ViewPager轮播图 Banner方式实现

1.提取的基类

package com.example.viewpager_demo;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;

public abstract class BaseActivity extends AppCompatActivity {
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(getLayoutResId());
        //初始化视图
        initView();
        //加载数据
        initData();
    }
    protected abstract int getLayoutResId();
    //初始化视图
    protected abstract void initView();
    //加载数据
    protected abstract void initData();


}

2.BunnerActivity主页面

package com.example.viewpager_demo;

import android.content.Context;
import android.view.View;
import android.widget.ImageView;

import com.example.Bean.BunnerBean;
import com.example.Util.NetUtils;
import com.youth.banner.Banner;
import com.youth.banner.BannerConfig;
import com.youth.banner.loader.ImageLoaderInterface;

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

public class BunnerActivity extends BaseActivity {

    private Banner banner;
    private String imageUrl = "https://api.tianapi.com/wxnew/?key=605fa0a929c8d8b116424df0510c6b2a&num=6&page=1";
    @Override
    protected int getLayoutResId() {
        return R.layout.activity_bunner;
    }
    //初始化view
    @Override
    protected void initView() {
        //获取资源id
        banner = findViewById(R.id.bunner);
        //设置banner样式
        banner.setBannerStyle(BannerConfig.CIRCLE_INDICATOR_TITLE_INSIDE);
        //设置图片加载器
        banner.setImageLoader(new ImageLoaderInterface<ImageView>() {
            @Override
            public void displayImage(Context context, Object path, ImageView imageView) {
                BunnerBean.NewslistBean bean = (BunnerBean.NewslistBean) path;
               com.nostra13.universalimageloader.core.ImageLoader.getInstance().displayImage(
                       bean.getPicUrl(),imageView
               );
            }

            @Override
            public ImageView createImageView(Context context) {
                ImageView imageView = new ImageView(context);
                imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
                return imageView;
            }
        });
    }

    @Override
    protected void initData() {
        NetUtils.getInstance().getRequest(imageUrl, BunnerBean.class, new NetUtils.CallBack<BunnerBean>() {
            @Override
            public void onSuccess(BunnerBean o) {
            //设置图片集合
                banner.setImages(o.getNewslist());
                banner.setBannerTitles(getTitles(o));
             //banner设置的方法全部调用完是最后执行
                banner.start();
            }


        });
    }
    private List<String> getTitles(BunnerBean o) {
            List<String> list = new ArrayList<>();
        for(BunnerBean.NewslistBean banner:o.getNewslist()){
            list.add(banner.getTitle());
        }
        return list;
    }
}

3.工具类

package com.example.Util;

import android.annotation.SuppressLint;
import android.os.AsyncTask;

import com.google.gson.Gson;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;


public class NetUtils {
    private static NetUtils instance;
    private Gson gson;
    public NetUtils() {
        gson = new Gson();
    }

    public static NetUtils getInstance() {
        if(instance == null){
            instance = new NetUtils();
        }
        return instance;
    }
    //执行一个网络请求返回string
    public String getRequest(String urlStr){
        String result = "";
        try {
            //定义url地址
            URL url = new URL(urlStr);
            //打开连接
            HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
            //设置请求格式
            urlConnection.setRequestMethod("GET");
            //设置超时
            urlConnection.setReadTimeout(5000);
            urlConnection.setConnectTimeout(5000);
            //获取请求码
            int responseCode = urlConnection.getResponseCode();
            if(responseCode == 200){
                result = stream2String(urlConnection.getInputStream());
            }
        } catch (MalformedURLException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return result;
    }
    //将字节流转换为字符流
    private String stream2String(InputStream inputStream) throws IOException {
        StringBuilder builder = new StringBuilder();
        BufferedReader br = new BufferedReader(new InputStreamReader(inputStream));
        for (String tmp = br.readLine();tmp!=null;tmp = br.readLine()){
            builder.append(tmp);
        }
        return builder.toString();
    }
    //执行一个网络请求返回bean
    public <E> E getRequest(String urlStr,Class clazz){
        return (E) gson.fromJson(getRequest(urlStr),clazz);
    }
    //定义接口
    public interface CallBack<E>{
        void onSuccess(E e);
    }
    //异步 回调请求
    @SuppressLint("StaticFieldLeak")
    public void getRequest(String urlStr, final Class clazz, final CallBack callBack){
        new AsyncTask<String,Void,Object>(){
            @Override
            protected Object doInBackground(String... strings) {
                return getRequest(strings[0],clazz);
            }

            @Override
            protected void onPostExecute(Object o) {
                callBack.onSuccess(o);
            }
        }.execute(urlStr);
    }
}

4.bean类

package com.example.Bean;

import java.util.List;

public class BunnerBean {

    private int code;
    private String msg;
    private List<NewslistBean> newslist;
    private final int SUCCESS_CODE = 200;
    public boolean isSuccess(){
        return SUCCESS_CODE == code;
    }
    public int getCode() {
        return code;
    }

    public void setCode(int code) {
        this.code = code;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }

    public List<NewslistBean> getNewslist() {
        return newslist;
    }

    public void setNewslist(List<NewslistBean> newslist) {
        this.newslist = newslist;
    }

    public static class NewslistBean {
        private String ctime;
        private String title;
        private String description;
        private String picUrl;
        private String url;

        public String getCtime() {
            return ctime;
        }

        public void setCtime(String ctime) {
            this.ctime = ctime;
        }

        public String getTitle() {
            return title;
        }

        public void setTitle(String title) {
            this.title = title;
        }

        public String getDescription() {
            return description;
        }

        public void setDescription(String description) {
            this.description = description;
        }

        public String getPicUrl() {
            return picUrl;
        }

        public void setPicUrl(String picUrl) {
            this.picUrl = picUrl;
        }

        public String getUrl() {
            return url;
        }

        public void setUrl(String url) {
            this.url = url;
        }
    }
}

5.布局页面

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto">
    <com.youth.banner.Banner
        android:id="@+id/bunner"
        android:layout_width="0dp"
        android:layout_height="200dp"
        app:layout_constraintLeft_toLeftOf="parent"
        app:layout_constraintRight_toRightOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:indicator_width="8dp"
        app:indicator_height="8dp"
        app:indicator_drawable_selected="@drawable/shape_sel_dot"
        app:indicator_drawable_unselected="@drawable/shape_normal_dot"
        />
</android.support.constraint.ConstraintLayout>

6.Banner需要导入的依赖

compile 'com.youth.banner:banner:1.4.10'

7.轮播图小圆点

7.1默认圆点颜色
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval"
    >
    <size
        android:width="8dp"
        android:height="8dp"
        />
    <solid
        android:color="#909090"
        />
</shape>

7.2选中圆点颜色
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="oval"
    >
    <size
        android:width="8dp"
        android:height="8dp"
        />
    <solid
        android:color="#900000"
        />
</shape>

7.3select设置选中
<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:drawable="@drawable/shape_sel_dot" android:state_selected="true"></item>
    <item android:drawable="@drawable/shape_normal_dot" ></item>
</selector>

ViewPager轮播图 Banner方式实现

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