Android執行完美，但不顯示任何東西

我試圖解析一個JSON對象的幫助下（本軟件包http://www.youtube.com/watch?v=0Lr37suTPpg）的幫助。我一步一步地按照說明操作，並設法得到了工作的例子。但是，當我修改示例以使用我自己的json對象時，雖然沒有錯誤，但模擬器只顯示空白屏幕。Android執行完美，但不顯示任何東西

請記住，我的json對象是匿名的（請參閱下面的鏈接）不像這個例子。我已經在代碼中對這個問題做了一些修改，但是我不確定它們。無論如何，我一直無法找出問題的原因，所以我想請求你的幫助。下面是我的代碼（3個java文件和2個xml），下面是這個例子的代碼（顯然也是3個java和2個xml）。

Sights.java（又名MainActivity.java /同樣在這裏是JSON對象的鏈接）

package com.example.thodoras.jsontutorialtest; 

import android.app.Activity; 
import android.os.AsyncTask; 
import android.os.Bundle; 
import android.widget.ListView; 

import org.apache.http.HttpEntity; 
import org.apache.http.HttpResponse; 
import org.apache.http.client.HttpClient; 
import org.apache.http.client.methods.HttpPost; 
import org.apache.http.impl.client.DefaultHttpClient; 
import org.apache.http.util.EntityUtils; 
import org.json.JSONArray; 
import org.json.JSONException; 
import org.json.JSONObject; 

import java.io.IOException; 
import java.util.ArrayList; 


public class Sights extends Activity { 

ListView list; 
SightsAdapter adapter; 
ArrayList<HelperSights> sightsList; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_sights); 

    list = (ListView) findViewById(R.id.list); 
    sightsList = new ArrayList<HelperSights>(); 

    new SightsAsyncTask().execute("http://www.escapeguide.gr/en/rest/views/mobile_listings.json?display_id=sights_service"); 
} 

public class SightsAsyncTask extends AsyncTask<String, Void, Boolean> { 

    @Override 
    protected Boolean doInBackground(String... params) { 


     try { 

      HttpClient client = new DefaultHttpClient(); 
      HttpPost post = new HttpPost(params[0]); 
      HttpResponse response = client.execute(post); 
      int status = response.getStatusLine().getStatusCode(); 
      if (status == 200) { 

       HttpEntity entity = response.getEntity(); 
       String data = EntityUtils.toString(entity); 
       JSONArray array = new JSONArray(data); 

       for (int i = 0; i < array.length(); i++) { 

        HelperSights sights = new HelperSights(); 

        JSONObject obj = array.getJSONObject(i); 


        sights.setImage(obj.getString("cover image")); 
        sights.setTitle(obj.getString("title")); 
        sights.setLocation(obj.getString("location")); 

        sightsList.add(sights); 
       } 

       return true; 
      } 

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

     return false; 
    } 


    @Override 
    protected void onPostExecute(Boolean result) { 
     super.onPostExecute(result); 

     if (result == false) { 
      //something 
     } else { 
      SightsAdapter adapter = new SightsAdapter(getApplicationContext(), R.layout.row, sightsList); 
      list.setAdapter(adapter); 
     } 
    } 

} 

} 

package com.example.thodoras.jsontutorialtest;

HelperSights.java（包含吸氣劑設置器）

public class HelperSights { 

private String image; 
private String title; 
private String location; 

public HelperSights(){ 

} 

public String getImage() { 
    return image; 
} 

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

public String getTitle() { 
    return title; 
} 

public void setTitle(String title) { 
    this.title = title; 
} 

public String getLocation() { 
    return location; 
} 

public void setLocation(String location) { 
    this.location = location; 
} 
}

SightsAdapter.java

p ackage com.example.thodoras.jsontutorialtest;

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 java.io.InputStream; 
import java.util.ArrayList; 


public class SightsAdapter extends ArrayAdapter<HelperSights> { 

ArrayList<HelperSights> ArrayListSights; 
int Resource; 
Context context; 
LayoutInflater vi; 

public SightsAdapter(Context context, int resource, ArrayList<HelperSights> objects) { 
    super(context, resource, objects); 

    ArrayListSights = objects; 
    Resource = resource; 
    this.context = context; 
    vi = (LayoutInflater) context.getSystemService(context.LAYOUT_INFLATER_SERVICE); 
} 

@Override 
public View getView(int position, View convertView, ViewGroup parent) { 

