我试图做一个圆形的ListView与列表项安排在半圈。它应该是这个样子：

I'm Trying to make a Circular ListView with List Items arranged on Half Circle. it should look something like this:

有一个related帖子但它被关闭。

我在我自己的自定义通知ListView和它工作正常，但我的问题是，我不能安排列表项半圆的方式，因为它显示在图像上。我试了好东西，但它是没有用的，我不知道该怎么做。

I made my own Circular Custom ListView and it works fine but my Problem is that i can't arrange List Items Half Circle way as it is shown on the image. I tried several things but it was useless, I don't know how to do it.

推荐答案

所以，当我做了示例应用程序来演示这个我必须做两件事情。

So when I made the sample app to demo this I had to do 2 things.

首先，是编辑的OnDraw（画布）在我的自定义视图。这可能是任何看法，我让一个TextView的简单性。这让我推的景色根据一个方程式。

First, was edit the onDraw(Canvas) on my custom view. This could be any view, I make it a TextView for simplicity. This allows me to push the view over based on an equation.

public class MyView extends TextView {

    private static final int MAX_INDENT = 300;
    private static final String TAG = MyView.class.getSimpleName();

    public MyView(Context context) {
        super(context);
    }

    public void onDraw(Canvas canvas){
        canvas.save();
        float indent = getIndent(getY());
        canvas.translate(indent, 0);
        super.onDraw(canvas);
        canvas.restore();
    }

    public float getIndent(float distance){
        float x_vertex = MAX_INDENT;
        DisplayMetrics displayMetrics = getContext().getResources().getDisplayMetrics();
        float y_vertex = displayMetrics.heightPixels / 2 / displayMetrics.density;
        double a = ( 0 - x_vertex ) / ( Math.pow(( 0 - y_vertex), 2) ) ;
        float indent = (float) (a * Math.pow((distance - y_vertex), 2) + x_vertex);
        return indent;
    }
}

第二件事情我必须做的是重写的ListView类，使其实现OnScrollListener并调用 setOnScrollListener（本）; 。现在我能在列表中滚动，接下去我把视图中的公式。

The second thing I had to do was to Override the ListView class, make it implement OnScrollListener and call setOnScrollListener(this);. Now I am able to scroll through the list, it follows the equation that I put in the view.

public class HalfCircleListView extends ListView implements AbsListView.OnScrollListener {
    public HalfCircleListView(Context context) {
        super(context);
        setOnScrollListener(this);
    }


    @Override
    public void onScrollStateChanged(AbsListView absListView, int i) {
        //Ignored
    }

    @Override
    public void onScroll(AbsListView absListView, int i, int i2, int i3) {
        absListView.invalidateViews();
    }
}

您可以从我的吉斯特的完整源代码。

You can download the full source from my Gist.

初始状态 滚动州

Initial State Scrolled State

正如你可以看到我的数学是有点过......我用一个抛物线VS了一圈，这样就必须改变。

As you can see my math is a little off... I use a parabola vs a circle, so that will have to be changed.