我想在两点之间划一条线。我可以在2点之间绘制一条线，如：A到B到C.但我想在它们之间绘制线条，如A到C或C到A.
我还想在图像背景上绘制这些线条。我有一个背景，但当我画一个背景线我的应用程序是滞后的。
以下是代码：
package com.example.grzegorz.kropy;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Point;
import android.graphics.drawable.*;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.MotionEvent;
import android.view.View;
import android.graphics.BitmapFactory;
import java.util.ArrayList;
import java.util.List;
public class PaintView extends View {
private Bitmap mBitmap;
private Canvas mCanvas; // holds the "draw" calls
private Path mPath; //Create an empty path
private Paint mPaint; // the style and color information about how to draw geometries, text and bitmaps.
private static final int TOUCH_TOLERANCE_DP = 24;
private static final int BACKGROUND =0xFFCC00 ;
private List<Point> mPoints = new ArrayList<Point>();
private int mLastPointIndex = 0;
private int mTouchTolerance;
private boolean isPathStarted = false;
public PaintView(Context context) {
super(context);
mCanvas = new Canvas();
mPath = new Path();
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setColor(Color.BLACK);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setStrokeWidth(12);
mTouchTolerance = dp2px(TOUCH_TOLERANCE_DP);
// TODO just test points
Point p1 = new Point(20, 20);
Point p2 = new Point(100, 100);
Point p3 = new Point(200, 250);
Point p4 = new Point(280, 400);
Point p5 = new Point(350, 600);
Point p6 = new Point(400, 500);
Point p7 = new Point(450, 500);
mPoints.add(p1);
mPoints.add(p2);
mPoints.add(p3);
mPoints.add(p4);
mPoints.add(p5);
mPoints.add(p6);
mPoints.add(p7);
}
public PaintView(Context context, AttributeSet attrs) {
super(context, attrs);
mBitmap = BitmapFactory.decodeResource(getResources(),R.drawable.polacz);
mCanvas = new Canvas();
mPath = new Path();
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setColor(Color.BLACK);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setStrokeWidth(12);
mTouchTolerance = dp2px(TOUCH_TOLERANCE_DP);
// TODO just test points
Point p1 = new Point(20, 20);
Point p2 = new Point(100, 100);
Point p3 = new Point(200, 250);
Point p4 = new Point(280, 400);
Point p5 = new Point(350, 600);
Point p6 = new Point(400, 500);
Point p7 = new Point(450, 500);
mPoints.add(p1);
mPoints.add(p2);
mPoints.add(p3);
mPoints.add(p4);
mPoints.add(p5);
mPoints.add(p6);
mPoints.add(p7);
}
public PaintView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
// TODO Auto-generated constructor stub
mCanvas = new Canvas();
mPath = new Path();
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setColor(Color.BLACK);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setStrokeWidth(12);
mTouchTolerance = dp2px(TOUCH_TOLERANCE_DP);
}
@Override
protected void onSizeChanged(int width, int height, int oldWidth, int oldHeight) {
super.onSizeChanged(width, height, oldWidth, oldHeight);
clear();
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
//canvas.drawColor(BACKGROUND);
Drawable d = getResources().getDrawable(R.drawable.polacz);
d.setBounds(canvas.getClipBounds());
d.draw(canvas);
// mCustomImage.setBounds(canvas.getClipBounds());
// mCustomImage.draw(canvas);
canvas.drawBitmap(mBitmap, 0, 0, null);
// canvas.drawBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.polacz1), 0, 0, null);
canvas.drawPath(mPath, mPaint);
// TODO remove if you dont want points to be drawn
for (Point point : mPoints) {
canvas.drawPoint(point.x, point.y, mPaint);
}
}
@Override
public boolean onTouchEvent(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(x, y);
invalidate();
break;
}
return true;
}
private void touch_start(float x, float y) {
if (checkPoint(x, y, mLastPointIndex)) {
mPath.reset();
// user starts from given point so path can beis started
isPathStarted = true;
} else {
// user starts move from point which doen's belongs to mPinst list
isPathStarted = false;
}
}
private void touch_move(float x, float y) {
// draw line with finger move
if (isPathStarted) {
mPath.reset();
Point p = mPoints.get(mLastPointIndex);
mPath.moveTo(p.x, p.y);
if (checkPoint(x, y, mLastPointIndex + 1)) {
p = mPoints.get(mLastPointIndex + 1);
mPath.lineTo(p.x, p.y);
mCanvas.drawPath(mPath, mPaint);
mPath.reset();
++mLastPointIndex;
} else {
mPath.lineTo(x, y);
}
}
}
/**
* Draws line.
