038 Android Magicindicator开源框架实现viewpager底部圆形指示器

1.Magicindicator介绍

　　Magicindicator是一个强大、可定制、易扩展的 ViewPager 指示器框架。是ViewPagerIndicator、TabLayout、PagerSlidingTabStrip的最佳替代品。支持角标，更支持在非ViewPager场景下使用（使用hide()、show()切换Fragment或使用setVisibility切换FrameLayout里的View等）。

2.Magicindicator使用环境配置

repositories {

    ...

    maven {

        url "https://jitpack.io"

    }

}

dependencies {

    ...

    compile 'com.github.hackware1993:MagicIndicator:1.5.0'

}

3.利用Magicindicator实现viewpager底部的圆形指示器

(1)xml布局

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout

    xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical">

    <!--利用帧布局实现在viewpager上添加标题-->

    <FrameLayout

        android:layout_width="match_parent"

        android:layout_height="180dp">

        <!--利用ViewPager实现轮播图效果-->

        <android.support.v4.view.ViewPager

            android:id="@+id/vp_news_center"

            android:layout_width="match_parent"

            android:layout_height="match_parent">

        </android.support.v4.view.ViewPager>

        <RelativeLayout

            android:layout_width="match_parent"

            android:layout_height="wrap_content"

            android:layout_gravity="bottom"

            android:background="#a000"

            android:padding="10dp">

            <TextView

                android:id="@+id/tv_news_vp_title"

                android:text="标题"

                android:textColor="#fff"

                android:textSize="16dp"

                android:layout_width="wrap_content"

                android:layout_height="wrap_content" />

            <!--MagicIndicator的使用-->

            <net.lucode.hackware.magicindicator.MagicIndicator

                android:id="@+id/magic_indicator1"

                android:layout_width="wrap_content"

                android:layout_alignParentRight="true"

                android:layout_centerVertical="true"

                android:layout_height="wrap_content" />

        </RelativeLayout>

    </FrameLayout>

</LinearLayout>

(2)java后台

package com.example.administrator.test66smartbeijing.fragment;

import android.annotation.SuppressLint;

import android.graphics.Color;

import android.os.Bundle;

import android.support.annotation.NonNull;

import android.support.annotation.Nullable;

import android.support.v4.app.Fragment;

import android.support.v4.view.PagerAdapter;

import android.support.v4.view.ViewPager;

import android.view.LayoutInflater;

import android.view.View;

import android.view.ViewGroup;

import android.widget.ImageView;

import android.widget.TextView;

import com.alibaba.fastjson.JSONObject;

import com.bumptech.glide.Glide;

import com.example.administrator.test66smartbeijing.R;

import com.example.administrator.test66smartbeijing.javabean.NewsMenu;

import com.example.administrator.test66smartbeijing.javabean.NewsTabBean;

import com.example.administrator.test66smartbeijing.utils.CacheUtils;

import com.example.administrator.test66smartbeijing.utils.ConstantValue;

import com.example.administrator.test66smartbeijing.utils.RecyclerAdapter;

import net.lucode.hackware.magicindicator.MagicIndicator;

import net.lucode.hackware.magicindicator.ViewPagerHelper;

import net.lucode.hackware.magicindicator.buildins.circlenavigator.CircleNavigator;

import org.xutils.common.Callback;

import org.xutils.http.RequestParams;

import org.xutils.image.ImageOptions;

import org.xutils.x;

import java.util.ArrayList;

import static android.media.AudioRecord.MetricsConstants.CHANNELS;

/**

 *

 */

public class TabDataFragment extends Fragment {

    String queryResultStr="";

    NewsMenu newsMenu;

    ArrayList<NewsTabBean.TopNews> topnews;

    private ViewPager viewPager;

    TextView tv_news_vp_title;

    public TabDataFragment() {

    }

    @SuppressLint("ValidFragment")

    public TabDataFragment(NewsMenu newsMenu) {

        this.newsMenu=newsMenu;

    }

    //新建一个Fragment实例

    public static Fragment newInstance() {

        TabDataFragment fragment = new TabDataFragment();

        return fragment;

