我的问题如下：
我有一个在线mysql数据库，我通过JSON将一些数据绑定到片段内的列表视图。我之前使用本地sqlite数据库中的游标适配器已经多次这样做了，但我现在遇到了一些JSON问题。
数据显示在自定义列表视图中，但是当我点击一个项目时，我想从在线数据库中获取ID（以及其他行）并通过intent.putExtra（）将其传递给下一个活动
数据存储在一个模型中，但是目前我正在将ID TextView的可见性设置为“已消失”，只是存储编辑文本的值，但这并不是非常有效，因为我在应用程序中有很多列表视图。我不确定我是否正确启动模型，因为它给了我错误，因此我又回到了用于存储ID的get.Text.toString方法。
如何从阵列适配器获取存储在模型中的ID？
干杯:)有些东西我没得到......
DietNameModel dm = data.get(position);
int id2 = dm.getDietID();
String weight_id = String.valueOf(id2);
Toast.makeText(getActivity(), weight_id, Toast.LENGTH_LONG).show();
我在logcat中收到以下错误。
01-31 04:11:24.895: W/dalvikvm(1260): threadid=1: thread exiting with uncaught exception (group=0xa621c908)
01-31 04:11:24.899: E/AndroidRuntime(1260): FATAL EXCEPTION: main
01-31 04:11:24.899: E/AndroidRuntime(1260): java.lang.NullPointerException
01-31 04:11:24.899: E/AndroidRuntime(1260): at com.dietmanager.main.DietsFragmentJSON$1.onItemClick(DietsFragmentJSON.java:100)
01-31 04:11:24.899: E/AndroidRuntime(1260): at android.widget.AdapterView.performItemClick(AdapterView.java:298)
01-31 04:11:24.899: E/AndroidRuntime(1260): at android.widget.AbsListView.performItemClick(AbsListView.java:1100)
01-31 04:11:24.899: E/AndroidRuntime(1260): at android.widget.AbsListView$PerformClick.run(AbsListView.java:2749)
01-31 04:11:24.899: E/AndroidRuntime(1260): at android.widget.AbsListView$1.run(AbsListView.java:3423)
01-31 04:11:24.899: E/AndroidRuntime(1260): at android.os.Handler.handleCallback(Handler.java:725)
01-31 04:11:24.899: E/AndroidRuntime(1260): at android.os.Handler.dispatchMessage(Handler.java:92)
01-31 04:11:24.899: E/AndroidRuntime(1260): at android.os.Looper.loop(Looper.java:137)
01-31 04:11:24.899: E/AndroidRuntime(1260): at android.app.ActivityThread.main(ActivityThread.java:5041)
01-31 04:11:24.899: E/AndroidRuntime(1260): at java.lang.reflect.Method.invokeNative(Native Method)
01-31 04:11:24.899: E/AndroidRuntime(1260): at java.lang.reflect.Method.invoke(Method.java:511)
01-31 04:11:24.899: E/AndroidRuntime(1260): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
01-31 04:11:24.899: E/AndroidRuntime(1260): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
01-31 04:11:24.899: E/AndroidRuntime(1260): at dalvik.system.NativeStart.main(Native Method)
public class DietsFragmentJSON extends Fragment implements FetchDietNameListener {
private List<DietNameModel> data;
Activity mActivity;
View rootView;
private int dietID;
private ListView listview;
private String diet_ID, diet_name, diet_category, diet_desc ;
private ProgressDialog dialog;
private EditText et;
private ListView lv;
private TextView idTxt, weight_loss, diet_desc_text, diet_rating, diet_followers_txt, diet_duration;
private static List<DietNameModel> dietnamemodel;
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
rootView = inflater.inflate(R.layout.diet_name_fragment, container, false);
listview = (ListView) rootView.findViewById(R.id.listview);
mActivity = getActivity();
initView();
return rootView;
}
private void initView() {
// show progress dialog
dialog = ProgressDialog.show(mActivity, "", "Loading...");
String url = "http:xxxxxxxxxxxxxxx.diet_name.php";
FetchDietDataTask task = new FetchDietDataTask(this);
task.execute(url);
}
public void onFetchComplete(List<DietNameModel> data) {
// dismiss the progress dialog
if(dialog != null) dialog.dismiss();
// create new adapter
DietNameAdapter adapter = new DietNameAdapter(getActivity(), data);
// set the adapter to list
listview.setAdapter(adapter);
listview.setOnItemClickListener(myOnItemClickListener);
}
OnItemClickListener myOnItemClickListener
= new OnItemClickListener(){
@SuppressLint("NewApi") @Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
//DietNameModel dm = data.get(position);
//String dietname = dm.getDietName();
//HERE NEED TO GET ID FROM THE MODEL
idTxt = (TextView)view.findViewById(R.id.diet_iD);
dietID = Integer.valueOf(idTxt.getText().toString());
