抽取基类+上拉下拉的简单使用+跳转展示轮播和Webview

（一）简单配置

1.先写图片的全局配置，例如：

public class MyAppliction extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
        initD();
    }

    private void initD() {
        ImageLoaderConfiguration configuration = new ImageLoaderConfiguration
                .Builder(getApplicationContext())
                .build();
        ImageLoader.getInstance().init(configuration);
    }
}

2.先写一个外部的数据返回接口，例如：

public interface HttpCallback {
    void onSuccess(String result);
    void onError(String errorMsg);
}

3.网络工具类，例如：

public class HttpUtils {
    private static final HttpUtils ourInstance = new HttpUtils();

    public static HttpUtils getInstance() {
        return ourInstance;
    }
    private HttpUtils() {
    }
    /* 封装get  Http 请求数据*/
    public void getDataFromService(String url,HttpCallback callback){
        new LoadDataTask(callback).execute(url);
    }
    class LoadDataTask extends AsyncTask<String,Void,String>{
        //有参函数
        private HttpCallback callback;

        public LoadDataTask(HttpCallback callback) {
            this.callback = callback;
        }

        @Override
        protected String doInBackground(String... strings) {
            try {
                URL url = new URL(strings[0]);
                HttpURLConnection connection= (HttpURLConnection) url.openConnection();
                connection.setConnectTimeout(5000);
                connection.setReadTimeout(5000);
                if (connection.getResponseCode()==HttpURLConnection.HTTP_OK){
                    return CharStreams.toString(new InputStreamReader(connection.getInputStream(),"UTF-8"));
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(String s) {
            if (callback!=null){
                if (!TextUtils.isEmpty(s)){
                    callback.onSuccess(s);
                }else{
                    callback.onError("没有数据");
                }
            }
        }
    }
}

4.多条j目的adapter不需要继承基类所以写在上面，例如：

public class MainAdapter extends BaseAdapter {
    private Context context;
    private List<MainBean.ResultBean.DataBean> dataBeanList;

    public MainAdapter(Context context, List<MainBean.ResultBean.DataBean> dataBeanList) {
        this.context = context;
        this.dataBeanList = dataBeanList;
    }

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

    @Override
    public MainBean.ResultBean.DataBean getItem(int position) {
        return dataBeanList.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }


    @Override
    public int getItemViewType(int position) {
        if (!TextUtils.isEmpty(dataBeanList.get(position).getThumbnail_pic_s03())) {
            return VIEW_TYPE_TWO;
        } else {
            return VIEW_TYPE_ONE;
        }
    }

    @Override
    public int getViewTypeCount() {
        return super.getViewTypeCount() + 3;
    }

    private final int VIEW_TYPE_ONE = 1;
    private final int VIEW_TYPE_TWO = 2;

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        int viewType = getItemViewType(position);
        switch (viewType) {
            case VIEW_TYPE_ONE:
                ViewHodler hodler = null;
                if (convertView == null) {
                    hodler = new ViewHodler();
                    convertView = LayoutInflater.from(context).inflate(R.layout.main_list_item_one, null, false);
                    hodler.tvTitle = convertView.findViewById(R.id.tv_title);
                    hodler.ivImage = convertView.findViewById(R.id.iv_image);
                    convertView.setTag(hodler);
                } else {
                    hodler = (ViewHodler) convertView.getTag();
                }
                hodler.tvTitle.setText(dataBeanList.get(position).getTitle());
                ImageLoader.getInstance().displayImage(dataBeanList.get(position).getThumbnail_pic_s(), hodler.ivImage);
                break;
            case VIEW_TYPE_TWO:
                ViewHolderTwo holderTwo = null;
                if (convertView == null) {
                    holderTwo = new ViewHolderTwo();
                    convertView = LayoutInflater.from(context).inflate(R.layout.main_list_item_two, null, false);
                    holderTwo.tvTitle = convertView.findViewById(R.id.tv_title);
                    holderTwo.ivImage = convertView.findViewById(R.id.iv_image);
                    holderTwo.ivImage2 = convertView.findViewById(R.id.iv_image2);
                    holderTwo.ivImage3 = convertView.findViewById(R.id.iv_image3);
                    convertView.setTag(holderTwo);
                } else {
                    holderTwo = (ViewHolderTwo) convertView.getTag();
                }
                holderTwo.tvTitle.setText(dataBeanList.get(position).getTitle());
                ImageLoader.getInstance().displayImage(dataBeanList.get(position).getThumbnail_pic_s(), holderTwo.ivImage);
                ImageLoader.getInstance().displayImage(dataBeanList.get(position).getThumbnail_pic_s02(), holderTwo.ivImage2);
                ImageLoader.getInstance().displayImage(dataBeanList.get(position).getThumbnail_pic_s03(), holderTwo.ivImage3);
                break;
        }
        return convertView;
    }