    }

    @Nullable

    @Override

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        // LayoutInflater.inflate()的功能是将一段 XML 资源文件加载成为 View。所以通常用于将 XML 文件实例化为 View。然后获取 View 上的组件最后操作之。

        View rootView = inflater.inflate(R.layout.fragment_tab_data, container, false);

        viewPager = rootView.findViewById(R.id.vp_news_center);

        tv_news_vp_title=rootView.findViewById(R.id.tv_news_vp_title);

        getDataFromServer();

        return rootView;

    }

    /**

     * viewPager的数据适配器

     */

    class NewsCenterAdapter extends PagerAdapter{

        @Override

        public int getCount() {

            return topnews.size();

        }

        @Override

        public boolean isViewFromObject(@NonNull View view, @NonNull Object object) {

            return view==object;

        }

        @NonNull

        @Override

        public Object instantiateItem(@NonNull ViewGroup container, int position) {

            ImageView imageView=new ImageView(getActivity());

            //imageView.setImageResource(R.mipmap.news_pic_default);

            String imageUrlTemp=topnews.get(position).topimage;

            //String imageUrl="http://118.25.152.62:8080/zhbj/10007/1452327318UU91.jpg";

            String imageUrl=ConstantValue.SERVER_URL+imageUrlTemp.substring(25);

            System.out.println(imageUrl);

            //利用Glide开源框架，加载网络图片

            Glide.with(getActivity()).load(imageUrl).into(imageView);

            container.addView(imageView);

            return imageView;

        }

        //销毁item

        @Override

        public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {

            container.removeView((View) object);

        }

    }

    /**

     * 从服务器获取数据

     */

    private void getDataFromServer() {

        //请求地址

        String url=ConstantValue.SERVER_URL+newsMenu.data.get(0).children.get(0).url;

        RequestParams params = new RequestParams(url);

        x.http().get(params, new Callback.CommonCallback<String>() {

            @Override

            public void onSuccess(String result) {

                //解析result

                queryResultStr=result;

                System.out.println(result);

                processData(queryResultStr);

                //写缓存

                CacheUtils.setCache(ConstantValue.NEWSCENTER_URL,queryResultStr,getActivity());

            }

            //请求异常后的回调方法

            @Override

            public void onError(Throwable ex, boolean isOnCallback) {

            }

            //主动调用取消请求的回调方法

            @Override

            public void onCancelled(CancelledException cex) {

            }

            @Override

            public void onFinished() {

            }

        });

    }

    /**

     * @param queryResultStr 服务器返回结果

     */

    private void processData(String queryResultStr) {

        NewsTabBean newsTabBean = JSONObject.parseObject(queryResultStr,NewsTabBean.class);

        //利用viewPager实现图片轮播效果

        topnews = newsTabBean.data.topnews;

        if(topnews!=null){

            viewPager.setAdapter(new NewsCenterAdapter());

            viewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {

                @Override

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

                }

                @Override

                public void onPageSelected(int position) {

                    //设置viewpager上图片的标题

                    tv_news_vp_title.setText(topnews.get(position).title);

                }

                @Override

                public void onPageScrollStateChanged(int state) {

                }

            });

            //更新第一个头条新闻标题

            tv_news_vp_title.setText(topnews.get(0).title);

            initMagicIndicator1();

        }

    }

    /**

     * 初始化MagicIndicator

     */

    private void initMagicIndicator1() {

        MagicIndicator magicIndicator = getActivity().findViewById(R.id.magic_indicator1);

        CircleNavigator circleNavigator = new CircleNavigator(getActivity());

        circleNavigator.setCircleCount(topnews.size());

        circleNavigator.setCircleColor(Color.RED);

        circleNavigator.setCircleClickListener(new CircleNavigator.OnCircleClickListener() {

            @Override

            public void onClick(int index) {

                viewPager.setCurrentItem(index);

            }

        });

        magicIndicator.setNavigator(circleNavigator);

        ViewPagerHelper.bind(magicIndicator, viewPager);

    }

}

4.效果图