在片段自定义阵列适配器 [英] Custom Array adapter in fragment
本文介绍了在片段自定义阵列适配器的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我在Andriod的非常新。我已经试过很多次，但因为很长一段时间就死在了这个问题。我有一个名为ProductListActivity一个活动，这个活动我有一个片段。现在我想显示列表并为我创造了我自己的自定义阵列适配器。其工作正常，当我不使用时的片段但片段给我NullPointerException异常。调试我的code。请帮我出guys.Thanks审议。
在这里我粘贴我的code。
活动类：
公共类ProductListActivity扩展活动实现ProductInterface {
公共静态字符串的cookie;
公共静态字符串jsonSettingsResponse;
公共静态的String [] TIDS;
公共静态字符串jsonPorductsCategoryListResponseString;
公共JSONArray jsonPorductsCategoryListResponseArray;
公共静态字符串VID;
公共静态字符串publicPath;
公共静态JSONArray产品列表;
公众的ArrayList＆LT;串GT; listItems中;
公众的String [] listProCategory;@覆盖
保护无效的onCreate（捆绑savedInstanceState）{
super.onCreate（savedInstanceState）;
的setContentView（R.layout.product_category_and_list）;
意向意图= getIntent（）;
饼干= intent.getStringExtra（BConstant.WEB_SERVICES_COOKIES）;
产品列表=新JSONArray（）;
FetchProductCategories产品=新FetchProductCategories（）;
产品列表= products.fetchProducts（）;
listProCategory = products.onDisplayProductList（产品列表）.toArray（
新的String [0]）; 束束=新包（）;
bundle.putString（BConstant.WEB_SERVICES_COOKIES，饼干）;
bundle.putString（BConstant.PUBLIC_PATH，publicPath）;
bundle.putStringArray（BConstant.TAXONOMY_TID，TIDS）;
bundle.putStringArray（BConstant.PRODUCT_CATEGORY_NAMES，listProCategory）;
ProductCategoryFragment productCategoryFragment =新ProductCategoryFragment（）;
FragmentManager经理= getFragmentManager（）;
productCategoryFragment.setArguments（包）;}私有类FetchProductCategories {
保护JSONArray fetchProducts（字符串... PARAMS）{
jsonSettingsResponse = WebserviceBUtil
.callWebServicesGetVocabularyList（饼干）;
VID = JSONUtil.parseJSONResponse（jsonSettingsResponse，
BConstant.TAXONOMY_VID）;
publicPath = JSONUtil.parseJSONResponse（jsonSettingsResponse，
BConstant.PUBLIC_PATH）;
jsonPorductsCategoryListResponseString = WebserviceBUtil
.callWebServicesGetProductsList（饼干，VID）;
TIDS = ProductCategoryIds.parseJSONResponseToGetTidsOfProducts（
jsonPorductsCategoryListResponseString，
BConstant.TAXONOMY_TID）;
尝试{
jsonPorductsCategoryListResponseArray =新JSONArray（
jsonPorductsCategoryListResponseString）;
}赶上（JSONException E）{
e.printStackTrace（）;
}
返回jsonPorductsCategoryListResponseArray;
}
保护的ArrayList＆LT;串GT; onDisplayProductList（JSONArray结果）{
时listItems =新的ArrayList＆LT;串GT;（）;
的for（int i = 0; I＆LT; result.length（）;我++）{
尝试{
listItems中
。新增（result.getJSONObject（I）
.getString（BConstant.NAME_CONSTANT）
的ToString（））;
}赶上（例外前）{
ex.printStackTrace（）;
}
}
返回时listItems;
}
}
@覆盖
公众的HashMap＆LT;整数，位图＆GT; DownloadImages（HashMap的＆LT;整数，字符串＆GT; productCategoryImagePath）{
HashMap的＆LT;整数，位图＆GT; imgBitmap =新的HashMap＆LT;整数，位图＆GT;（）;
对（INT POS = 0; POS及下; productCategoryImagePath.size（）; POS ++）{
位图BVAL = ImageDownloader
.getBitmapFromURL（productCategoryImagePath.get（POS））;
imgBitmap.put（POS，BVAL）;
}
返回imgBitmap;}
}
Fragments类：
公共类ProductCategoryFragment扩展片段{
ProductInterface productInterface;
私有静态的String [] TIDS;
私有静态HashMap的＆LT;整数，字符串＆GT; productCategoryImagePath;
私人静态字符串jsonPorductsDetailsImagePathResponse;
私人静态字符串publicPath;
私人静态字符串的cookie;
公众的String [] listProCategory;
公众的ListView listOfProductsCategory;
私有静态HashMap的＆LT;整数，位图＆GT; imgBitmapUrls;
DisplayProductListArrayAdapter适配器;
@覆盖
公共查看onCreateView（LayoutInflater充气器，容器的ViewGroup，
捆绑savedInstanceState）{
查看fragProcatView = inflater.inflate（R.layout.product_category_list，集装箱，
假）;
listOfProductsCategory =（ListView控件）getActivity（）findViewById（R.id.productCategorylistView）。
返回fragProcatView;}@覆盖
