使用瀑布流展示数据中的图片，点击item通过viewpager展

作者: 沈溺_16e5 | 来源:发表于2019-04-15 21:12 被阅读0次

使用瀑布流展示数据中的图片，点击item通过viewpager展
Swift-WKWebView与JS交互处理H5页面问题
Android 关于RecyclerView瀑布流显示图片时It
瀑布流使用小框架
图片瀑布流
[iOS]自定义的UICollectionViewLayout
ViewPager2 嵌套 ViewPager2 解决方案
iOS之瀑布流demo练习
WXHWaterFlow
Fragment 懒加载

1.gif

依赖

    //    侧滑菜单、TabLayout
    implementation 'com.android.support:design:28.0.0'

    //    gson
    implementation 'com.google.code.gson:gson:2.2.4'

    //glide加载图片
    implementation 'com.github.bumptech.glide:glide:4.9.0'

    //xrecyclerview
    implementation 'com.jcodecraeer:xrecyclerview:1.5.9'

    //retrofit
    implementation 'com.squareup.retrofit2:retrofit:2.5.0'
    implementation 'com.squareup.retrofit2:converter-gson:2.3.0'//转换器，请求结果转换成Model
    implementation 'com.squareup.retrofit2:adapter-rxjava2:2.3.0'//配合Rxjava 使用

    //Rxjava
    implementation 'io.reactivex.rxjava2:rxjava:2.2.4'
    implementation 'io.reactivex.rxjava2:rxandroid:2.1.0'

    // 图片处理
    implementation 'jp.wasabeef:glide-transformations:3.3.0'

xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity"
    android:orientation="vertical">

    <com.jcodecraeer.xrecyclerview.XRecyclerView
        android:id="@+id/xrv"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

    </com.jcodecraeer.xrecyclerview.XRecyclerView>

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/rl"
        android:visibility="gone">

        <android.support.v4.view.ViewPager
            android:id="@+id/viewpager"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            >

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

        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            android:layout_marginBottom="30dp"
            android:orientation="horizontal"
            android:layout_centerHorizontal="true">

            <TextView
                android:id="@+id/position"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textSize="30sp"/>

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="/"
                android:textSize="30sp"/>

            <TextView
                android:id="@+id/size"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:textSize="30sp"/>

        </LinearLayout>

    </RelativeLayout>

</LinearLayout>

ArticleBean（数据的bean类）

import java.util.List;

