当执行代码那个时间，空指针到来时，我无法理解下一步该做什么？
activity_main.xml中
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.siliconinfo.loadmoredemo.MainActivity">
<Button
android:id="@+id/openFragment"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Click to open" />
<FrameLayout android:id="@+id/contain"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/grey_dark"
xmlns:android="http://schemas.android.com/apk/res/android">
</FrameLayout>
</LinearLayout>
fragment_product.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<LinearLayout
android:id="@+id/filterSortLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@color/white_dim_filter"
android:visibility="gone"
android:orientation="horizontal">
<TextView
android:id="@+id/filterProductLsit"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:drawableLeft="@mipmap/ic_filter_icon"
android:drawablePadding="@dimen/margin_10"
android:gravity="center_vertical"
android:padding="@dimen/margin_5"
android:text="@string/filter_text"
android:textColor="@color/grey_dark"
android:textSize="@dimen/drawer_subheader" />
<TextView
android:id="@+id/sortProductList"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:layout_marginLeft="@dimen/margin_5"
android:drawableLeft="@mipmap/ic_sort_icon"
android:drawablePadding="@dimen/margin_10"
android:gravity="center_vertical"
android:padding="@dimen/margin_5"
android:text="@string/sort_text"
android:textColor="@color/grey_dark"
android:textSize="@dimen/drawer_subheader" />
<ImageView
android:id="@+id/gridListToggle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:padding="@dimen/activity_horizontal_margin"
android:src="@mipmap/gri_view_icon" />
</LinearLayout>
<View
android:layout_width="match_parent"
android:layout_height="1px"
android:background="@color/skyblue_view" />
<TextView
android:id="@+id/noDataMessageText"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:text="@string/no_item_found"
android:visibility="gone" />
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@mipmap/bestsellers_mainbg">
<ProgressBar
android:id="@+id/progressBarItemsRecycler"
style="?android:progressBarStyleLarge"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center" />
<android.support.v7.widget.RecyclerView
android:id="@+id/productListRecyclerView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/white_dim_details"
android:fitsSystemWindows="true"
android:visibility="gone" />
<ProgressBar
android:id="@+id/progressBarItemsRecyclerOuter"
style="?android:progressBarStyleLarge"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:visibility="gone" />
</FrameLayout>
</LinearLayout>
在适配器中设置的行布局
row_gridviewtype.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@mipmap/bestsellers_pro_listbg"
android:orientation="vertical"
android:padding="@dimen/margin_5">
<FrameLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center">
<ProgressBar
android:id="@+id/progressBarItems"
style="?android:progressBarStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center" />
<ImageView
android:id="@+id/imageview"
android:layout_width="@dimen/row_accessories_grid_width"
android:layout_height="@dimen/row_accessories_grid_width_hight"
android:src="@mipmap/no_image_available"
android:layout_gravity="center_horizontal" />
</FrameLayout>
<TextView
android:id="@+id/productNameText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center_horizontal"
android:singleLine="true"
android:textSize="@dimen/text_header" />
<TextView
android:id="@+id/productPriceText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center_horizontal"
android:paddingBottom="@dimen/margin_5"
android:paddingTop="@dimen/margin_5"
android:singleLine="true"
android:textColor="@color/skyblue_view"
android:textSize="@dimen/text_header" />
<TextView
android:id="@+id/productRegularPriceText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center_horizontal"
