Android超简单实现动画悬浮菜单

目录

效果展示

代码展示

class AnimMenuActivity : AppCompatActivity(){
    private var isOpen = false //菜单是否打开
    private var menuArray = ArrayList<View>()
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_animmenu)
        img_00.setOnClickListener {
            opreaMenu()
        }
        menuArray.add(img_01)
        menuArray.add(img_02)
        menuArray.add(img_03)
        menuArray.add(img_04)
        menuArray.add(img_05)
        menuArray.add(img_06)
        for ((index,view) in menuArray.withIndex()){
            view.setOnClickListener {
                Toast.makeText(this@AnimMenuActivity,"我是$index",Toast.LENGTH_SHORT).show()
            }
        }
    }

    /**
     * 操作菜单
     */
    private fun opreaMenu() {
        val openAnimator:ValueAnimator = if(isOpen){
            isOpen = false
            ValueAnimator.ofFloat(200f, 0f)
        }else{
            isOpen = true
            ValueAnimator.ofFloat(0f, 200f)
        }
        openAnimator.duration = 600
        openAnimator.addUpdateListener {
            val animVal = it.animatedValue as Float
            for ((index,view) in menuArray.withIndex()){
                //位移
                val degree = 360.0 / menuArray.size * index
                //计算位置
                val translateX = animVal * cos(Math.toRadians(degree))
                val translateY = animVal * sin(Math.toRadians(degree))
                view.translationX = translateX.toFloat()
                view.translationY = translateY.toFloat()

                //旋转
                view.rotation = 360f * it.animatedFraction

                //缩放
                if(animVal > 0){
                    view.scaleX = animVal / 200f
                    view.scaleY = animVal / 200f
                }

                //透明
                if(animVal > 0){
                    view.alpha = animVal / 200f
                }
            }
        }
        openAnimator.start()
    }
}

难点公式

以（x,y）为中心，中心到顶点的距离为a，degree为旋转的角度，正N边形的顶点坐标公式为：
X=a * cos(degree)+x
Y=a * sin(degree)+y
这个公式是用来计算位移位置的，之前的一篇蛛网效果也主要用的是它（https://www.jianshu.com/p/26e5a2465fae）

案例源码

https://github.com/myml666/CustomDemo