*/
private void touch_up(float x, float y) {
mPath.reset();
if (checkPoint(x, y, mLastPointIndex + 1) && isPathStarted) {
// move finished at valid point so draw whole line
// start point
Point p = mPoints.get(mLastPointIndex);
mPath.moveTo(p.x, p.y);
// end point
p = mPoints.get(mLastPointIndex + 1);
mPath.lineTo(p.x, p.y);
mCanvas.drawPath(mPath, mPaint);
mPath.reset();
// increment point index
++mLastPointIndex;
isPathStarted = false;
}
}
/**
* Sets paint
*
* @param paint
*/
public void setPaint(Paint paint) {
this.mPaint = paint;
}
/**
* Returns image as bitmap
*
* @return
*/
public Bitmap getBitmap() {
return mBitmap;
}
/**
* Clears canvas
*/
public void clear() {
mBitmap = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
mBitmap.eraseColor(BACKGROUND);
mCanvas.setBitmap(mBitmap);
invalidate();
}
/**
* Checks if user touch point with some tolerance
*/
private boolean checkPoint(float x, float y, int pointIndex) {
if (pointIndex == mPoints.size()) {
// out of bounds
return false;
}
Point point = mPoints.get(pointIndex);
//EDIT changed point.y to poin.x in the first if statement
if (x > (point.x - mTouchTolerance) && x < (point.x + mTouchTolerance)) {
if (y > (point.y - mTouchTolerance) && y < (point.y + mTouchTolerance)) {
return true;
}
}
return false;
}
public List<Point> getPoints() {
return mPoints;
}
public void setPoints(List<Point> points) {
this.mPoints = points;
}
private int dp2px(int dp) {
Resources r = getContext().getResources();
float px = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp, r.getDisplayMetrics());
return (int) px;
}
}
XML：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity"
android:focusableInTouchMode="false">
<com.example.grzegorz.kropy.PaintView
android:layout_width="670dp"
android:layout_height="820dp"
/>
<!--<Button-->
<!--android:layout_width="wrap_content"-->
<!--android:layout_height="wrap_content"-->
<!--android:text="graj"-->
<!--android:id="@+id/button"-->
<!--android:layout_alignParentTop="true"-->
<!--android:layout_alignParentLeft="true"-->
<!--android:onClick="gra"-->
<!--android:layout_alignParentStart="true" />-->
</RelativeLayout>
答案 0 :(得分：1)
public class DrawView extends View {
Paint paint = new Paint();
View startView1;
View endView1;
int myToken;
float sX,sY,eX,eY;
public DrawView(Context context,View startView ,View endView) {
super(context);
paint.reset();
myToken=token;
paint.setStrokeWidth(3);
this.startView1 = startView;
this.endView1 = endView;
}
public void onDraw(Canvas canvas) {
paint.setColor(Color.GREEN);
canvas.drawLine(startView1.getX()+startView1.getWidth() / 2.F, startView1.getY()+startView1.getHeight()/ 2.F, endView1.getX()+endView1.getWidth() / 2.F, endView1.getY()+endView1.getHeight() / 2.F, paint);
}
}
and call this DrawView class as :
Button btn1=(Button) findViewById(id1);
Button btn2=(Button) findViewById(id2);
DrawView drawView = new DrawView(RoasterScreen.this,btn1,btn2);
rootLayout.addView(drawView);
答案 1 :(得分：0)
public class DrawingPanel extends View implements OnTouchListener {
private Canvas mCanvas;
private Path mPath;
private Paint mPaint, mBitmapPaint;
private ArrayList<PathPoints> paths = new ArrayList<PathPoints>();
private ArrayList<PathPoints> undonePaths = new ArrayList<PathPoints>();
private Bitmap mBitmap;
private int color;
public int SSL = Color.WHITE;
private int x, y;
private int strockWidth = 3;
private String textToDraw = null;
public static boolean isTextModeOn = false;
//public static boolean flag = true;
//public static int angle = 0;
public DrawingPanel(Context context, int color, Bitmap bitmap) {
super(context);
this.color = color;
System.out.println("---> Drawing pannel Construction <--- ");
setFocusable(true);
setFocusableInTouchMode(true);
this.setOnTouchListener(this);
mBitmap = bitmap;
mBitmapPaint = new Paint(Paint.DITHER_FLAG);
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setDither(true);
mPaint.setColor(color);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setStrokeWidth(strockWidth);
mPaint.setTextSize(30);
