Wie findet man in Android Java die Länge der Zeichenzeile?

Question

Heres mein Code zum Zeichnen mit Fingern malen Linie und Kreis zeichnen. Ich möchte wissen, wie man die Länge der Linie findet und einen Kreis mit der Länge der Radiuslinie zeichnen möchte.

Wie kann ich das tun?

Und wohin diese Linie?

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

löste ich.

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; 
     }