片段视图中未显示ListView（Android）

Question

因此，我在遵循本教程http://www.wingnity.com/blog/android-json-parsing-and-image-loading-tutorial/上了解如何解析JSON Api并将数据显示到Listview

我试图在onCreateView方法中调整片段中的代码，但未显示Listview（空白片段）。 而且我不知道为什么。

我导入了所有必需的库

Actor.java

public class Actors {

private String name;
private String description;
private String dob;
private String country;
private String height;
private String spouse;
private String children;
private String image;

public Actors() {
    // TODO Auto-generated constructor stub
}

public Actors(String name, String description, String dob, String country,
              String height, String spouse, String children, String image) {
    super();
    this.name = name;
    this.description = description;
    this.dob = dob;
    this.country = country;
    this.height = height;
    this.spouse = spouse;
    this.children = children;
    this.image = image;
}


public String getName() {
    return name;
}

public void setName(String name) {
    this.name = name;
}

public String getDescription() {
    return description;
}

public void setDescription(String description) {
    this.description = description;
}

public String getDob() {
    return dob;
}

public void setDob(String dob) {
    this.dob = dob;
}

public String getCountry() {
    return country;
}

public void setCountry(String country) {
    this.country = country;
}

public String getHeight() {
    return height;
}

public void setHeight(String height) {
    this.height = height;
}

public String getSpouse() {
    return spouse;
}

public void setSpouse(String spouse) {
    this.spouse = spouse;
}

public String getChildren() {
    return children;
}

public void setChildren(String children) {
    this.children = children;
}

public String getImage() {
    return image;
}

public void setImage(String image) {
    this.image = image;
}

}

ActorAdapter.java

import java.io.InputStream;
import java.util.ArrayList;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import info.androidhive.navigationdrawer.R;

public class ActorAdapter extends ArrayAdapter<Actors> {
ArrayList<Actors> actorList;
LayoutInflater vi;
int Resource;
ViewHolder holder;

public ActorAdapter(Context context, int resource, ArrayList<Actors> objects) {
    super(context, resource, objects);
    vi = (LayoutInflater) context
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    Resource = resource;
    actorList = objects;
}


@Override
public View getView(int position, View convertView, ViewGroup parent) {
    // convert view = design
    View v = convertView;
    if (v == null) {
        holder = new ViewHolder();
        v = vi.inflate(Resource, null);
        holder.imageview = (ImageView) v.findViewById(R.id.ivImage);
        holder.tvName = (TextView) v.findViewById(R.id.tvName);
        holder.tvDescription = (TextView) v.findViewById(R.id.tvDescriptionn);
        holder.tvDOB = (TextView) v.findViewById(R.id.tvDateOfBirth);
        holder.tvCountry = (TextView) v.findViewById(R.id.tvCountry);
        holder.tvHeight = (TextView) v.findViewById(R.id.tvHeight);
        holder.tvSpouse = (TextView) v.findViewById(R.id.tvSpouse);
        holder.tvChildren = (TextView) v.findViewById(R.id.tvChildren);
        v.setTag(holder);
    } else {
        holder = (ViewHolder) v.getTag();
    }
    holder.imageview.setImageResource(R.drawable.imgadd);
    new DownloadImageTask(holder.imageview).execute(actorList.get(position).getImage());
    holder.tvName.setText(actorList.get(position).getName());
    holder.tvDescription.setText(actorList.get(position).getDescription());
    holder.tvDOB.setText("B'day: " + actorList.get(position).getDob());
    holder.tvCountry.setText(actorList.get(position).getCountry());
    holder.tvHeight.setText("Height: " + actorList.get(position).getHeight());
    holder.tvSpouse.setText("Spouse: " + actorList.get(position).getSpouse());
    holder.tvChildren.setText("Children: " + actorList.get(position).getChildren());
    return v;

}

static class ViewHolder {
    public ImageView imageview;
    public TextView tvName;
    public TextView tvDescription;
    public TextView tvDOB;
    public TextView tvCountry;
    public TextView tvHeight;
    public TextView tvSpouse;
    public TextView tvChildren;

}

private class DownloadImageTask extends AsyncTask<String, Void, Bitmap> {
    ImageView bmImage;

    public DownloadImageTask(ImageView bmImage) {
        this.bmImage = bmImage;
    }

    protected Bitmap doInBackground(String... urls) {
        String urldisplay = urls[0];
        Bitmap mIcon11 = null;
        try {
            InputStream in = new java.net.URL(urldisplay).openStream();
            mIcon11 = BitmapFactory.decodeStream(in);
        } catch (Exception e) {
            Log.e("Error", e.getMessage());
            e.printStackTrace();
        }
        return mIcon11;
    }

    protected void onPostExecute(Bitmap result) {
        bmImage.setImageBitmap(result);
    }

}
}

Articles.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/LinearLayout1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="4dp"
android:orientation="vertical" >

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content" >

    <ImageView
        android:id="@+id/ivImage"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="8dp"
        android:src="@drawable/imgadd" />

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical" >

        <TextView
            android:id="@+id/tvName"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Tom Cruise"
            android:textColor="#166CED"
            android:textAppearance="?android:attr/textAppearanceLarge" />

        <TextView
            android:id="@+id/tvDateOfBirth"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#D64530"
            android:text="Date of Birth: July 3, 1962" />

        <TextView
            android:id="@+id/tvHeight"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Height: 1.80 m"
            android:textColor="#D64530"
            android:textAppearance="?android:attr/textAppearanceSmall" />

