如何将线附加到imageview？

Question

我有两个imageView，我需要在它们之间放一条线，当通过触摸线移动其中一个图像时，必须遵循imageView（拉伸）。如何将行起点和终点附加到两个不同的imageView并动态更改行？ 这是我的代码：

public class MainActivity extends AppCompatActivity implements View.OnTouchListener {

    ImageView mLeftTop;
    ImageView mCenterTop;
    float dX, dY;
    PathView mPathView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        mPathView = (PathView)findViewById(R.id.path_view);

        mLeftTop = (ImageView)findViewById(R.id.left_top);
        mCenterTop = (ImageView)findViewById(R.id.center_top);

        mLeftTop.setOnTouchListener(this);
        mCenterTop.setOnTouchListener(this);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @Override
    public boolean onTouch(View v, MotionEvent event) {

        switch (event.getActionMasked()) {

            case MotionEvent.ACTION_DOWN:

                dX = v.getX() - event.getRawX();
                dY = v.getY() - event.getRawY();
                break;

            case MotionEvent.ACTION_MOVE:

                v.animate()
                        .x(event.getRawX() + dX)
                        .y(event.getRawY() + dY)
                        .setDuration(0)
                        .start();
                break;
            default:
                return false;
        }
        return true;
    }

}

自定义视图：

public class PathView extends View {

    private Paint mPaint;
    private Path mPath;

    public PathView(Context context) {
        super(context);
        init();
    }

    public PathView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public PathView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    public PathView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
        init();
    }

    private void init() {
        mPaint = new Paint();
        mPaint.setStyle(Paint.Style.STROKE);
        mPath = new Path();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        mPaint.setColor(Color.BLACK);
        mPaint.setStrokeWidth(8);
        mPath.moveTo(100, 400);
        mPath.lineTo(400, 800);

        canvas.drawPath(mPath, mPaint);
    }
}