android - 如何在特定位置绘制点并在这些点之间用手指拖动画线？

Question

我正在尝试在屏幕上绘制两个点，当我触摸 point1 并将其拖动到 point2 时，需要从 point1 到 point2 绘制一条线。

如下图所示

Answer 1

按照此代码触摸事件进行拖动

@Override
public boolean onTouchEvent (MotionEvent event) {

  if (event.getAction() == MotionEvent.ACTION_DOWN) {

    start_x = event.getX();
    start_y = event.getY();     

  } else if (event.getAction() == MotionEvent.ACTION_MOVE) {

    //create the line from start_x and start_y to the current location
    //don't forget to invalidate the View otherwise your line won't get redrawn

  } else if (event.getAction() == MotionEvent.ACTION_UP) {

    //might not need anything here

  }

对于画线，请点击此链接 How to draw a line in android