公共无效onActivityCreated（捆绑savedInstanceState）{
super.onActivityCreated（savedInstanceState）;
publicPath = getArguments（）的getString（BConstant.PUBLIC_PATH）。
饼干= getArguments（）的getString（BConstant.WEB_SERVICES_COOKIES）。
TIDS = getArguments（）getStringArray（BConstant.TAXONOMY_TID）。
listProCategory = getArguments（）。getStringArray（
BConstant.PRODUCT_CATEGORY_NAMES）;
束B = getActivity（）getIntent（）getExtras（）。
publicPath = b.getString（BConstant.PUBLIC_PATH）;
饼干= b.getString（BConstant.WEB_SERVICES_COOKIES）;
TIDS = b.getStringArray（BConstant.TAXONOMY_TID）;
listProCategory = b.getStringArray（
BConstant.PRODUCT_CATEGORY_NAMES）;
productInterface =（ProductInterface）getActivity（）;
productCategoryImagePath =新的HashMap＆LT;整数，字符串＆GT;（）;
的for（int i = 0; I＆LT; tids.length;我++）{
jsonPorductsDetailsImagePathResponse = WebserviceBUtil
.callWebServicesGetProductsDetails（饼干，TIDS [I]）;
字符串文件名= ProductCategoryIds
.parseJSONResponseToGetVidOfProductsFromVocabulary（
jsonPorductsDetailsImagePathResponse，
BConstant.FILE_NAME）;
字符串completeUrl = publicPath +文件名;
productCategoryImagePath.put（ⅰ，completeUrl）;
}
imgBitmapUrls = productInterface
.DownloadImages（productCategoryImagePath）;
适配器=新DisplayProductListArrayAdapter（
getActivity（），listProCategory，
imgBitmapUrls）;
listOfProductsCategory.setAdapter（适配器）;
}
/ **
* ExtendsArrayAdapterClassToDisplayCustomListView
* /
公共类DisplayProductListArrayAdapter扩展ArrayAdapter＆LT;串GT; { 上下文语境;
HashMap的＆LT;整数，位图＆GT; prodctImgs;
的String [] proCategoryNames;
HashMap的＆LT;整数，位图＆GT; biturls;
DisplayProductListArrayAdapter（上下文C，
的String [] listCategory，HashMap的＆LT;整数，位图＆GT; imgUrls）{
超（C，
R.layout.product_category_single_layout，
R.id.productCategoryName，listCategory）;
this.context = C;
this.prodctImgs = imgUrls;
this.proCategoryNames = listCategory;
this.biturls = imgUrls;
} @覆盖
公共查看getView（INT位置，查看convertView，父母的ViewGroup）{
// LayoutInflater吹气=（LayoutInflater）上下文
// .getSystemService（Context.LAYOUT_INFLATER_SERVICE）;
LayoutInflater充气=（（活动）上下文）.getLayoutInflater（）;
查看排= inflater.inflate（R.layout.product_category_single_layout，父母，假）;
ImageView的productCategoryImage =（ImageView的）行
.findViewById（R.id.productCategoryImageId）;
位图位图= imgBitmapUrls.get（位置）;
// productCategoryImage.setFocusable（假）;
TextView的productCategoryName =（TextView中）一行
.findViewById（R.id.productCategoryName）;
productCategoryImage.setImageBitmap（位图）;
productCategoryName.setText（proCategoryNames [位置]）;
返回行;
}
}
}
解决方案
修改
listOfProductsCategory =（ListView控件）getActivity（）findViewById（R.id.productCategorylistView）。
到
listOfProductsCategory =（ListView控件）fragProcatView .findViewById（R.id.productCategorylistView）;
findViewById 查找在当前infalted布局id的视图。因此，使用视图对象来初始化列表视图。
编辑：
您做这样的事情。
静态ProductCategoryFragment的newInstance（INT NUM）{
ProductCategoryFragment F =新ProductCategoryFragment（）; //供应NUM输入作为参数。
捆绑ARGS =新包（）;
args.putInt（民，NUM）;
f.setArguments（参数）; 返回F;
}
然后
int值= getArguments（）调用getInt（民）;
在活动
ProductCategoryFragment newFragment = ProductCategoryFragment.newInstance（10）;
I am very new in Andriod. i have tried so many times but got stuck on this problem since long time. I have an activity named ProductListActivity and in this activity i have one fragments. now i want to display List and for that i have created my own custom array adapter. its working fine when when i am not using fragments but for fragments giving me NullPointerException. I debug my code. Please help me out guys.Thanks for considering. Here i am pasting my code.