public class ArticleBean {

    /**
     * error : false
     * results : [{"_id":"5c6a4ae99d212226776d3256","createdAt":"2019-02-18T06:04:25.571Z","desc":"2019-02-18","publishedAt":"2019-02-18T06:05:41.975Z","source":"web","type":"福利","url":"https://ws1.sinaimg.cn/large/0065oQSqly1g0ajj4h6ndj30sg11xdmj.jpg","used":true,"who":"lijinshanmx"},{"_id":"5c6385b39d21225dd7a417ce","createdAt":"2019-02-13T02:49:23.946Z","desc":"2019-02-13","publishedAt":"2019-02-13T02:49:33.16Z","source":"web","type":"福利","url":"https://ws1.sinaimg.cn/large/0065oQSqly1g04lsmmadlj31221vowz7.jpg","used":true,"who":"lijinshanmx"},{"_id":"5c4578db9d212264d4501d40","createdAt":"2019-01-21T07:46:35.304Z","desc":"2019-01-21","publishedAt":"2019-01-21T00:00:00.0Z","source":"web","type":"福利","url":"https://ws1.sinaimg.cn/large/0065oQSqgy1fze94uew3jj30qo10cdka.jpg","used":true,"who":"lijinshanmx"},{"_id":"5c2dabdb9d21226e068debf9","createdAt":"2019-01-03T06:29:47.895Z","desc":"2019-01-03","publishedAt":"2019-01-03T00:00:00.0Z","source":"web","type":"福利","url":"https://ws1.sinaimg.cn/large/0065oQSqly1fytdr77urlj30sg10najf.jpg","used":true,"who":"lijinshanmx"},{"_id":"5c25db189d21221e8ada8664","createdAt":"2018-12-28T08:13:12.688Z","desc":"2018-12-28","publishedAt":"2018-12-28T00:00:00.0Z","source":"web","type":"福利","url":"https://ws1.sinaimg.cn/large/0065oQSqly1fymj13tnjmj30r60zf79k.jpg","used":true,"who":"lijinshanmx"},{"_id":"5c12216d9d21223f5a2baea2","createdAt":"2018-12-13T09:07:57.2Z","desc":"2018-12-13","publishedAt":"2018-12-13T00:00:00.0Z","source":"web","type":"福利","url":"https://ws1.sinaimg.cn/large/0065oQSqgy1fy58bi1wlgj30sg10hguu.jpg","used":true,"who":"lijinshanmx"},{"_id":"5bfe1a5b9d2122309624cbb7","createdAt":"2018-11-28T04:32:27.338Z","desc":"2018-11-28","publishedAt":"2018-11-28T00:00:00.0Z","source":"web","type":"福利","url":"https://ws1.sinaimg.cn/large/0065oQSqgy1fxno2dvxusj30sf10nqcm.jpg","used":true,"who":"lijinshanmx"},{"_id":"5bf22fd69d21223ddba8ca25","createdAt":"2018-11-19T03:36:54.950Z","desc":"2018-11-19","publishedAt":"2018-11-19T00:00:00.0Z","source":"web","type":"福利","url":"https://ws1.sinaimg.cn/large/0065oQSqgy1fxd7vcz86nj30qo0ybqc1.jpg","used":true,"who":"lijinshanmx"},{"_id":"5be14edb9d21223dd50660f8","createdAt":"2018-11-06T08:20:43.656Z","desc":"2018-11-06","publishedAt":"2018-11-06T00:00:00.0Z","source":"web","type":"福利","url":"https://ws1.sinaimg.cn/large/0065oQSqgy1fwyf0wr8hhj30ie0nhq6p.jpg","used":true,"who":"lijinshanmx"},{"_id":"5bcd71979d21220315c663fc","createdAt":"2018-10-22T06:43:35.440Z","desc":"2018-10-22","publishedAt":"2018-10-22T00:00:00.0Z","source":"web","type":"福利","url":"https://ws1.sinaimg.cn/large/0065oQSqgy1fwgzx8n1syj30sg15h7ew.jpg","used":true,"who":"lijinshanmx"},{"_id":"5bc434ac9d212279160c4c9e","createdAt":"2018-10-15T06:33:16.497Z","desc":"2018-10-15","publishedAt":"2018-10-15T00:00:00.0Z","source":"web","type":"福利","url":"https://ws1.sinaimg.cn/large/0065oQSqly1fw8wzdua6rj30sg0yc7gp.jpg","used":true,"who":"lijinshanmx"},{"_id":"5bbb0de09d21226111b86f1c","createdAt":"2018-10-08T07:57:20.978Z","desc":"2018-10-08","publishedAt":"2018-10-08T00:00:00.0Z","source":"web","type":"福利","url":"https://ws1.sinaimg.cn/large/0065oQSqly1fw0vdlg6xcj30j60mzdk7.jpg","used":true,"who":"lijinshanmx"},{"_id":"5ba206ec9d2122610aba3440","createdAt":"2018-09-19T08:21:00.295Z","desc":"2018-09-19","publishedAt":"2018-09-19T00:00:00.0Z","source":"web","type":"福利","url":"https://ws1.sinaimg.cn/large/0065oQSqly1fvexaq313uj30qo0wldr4.jpg","used":true,"who":"lijinshanmx"},{"_id":"5b9771a29d212206c1b383d0","createdAt":"2018-09-11T07:41:22.491Z","desc":"2018-09-11","publishedAt":"2018-09-11T00:00:00.0Z","source":"web","type":"福利","url":"https://ws1.sinaimg.cn/large/0065oQSqly1fv5n6daacqj30sg10f1dw.jpg","used":true,"who":"lijinshanmx"},{"_id":"5b830bba9d2122031f86ee51","createdAt":"2018-08-27T04:21:14.703Z","desc":"2018-08-27","publishedAt":"2018-08-28T00:00:00.0Z","source":"web","type":"福利","url":"https://ws1.sinaimg.cn/large/0065oQSqly1fuo54a6p0uj30sg0zdqnf.jpg","used":true,"who":"lijinshanmx"},{"_id":"5b7b836c9d212201e982de6e","createdAt":"2018-08-21T11:13:48.989Z","desc":"2018-08-21","publishedAt":"2018-08-21T00:00:00.0Z","source":"web","type":"福利","url":"https://ws1.sinaimg.cn/large/0065oQSqly1fuh5fsvlqcj30sg10onjk.jpg","used":true,"who":"lijinshanmx"},{"_id":"5b74e9409d21222c52ae4cb4","createdAt":"2018-08-16T11:02:24.289Z","desc":"2018-08-16","publishedAt":"2018-08-16T00:00:00.0Z","source":"api","type":"福利","url":"https://ws1.sinaimg.cn/large/0065oQSqly1fubd0blrbuj30ia0qp0yi.jpg","used":true,"who":"lijinshan"},{"_id":"5b7102749d2122341d563844","createdAt":"2018-08-13T12:00:52.458Z","desc":"2018-08-13","publishedAt":"2018-08-13T00:00:00.0Z","source":"api","type":"福利","url":"https://ww1.sinaimg.cn/large/0065oQSqly1fu7xueh1gbj30hs0uwtgb.jpg","used":true,"who":"lijinshan"},{"_id":"5b6bad449d21226f45755582","createdAt":"2018-08-09T10:56:04.962Z","desc":"2018-08-09","publishedAt":"2018-08-09T00:00:00.0Z","source":"web","type":"福利","url":"https://ww1.sinaimg.cn/large/0065oQSqgy1fu39hosiwoj30j60qyq96.jpg","used":true,"who":"lijinshanmx"},{"_id":"5b67b7fd9d2122195bdbd806","createdAt":"2018-08-06T10:52:45.809Z","desc":"2018-08-06","publishedAt":"2018-08-06T00:00:00.0Z","source":"api","type":"福利","url":"https://ww1.sinaimg.cn/large/0065oQSqly1ftzsj15hgvj30sg15hkbw.jpg","used":true,"who":"lijinshan"}]
     */