diet_name = ((TextView) view.findViewById(R.id.titleTxt)).getText().toString();
Intent intent = new Intent(getActivity(), DietActivity.class);
Bundle bundle = ActivityOptions.makeCustomAnimation(getActivity(), R.anim.left_slide_in, R.anim.left_slide_out).toBundle();
intent.putExtra("id", dietID);
intent.putExtra("dietname", diet_name);
//intent.putExtra("diet_duration_string", diet_duration_String);
getActivity().startActivity(intent, bundle);
}
};
@Override
public void onFetchFailure(String msg) {
// dismiss the progress dialog
if(dialog != null) dialog.dismiss();
Toast.makeText(getActivity(), msg, Toast.LENGTH_LONG).show();
}
}
public class DietNameModel {
private String diet_name;
private String diet_desc;
private long followers;
private int rating;
private int _id;
private int diet_duration;
private int weight_loss_total_kg;
private String diet_category;
public DietNameModel(){
}
public DietNameModel(int id, int diet_duration, int rating, long followers, String diet_name, String diet_desc, String diet_cat){
this._id = id;
this.rating = rating;
this.followers = followers;
this.diet_duration = diet_duration;
this.diet_name = diet_name;
this.diet_desc = diet_desc;
this.diet_category = diet_cat;
}
public DietNameModel(String diet_name, String diet_desc, String diet_cat){
this.diet_name = diet_name;
this.diet_desc = diet_desc;
this.diet_category = diet_cat;
}
public String getDietCategory() {
return diet_category;
}
public void setDietCategory(String diet_category) {
this.diet_category = diet_category;
}
public String getDietName() {
return diet_name;
}
public void setDietName(String diet_name) {
this.diet_name = diet_name;
}
public String getDietDesc() {
return diet_desc;
}
public void setDietDesc(String diet_desc) {
this.diet_desc = diet_desc;
}
public long getFollowers() {
return followers;
}
public void setFollowers(long followers) {
this.followers = followers;
}
public int getRating() {
return rating;
}
public void setRating(int rating) {
this.rating = rating;
}
public int getDietID() {
return _id;
}
public void setDietID(int _id) {
this._id = _id;
}
public int getTotalWeightLoss() {
return weight_loss_total_kg;
}
public void setTotalWeightLoss(int weight_loss_total_kg) {
this.weight_loss_total_kg = weight_loss_total_kg;
}
public int getDietDuration() {
return diet_duration;
}
public void setDietDuration(int diet_duration) {
this.diet_duration = diet_duration;
}
}
public class FetchDietDataTask extends AsyncTask<String, Void, String>{
private final FetchDietNameListener listener;
private String msg;
public FetchDietDataTask(FetchDietNameListener listener) {
this.listener = listener;
}
@Override
protected String doInBackground(String... params) {
if(params == null) return null;
// get url from params
String url = params[0];
try {
// create http connection
HttpClient client = new DefaultHttpClient();
HttpGet httpget = new HttpGet(url);
// connect
HttpResponse response = client.execute(httpget);
// get response
HttpEntity entity = response.getEntity();
if(entity == null) {
msg = "No response from server";
return null;
}
// get response content and convert it to json string
InputStream is = entity.getContent();
return streamToString(is);
}
catch(IOException e){
msg = "No Network Connection";
}
return null;
}
@Override
protected void onPostExecute(String sJson) {
if(sJson == null) {
if(listener != null) listener.onFetchFailure(msg);
return;
}
try {
// convert json string to json array
JSONArray aJson = new JSONArray(sJson);
// create list list
List<DietNameModel> dietnamemodellist = new ArrayList<DietNameModel>();
for(int i=0; i<aJson.length(); i++) {
JSONObject json = aJson.getJSONObject(i);
DietNameModel dietnamemodel = new DietNameModel();
dietnamemodel.setDietID(Integer.parseInt(json.getString("_id")));
dietnamemodel.setDietName(json.getString("diet_name"));
dietnamemodel.setDietCategory(json.getString("diet_category"));