    class ViewHodler {
        TextView tvTitle;
        ImageView ivImage;
    }

    class ViewHolderTwo {
        TextView tvTitle;
        ImageView ivImage;
        ImageView ivImage2;
        ImageView ivImage3;
    }
}

（二）抽取基类

1.抽取基类，例如：

public abstract class BaseActivity extends AppCompatActivity {
    protected HttpUtils httpUtils;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        init();
    }
    /*初始化*/
    private void init() {
        setContentView(initLayout());
        findView();
        httpUtils = HttpUtils.getInstance();
        setListener();
        initFinish();
    }
    /*初始化完成*/
    protected abstract void initFinish();

    /*设置事件*/
    protected abstract void setListener();

    /*查找控件*/
    protected abstract void findView();

    /*填充布局*/
    protected abstract int initLayout();
}

2.抽取过基类后其他的Activity都需要继承基类BaseActivity ，例如：

public class MainActivity extends BaseActivity implements HttpCallback{

    private String api = "http://172.17.8.100/mobile/exam/findNewList";
    //上拉
    private boolean isPall = false;
    private PullToRefreshListView pull;
    private ArrayList<MainBean.ResultBean.DataBean> dataBeanslist = new ArrayList<>();//数据的集合
    private MainAdapter mainAdapter;

    /*初始化完成*/
    @Override
    protected void initFinish() {
        //设置PullToRefreshListView的上拉下拉
        pull.setMode(PullToRefreshBase.Mode.BOTH);
        //监听事件
        pull.setOnRefreshListener(new PullToRefreshBase.OnRefreshListener2<ListView>() {
            @Override
            public void onPullDownToRefresh(PullToRefreshBase<ListView> pullToRefreshBase) {
                //下拉
                isPall=true;
                lodData();
            }

            @Override
            public void onPullUpToRefresh(PullToRefreshBase<ListView> pullToRefreshBase) {
                lodData();
            }
        });
        /*设置适配器*/
        mainAdapter = new MainAdapter(MainActivity.this, dataBeanslist);
        pull.setAdapter(mainAdapter);
        /*显示数据的方法*/
        lodData();
    }
    /*显示数据的方法*/
    private void lodData() {
        /*显示数据*/
        httpUtils.getDataFromService(api,this);
    }
    /*设置事件*/
    @Override
    protected void setListener() {

    }
    /*查找控件*/
    @Override
    protected void findView() {
        pull = findViewById(R.id.pull);
    }
    /*填充布局*/
    @Override
    protected int initLayout() {
        return R.layout.activity_main;
    }
    /*这两个方法是HttpCallback生成*/
    @Override
    public void onSuccess(String result) {
        //解析数据
        Gson gson = new Gson();
        MainBean mainBean = gson.fromJson(result, MainBean.class);
        if (isPall){//如果是上拉
            isPall=!isPall;//改成下拉
            dataBeanslist.clear();//只显示第一页数据
        }
        //添加数据
        dataBeanslist.addAll(mainBean.getResult().getData());
        //更新数据
        mainAdapter.notifyDataSetChanged();
        //停止刷新
        pull.onRefreshComplete();
    }