    private boolean error;
    private List<ResultsBean> results;

    public boolean isError() {
        return error;
    }

    public void setError(boolean error) {
        this.error = error;
    }

    public List<ResultsBean> getResults() {
        return results;
    }

    public void setResults(List<ResultsBean> results) {
        this.results = results;
    }

    public static class ResultsBean {
        /**
         * _id : 5c6a4ae99d212226776d3256
         * createdAt : 2019-02-18T06:04:25.571Z
         * desc : 2019-02-18
         * publishedAt : 2019-02-18T06:05:41.975Z
         * source : web
         * type : 福利
         * url : https://ws1.sinaimg.cn/large/0065oQSqly1g0ajj4h6ndj30sg11xdmj.jpg
         * used : true
         * who : lijinshanmx
         */

        private String _id;
        private String createdAt;
        private String desc;
        private String publishedAt;
        private String source;
        private String type;
        private String url;
        private boolean used;
        private String who;
        //宽高比
        private float scale;

        public String get_id() {
            return _id;
        }

        public void set_id(String _id) {
            this._id = _id;
        }

        public String getCreatedAt() {
            return createdAt;
        }

        public void setCreatedAt(String createdAt) {
            this.createdAt = createdAt;
        }

        public String getDesc() {
            return desc;
        }

        public void setDesc(String desc) {
            this.desc = desc;
        }

        public String getPublishedAt() {
            return publishedAt;
        }

        public void setPublishedAt(String publishedAt) {
            this.publishedAt = publishedAt;
        }

        public String getSource() {
            return source;
        }

        public void setSource(String source) {
            this.source = source;
        }

        public String getType() {
            return type;
        }

        public void setType(String type) {
            this.type = type;
        }

        public String getUrl() {
            return url;
        }

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

        public boolean isUsed() {
            return used;
        }

        public void setUsed(boolean used) {
            this.used = used;
        }

        public String getWho() {
            return who;
        }

        public void setWho(String who) {
            this.who = who;
        }

        public float getScale() {
            return scale;
        }

        public void setScale(float scale) {
            this.scale = scale;
        }
    }
}

HttpService

import com.example.exam.bean.ArticleBean;

import io.reactivex.Observable;
import retrofit2.http.GET;
import retrofit2.http.Path;

public interface HttpService {
    String url="http://gank.io/api/data/%E7%A6%8F%E5%88%A9/20/";
    @GET("{page}")
    Observable<ArticleBean> getData(@Path("page") int page);
}

Activity

import android.os.Bundle;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.util.Log;
import android.view.KeyEvent;
import android.view.View;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.widget.TextView;
import android.widget.Toast;

import com.bumptech.glide.Glide;
import com.example.exam.adapter.MyViewPagerAdapter;
import com.example.exam.adapter.MyXRecyclerViewAdapter;
import com.example.exam.bean.ArticleBean;
import com.jcodecraeer.xrecyclerview.XRecyclerView;