Activity class:
public class ProductListActivity extends Activity implements ProductInterface{
public static String cookie;
public static String jsonSettingsResponse;
public static String[] tids;
public static String jsonPorductsCategoryListResponseString;
public JSONArray jsonPorductsCategoryListResponseArray;
public static String vid;
public static String publicPath;
public static JSONArray productsList;
public ArrayList<String> listItems;
public String[] listProCategory;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.product_category_and_list);
Intent intent = getIntent();
cookie = intent.getStringExtra(BConstant.WEB_SERVICES_COOKIES);
productsList = new JSONArray();
FetchProductCategories products = new FetchProductCategories();
productsList = products.fetchProducts();
listProCategory = products.onDisplayProductList(productsList).toArray(
new String[0]);
Bundle bundle = new Bundle();
bundle.putString(BConstant.WEB_SERVICES_COOKIES, cookie);
bundle.putString(BConstant.PUBLIC_PATH, publicPath);
bundle.putStringArray(BConstant.TAXONOMY_TID, tids);
bundle.putStringArray(BConstant.PRODUCT_CATEGORY_NAMES, listProCategory);
ProductCategoryFragment productCategoryFragment = new ProductCategoryFragment();
FragmentManager manager = getFragmentManager();
productCategoryFragment.setArguments(bundle);
}
private class FetchProductCategories {
protected JSONArray fetchProducts(String... params) {
jsonSettingsResponse = WebserviceBUtil
.callWebServicesGetVocabularyList(cookie);
vid = JSONUtil.parseJSONResponse(jsonSettingsResponse,
BConstant.TAXONOMY_VID);
publicPath = JSONUtil.parseJSONResponse(jsonSettingsResponse,
BConstant.PUBLIC_PATH);
jsonPorductsCategoryListResponseString = WebserviceBUtil
.callWebServicesGetProductsList(cookie, vid);
tids = ProductCategoryIds.parseJSONResponseToGetTidsOfProducts(
jsonPorductsCategoryListResponseString,
BConstant.TAXONOMY_TID);
try {
jsonPorductsCategoryListResponseArray = new JSONArray(
jsonPorductsCategoryListResponseString);
} catch (JSONException e) {
e.printStackTrace();
}
return jsonPorductsCategoryListResponseArray;
}
protected ArrayList<String> onDisplayProductList(JSONArray result) {
listItems = new ArrayList<String>();
for (int i = 0; i < result.length(); i++) {
try {
listItems
.add(result.getJSONObject(i)
.getString(BConstant.NAME_CONSTANT)
.toString());
} catch (Exception ex) {
ex.printStackTrace();
}
}
return listItems;
}
}
@Override
public HashMap<Integer, Bitmap> DownloadImages(HashMap<Integer, String> productCategoryImagePath) {
HashMap<Integer, Bitmap> imgBitmap = new HashMap<Integer, Bitmap>();
for (int pos = 0; pos < productCategoryImagePath.size(); pos++) {
Bitmap bval = ImageDownloader
.getBitmapFromURL(productCategoryImagePath.get(pos));
imgBitmap.put(pos, bval);
}
return imgBitmap;
}
}
Fragments class:
public class ProductCategoryFragment extends Fragment {
ProductInterface productInterface;
private static String[] tids;
private static HashMap<Integer, String> productCategoryImagePath;
private static String jsonPorductsDetailsImagePathResponse;
private static String publicPath;
private static String cookie;
public String[] listProCategory;
public ListView listOfProductsCategory;
private static HashMap<Integer, Bitmap> imgBitmapUrls;
DisplayProductListArrayAdapter adapter;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View fragProcatView = inflater.inflate(R.layout.product_category_list, container,
false);
