致命例外︰主，但日食並沒有顯示任何錯誤

Question

這裏是我的問題， 我在我的代碼中放了一些log.i，甚至在最後，他們都打印在logCat，這意味着它會直到結束，但一些錯誤不斷下來...

感謝您的幫助！

日誌：

08-02 13:14:11.030: I/Process(1817): Sending signal. PID: 1817 SIG: 9 
08-02 13:15:36.670: D/dalvikvm(1854): GC_FOR_ALLOC freed 36K, 4% free 6347K/6595K, paused 60ms 
08-02 13:15:36.790: I/dalvikvm-heap(1854): Grow heap (frag case) to 12.983MB for 7056016-byte allocation 
08-02 13:15:36.880: D/dalvikvm(1854): GC_FOR_ALLOC freed <1K, 3% free 13237K/13511K, paused 60ms 
08-02 13:15:37.020: D/dalvikvm(1854): GC_CONCURRENT freed <1K, 3% free 13237K/13511K, paused 4ms+3ms 
08-02 13:15:38.940: D/dalvikvm(1854): GC_CONCURRENT freed 3K, 1% free 15246K/15367K, paused 3ms+3ms 
08-02 13:15:41.521: D/dalvikvm(1854): GC_FOR_ALLOC freed 28K, 1% free 15555K/15687K, paused 59ms 
08-02 13:15:41.551: I/dalvikvm-heap(1854): Grow heap (frag case) to 17.630MB for 2499884-byte allocation 
08-02 13:15:41.701: D/dalvikvm(1854): GC_FOR_ALLOC freed <1K, 2% free 17996K/18183K, paused 59ms 
08-02 13:15:41.851: D/dalvikvm(1854): GC_CONCURRENT freed <1K, 2% free 17996K/18183K, paused 6ms+3ms 
08-02 13:15:42.712: I/log_tag(1854): ID_ville: 3, Nom_ville: Lyon 
08-02 13:15:42.712: I/log_tag(1854): ID_ville: 10, Nom_ville: Lille 
08-02 13:15:42.712: I/test tableau(1854): Lyon 
08-02 13:15:42.720: I/test 2 tableau(1854): Lille 
08-02 13:15:42.750: D/AndroidRuntime(1854): Shutting down VM 
08-02 13:15:42.750: W/dalvikvm(1854): threadid=1: thread exiting with uncaught exception (group=0x40014760) 
08-02 13:15:42.781: E/AndroidRuntime(1854): FATAL EXCEPTION: main 
08-02 13:15:42.781: E/AndroidRuntime(1854): java.lang.NullPointerException 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.widget.ArrayAdapter.createViewFromResource(ArrayAdapter.java:398) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.widget.ArrayAdapter.getView(ArrayAdapter.java:366) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.widget.AbsListView.obtainView(AbsListView.java:1949) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.widget.ListView.measureHeightOfChildren(ListView.java:1228) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.widget.ListView.onMeasure(ListView.java:1139) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.view.View.measure(View.java:10828) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:581) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:365) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.view.View.measure(View.java:10828) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4351) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.widget.FrameLayout.onMeasure(FrameLayout.java:267) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.view.View.measure(View.java:10828) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.widget.LinearLayout.measureVertical(LinearLayout.java:764) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.widget.LinearLayout.onMeasure(LinearLayout.java:519) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.view.View.measure(View.java:10828) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:4351) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.widget.FrameLayout.onMeasure(FrameLayout.java:267) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:1889) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.view.View.measure(View.java:10828) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.view.ViewRoot.performTraversals(ViewRoot.java:938) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.view.ViewRoot.handleMessage(ViewRoot.java:2040) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.os.Handler.dispatchMessage(Handler.java:99) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.os.Looper.loop(Looper.java:132) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at android.app.ActivityThread.main(ActivityThread.java:4123) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at java.lang.reflect.Method.invokeNative(Native Method) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at java.lang.reflect.Method.invoke(Method.java:491) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599) 
08-02 13:15:42.781: E/AndroidRuntime(1854):  at dalvik.system.NativeStart.main(Native Method) 
08-02 13:16:04.090: I/Process(1854): Sending signal. PID: 1854 SIG: 9 

代碼：

import android.os.Bundle; 
import android.app.Activity; 
import java.io.BufferedReader; 
import java.io.InputStream; 
import java.io.InputStreamReader; 
import java.util.ArrayList; 

import org.apache.http.HttpEntity; 
import org.apache.http.HttpResponse; 
import org.apache.http.NameValuePair; 
import org.apache.http.client.HttpClient; 
import org.apache.http.client.entity.UrlEncodedFormEntity; 
import org.apache.http.client.methods.HttpPost; 
import org.apache.http.impl.client.DefaultHttpClient; 
import org.apache.http.message.BasicNameValuePair; 
import org.json.JSONArray; 
import org.json.JSONException; 
import org.json.JSONObject; 

import android.util.Log; 
import android.widget.ArrayAdapter; 
import android.widget.ListView; 
import android.widget.TextView; 

public class MainClient extends Activity { 
TextView txt; 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main_client); 
    String[] listeStrings = new String[999]; 
    listeStrings = getServerData(strURL); 
    ListView lvListe = (ListView)findViewById(R.id.ClientList); 
    Log.i("test tableau", listeStrings[0]); 
    lvListe.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1,listeStrings)); 
    Log.i("test 2 tableau", listeStrings[1]); 
} 

public static final String strURL = "http://www.kogitus.com/test/ville.php"; 

private String[] getServerData(String returnString) { 
    InputStream is = null; 
    String result = ""; 
    String[] listeStrings = new String[999]; 
    // Envoyer la requête au script PHP. 
    // Script PHP : $sql=mysql_query("select * from tblVille where Nom_ville like '".$_REQUEST['ville']."%'"); 
    // $_REQUEST['ville'] sera remplacé par L dans notre exemple. 
    // Ce qui veut dire que la requête enverra les villes commençant par la lettre L 
    ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(); 
    nameValuePairs.add(new BasicNameValuePair("ville","L")); 

    try{ 
     HttpClient httpclient = new DefaultHttpClient(); 
     HttpPost httppost = new HttpPost(strURL); 
     httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs)); 
     HttpResponse response = httpclient.execute(httppost); 
     HttpEntity entity = response.getEntity(); 
     is = entity.getContent(); 