    ViewHolder holder; 

    if(convertView == null){ 
     convertView = vi.inflate(Resource, null); 
     holder = new ViewHolder(); 
     holder.sImage = (ImageView)convertView.findViewById(R.id.sImage); 
     holder.sTitle = (TextView)convertView.findViewById(R.id.sTitle); 
     holder.sLocation = (TextView)convertView.findViewById(R.id.sLocation); 

     convertView.setTag(holder); 
    } else { 
     holder = (ViewHolder)convertView.getTag(); 
    } 

    new DownloadImageTask(holder.sImage) 
    .execute(ArrayListSights.get(position).getImage()); 
    holder.sTitle.setText(ArrayListSights.get(position).getTitle()); 
    holder.sLocation.setText(ArrayListSights.get(position).getLocation()); 

    return convertView; 

} 

static class ViewHolder{ 

    public ImageView sImage; 
    public TextView sTitle; 
    public TextView sLocation; 

} 

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); 
    } 

} 
}

activity_sights.xml

<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="match_parent" 
android:orientation="vertical" android:background="#F1F1F1" 
tools:context=".MainActivity" > 

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

</ListView> 

</LinearLayout>

row.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:id="@+id/LinearLayout1" 
android:layout_height="match_parent"> 

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

    <ImageView 
     android:layout_width="100dp" 
     android:layout_height="100dp" 
     android:id="@+id/sImage" 
     android:scaleType="fitXY" 
     android:src="@drawable/ic_launcher"/> 

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

     <TextView 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:id="@+id/sTitle" 
      android:text="Yo 
      "/> 

     <TextView 
      android:layout_width="wrap_content" 
      android:layout_height="wrap_content" 
      android:id="@+id/sLocation" 
      android:text="Man"/> 

     </LinearLayout> 


    </LinearLayout> 

    </LinearLayout>

下面是成功的例子，可以幫助你比較的文件。

MainActivity.java（包含JSON對象的鏈接）

package com.example.thodoras.jsontutorail; 

import android.app.Activity; 
import android.os.AsyncTask; 
import android.os.Bundle; 
import android.widget.ListView; 

import org.apache.http.HttpEntity; 
import org.apache.http.HttpResponse; 
import org.apache.http.client.HttpClient; 
import org.apache.http.client.methods.HttpPost; 
import org.apache.http.impl.client.DefaultHttpClient; 
import org.apache.http.util.EntityUtils; 
import org.json.JSONArray; 
import org.json.JSONException; 
import org.json.JSONObject; 

import java.io.IOException; 
import java.util.ArrayList; 


public class MainActivity extends Activity { 

ListView list; 
ActorsAdapter adapter; 
ArrayList<Actors> actorsList; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 

    list = (ListView) findViewById(R.id.list); 
    actorsList = new ArrayList<Actors>(); 

    new ActorAsyncTask() 
.execute("http://microblogging.wingnity.com/JSONParsingTutorial/jsonActors"); 
} 

public class ActorAsyncTask extends AsyncTask<String, Void, Boolean>{ 

    @Override 
    protected Boolean doInBackground(String... params) { 


     try { 
      HttpClient client = new DefaultHttpClient(); 
      HttpPost post = new HttpPost(params[0]); 
      HttpResponse response = client.execute(post); 
      int status = response.getStatusLine().getStatusCode(); 
      if (status == 200) { 
       HttpEntity entity = response.getEntity(); 
       String data = EntityUtils.toString(entity); 
       JSONObject jObj = new JSONObject(data); 
       JSONArray jArray = jObj.getJSONArray("actors"); 

       for (int i = 0; i < jArray.length(); i++) { 

        Actors actor = new Actors(); 

        JSONObject jRealObject = jArray.getJSONObject(i); 

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

        actorsList.add(actor); 

       } 

       return true; 
      } 

     } catch (IOException e) { 
      e.printStackTrace(); 
     } catch (JSONException e) { 
      e.printStackTrace(); 
     } 
     return false; 
    } 

    @Override 
    protected void onPostExecute(Boolean result) { 
     super.onPostExecute(result); 

     if(result == false){ 
      finish(); 
     } else { 
      ActorsAdapter adapter = new ActorsAdapter 
      (getApplicationContext(),R.layout.row, actorsList); 
      list.setAdapter(adapter); 
     } 
    } 
} 
}

Actors.java（類似於HelperSights.java）

package com.example.thodoras.jsontutorail; 



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(){ 

} 

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; 
} 
}

ActorsAdapter.java

package com.example.thodoras.jsontutorail; 