    @Override
    public void onError(String errorMsg) {

    }
}

最后

即可实现抽取基类并且上拉加载下拉刷新的多条目展示

接口，例如：http://172.17.8.100/mobile/exam/findNewList

（三）点击跳转展示轮播和Webview

1.在MainActivity中的设置事件里写，例如：

/*设置事件*/
@Override
protected void setListener() {
    pull.setOnItemClickListener(this);
}

/*点击条目跳转*/
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
    //意图对象
    Intent intent = new Intent(this, DetailActivity.class);
    //得到条目
    MainBean.ResultBean.DataBean item = mainAdapter.getItem(position);
    //传值
    intent.putExtra("url",item.getUrl());
    startActivity(intent);
}

2.跳转到DetailActivity页面后先展示Webview再加载图片，例如：

public class DetailActivity extends BaseActivity implements HttpCallback {
    private String apilb = "https://api.yunxuekeji.cn/yunxue_app_api/content/getIndexBanner/1";
    private String url;
    private ViewPager banner;
    private WebView web_view;
    private List<ImageView> bannerImages = new ArrayList<>();

    /*初始化完成*/
    @Override
    protected void initFinish() {
        webView.setWebViewClient(new WebViewClient());
        webView.setWebChromeClient(new WebChromeClient());
        //WebView显示
        web_view.loadUrl(url);
        //设置轮播
        loadBannerData();
        //轮播点击停止--可写可不写
        banner.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                switch (event.getAction()){
                    case MotionEvent.ACTION_DOWN://按下
                        stopBanner();
                        break;
                    case MotionEvent.ACTION_UP://抬起
                        startBanner();
                        break;
                }
                return false;
            }
        });

    }
    //停止轮播
    private void stopBanner() {
        handler.removeCallbacksAndMessages(null);
    }

    //加载轮播数据---开始轮播
    private void loadBannerData() {
        httpUtils.getDataFromService(apilb,this);
    }

    /*设置事件*/
    @Override
    protected void setListener() {

    }
    /*查找控件*/
    @Override
    protected void findView() {
        //接收跳转时带过来的值
        url = getIntent().getStringExtra("url");
        //轮播
        banner = findViewById(R.id.banner);
        //WebView
        web_view = findViewById(R.id.web_view);
    }
    /*填充布局*/
    @Override
    protected int initLayout() {
        return R.layout.activity_detail;
    }

    @Override
    public void onSuccess(String result) {
        //解析数据
        Gson gson = new Gson();
        BannerBean bannerBean = gson.fromJson(result, BannerBean.class);
        //遍历图片
        for (BannerBean.BodyBean.ResultBean resultBean : bannerBean.getBody().getResult()) {
            ImageView imageView = new ImageView(this);
            imageView.setScaleType(ImageView.ScaleType.FIT_XY);
            ImageLoader.getInstance().displayImage(resultBean.getBarnerPic(),imageView);
            bannerImages.add(imageView);
        }
        //轮播适配器
        banner.setAdapter(new BannerAdapter(bannerImages));
        //开始轮播
        startBanner();
    }
    //开始轮播
    private void startBanner() {
        handler.sendEmptyMessageDelayed(1,2000);
    }
    //Handler发送消息开始轮播
    private Handler handler = new Handler(){
        @Override
        public void handleMessage(Message msg) {
            switch (msg.what){
                case 1:
                    int currentItem = banner.getCurrentItem();
                    currentItem++;
                    banner.setCurrentItem(currentItem);
                    sendEmptyMessageDelayed(1,2000);
                    break;
            }
        }
    };

    @Override
    public void onError(String errorMsg) {

    }
}

展示轮播的时候需要加载网络数据设置adapter，例如：

public class BannerAdapter extends PagerAdapter {
    private List<ImageView> imageViewList;

    public BannerAdapter(List<ImageView> imageViewList) {
        this.imageViewList = imageViewList;
    }

    @Override
    public int getCount() {
        return Integer.MAX_VALUE;
    }

    @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 = imageViewList.get(position % imageViewList.size());
        ViewGroup par = (ViewGroup) imageView.getParent();
        if (par!=null){
            par.removeView(imageView);
        }else{
            container.addView(imageView);
        }
        return imageView;
    }

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