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

import io.reactivex.Observer;
import io.reactivex.android.schedulers.AndroidSchedulers;
import io.reactivex.disposables.Disposable;
import io.reactivex.schedulers.Schedulers;
import retrofit2.Retrofit;
import retrofit2.adapter.rxjava2.RxJava2CallAdapterFactory;
import retrofit2.converter.gson.GsonConverterFactory;

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "MainActivity";

    int page = 1;

    int newPosition = 0;

    private XRecyclerView xrv;
    private ViewPager viewpager;
    private ArrayList<ArticleBean.ResultsBean> xrvList;
    private MyXRecyclerViewAdapter myXRecyclerViewAdapter;
    private TextView position;
    private TextView size;
    private RelativeLayout rl;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initView();
        // 加载数据
        initData();
    }

    private void initView() {
        xrv = (XRecyclerView) findViewById(R.id.xrv);
        viewpager = (ViewPager) findViewById(R.id.viewpager);
        position = (TextView) findViewById(R.id.position);
        size = (TextView) findViewById(R.id.size);
        rl = (RelativeLayout) findViewById(R.id.rl);

        // 设置布局使用瀑布流
        StaggeredGridLayoutManager layoutManager = new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL);
        xrv.setLayoutManager(layoutManager);

        // 下拉刷新，上拉加载
        xrv.setLoadingListener(new XRecyclerView.LoadingListener() {
            @Override
            public void onRefresh() {
                page = 1;
                xrvList.clear();
                initData();
            }

            @Override
            public void onLoadMore() {
                page++;
                initData();
            }
        });

        xrvList = new ArrayList<>();
        myXRecyclerViewAdapter = new MyXRecyclerViewAdapter(xrvList, MainActivity.this);
        xrv.setAdapter(myXRecyclerViewAdapter);

        // item条目的点击监听
        myXRecyclerViewAdapter.setOnItemClickListener(new MyXRecyclerViewAdapter.OnItemClickListener() {

            @Override
            public void onItemClick(int p, String url) {
                xrv.setVisibility(View.GONE);
                rl.setVisibility(View.VISIBLE);

                ArrayList<ImageView> imageViews = new ArrayList<>();
                for (int i = 0; i < xrvList.size(); i++) {
                    ImageView imageView = new ImageView(MainActivity.this);

                    Glide.with(MainActivity.this).load(xrvList.get(i).getUrl()).into(imageView);

                    imageViews.add(imageView);
                }
                
                // Viewpager下方显示当前页面值，和总页面值
                position.setText(p + 1 + "");
                size.setText(xrvList.size() + "");
                MyViewPagerAdapter myViewPagerAdapter = new MyViewPagerAdapter(imageViews);
                viewpager.setAdapter(myViewPagerAdapter);
                // 设置Viewpager默认显示点击的那个图片
                viewpager.setCurrentItem(p);

                // Viewpager滑动监听，改变Viewpager下方的数值
                viewpager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
                    @Override
                    public void onPageScrolled(int i, float v, int i1) {

                    }

                    @Override
                    public void onPageSelected(int i) {
                        position.setText(i +1+ "");
                    }

                    @Override
                    public void onPageScrollStateChanged(int i) {

                    }
                });
            }
        });


    }

    private void initData() {
        Retrofit retrofit = new Retrofit.Builder()
                .baseUrl(HttpService.url)
                .addConverterFactory(GsonConverterFactory.create())
                .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
                .build();

        HttpService httpService = retrofit.create(HttpService.class);

        httpService.getData(page)
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(new Observer<ArticleBean>() {
                    @Override
                    public void onSubscribe(Disposable d) {

                    }

                    @Override
                    public void onNext(ArticleBean articleBean) {
                        myXRecyclerViewAdapter.setData(articleBean);
                        myXRecyclerViewAdapter.notifyDataSetChanged();
                        xrv.refreshComplete();
                        xrv.loadMoreComplete();
                    }

                    @Override
                    public void onError(Throwable e) {
                        Log.e(TAG, "onError: " + e.getMessage());
                    }

                    @Override
                    public void onComplete() {

                    }
                });
    }

    // 双击返回键退出应用
    private long firstTime = 0;