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 java.io.InputStream; 
import java.util.ArrayList; 


public class ActorsAdapter extends ArrayAdapter<Actors> { 

ArrayList<Actors> ArrayListActors; 
int Resource; 
Context context; 
LayoutInflater vi; 

public ActorsAdapter(Context context, int resource, ArrayList<Actors> objects) { 
    super(context, resource, objects); 

    ArrayListActors = objects; 
    Resource = resource; 
    this.context = context; 

    vi = (LayoutInflater) context.getSystemService(context.LAYOUT_INFLATER_SERVICE); 

} 

@Override 
public View getView(int position, View convertView, ViewGroup parent) { 

    ViewHolder holder; 

    if(convertView == null) { 
     convertView = vi.inflate(Resource, null); 
     holder = new ViewHolder(); 
     holder.tvName = (TextView)convertView.findViewById(R.id.tvName); 
     holder.tvDescription = (TextView)convertView.findViewById(R.id.tvDescriptionn); 
     holder.tvDob = (TextView)convertView.findViewById(R.id.tvDateOfBirth); 
     holder.tvCountry = (TextView)convertView.findViewById(R.id.tvCountry); 
     holder.tvHeight = (TextView)convertView.findViewById(R.id.tvHeight); 
     holder.tvSpouse = (TextView)convertView.findViewById(R.id.tvSpouse); 
     holder.tvChildren = (TextView)convertView.findViewById(R.id.tvChildren); 
     holder.imageView = (ImageView)convertView.findViewById(R.id.ivImage); 

     convertView.setTag(holder); 
    } 

    else { 
     holder = (ViewHolder)convertView.getTag(); 
    } 

    new DownloadImageTask(holder.imageView) 
    .execute(ArrayListActors.get(position).getImage()); 
    holder.tvName.setText(ArrayListActors.get(position).getName()); 
    holder.tvDescription.setText(ArrayListActors.get(position).getDescription()); 
    holder.tvDob.setText(ArrayListActors.get(position).getDob()); 
    holder.tvCountry.setText(ArrayListActors.get(position).getCountry()); 
    holder.tvHeight.setText(ArrayListActors.get(position).getHeight()); 
    holder.tvSpouse.setText(ArrayListActors.get(position).getSpouse()); 
    holder.tvChildren.setText(ArrayListActors.get(position).getChildren()); 

    return convertView; 
} 

static class ViewHolder{ 

    public TextView tvName; 
    public TextView tvDescription; 
    public TextView tvDob; 
    public TextView tvCountry; 
    public TextView tvHeight; 
    public TextView tvSpouse; 
    public TextView tvChildren; 
    public ImageView imageView; 
} 

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); 
    } 

} 
}

activity_main.xml中

<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="match_parent" 
android:orientation="vertical" android:background="#F1F1F1" 
tools:context=".MainActivity" > 

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

</ListView> 

</LinearLayout>

行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/ic_launcher" /> 

    <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>

來源

2014-09-19 Theodore

在原有例如Web服務是建立在一個不同的方式。

您應該在您的SightsAsyncTask中使用HttpGet向服務器請求數據。

此外，我建議你使用HttpUrlConnection而不是DefaultHttpClient。的請求來獲取數據將是這樣的：

URL url = new URL("http://www.escapeguide.gr/en/rest/views/mobile_listings.json?display_id=sights_service"); 
HttpURLConnection connection = (HttpURLConnection) url.openConnection(); 
int status = connection.getResponseCode(); 
if (status == HttpURLConnection.HTTP_OK) { 
    InputStream is = new BufferedInputStream(connection.getInputStream()); 
    ByteArrayBuffer buffer = new ByteArrayBuffer(4096); 
    int byteCount = 0; 
    byte[] bytes = new byte[4096]; 
    do buffer.append(bytes, 0, byteCount); while ((byteCount = is.read(bytes)) != -1); 
} 
JSONArray array = new JSONArray(new String(buffer));

注：上面的實現讀取輸入流以一個字節數組。但是，由於服務器響應的ContentType是文本（JSON），因此可以將其讀取到String或StringBuilder。讀取到字節數組可以用作通用解決方案，以請求以不同格式返回數據（如PDF文件）

來源

2014-09-19 22:49:32

非常感謝！ HttpGet而不是HttpPost就足夠了。當我有更多時間時，我會仔細研究其餘的建議。現在，說實話，我並不完全理解我應該在哪裏實現您提供的代碼，以及我應該刪除哪些代碼。 – Theodore 2014-09-20 12:30:56

Android執行完美，但不顯示任何東西

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