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);
}