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK && event.getAction() == KeyEvent.ACTION_DOWN) {
            if ((System.currentTimeMillis() - firstTime) > 1000) {
                Toast.makeText(this, "再按一次退出", Toast.LENGTH_SHORT).show();
                firstTime = System.currentTimeMillis();
                xrv.setVisibility(View.VISIBLE);
                rl.setVisibility(View.GONE);
            } else {
                finish();
                System.exit(0);
            }
            return true;
        }
        return super.onKeyDown(keyCode, event);
    }
}

adapter

XRecyclerViewAdapter

import android.content.Context;
import android.graphics.drawable.Drawable;
import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.LinearLayout;

import com.bumptech.glide.Glide;
import com.bumptech.glide.load.resource.bitmap.RoundedCorners;
import com.bumptech.glide.request.RequestOptions;
import com.bumptech.glide.request.target.SimpleTarget;
import com.bumptech.glide.request.transition.Transition;
import com.example.exam.MyApplication;
import com.example.exam.R;
import com.example.exam.SystemUtil;
import com.example.exam.bean.ArticleBean;

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

import io.reactivex.annotations.Nullable;
import jp.wasabeef.glide.transformations.RoundedCornersTransformation;


public class MyXRecyclerViewAdapter extends RecyclerView.Adapter<MyXRecyclerViewAdapter.ViewHolder> {
    private ArrayList<ArticleBean.ResultsBean> xrvList;
    Context context;

    public MyXRecyclerViewAdapter(ArrayList<ArticleBean.ResultsBean> xrvList, Context context) {
        this.xrvList = xrvList;
        this.context = context;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(context).inflate(R.layout.item, null);
        ViewHolder viewHolder = new ViewHolder(view);
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, final int position) {
        final ArticleBean.ResultsBean resultsBean = xrvList.get(position);

        //设置图片之前需要重新设置ImageView的宽高
        // imageWidth 根据屏幕的宽算出图片的宽
        int imageWidth = MyApplication.mWidthPixels / 2 - SystemUtil.dp2px(8);

        // LinearLayout.LayoutParams  适配器的item条目的最外层布局是什么LayoutParams前面就是什么
        // layoutParams 可以得到图片的宽高
        LinearLayout.LayoutParams layoutParams =
                (LinearLayout.LayoutParams) holder.url.getLayoutParams();

        // 图片的宽
        layoutParams.width = imageWidth;

        if (resultsBean.getScale()!=0){
            layoutParams.height = (int) (imageWidth/resultsBean.getScale());
        }
        layoutParams.leftMargin = layoutParams.topMargin = SystemUtil.dp2px(4);
        holder.url.setLayoutParams(layoutParams);

        // 给图片设置圆角
        // 这种方式除了Glide依赖还需要再添加一个依赖
        // implementation 'jp.wasabeef:glide-transformations:3.3.0'     // 图片处理
        RequestOptions options = new RequestOptions().transform(new RoundedCornersTransformation(SystemUtil.dp2px(6), 0));
        Glide.with(context).load(resultsBean.getUrl()).apply(options).into(holder.url);
        /**
         * 设置圆角的第二种方式
         * RoundedCorners roundedCorners = new RoundedCorners(20);
         * RequestOptions requestOptions = RequestOptions.bitmapTransform(roundedCorners);
         */

        holder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (onItemClickListener!=null){
                    onItemClickListener.onItemClick(position,resultsBean.getUrl());
                }
            }
        });
    }

    @Override
    public int getItemCount() {
        return xrvList.size();
    }

    public void setData(ArticleBean articleBean) {
        List<ArticleBean.ResultsBean> results = articleBean.getResults();
        xrvList.addAll(results);
        setImageScale();
    }

    //计算图片的宽高比
    private void setImageScale() {
        for (final ArticleBean.ResultsBean bean : xrvList) {
            if (bean.getScale() == 0) {
                Glide.with(context).load(bean.getUrl()).into(
                        new SimpleTarget<Drawable>() {
                            @Override
                            public void onResourceReady(@NonNull Drawable resource,
                                                        @Nullable Transition<? super Drawable> transition) {
                                //宽高比
                                float scale = resource.getIntrinsicWidth() * 1.0f / resource.getIntrinsicHeight();
                                bean.setScale(scale);
                                notifyDataSetChanged();
                            }
                        });
            } else {
                notifyDataSetChanged();
            }
        }
    }

    public class ViewHolder extends RecyclerView.ViewHolder {

        private ImageView url;

        public ViewHolder(View itemView) {
            super(itemView);
            url=itemView.findViewById(R.id.url);
        }
    }

