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私の問題はjsonを使用してリサイクラビューを作成しているときですが、この問題を解決するためにはどれも問題を解決できますこのエラー？プログラムでjsonを使用してデータを取得するときのRecyclerビューの問題
public class MainActivity extends Activity {
Button b;
TextView tv;
ListView lists;
RecyclerView recyclerView;
List<Your> yourss;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
recyclerView = (RecyclerView) findViewById(R.id.recycle);
LinearLayoutManager ll = new LinearLayoutManager(MainActivity.this);
recyclerView.setHasFixedSize(true);
recyclerView.setLayoutManager(ll);
new JsonTask().execute("http://yoursubshop.com/webservices/categories.php");
}
public class JsonTask extends AsyncTask<String, String, List<Your>> {
@Override
protected List<Your> doInBackground(String... params) {
HttpURLConnection httpURLConnection = null;
BufferedReader bufferedReader = null;
try {
URL url = new URL(params[0]);
httpURLConnection = (HttpURLConnection) url.openConnection();
InputStreamReader inputStreamReader = new InputStreamReader(httpURLConnection.getInputStream());
bufferedReader = new BufferedReader(inputStreamReader);
StringBuffer sb = new StringBuffer();
String line = "";
while ((line = bufferedReader.readLine()) != null) {
sb.append(line);
}
String finaljson = sb.toString();
JSONObject firstobject = new JSONObject(finaljson);
JSONArray firstarray = firstobject.getJSONArray("data");
List<Your> yo = new ArrayList<>();
for (int i = 0; i < firstarray.length(); i++) {
JSONObject finalobject = firstarray.getJSONObject(i);
Your yos = new Your();
yos.category_id = finalobject.getString("category_id");
yos.category_name = finalobject.getString("category_name");
yo.add(yos);
}
return yo;
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
} finally {
if (httpURLConnection != null) {
httpURLConnection.disconnect();
}
try {
if (bufferedReader != null) {
bufferedReader.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}
@Override
protected void onPostExecute(List<Your> result) {
super.onPostExecute(result);
Rvadapter listAdapter = new Rvadapter(MainActivity.this, yourss);
recyclerView.setAdapter(listAdapter);
}
}
public class Rvadapter extends RecyclerView.Adapter<Rvadapter.Myadapter> {
List<Your> yours = Collections.emptyList();
Context c;
public class Myadapter extends RecyclerView.ViewHolder {
TextView id;
TextView name;
CardView cv;
public Myadapter(View itemView) {
super(itemView);
id = (TextView) itemView.findViewById(R.id.texts);
name = (TextView) itemView.findViewById(R.id.textsa);
cv = (CardView)itemView.findViewById(R.id.card);
}
}
public Rvadapter(Context c, List<Your> yours) {
this.yours = yours;
this.c = c;
}
@Override
public Myadapter onCreateViewHolder(ViewGroup parent, int viewType) {
View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.lists, parent, false);
Myadapter m = new Myadapter(v);
return m;
}
@Override
public void onBindViewHolder(Myadapter holder, int position) {
Your y = yours.get(position);
holder.id.setText(y.category_id);
holder.name.setText(y.category_name);
}
@Override
public int getItemCount() {
return yours.size();
}
@Override
public void onAttachedToRecyclerView(RecyclerView recyclerView) {
super.onAttachedToRecyclerView(recyclerView);
}
}
Eception
06-28 17:03:34.078 802-802/com.example.anilkumar.json E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.NullPointerException
at com.example.anilkumar.json.MainActivity$Rvadapter.getItemCount(MainActivity.java:154)
at android.support.v7.widget.RecyclerView.dispatchLayoutStep1(RecyclerView.java:3170)
at android.support.v7.widget.RecyclerView.onMeasure(RecyclerView.java:2782)
at android.view.View.measure(View.java:12723)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1369)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:660)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:553)
at android.view.View.measure(View.java:12723)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:293)
at android.view.View.measure(View.java:12723)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1369)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:660)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:553)
at android.view.View.measure(View.java:12723)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4698)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:293)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2092)
at android.view.View.measure(View.java:12723)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1064)
at android.view.ViewRootImpl.handleMessage(ViewRootImpl.java:2442)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:137)
at android.app.ActivityThread.main(ActivityThread.java:4424)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:511)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
lists.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="match_parent">
<android.support.v7.widget.CardView
android:layout_width="300dp"
android:layout_height="80dp"
android:id="@+id/card">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/texts"
android:text="id"
android:padding="20dp"
android:layout_margin="20sp"
android:textSize="20sp"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/textsa"
android:layout_margin="20sp"
android:text="Resturants"
android:textSize="20sp"/>
</android.support.v7.widget.CardView>
エラーが解決しますが、アプリdoesnot殺したが、データは、このエラーは、あなたに正しい項目を追加していないことを意味 –
まあ何であるかを画面上に表示されませんでしたアダプタ。 #Drvと同じように、onPostExecute（結果としてリストの結果）から取得した結果をアダプターに追加してみてください。 –
toshkinl
yessは動作していますが、カードビューの間にアイテム間にギャップが発生しました。どうすればこの問題を解決できますか？ –