Android的对话框DialogFragment指定弹窗口大小，设置圆角

  @Override
  public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container,
      @Nullable Bundle savedInstanceState) {
    getDialog().getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));//1.必须设置dialog的window背景为透明颜色，不然圆角无效或者是系统默认的颜色
    return inflater.inflate(R.layout.dialog_pay_sure_alert, container);
  }

<FrameLayout　　//2.必须布局文件最外层包裹一层，这样才能显示指定的对话框大小，比如这里的 380dp x 205dp
  xmlns:andro>
  </android.support.constraint.ConstraintLayout>
</FrameLayout>

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:andro/>
    </shape>
  </item>
</layer-list>