Android應用程序無法在Android 4.0上啓動

Question

好的，我正在開發一個Android應用程序，可以向您展示一些使用RSS的電視節目，新聞，Wather Forecast和星座運勢等內容。該應用程序的工作原理應該是在Android 2.1或2.3.X上，但是當我在4.0或4.1上啓動它時，在我從main中選擇任何選項後它會停止工作。

應用程序的結構是：

- 主要

-activity具體的事情（像剛纔新聞），有一個觀點

由以前的類

稱爲

-XML解析器類

-Signature View的活動（如同整條新聞中的一條信息）

這裏我提供了Manifest，L OG和幾類：

<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
package="com.mtel.vodic" 
android:versionCode="1" 
android:versionName="1.0" > 

<uses-sdk 
    android:minSdkVersion="7" 
    android:targetSdkVersion="14" /> 

<application 
    android:icon="@drawable/ic_launcher" 
    android:label="@string/app_name" 
    android:theme="@style/AppTheme" > 
    <activity 
     android:name=".Vodic" 
     android:label="@string/title_activity_pocetna" > 
     <intent-filter> 
      <action android:name="android.intent.action.MAIN" /> 

      <category android:name="android.intent.category.LAUNCHER" /> 
     </intent-filter> 
    </activity> 

    <activity 
     android:name=".Pomoc" 
     android:label="@string/m_tel_vodi_za_odlu_ne" 
     ></activity> 
    <activity 
     android:name=".Pomocna" 
     android:label="@string/m_tel_vodi_za_odlu_ne" 
     ></activity> 
    <activity 
     android:name=".SingleMenuItemActivity" 
     android:label="@string/m_tel_vodi_za_odlu_ne" 
     ></activity> 
    . 
    . 
    . 

</application> 

<uses-permission android:name="android.permission.INTERNET" /> 

<!-- Needed to check when the network connection changes --> 
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/> 
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/> 

</manifest> 

錯誤日誌：

10-18 20:35:05.457: E/Trace(730): error opening trace file: No such file or directory  (2) 
10-18 20:35:06.197: I/Choreographer(730): Skipped 30 frames! The application may be doing too much work on its main thread. 
10-18 20:35:06.257: D/gralloc_goldfish(730): Emulator without GPU emulation detected. 
10-18 20:35:11.316: D/AndroidRuntime(730): Shutting down VM 
10-18 20:35:11.316: W/dalvikvm(730): threadid=1: thread exiting with uncaught exception (group=0x40a13300) 
10-18 20:35:11.347: E/AndroidRuntime(730): FATAL EXCEPTION: main 
10-18 20:35:11.347: E/AndroidRuntime(730): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.mtel.vodic/com.mtel.vodic.Vijesti}: java.lang.NullPointerException 
10-18 20:35:11.347: E/AndroidRuntime(730): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059) 
10-18 20:35:11.347: E/AndroidRuntime(730): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084) 
10-18 20:35:11.347: E/AndroidRuntime(730): at android.app.ActivityThread.access$600(ActivityThread.java:130) 
10-18 20:35:11.347: E/AndroidRuntime(730): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195) 
10-18 20:35:11.347: E/AndroidRuntime(730): at android.os.Handler.dispatchMessage(Handler.java:99) 
10-18 20:35:11.347: E/AndroidRuntime(730): at android.os.Looper.loop(Looper.java:137) 
10-18 20:35:11.347: E/AndroidRuntime(730): at android.app.ActivityThread.main(ActivityThread.java:4745) 
10-18 20:35:11.347: E/AndroidRuntime(730): at java.lang.reflect.Method.invokeNative(Native Method) 
10-18 20:35:11.347: E/AndroidRuntime(730): at java.lang.reflect.Method.invoke(Method.java:511) 
10-18 20:35:11.347: E/AndroidRuntime(730): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 
10-18 20:35:11.347: E/AndroidRuntime(730): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
10-18 20:35:11.347: E/AndroidRuntime(730): at dalvik.system.NativeStart.main(Native Method) 
10-18 20:35:11.347: E/AndroidRuntime(730): Caused by: java.lang.NullPointerException 
10-18 20:35:11.347: E/AndroidRuntime(730): at com.mtel.vodic.Vijesti.onCreate(Vijesti.java:61) 
10-18 20:35:11.347: E/AndroidRuntime(730): at android.app.Activity.performCreate(Activity.java:5008) 
10-18 20:35:11.347: E/AndroidRuntime(730): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079) 
10-18 20:35:11.347: E/AndroidRuntime(730): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023) 
10-18 20:35:11.347: E/AndroidRuntime(730): ... 11 more 
10-18 20:35:13.926: I/Process(730): Sending signal. PID: 730 SIG: 9 