    }catch(Exception e){ 
     Log.e("log_tag", "Error in http connection " + e.toString()); 
    } 

    try{ 
     BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8); 
     StringBuilder sb = new StringBuilder(); 
     String line = null; 
     while ((line = reader.readLine()) != null) { 
      sb.append(line + "\n"); 
     } 
     is.close(); 
     result=sb.toString(); 
    }catch(Exception e){ 
     Log.e("log_tag", "Error converting result " + e.toString()); 
    } 

    try{ 
     JSONArray jArray = new JSONArray(result); 
     returnString = ""; 
     for(int i=0;i<jArray.length();i++){ 
      JSONObject json_data = jArray.getJSONObject(i); 
      // Affichage ID_ville et Nom_ville dans le LogCat 
      Log.i("log_tag","ID_ville: "+json_data.getInt("ID_ville")+ 
        ", Nom_ville: "+json_data.getString("Nom_ville")); 
      listeStrings[i] = json_data.getString("Nom_ville"); 
      // Résultats de la requête 
      //if (returnString == "") 
       //returnString += json_data.getString("Nom_ville"); 
      //else 
       //returnString += "\n" + jArray.getJSONObject(i); 
     } 
    }catch(JSONException e){ 
     Log.e("log_tag", "Error parsing data " + e.toString()); 
    } 
    return listeStrings; 
} 

}

和他的XML文件：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:tools="http://schemas.android.com/tools" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
android:background="@drawable/wallpaper" > 

<ImageView 
    android:id="@+id/BottomBar" 
    android:layout_width="fill_parent" 
    android:layout_height="80dp" 
    android:layout_alignParentBottom="true" 
    android:layout_alignParentLeft="true" 
    android:scaleType="fitXY" 
    android:src="@drawable/bottombar" /> 

<ImageView 
    android:id="@+id/MenuClient" 
    android:layout_width="453dp" 
    android:layout_height="620dp" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentTop="true" 
    android:scaleType="fitXY" 
    android:src="@drawable/menuclient" /> 

<ImageView 
    android:id="@+id/RightBar" 
    android:layout_width="160dp" 
    android:layout_height="620dp" 
    android:layout_alignParentRight="true" 
    android:layout_alignParentTop="true" 
    android:scaleType="fitXY" 
    android:src="@drawable/rightbar" /> 

<Button 
    android:id="@+id/BoutonBills" 
    style="@android:style/Animation.Activity" 
    android:layout_width="152dp" 
    android:layout_height="129dp" 
    android:layout_marginTop="480dp" 
    android:layout_alignParentRight="true" 
    android:background="@drawable/bills" /> 

<Button 
    android:id="@+id/BoutonProviders" 
    style="@android:style/Animation.Activity" 
    android:layout_width="152dp" 
    android:layout_height="129dp" 
    android:layout_marginTop="360dp" 
    android:layout_alignParentRight="true" 
    android:background="@drawable/providers" /> 

<Button 
    android:id="@+id/BoutonPieces" 
    style="@android:style/Animation.Activity" 
    android:layout_width="152dp" 
    android:layout_height="129dp" 
    android:layout_alignParentRight="true" 
    android:layout_alignParentTop="true" 
    android:layout_marginTop="120dp" 
    android:background="@drawable/pieces" /> 

<Button 
    android:id="@+id/BoutonTrucks" 
    style="@android:style/Animation.Activity" 
    android:layout_width="152dp" 
    android:layout_height="129dp" 
    android:layout_alignParentRight="true" 
    android:layout_marginTop="240dp"  
    android:background="@drawable/trucks" /> 

<ListView 
    android:id="@+id/ClientList" 
    android:layout_width="453dp" 
    android:layout_height="600dp" 
    android:layout_alignParentLeft="true" 
    android:layout_alignParentTop="true" > 
</ListView> 

</RelativeLayout> 

Answer 1

你有一個java.lang中。在您的代碼中的NullPointerException。確保您不訪問任何未初始化的對象。

方式：

Object myObj; 
myObj.doSomething(); 

是將提高顯示java.lang.NullPointerException

你需要這個順序：

Object myObj; 
myObj = new Object(); 
myObj.doSomething(); 

沒有代碼，我說不出哪裏發生這種情況

Answer 2

你聲明你的列表數組是這樣的：

String[] listeStrings = new String[999]; 

然後你找回這樣的服務器數據：

listeStrings = getServerData(strURL); 

我的問題是：你確定檢索列表正好包含999元服務器的數據後？

我假設getServerData()回報更少的元素比999在當你通過listeString到ArrayAdapter這種情況下，一個ArrayAdapter會嘗試從數組提取一個接一個的所有記錄，並在一段時間內它將到達元素將爲空的位置，導致NullPointerException。

解決的辦法是爲您的字符串數組分配多個位置，因爲您的JSON數組返回的元素很多。
但是，我會建議使用ArrayList而不是String[]陣列，它們是dinamically分配。