android:paddingBottom="@dimen/margin_5"
android:paddingTop="@dimen/margin_5"
android:singleLine="true"
android:textColor="@color/grey"
android:textSize="@dimen/text_header" />
</LinearLayout>
这是进度条，在滚动回收站视图时加载到recyclerview下方。
row_load.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="10dp">
<ProgressBar
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/progressBar"
android:layout_gravity="center_horizontal" />
</LinearLayout>
DesktopFragment cointain list
public class DeskPortTprtOurFvtAromaThrpyFragment extends Fragment implements View.OnClickListener {
private static String TAG ="DeskPortTprtOurFvtAromaThrpyFragment";
private View mRoot;
private SharedPreferences mPreferences;
private Typeface mTypefaceBold,mTypefaceSemiBold,mTypefaceRegular;
private RecyclerView mProductListRecyclerView;
privateArrayList<ProductListResponseModel>
mProductListResponseModelArrayList = new ArrayList<ProductListResponseModel>();
private ProgressBar mProgressBarRecycleView, mProgressBarOuter;
private boolean mVieType = true;
private String
mProductResponsePortableStr,mProductResponseDesktopStr,
mProductResponseTopRatedStr,mProductResponseOurFavouriteStr,
mProductResponseAromaTherapyStr, mCategoryStr;
String pageNumber = "", shortValue = "", storeId = "", shopByFrom= "", shopByTo = "";
private TextView mFilterTextView, mSortTextView;
private ArrayList<String> categoryID = new ArrayList<String>();
ArrayList<String> mCAtegoryIdFilter = new ArrayList<String>();
private String shopByFrom1 = "", shopByFrom2 = "", shopByFrom3="", shopByTo1 = "", shopByTo2 = "", shopByTo3 = "";
View.OnClickListener mFilterClickListener;
private String mFilterTag = "NO";
private boolean zeroPosition = false, onePosition = false, secondPositon = false, thirdPosition = false;
String pageNo = "0";
private ImageView mToggleViewListGridImageView;
Bundle productID;
ProductListAdaptr mProductListAdaptr;
private boolean loading = true;
int pastVisiblesItems, visibleItemCount, totalItemCount;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
mRoot = inflater.inflate(R.layout.fragment_product, container,false);
initView();
return mRoot;
}
private void initView() {
mPreferences = getActivity().getSharedPreferences(Utils.PREF_NAME, Context.MODE_PRIVATE);
mToggleViewListGridImageView = (ImageView)mRoot.findViewById(R.id.gridListToggle);
((ImageView)mRoot.findViewById(R.id.gridListToggle)).setOnClickListener(this);
mProductListRecyclerView = (RecyclerView) mRoot.findViewById(R.id.productListRecyclerView);
mFilterTextView = (TextView) mRoot.findViewById(R.id.filterProductLsit);
mSortTextView = (TextView) mRoot.findViewById(R.id.sortProductList);
((TextView) mRoot.findViewById(R.id.filterProductLsit)).setOnClickListener(this);
((TextView) mRoot.findViewById(R.id.sortProductList)).setOnClickListener(this);
Logger.e("TAG", "Product ID is : " + categoryID);
mProgressBarRecycleView = (ProgressBar) mRoot.findViewById(R.id.progressBarItemsRecycler);
mProgressBarOuter = (ProgressBar) mRoot.findViewById(R.id.progressBarItemsRecyclerOuter);
categoryID.add("10");
mProductListAdaptr = new ProductListAdaptr(getContext(), mProductListResponseModelArrayList, mProductClickListener, 0);
final LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity(), LinearLayoutManager.VERTICAL, false);
mProductListRecyclerView.setLayoutManager(linearLayoutManager);
mProductListRecyclerView.setItemAnimator(new DefaultItemAnimator());
mProductListAdaptr.setLoadMoreListener(new ProductListAdaptr.OnLoadMoreListener() {
@Override
public void onLoadMore() {
mProductListRecyclerView.post(new Runnable() {
@Override
public void run() {
int index = mProductListResponseModelArrayList.size() - 1;
loadMore(index);
}
});
}
});
load(0);
}
private void load(int index) {
