package com.novelbook.android.utils;

import android.content.Context;
import android.support.v4.view.ViewPager;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.LinearLayout;

import com.novelbook.android.R;

import java.util.ArrayList;
import java.util.List;

public class CyclePageIndicator  implements ViewPager.OnPageChangeListener {
        private int mPageCount;//页数
        private List<ImageView> mImgList;//保存img总个数
        private int img_select;
        private int img_unSelect;

        public CyclePageIndicator(Context context, LinearLayout linearLayout, int pageCount) {
            this.mPageCount = pageCount;

            mImgList = new ArrayList<>();
            img_select = R.drawable.cyle_indicator_selected;
            img_unSelect = R.drawable.cycle_indicator_unselected;
            final int imgSize = 25;

            for (int i = 0; i < mPageCount; i++) {
                ImageView imageView = new ImageView(context);
                LinearLayout.LayoutParams params = new LinearLayout.LayoutParams(new ViewGroup.LayoutParams(
                        ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT));
                //为小圆点左右添加间距
                params.leftMargin = 10;
                params.rightMargin = 10;
                //给小圆点一个默认大小
                params.height = imgSize;
                params.width = imgSize;
                if (i == 0) {
                    imageView.setBackgroundResource(img_select);
                } else {
                    imageView.setBackgroundResource(img_unSelect);
                }
                //为LinearLayout添加ImageView
                linearLayout.addView(imageView, params);
                mImgList.add(imageView);
            }
        }

        @Override
        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {}

        @Override
        public void onPageSelected(int position) {
            for (int i = 0; i < mPageCount; i++) {
                //选中的页面改变小圆点为选中状态，反之为未选中
                if ((position % mPageCount) == i) {
                    (mImgList.get(i)).setBackgroundResource(img_select);
                } else {
                    (mImgList.get(i)).setBackgroundResource(img_unSelect);
                }
            }
        }

        @Override
        public void onPageScrollStateChanged(int state) {}
    }