveTo(eventX, eventY);
return true;
case MotionEvent.ACTION_MOVE:
holderList.get(holderList.size() - 1).path.lineTo(eventX, eventY);
break;
case MotionEvent.ACTION_UP:
break;
default:
return false;
}
invalidate();
return true;
}
public void resetPaths() {
for (Holder holder : holderList) {
holder.path.reset();
}
invalidate();
}
public void setBrushColor(int color) {
this.color = color;
}
}
public类PaintView扩展了ImageView{
私人阶级持有者{
路径;
油漆;
支架(内部颜色){
路径=新路径();
油漆=新油漆();
paint.setAntiAlias(真);
油漆。设置行程宽度(4f);
油漆。设置颜色(颜色);
绘制.设置样式(绘制.样式.笔划);
绘制.设置行程连接(绘制.连接.圆形);
油漆固定行程盖(油漆固定行程盖圆形);
}
}
私有int color=color.WHITE;
私有列表持有者列表=新的ArrayList();
公共PaintView(上下文){
超级(上下文);
init();
}
公共画图视图(上下文、属性集属性){
超级(上下文,attrs);
init();
}
公共画图视图(上下文、属性集属性、int-defStyle){
超级(上下文、属性、定义样式);
init();
}
私有void init(){
holderList.add(新的Holder(颜色));
}
@凌驾
受保护的void onDraw(画布){
super.onDraw(帆布);
用于(持有者:持有者列表){
画布.drawPath(holder.path,holder.paint);
}
}
@凌驾
公共布尔onTouchEvent(运动事件){
float eventX=event.getX();
float eventY=event.getY();
开关(event.getAction()){
case MotionEvent.ACTION\u DOWN:
holderList.add(新的Holder(颜色));
get(holderList.size()-1.path.moveTo(eventX,eventY);
返回true;
case MotionEvent.ACTION\u移动:
get(holderList.size()-1.path.lineTo(eventX,eventY);
打破
case MotionEvent.ACTION\u UP:
打破
违约:
返回false;
}
使无效();
返回true;
}
公共无效重置路径(){
用于(持有者:持有者列表){
holder.path.reset();
}
使无效();
}
公共颜色(内部颜色){
这个颜色=颜色;
}
}
切换到新颜色时,应该使用Path.reset()来解决问题 。检查此编辑部分,如果它有帮助谢谢,这似乎是我正在寻找的,我将如何使用您的方法来解决我的问题?如何检索动作中最后添加的路径?请检查我刚才添加的示例