        <TextView
            android:id="@+id/tvCountry"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textColor="#D64530"
            android:text="United States" />

    </LinearLayout>

</LinearLayout>

<TextView
    android:id="@+id/tvDescriptionn"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textColor="#009A57"
    android:text="Description" />

<TextView
    android:id="@+id/tvSpouse"
    android:layout_width="wrap_content" android:textColor="#166CED"
    android:layout_height="wrap_content"
    android:text="Spouse: Katie Holmes" />

<TextView
    android:id="@+id/tvChildren"
    android:layout_width="wrap_content" android:textColor="#166CED"
    android:layout_height="wrap_content"
    android:text="Children: Suri Cruise, Isabella Jane Cruise, Connor Cruise" />

</LinearLayout>

Fragment_accueil.xml（我的片段布局）

<?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:id="@+id/LinearLayout1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="4dp"
android:orientation="vertical"
tools:context="info.androidhive.navigationdrawer.fragment.AccueilFragment">

<ListView
    android:id="@+id/list"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    tools:listitem="@layout/articles">

</ListView>

</LinearLayout>

fragment_accueil.java（我的片段活动）

//import.....
public class AccueilFragment extends Fragment {
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";

private String mParam1;
private String mParam2;
int score = 0;
TextView t1, t2, t3,t4;
ImageView img;

private OnFragmentInteractionListener mListener;

public AccueilFragment() {
}

public static AccueilFragment newInstance(String param1, String param2) {
    AccueilFragment fragment = new AccueilFragment();
    Bundle args = new Bundle();
    args.putString(ARG_PARAM1, param1);
    args.putString(ARG_PARAM2, param2);
    fragment.setArguments(args);
    return fragment;
}

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (getArguments() != null) {
        mParam1 = getArguments().getString(ARG_PARAM1);
        mParam2 = getArguments().getString(ARG_PARAM2);
    }

}


@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    View view = inflater.inflate(R.layout.fragment_accueil, container, false);


    t1 = (TextView) view.findViewById(R.id.tvName);
    t2 = (TextView) view.findViewById(R.id.tvDateOfBirth);
    t3 = (TextView) view.findViewById(R.id.tvHeight);
    t3 = (TextView) view.findViewById(R.id.tvCountry);
    img = (ImageView) view.findViewById(R.id.ivImage);
    ArrayList actorsList = new ArrayList<Actors>();

    ListView listview = (ListView) view.findViewById(R.id.list);
    ListAdapter adapter = new ActorAdapter(getActivity().getApplicationContext(), R.layout.articles, actorsList);

    listview.setAdapter(adapter);

    new getData().execute();


    return view;

}



public void onButtonPressed(Uri uri) {
    if (mListener != null) {
        mListener.onFragmentInteraction(uri);
    }
}

class getData extends AsyncTask<String, String, String> {

    HttpURLConnection urlConnection;


    @Override
    protected String doInBackground(String... args) {

        StringBuilder result = new StringBuilder();

        try {
            URL url = new URL("http://microblogging.wingnity.com/JSONParsingTutorial/jsonActors");
            urlConnection = (HttpURLConnection) url.openConnection();
            InputStream in = new BufferedInputStream(urlConnection.getInputStream());

            BufferedReader reader = new BufferedReader(new InputStreamReader(in));

            String line;
            while ((line = reader.readLine()) != null) {
                result.append(line);
            }

        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            urlConnection.disconnect();
        }


        return result.toString();
    }



    @Override
    protected void onPostExecute(String result) {
        try {
            JSONObject jsono = new JSONObject(result);
            JSONArray jarray = jsono.getJSONArray("actors");

            for (int i = 0; i < jarray.length(); i++) {
                JSONObject object = jarray.getJSONObject(i);

                Actors actor = new Actors();

                actor.setName(object.getString("name"));
                actor.setDescription(object.getString("description"));
                actor.setDob(object.getString("dob"));
                actor.setCountry(object.getString("country"));
                actor.setHeight(object.getString("height"));
                actor.setSpouse(object.getString("spouse"));
                actor.setChildren(object.getString("children"));
                actor.setImage(object.getString("image"));

            }


        } catch (JSONException e) {
            e.printStackTrace();
        }
    }
}

@Override
public void onAttach(Context context) {
    super.onAttach(context);
}

@Override
public void onDetach() {
    super.onDetach();
    mListener = null;
}
public interface OnFragmentInteractionListener {

    void onFragmentInteraction(Uri uri);
}



}

有什么问题以及如何解决？ 谢谢

Answer 1

您是否要在片段中添加ListView以使其显示，例如：

public class FragmentMain extends Fragment
{
    private ListView listView; //Define the list view up here. 

    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    //Set the listview equal to the fragment name
    listView = inflater.inflate(R.layout.fragment_name, container, false);

    }
}

这应该工作，让我知道是否otherwize :)

Answer 2

有几处错误：

1.您没有添加Actors actor = new Actors(); actorsList

2.调用此：

 ArrayList actorsList = new ArrayList<Actors>();

 ListView listview = (ListView) view.findViewById(R.id.list);
 ListAdapter adapter = new ActorAdapter(getActivity().getApplicationContext(), R.layout.articles, actorsList);

将在listview重新使用空白数据

3. 我建议您将onPostExecute()的数据添加到Arraylist中，然后使用该数据初始化适配器。

或者你也可以打电话

adapter.notifyDataSetChanged() in onPostExecute()