getProductList(categoryID, String.valueOf(index), "", "", "", "", "", "", "", "", "");
}
private void loadMore(int index) {
}
private void showProductList() {
((LinearLayout) mRoot.findViewById(R.id.filterSortLayout)).setVisibility(View.VISIBLE);
((TextView) mRoot.findViewById(R.id.noDataMessageText)).setVisibility(View.GONE);
mProductListRecyclerView.setVisibility(View.VISIBLE);
if (mVieType == true) {
LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity(), LinearLayoutManager.VERTICAL, false);
mProductListRecyclerView.setLayoutManager(linearLayoutManager);
ProductListRecyclerView.setItemAnimator(newDefaultItemAnimator());
mProductListRecyclerView.setAdapter(new ProductListAdaptr(getContext(), mProductListResponseModelArrayList, mProductClickListener, 0));
} else if (mVieType == false) {
final GridLayoutManager mLayoutManager = new GridLayoutManager(getActivity(), 2);
mProductListRecyclerView.setLayoutManager(mLayoutManager);
mProductListRecyclerView.setItemAnimator(new DefaultItemAnimator());
mProductListRecyclerView.setAdapter(new ProductListAdaptr(getContext(), mProductListResponseModelArrayList, mProductClickListener, 1));
}
mProductListResponseModelArrayList.addAll(mProductListResponseModelArrayList);
mProductListAdaptr.notifyDataChanged();
}
private View.OnClickListener mProductClickListener = new View.OnClickListener() {
@Override
public void onClick(View v) {
int position = (int) v.getTag();
}
};
private void getProductList(ArrayList<String> categoryId, String pagenumber, String shopByFrom1, String shopByTo1,
String shopByFrom2, String shopByTo2, String shopByFrom3, String shopByTo3, String shortValue, String storesID, String FilterTag) {
String categoryListString = "";
for (int i = 0; i < categoryId.size(); i++) {
if (i == 0)
categoryListString = categoryId.get(i).toString();
else
categoryListString = categoryListString + ", " + categoryId.get(i).toString();
}
if (Utils.checkInternetConnection(getActivity())) {
final ProdcutListRequestTask mProductListRequestTask = new ProdcutListRequestTask(getActivity());
mProductListRequestTask.setAsyncCallListener(new AsyncCallListener() {
@Override
public void onResponseReceived(Object response) {
mProductListResponseModelArrayList (ArrayList<ProductListResponseModel>) response;
((LinearLayout)mRoot.findViewById(R.id.filterSortLayout)).setVisibility(View.VISIBLE);
mProgressBarOuter.setVisibility(View.GONE);
mProgressBarRecycleView.setVisibility(View.GONE);
if (mProductListResponseModelArrayList != null) {
Logger.e(TAG, "DektoPportaOurFavouriteFragment : " + mProductListResponseModelArrayList.size());
}
if (response == null) return;
if (mProductListResponseModelArrayList == null || mProductListResponseModelArrayList.size() == 0) {
((TextView) mRoot.findViewById(R.id.noDataMessageText)).setTypeface(mTypefaceBold);
((TextView) mRoot.findViewById(R.id.noDataMessageText)).setVisibility(View.VISIBLE);
((LinearLayout) mRoot.findViewById(R.id.filterSortLayout)).setVisibility(View.GONE);
return;
}
showProductList();
}
@Override
public void onErrorReceived(String error) {
mProgressBarOuter.setVisibility(View.GONE);
}
});
mProductListRequestTask.execute(categoryListString, pagenumber, shopByFrom1, shopByTo1, shopByFrom2, shopByTo2, shopByFrom3, shopByTo3,
shortValue, storesID, FilterTag);
} else {
Toast.makeText(getActivity(), getString(R.string.no_internet), Toast.LENGTH_SHORT).show();
mProgressBarOuter.setVisibility(View.GONE);
}
}
}
答案 0 :(得分：0)
使用它，为我工作。
recyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
if (hasMore && !(hasFooter())) {
LinearLayoutManager layoutManager = (LinearLayoutManager) recyclerView.getLayoutManager();
//position starts at 0
if (layoutManager.findLastCompletelyVisibleItemPosition() == layoutManager.getItemCount() - 2) {
new GetPostData().execute();
}
}
else{
}
}
});
希望它也会帮助你。