Comment trouver dessiné avec la longueur de la ligne de peinture dans Android Java?

Question

Voici mon code pour dessiner avec les doigts peindre la ligne et dessiner un cercle. Je veux savoir comment trouver la longueur de la ligne et je veux dessiner un cercle avec la longueur de la ligne du rayon.

Comment est-ce que je peux faire ceci?

Et où mettre cette ligne?

circlePath.addCircle(mX, mY, "line's length", Path.Direction.CW);

public class MainActivity extends Activity { 
    /** Called when the activity is first created. */ 
    Paint mPaint; 

    float Mx1,My1; 
    float x,y; 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     // setContentView(R.layout.main); 
     MyView view1 =new MyView(this); 
     view1.setBackgroundResource(R.color.colorPrimary); 
     setContentView(view1); 

     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(10); 

    } 

    public class MyView extends View { 

     private static final float MINP = 0.25f; 
     private static final float MAXP = 0.75f; 

     private Bitmap mBitmap; 
     private Canvas mCanvas; 
     private Path mPath; 
     private Paint mBitmapPaint; 
     private Paint circlePaint; 
     private Path circlePath; 
     public MyView(Context c) { 
      super(c); 

      mPath = new Path(); 
      mBitmapPaint = new Paint(Paint.DITHER_FLAG); 

      circlePaint = new Paint(); 
      circlePath = new Path(); 
      circlePaint.setAntiAlias(true); 
      circlePaint.setColor(Color.BLUE); 
      circlePaint.setStyle(Paint.Style.STROKE); 
      circlePaint.setStrokeJoin(Paint.Join.MITER); 
      circlePaint.setStrokeWidth(8f); 

     } 

     @Override 
     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_8888); 
      mCanvas = new Canvas(mBitmap); 
     } 

     @Override 
     protected void onDraw(Canvas canvas) { 


      canvas.drawColor(Color.WHITE); 
      //canvas.drawLine(mX, mY, Mx1, My1, mPaint); 
      //canvas.drawLine(mX, mY, x, y, mPaint); 
      canvas.drawBitmap(mBitmap, 0, 0, mBitmapPaint); 
      canvas.drawPath(mPath, mPaint); 

      canvas.drawPath(circlePath, circlePaint); 

     } 

     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; 
      } 

      //circlePath.reset(); 
      //circlePath.addCircle(mX, mY, Math.abs(mX - mY), Path.Direction.CW); 

     } 
     private void touch_up() { 
      mPath.lineTo(mX, mY); 

      //circlePath.reset(); 
      // commit the path to our offscreen 
      mCanvas.drawPath(mPath, mPaint); 
      // kill this so we don't double draw 
      mPath.reset(); 
     } 

     @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); 
        circlePath.addCircle(mX, mY, x, Path.Direction.CW); 
        invalidate(); 
        break; 
       case MotionEvent.ACTION_UP: 
        touch_up(); 
        //Mx1=(int) event.getX(); 
        //My1= (int) event.getY(); 
        invalidate(); 
        break; 
      } 
      return true; 
     } 

    } 


} 

Answer 1

Je résolus.

float first_x, first_y, last_x, last_y, line_lenght; 
     @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); 
        first_x = x; 
        first_y = y; 

        invalidate(); 
        break; 
       case MotionEvent.ACTION_MOVE: 
        touch_move(x, y); 
        last_x = x; 
        last_y = y; 
        line_lenght = (float) Math.pow(Math.abs(first_x-last_x),2) + (float) Math.pow(Math.abs(first_y-last_y),2); 
        line_lenght = (float) Math.sqrt(line_lenght); 
        circlePath.reset(); 
        circlePath.addCircle(mX, mY, line_lenght, Path.Direction.CW); 

        invalidate(); 
        break; 
       case MotionEvent.ACTION_UP: 

        last_x = x; 
        last_y = y; 
        line_lenght = (float) Math.pow(Math.abs(first_x-last_x),2) + (float) Math.pow(Math.abs(first_y-last_y),2); 
        line_lenght = (float) Math.sqrt(line_lenght); 
        circlePath.reset(); 
        circlePath.addCircle(mX, mY, line_lenght, Path.Direction.CW); 

        touch_up(); 


        //Mx1=(int) event.getX(); 
        //My1= (int) event.getY(); 
        invalidate(); 
        break; 
      } 
      return true; 
     }