dietnamemodel.setDietDuration(Integer.parseInt(json.getString("diet_duration")));
dietnamemodel.setTotalWeightLoss(Integer.parseInt(json.getString("total_weight_loss")));
dietnamemodel.setFollowers(Long.parseLong(json.getString("followers")));
dietnamemodel.setRating(Integer.parseInt(json.getString("rating")));
// dietnamemodel.setIcon(json.getString("icon"));
// add the name to list
dietnamemodellist.add(dietnamemodel);
}
//notify the activity that fetch data has been complete
if(listener != null) listener.onFetchComplete(dietnamemodellist);
} catch (JSONException e) {
msg = "Invalid response";
if(listener != null) listener.onFetchFailure(msg);
return;
}
}
/**
* This function will convert response stream into json string
* @param is respons string
* @return json string
* @throws IOException
*/
public String streamToString(final InputStream is) throws IOException{
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line = null;
try {
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
}
catch (IOException e) {
throw e;
}
finally {
try {
is.close();
}
catch (IOException e) {
throw e;
}
}
return sb.toString();
}
}
public class DietNameAdapter extends ArrayAdapter<DietNameModel>{
private List<DietNameModel> items;
private TextView diet_name, diet_cat, diet_duration, diet_weight_loss, diet_ID ;
private LinearLayout ratingCntr;
private TextView followersText;
public DietNameAdapter(Context context, List<DietNameModel> items) {
super(context, R.layout.row_diet_name_dev);
this.items = items;
}
public int getCount() {
return items.size();
}
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
if(v == null) {
LayoutInflater li = LayoutInflater.from(getContext());
v = li.inflate(R.layout.row_diet_name_dev, null);
}
DietNameModel infomodel = items.get(position);
if(infomodel != null) {
diet_ID = (TextView)v.findViewById(R.id.diet_iD);
diet_name = (TextView)v.findViewById(R.id.titleTxt);
ratingCntr = (LinearLayout)v.findViewById(R.id.ratingCntr);
followersText = (TextView)v.findViewById(R.id.followers);
diet_cat = (TextView)v.findViewById(R.id.dietCatTxt);
diet_duration = (TextView)v.findViewById(R.id.diet_duration_txt);
diet_weight_loss = (TextView)v.findViewById(R.id.diet_weight_lost);
if( diet_ID != null) {
NumberFormat nf2 = NumberFormat.getNumberInstance();
diet_ID.setText(nf2.format(infomodel.getDietID()));
}
if( diet_name != null) diet_name.setText(infomodel.getDietName());
if( diet_cat != null) diet_cat.setText(infomodel.getDietCategory());
if(followersText != null) {
NumberFormat nf = NumberFormat.getNumberInstance();
followersText.setText("Followers: " + nf.format(infomodel.getFollowers()));
}
if( diet_duration != null) {
NumberFormat nf2 = NumberFormat.getNumberInstance();
diet_duration.setText(nf2.format(infomodel.getDietDuration()));
}
if( diet_weight_loss != null) {
NumberFormat nf2 = NumberFormat.getNumberInstance();
diet_weight_loss.setText(nf2.format(infomodel.getTotalWeightLoss()));
}
if(ratingCntr != null && ratingCntr.getChildCount() == 0) {
/*
* max rating: 5
*/
for(int i=1; i<=5; i++) {
ImageView iv = new ImageView(getContext());
if(i <= infomodel.getRating()) {
iv.setImageDrawable(getContext().getResources().getDrawable(R.drawable.start_checked));
}
ratingCntr.addView(iv);
}
}
}
return v;
}
}
答案 0 :(得分：1)
空指针指向未正确设置的数据列表，问题现已解决。必须添加的行是this.data = data;
public void onFetchComplete(List<DietNameModel> data) {
this.data = data;
if(dialog != null)
dialog.dismiss();
// create new adapter
adapter = new DietNameAdapter(getActivity(), data);
// set the adapter to list
listview.setAdapter(adapter);
listview.setOnItemClickListener(myOnItemClickListener);
}
答案 1 :(得分：0)
在ListView的OnItemClickListener中，您是否尝试获取此ID：
OnItemClickListener myOnItemClickListener = new OnItemClickListener(){
@SuppressLint("NewApi") @Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
DietNameModel dm = data.get(position);
int id = dm.getDietID();
...