在Android的移动圈子 [英] Moving circles in android

问题描述

我有一个任务。这是画一些（不止一个）圆在屏幕上移动。他们必须开始点击它们后移动。我有code只为​​一个圆。给我的路该怎么做这个任务，例如，5圈。在此先感谢！

 公共类MainActivity延伸活动{

    @覆盖
    公共无效的onCreate（包savedInstanceState）{
        super.onCreate（savedInstanceState）;
        的setContentView（新MyView的（这个））;
    }

    一流的MyView的扩展视图{
        //公共油漆℃;
        公共涂料P;

        私有静态最终诠释半径= 46;

        私人诠释的centerX;
        私人诠释centerY;
        私人诠释speedX = 50;
        私人诠释SPEEDY = 40;
        //专用涂料粉刷; //Создайегогде-нибудьтамвконструкторе


        公共MyView的（上下文的背景下）{
            超（上下文）;
            P =新的油漆（）;
            p.setColor（Color.GREEN）;
        }

        @覆盖
        保护无效onSizeChanged（INT W，INT小时，INT oldW，诠释oldH）{
            的centerX =瓦特/ 2;
            centerY = H / 2;
        }

        保护无效的OnDraw（帆布C）{
            INT W =的getWidth（）;
            INT H =的getHeight（）;
            的centerX + = speedX;
            centerY + =快捷;
            INT rightLimit = W  -​​  RADIUS;
            INT bottomLimit = H  -  RADIUS;

            如果（的centerX＆GT; = rightLimit）{
                的centerX = rightLimit;
                speedX * = -1;
            }
            如果（的centerX＆LT; = RADIUS）{
                的centerX = RADIUS;
                speedX * = -1;
            }
            如果（centerY＆GT; = bottomLimit）{
                centerY = bottomLimit;
                快速* = -1;
            }
            如果（centerY＆LT; = RADIUS）{
                centerY = RADIUS;
                快速* = -1;
            }

            c.drawCircle（的centerX，centerY，RADIUS，P）;
            postInvalidateDelayed（200）;
        }
    }
}
 

解决方案

您必须改变这一部分：

 私人诠释的centerX;
  私人诠释centerY;
  私人诠释speedX = 50;
  私人诠释SPEEDY = 40;
 

和其转换到

 类圆{
  私人诠释的centerX;
  私人诠释centerY;
  私人诠释speedX = 50;
  私人诠释SPEEDY = 40;
  //添加构造函数在这里和其他的东西
};
 

然后让你的圈子集合：的ArrayList＆LT;圈＆GT;圈子然后，而不是和

 的centerX + = speedX;
centerY + =快捷;
INT rightLimit = W  -​​  RADIUS;
INT bottomLimit = H  -  RADIUS;

如果（的centerX＆GT; = rightLimit）{
  的centerX = rightLimit;
  speedX * = -1;
}
如果（的centerX＆LT; = RADIUS）{
  的centerX = RADIUS;
  speedX * = -1;
}
如果（centerY＆GT; = bottomLimit）{
  centerY = bottomLimit;
  快速* = -1;
}
如果（centerY＆LT; = RADIUS）{
  centerY = RADIUS;
  快速* = -1;
}
 

您需要做的是为每一个圈，像

 为（i = 0; I＆LT; circles.size（）;我++）{
    圈子[I] .centerX + =圈子[I] .speedX;
    圈子[I] .centerY + =圈子[I] .speedY;

    //итакдалее...
 

}

I have a task. It's to draw some (more than one) circles moving around the screen. They must start moving after click on them. I have the code only for one circle. Give me the way how to do this task, for example, 5 circles. Thanks in advance!

public class MainActivity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(new MyView(this));
    }

    class MyView extends View {
        //public    Paint c;
        public  Paint p;

        private static final int RADIUS = 46;

        private int centerX;
        private int centerY;
        private int speedX = 50;
        private int speedY = 40;
        //private Paint paint; // Создай его где-нибудь там в конструкторе


        public MyView(Context context) {
            super(context);
            p = new Paint();
            p.setColor(Color.GREEN);
        }

        @Override
        protected void onSizeChanged(int w, int h, int oldW, int oldH) {
            centerX = w / 2;
            centerY = h / 2;
        }

        protected void onDraw(Canvas c) {
            int w = getWidth();
            int h = getHeight();
            centerX += speedX;
            centerY += speedY;
            int rightLimit = w - RADIUS;
            int bottomLimit = h - RADIUS;

            if (centerX >= rightLimit) {
                centerX = rightLimit;
                speedX *= -1;
            }
            if (centerX <= RADIUS) {
                centerX = RADIUS;
                speedX *= -1;
            }
            if (centerY >= bottomLimit) {
                centerY = bottomLimit;
                speedY *= -1;
            }
            if (centerY <= RADIUS) {
                centerY = RADIUS;
                speedY *= -1;
            }

            c.drawCircle(centerX, centerY, RADIUS, p);
            postInvalidateDelayed(200);  
        }
    }
}

解决方案

you have to change this part:

  private int centerX;
  private int centerY;
  private int speedX = 50;
  private int speedY = 40;

and convert it to the

class Circle {
  private int centerX;
  private int centerY;
  private int speedX = 50;
  private int speedY = 40;
  // add constructor here and other things
};

then make a collection of your circles: ArrayList<Circle> circles, and then instead of

centerX += speedX;
centerY += speedY;
int rightLimit = w - RADIUS;
int bottomLimit = h - RADIUS;

if (centerX >= rightLimit) {
  centerX = rightLimit;
  speedX *= -1;
}
if (centerX <= RADIUS) {
  centerX = RADIUS;
  speedX *= -1;
}
if (centerY >= bottomLimit) {
  centerY = bottomLimit;
  speedY *= -1;
}
if (centerY <= RADIUS) {
  centerY = RADIUS;
  speedY *= -1;
}

you have to do it for every circle, like

for( i=0; i<circles.size(); i++) {
    circles[i].centerX += circles[i].speedX;
    circles[i].centerY += circles[i].speedY;

    // и так далее...

}

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