listOfProductsCategory = (ListView) getActivity().findViewById(R.id.productCategorylistView);
return fragProcatView;
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
publicPath = getArguments().getString(BConstant.PUBLIC_PATH);
cookie = getArguments().getString(BConstant.WEB_SERVICES_COOKIES);
tids = getArguments().getStringArray(BConstant.TAXONOMY_TID);
listProCategory = getArguments().getStringArray(
BConstant.PRODUCT_CATEGORY_NAMES);
Bundle b = getActivity().getIntent().getExtras();
publicPath = b.getString(BConstant.PUBLIC_PATH);
cookie = b.getString(BConstant.WEB_SERVICES_COOKIES);
tids =b.getStringArray(BConstant.TAXONOMY_TID);
listProCategory =b.getStringArray(
BConstant.PRODUCT_CATEGORY_NAMES);
productInterface = (ProductInterface) getActivity();
productCategoryImagePath = new HashMap<Integer, String>();
for (int i = 0; i < tids.length; i++) {
jsonPorductsDetailsImagePathResponse = WebserviceBUtil
.callWebServicesGetProductsDetails(cookie, tids[i]);
String filename = ProductCategoryIds
.parseJSONResponseToGetVidOfProductsFromVocabulary(
jsonPorductsDetailsImagePathResponse,
BConstant.FILE_NAME);
String completeUrl = publicPath + filename;
productCategoryImagePath.put(i, completeUrl);
}
imgBitmapUrls = productInterface
.DownloadImages(productCategoryImagePath);
adapter = new DisplayProductListArrayAdapter(
getActivity(), listProCategory,
imgBitmapUrls);
listOfProductsCategory.setAdapter(adapter);
}
/**
* ExtendsArrayAdapterClassToDisplayCustomListView
*/
public class DisplayProductListArrayAdapter extends ArrayAdapter<String> {
Context context;
HashMap<Integer, Bitmap> prodctImgs;
String[] proCategoryNames;
HashMap<Integer, Bitmap>biturls;
DisplayProductListArrayAdapter(Context c,
String[] listCategory, HashMap<Integer, Bitmap> imgUrls) {
super(c,
R.layout.product_category_single_layout,
R.id.productCategoryName, listCategory);
this.context = c;
this.prodctImgs = imgUrls;
this.proCategoryNames = listCategory;
this.biturls = imgUrls;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
//LayoutInflater inflater = (LayoutInflater) context
// .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
LayoutInflater inflater=((Activity)context).getLayoutInflater();
View row = inflater.inflate(R.layout.product_category_single_layout,parent,false);
ImageView productCategoryImage = (ImageView) row
.findViewById(R.id.productCategoryImageId);
Bitmap bitmap = imgBitmapUrls.get(position);
// productCategoryImage.setFocusable(false);
TextView productCategoryName = (TextView) row
.findViewById(R.id.productCategoryName);
productCategoryImage.setImageBitmap(bitmap);
productCategoryName.setText(proCategoryNames[position]);
return row;
}
}
}
解决方案
Change
listOfProductsCategory = (ListView) getActivity().findViewById(R.id.productCategorylistView);
to
listOfProductsCategory = (ListView) fragProcatView .findViewById(R.id.productCategorylistView);
findViewById looks for a view with the id in the current infalted layout. So use the view object to initialize your listview.
Edit:
You do something like this
static ProductCategoryFragment newInstance(int num) {
ProductCategoryFragment f = new ProductCategoryFragment();
// Supply num input as an argument.
Bundle args = new Bundle();
args.putInt("num", num);
f.setArguments(args);
return f;
}
Then
int value = getArguments().getInt("num");
In Activity
ProductCategoryFragment newFragment = ProductCategoryFragment.newInstance(10);
这篇关于在片段自定义阵列适配器的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
查看全文
