android九宫格可分页加载控件使用详解

 viewPager = findViewById(R.id.ninePages);
    //数据初始化
    List<List<TestEntity>> lists = new ArrayList<>();
    for (int i = 0; i < 6; i++) {//页数
      List<TestEntity> list1 = new ArrayList<>();
      for (int j = 0; j < 9; j++) {//每页个数
        TestEntity entity = new TestEntity();
        entity.setText("j=" + j + "/i=" + i);
        list1.add(entity);
      }
      lists.add(list1);
    }
    //设置不每页重复加载
    viewPager.setEveryRequest(false);
    //设置分页加载
    viewPager.setPagingLoad(true);
    viewPager.setListener(new RequestDataListener<TestEntity>() {
      @Override
      public void request(int position) {//分页加载
        List<TestEntity> changeList =new ArrayList<>();
        for (int i = 0; i < 9; i++) {
          TestEntity testEntity = new TestEntity();
          testEntity.setText("change" + i);
          changeList.add(testEntity);
        }
        //数据刷新
        viewPager.dataInvalidate(position,changeList);
      }

      @Override
      public int gridViewColumn() {//gridview列数
        return 3;
      }

      @Override
      public View getView(LayoutInflater inflater, int position, View convertView, ViewGroup parent, List<TestEntity> list) {
        ViewHolder viewHolder = null;
        if(convertView == null){
          convertView = inflater.inflate(R.layout.item_gridview,parent,false);
          viewHolder = new ViewHolder();
          viewHolder.textView = convertView.findViewById(R.id.textview);
          convertView.setTag(viewHolder);
        }else{
          viewHolder = (ViewHolder) convertView.getTag();
        }
        viewHolder.textView.setText(list.get(position).getText());
        return convertView;
      }
    });
     viewPager.setList(lists);
class ViewHolder{
    private TextView textView;
  }

public class NinePagesPagination<T> extends LinearLayout {
  private View mView;
  private ViewPager viewPager;
  private Context context;
  private List<List<T>> list = new ArrayList<>();
  //已经请求过的，不在重复请求
  private List<Integer> hasAdded = new ArrayList<>();
  //是否每次请求
  private boolean isEveryRequest;
  //是否进行分页加载
  private boolean isPagingLoad;
  private RequestDataListener listener;
  private MyViewPagerAdapter adapter;
  private ViewPager.OnPageChangeListener pageChangeListener;
  public NinePagesPagination(Context context, @Nullable AttributeSet attrs) {
    super(context, attrs);
    this.context = context;
    viewPager = new ViewPager(context);
    LayoutParams params = new LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
    viewPager.setLayoutParams(params);
    mView = viewPager;
    addView(mView);
  }

  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    if(listener!=null && listener.gridViewColumn() != 0){
      int column = listener.gridViewColumn();
      int row = (int) Math.ceil((double) list.get(0).size()/column);
      int heightMeasureSpec2 = MeasureSpec.makeMeasureSpec(row*getWidth()/column,
          MeasureSpec.AT_MOST);
      setMeasuredDimension(widthMeasureSpec,heightMeasureSpec2);
    }
  }

  public void setListener(RequestDataListener listener) {
    this.listener = listener;
  }

  public void setPageChangeListener(ViewPager.OnPageChangeListener pageChangeListener) {
    this.pageChangeListener = pageChangeListener;
  }

  public void setEveryRequest(boolean everyRequest) {
    isEveryRequest = everyRequest;
  }

  public void setPagingLoad(boolean pagingLoad) {
    isPagingLoad = pagingLoad;
  }

  public void setList(List<List<T>> list) {
    this.list = list;
    initView();
    invalidate();
  }

  private void initView() {
    adapter = new MyViewPagerAdapter(context, list,listener);
    viewPager.setAdapter(adapter);
    viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
      @Override
      public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
        if(pageChangeListener != null){
          pageChangeListener.onPageScrolled(position,positionOffset,positionOffsetPixels);
        }
      }

      @Override
      public void onPageSelected(int position) {
        if(pageChangeListener != null){
          pageChangeListener.onPageSelected(position);
        }
        if (isPagingLoad) {//分页加载
          if (isEveryRequest) {//每次都请求
            adapter.setCurrentPosition(position);
            listener.request(position);
          } else {//请求过一次将不在重复请求
            if (!hasAdded.contains(position)) {
              hasAdded.add(position);
              adapter.setCurrentPosition(position);
              listener.request(position);
            }
          }
        }
      }


      @Override
      public void onPageScrollStateChanged(int state) {
        if(pageChangeListener != null){
          pageChangeListener.onPageScrollStateChanged(state);
        }
      }
    });
  }
  //数据刷新
  public void dataInvalidate(int position,List<T> changeList){
    list.set(position, changeList);
    adapter.notifyDataSetChanged();
  }
}

public class MyViewPagerAdapter<T> extends PagerAdapter {
  private Context context;
  private List<List<T>> list;
  private LayoutInflater inflater;
  private MyGridViewAdapter adapter;
  private int currentPosition;
  private RequestDataListener listener;
  public MyViewPagerAdapter(Context context, List<List<T>> list,RequestDataListener listener) {
    this.context = context;
    this.list = list;
    this.listener = listener;
    inflater = LayoutInflater.from(context);
  }

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

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

  @NonNull
  @Override
  public Object instantiateItem(@NonNull ViewGroup container, int position) {
    GridView view = new GridView(context);
    ViewGroup.LayoutParams params = new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT);
    view.setLayoutParams(params);
    view.setTag(position);
    if(listener!=null && listener.gridViewColumn() != 0){
      view.setNumColumns(listener.gridViewColumn());
    }
    adapter = new MyGridViewAdapter(context, list.get(position),listener);
    view.setAdapter(adapter);
    container.addView(view);
    return view;
  }

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

  @Override
  public int getItemPosition(@NonNull Object object) {
    //viewpager立即刷新页面
    if (list != null && list.size() == 0) {
      return POSITION_NONE;
    }
    View view = (View) object;
    if (currentPosition == (Integer) view.getTag()) {
      return POSITION_NONE;
    } else {
      return POSITION_UNCHANGED;
    }
  }

  @Override
  public void notifyDataSetChanged() {
    super.notifyDataSetChanged();
    if(adapter != null){
      adapter.notifyDataSetChanged();
    }
  }

  public void setCurrentPosition(int currentPosition) {
    this.currentPosition = currentPosition;
  }
}

public class MyGridViewAdapter<T> extends BaseAdapter{
  private Context context;
  private List<T> list;
  private LayoutInflater inflater;
  private RequestDataListener listener;
  public MyGridViewAdapter(Context context, List<T> list,RequestDataListener listener){
    this.context = context;
    this.list = list;
    this.listener = listener;
    inflater = LayoutInflater.from(context);
  }
  @Override
  public int getCount() {
    return list.size();
  }

  @Override
  public Object getItem(int position) {
    return list.get(position);
  }

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

  @Override
  public View getView(int position, View convertView, ViewGroup parent) {
    convertView = listener.getView(inflater,position,convertView,parent,list);
    int width;
    //计算item的宽
    if(listener != null &listener.gridViewColumn() != 0){
       width = parent.getWidth()/listener.gridViewColumn();
    }else{
       width = parent.getWidth()/3;
    }
    //设置item的宽高相等
    convertView.setLayoutParams(new AbsListView.LayoutParams(width,width));
    return convertView;
  }
}

public interface RequestDataListener<T> {
  void request(int position);
  //gridView列数
  int gridViewColumn();
  View getView(LayoutInflater inflater, int position, View convertView, ViewGroup parent, List<T> list);
}