    OnItemClickListener onItemClickListener;

    public void setOnItemClickListener(OnItemClickListener onItemClickListener) {
        this.onItemClickListener = onItemClickListener;
    }

    public interface OnItemClickListener{
        void onItemClick(int position,String url);
    }
}

ViewPagerAdapter

import android.support.annotation.NonNull;
import android.support.v4.view.PagerAdapter;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;

import java.util.ArrayList;

public class MyViewPagerAdapter extends PagerAdapter{
    ArrayList<ImageView> imageViews;

    public MyViewPagerAdapter(ArrayList<ImageView> imageViews) {
        this.imageViews = imageViews;
    }

    @Override
    public int getCount() {
        return imageViews.size();
    }

    @Override
    public boolean isViewFromObject(@NonNull View view, @NonNull Object o) {
        return view==o;
    }

    @NonNull
    @Override
    public Object instantiateItem(@NonNull ViewGroup container, int position) {
        container.addView(imageViews.get(position));
        return imageViews.get(position);
    }

    @Override
    public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {
        container.removeView(imageViews.get(position));
    }
}

MyApplication

import android.app.Application;
import android.util.DisplayMetrics;
import android.view.Display;
import android.view.WindowManager;

public class MyApplication extends Application {

    private static MyApplication myApplication;
    public static int mWidthPixels;
    public static int mHeightPixels;

    @Override
    public void onCreate() {
        super.onCreate();
        myApplication = this;
        getScreenWH();
    }

    //计算屏幕宽高
    private void getScreenWH() {
        WindowManager manager = (WindowManager) getSystemService(WINDOW_SERVICE);
        Display defaultDisplay = manager.getDefaultDisplay();
        DisplayMetrics metrics = new DisplayMetrics();
        defaultDisplay.getMetrics(metrics);
        mWidthPixels = metrics.widthPixels;
        mHeightPixels = metrics.heightPixels;
    }

    public static MyApplication getMyApplication() {
        return myApplication;
    }
}

Constants 接口

import android.os.Environment;

import java.io.File;

public interface Constants {
    boolean isDebug = true;


    String PATH_SDCARD = Environment.getExternalStorageDirectory().getAbsolutePath() +
            File.separator + "codeest" + File.separator + "GeekNews";

    String FILE_PROVIDER_AUTHORITY="com.baidu.geek.fileprovider";

    //网络缓存的地址
    String PATH_DATA = MyApplication.getMyApplication().getCacheDir().getAbsolutePath() +
            File.separator + "data";

    String PATH_CACHE = PATH_DATA + "/NetCache";
    String DATA = "data";
    //夜间模式
    String MODE = "mode";
    String NIGHT_CURRENT_FRAG_POS = "fragment_pos";
    String DATE="date";
}

SystemUtil（工具类）

import android.content.ClipData;
import android.content.ClipboardManager;
import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.net.Uri;
import android.os.Build;
import android.provider.MediaStore;
import android.support.v4.content.FileProvider;
import android.text.TextUtils;
import android.view.View;
import android.widget.Toast;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.FileReader;
import java.io.IOException;

public class SystemUtil {

    /**
     * 检查WIFI是否连接
     */
    public static boolean isWifiConnected() {
        ConnectivityManager connectivityManager = (ConnectivityManager) MyApplication.getMyApplication().getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo wifiInfo = connectivityManager
                .getNetworkInfo(ConnectivityManager.TYPE_WIFI);
        return wifiInfo != null;
    }
    /**
     * 检查手机网络(4G/3G/2G)是否连接
     */
    public static boolean isMobileNetworkConnected() {
        ConnectivityManager connectivityManager = (ConnectivityManager) MyApplication.getMyApplication().getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo mobileNetworkInfo = connectivityManager
                .getNetworkInfo(ConnectivityManager.TYPE_MOBILE);
        return mobileNetworkInfo != null;
    }
    /**
     * 检查是否有可用网络
     */
    public static boolean isNetworkConnected() {
        ConnectivityManager connectivityManager = (ConnectivityManager) MyApplication.getMyApplication().getSystemService(Context.CONNECTIVITY_SERVICE);
        return connectivityManager.getActiveNetworkInfo() != null;
    }