mPath = new Path();
paths.add(new PathPoints(mPath, color,strockWidth, false));
mCanvas = new Canvas();
}
public void colorChanged(int color) {
this.color = color;
mPaint.setColor(color);
//invalidate();
}
public void changeWidthOfStrock(int strockWidth) {
this.strockWidth = strockWidth;
mPaint.setStrokeWidth(strockWidth);
//invalidate();
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
// mBitmap = AddReportItemActivity.mPhoto;
//mBitmap = getIntent().getExtras().getParcelable("Bitmap");
System.out.println("mBitmap"+mBitmap);
if(mBitmap != null) {
float xscale = (float) w / (float) mBitmap.getWidth();
float yscale = (float) h / (float) mBitmap.getHeight();
if (xscale > yscale) // make sure both dimensions fit (use the
xscale = yscale;
float newx = (float) w * xscale;
float newy = (float) h * xscale; // use the same scale for both
// dimensions
}
// if you want it centered on the display (black borders)
mBitmap = Bitmap.createScaledBitmap(mBitmap, this.getWidth(),this.getHeight(), true);
// mCanvas = new Canvas(mBitmap);
}
@Override
protected void onDraw(Canvas canvas) {
canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint);
for (PathPoints p : paths) {
mPaint.setColor(p.getColor());
mPaint.setStrokeWidth(p.getStrockWidth());
if (p.isTextToDraw()) {
//canvas.drawText(p.textToDraw, p.x, p.y, mPaint);
} else {
canvas.drawPath(p.getPath(), mPaint);
}
}
mPaint.setColor(SSL);
mPaint.setStrokeWidth(strockWidth);
canvas.drawPath(mPath, 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(new PathPoints(mPath, SSL,strockWidth ,false));
mPath = new Path();
}
private void drawText(int x, int y) {
//Log.v(TAG, "Here");
//Log.v(TAG, "X " + x + " Y " + y);
this.x = x;
this.y = y;
paths.add(new PathPoints(color, textToDraw, true, x, y));
// mCanvas.drawText(textToDraw, x, y, mPaint);
}
@Override
public boolean onTouch(View arg0, MotionEvent event) {
float x = event.getX();
float y = event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
if (!isTextModeOn) {
touch_start(x, y);
invalidate();
}
break;
case MotionEvent.ACTION_MOVE:
if (!isTextModeOn) {
touch_move(x, y);
invalidate();
}
break;
case MotionEvent.ACTION_UP:
if (isTextModeOn) {
drawText((int) x, (int) y);
invalidate();
} else {
touch_up();
invalidate();
}
break;
}
return true;
}
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
}
class PathPoints {
private Path path;
// private Paint mPaint;
private int color;
private int strockW;
private String textToDraw;
private boolean isTextToDraw;
private int x, y;
public PathPoints(Path path, int color,int strockWidth ,boolean isTextToDraw) {
this.path = path;
this.color = color;
this.strockW = strockWidth;
this.isTextToDraw = isTextToDraw;
}
public PathPoints(int color, String textToDraw, boolean isTextToDraw,int x, int y) {
this.color = color;
this.textToDraw = textToDraw;
this.isTextToDraw = isTextToDraw;
this.x = x;
this.y = y;
}
public Path getPath() {
return path;
}
public void setPath(Path path) {
this.path = path;
}
/*
* private Paint getPaint() { mPaint = new Paint();
* mPaint.setAntiAlias(true); mPaint.setColor(color);
* mPaint.setStyle(Paint.Style.STROKE);
* mPaint.setStrokeJoin(Paint.Join.ROUND);
* mPaint.setStrokeCap(Paint.Cap.ROUND); mPaint.setStrokeWidth(6);
* return mPaint; }
*/
public int getColor() {
return color;
}
public void setColor(int color) {
this.color = color;
}
public int getStrockWidth() {
return strockW;
}
public void setStrokWidth(int color) {
this.strockW = color;
}
public String getTextToDraw() {
return textToDraw;
}
public void setTextToDraw(String textToDraw) {
this.textToDraw = textToDraw;
}
public boolean isTextToDraw() {
return isTextToDraw;
}
public void setTextToDraw(boolean isTextToDraw) {
this.isTextToDraw = isTextToDraw;
}
public int getX() {
return x;
}
public void setX(int x) {
this.x = x;
}
public int getY() {
return y;
}
public void setY(int y) {
this.y = y;
}
}
}
将此视图添加到您的布局
DrawingPanel drawingPanel = new DrawingPanel（getApplicationContext（），color，bitmap）; rl_layout.addView（drawingPanel）;