    /**
     * 保存文字到剪贴板
     * @param context
     * @param text
     */
    public static void copyToClipBoard(Context context, String text) {
        ClipData clipData = ClipData.newPlainText("url", text);
        ClipboardManager manager = (ClipboardManager) context.getSystemService(Context.CLIPBOARD_SERVICE);
        manager.setPrimaryClip(clipData);
        Toast.makeText(context,"已复制到剪贴板",Toast.LENGTH_SHORT).show();
    }

    /**
     * 保存图片到本地
     * @param context
     * @param url
     * @param bitmap
     */
    public static Uri saveBitmapToFile(Context context, String url, Bitmap bitmap,
                                       View container, boolean isShare){
        String fileName = url.substring(url.lastIndexOf("/"),url.lastIndexOf(".")) + ".png";
        File fileDir = new File(Constants.PATH_SDCARD);
        if (!fileDir.exists()){
            fileDir.mkdirs();
        }
        File imageFile = new File(fileDir,fileName);
        Uri uri = Uri.fromFile(imageFile);
        if (isShare && imageFile.exists()) {
            if (Build.VERSION.SDK_INT >= 24) {
                uri = FileProvider.getUriForFile(context.getApplicationContext(),
                        Constants.FILE_PROVIDER_AUTHORITY, imageFile);
            }
            return uri;
        }
        try {
            FileOutputStream fos = new FileOutputStream(imageFile);
            boolean isCompress = bitmap.compress(Bitmap.CompressFormat.PNG, 90, fos);
            if (isCompress) {
                ToastUtil.showShort("保存妹纸成功n(*≧▽≦*)n");
            } else {
                ToastUtil.showShort("保存妹纸失败ヽ(≧Д≦)ノ");
            }
            fos.flush();
            fos.close();
        } catch (IOException e) {
            e.printStackTrace();
            ToastUtil.showShort("保存妹纸失败ヽ(≧Д≦)ノ");
        }
        try {
            MediaStore.Images.Media.insertImage(context.getContentResolver(), imageFile.getAbsolutePath(), fileName, null);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        context.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE,uri));
        if (Build.VERSION.SDK_INT >= 24) {
            uri = FileProvider.getUriForFile(context.getApplicationContext(),
                    Constants.FILE_PROVIDER_AUTHORITY, imageFile);
        }
        return uri;
    }

    /**
     * 根据手机的分辨率从 dp 的单位 转成为 px(像素)
     */
    public static int dp2px(Context context, float dpValue) {
        final float scale = context.getResources().getDisplayMetrics().density;
        return (int) (dpValue * scale + 0.5f);
    }

    public static int dp2px(float dpValue) {
        final float scale = MyApplication.getMyApplication().getResources().getDisplayMetrics().density;
        return (int) (dpValue * scale + 0.5f);
    }

    /**
     * 根据手机的分辨率从 px(像素) 的单位 转成为 dp
     */
    public static int px2dp(Context context, float pxValue) {
        final float scale = context.getResources().getDisplayMetrics().density;
        return (int) (pxValue / scale + 0.5f);
    }

    public static int px2dp(float pxValue) {
        final float scale = MyApplication.getMyApplication().getResources().getDisplayMetrics().density;
        return (int) (pxValue / scale + 0.5f);
    }

    /**
     * 获取进程号对应的进程名
     *
     * @param pid 进程号
     * @return 进程名
     */
    public static String getProcessName(int pid) {
        BufferedReader reader = null;
        try {
            reader = new BufferedReader(new FileReader("/proc/" + pid + "/cmdline"));
            String processName = reader.readLine();
            if (!TextUtils.isEmpty(processName)) {
                processName = processName.trim();
            }
            return processName;
        } catch (Throwable throwable) {
            throwable.printStackTrace();
        } finally {
            try {
                if (reader != null) {
                    reader.close();
                }
            } catch (IOException exception) {
                exception.printStackTrace();
            }
        }
        return null;
    }
}

ToastUtil（工具类）

import android.widget.Toast;

public class ToastUtil {
    public static void showShort(String msg){
        //避免内存泄漏的一个方法,用到上下文的地方,能用application的就application
        Toast.makeText(MyApplication.getMyApplication(),msg,Toast.LENGTH_SHORT).show();
    }
    public static void showLong(String msg){
        //避免内存泄漏的一个方法,用到上下文的地方,能用application的就application
        Toast.makeText(MyApplication.getMyApplication(),msg,Toast.LENGTH_LONG).show();
    }
}

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