主營：

public class Vodic extends Activity { 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_pocetna); 
    Button tv = (Button)findViewById(R.id.tv); 
    Button vijesti = (Button)findViewById(R.id.vijesti); 
    Button horoskop = (Button)findViewById(R.id.horoskop); 
    Button vremenska_prognoza = (Button)findViewById(R.id.vremenska_prognoza); 
    Button o_aplikaciji = (Button)findViewById(R.id.o_aplikaciji); 
    Button pomoc = (Button)findViewById(R.id.pomoc); 

    . 
    . 
    . 

    vijesti.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View arg0) { 
      Intent xw = new Intent(getApplicationContext(), Vijesti.class); 
      //xw.putExtra("A", "http://bih-x.info/feed/"); 
      xw.putExtra("A", "http://klix.ba/rss/naslovnica"); 
      if(!isOnline()) { 
       Toast.makeText(getApplicationContext(), "Niste povezani sa internetom!", Toast.LENGTH_SHORT).show(); 
      } else { 
       startActivity(xw); 
      } 
     } 
    }); 

    . 
    . 
    . 

public boolean isOnline() { 
    ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE); 
    NetworkInfo netInfo = cm.getActiveNetworkInfo(); 
    if(netInfo != null && netInfo.isConnected()) { 
     return true; 
    } 
    return false; 
} 
} 

活動：

public class Vijesti extends ListActivity { 

static String url =null; 

// XML node keys 
static final String KEY_ITEM = "item"; // parent node 
static final String KEY_TITLE = "title"; 
static final String KEY_DATE = "pubDate"; 
static final String KEY_DESC = "encoded"; 
static final String UVOD = "uvod"; 
static final String CLANAK = "clanak"; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 
    // TODO Auto-generated method stub 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.vijesti_m); 
    Intent in = getIntent(); 

    // Get XML values from previous intent 
    url = in.getStringExtra("A"); 
    final ArrayList<HashMap<String,String>> menuItems = new ArrayList<HashMap<String,String>>(); 
    ArrayList<String> xqw = new ArrayList<String>(); 

    ParserVijesti parser=null; 
    Document doc=null; 
    try { 
     parser = new ParserVijesti(); 
     String xml = parser.getXmlFromUrl(url); //get XML 
     doc = parser.getDomElement(xml); 
    } catch (Exception e1) { 
     finish(); 
    } 

    NodeList nl = doc.getElementsByTagName(KEY_ITEM); 
    //loop 
    for (int i=0; i< nl.getLength(); i++){ 
     HashMap<String, String> map = new HashMap<String, String>(); 
     HashMap<String, String> mapq = new HashMap<String, String>(); 

     Element e = (Element) nl.item(i); 

     //add to map 
     map.put(KEY_TITLE, parser.getValue(e, KEY_TITLE)); 
     map.put(KEY_DATE, parser.getValue(e, KEY_DATE)); 
     map.put(UVOD, parser.getValue(e,UVOD)); 
     map.put(CLANAK, parser.getValue(e,CLANAK)); 


     menuItems.add(map); 

     xqw.add(parser.getValue(e,KEY_TITLE)); 
    } 

    for(int gf=0; gf<xqw.size(); gf++){ 
     Log.w("ISPISI: ", xqw.get(gf)); 
    } 
    ArrayAdapter adapterx = new ArrayAdapter(this, R.layout.vijesti_m,R.id.tetkica, xqw); 


    setListAdapter(adapterx); 

    //singleView 
    ListView lv = getListView(); 

    lv.setOnItemClickListener(new OnItemClickListener(){ 
     @Override 
     public void onItemClick(AdapterView<?> parent, View view, int position, long id){ 

      int hg = position; 
      HashMap<String, String> kaktus = menuItems.get(hg); 
      String uvod1 = kaktus.get(UVOD); 
      String clanak1 = kaktus.get(CLANAK); 
      String dat1 = kaktus.get(KEY_DATE); 
      String tit1 = kaktus.get(KEY_TITLE); 



      //intent 
      Intent inx = new Intent(getApplicationContext(), VijestiSingle.class); 
      inx.putExtra(KEY_TITLE, tit1); 
      inx.putExtra(KEY_DATE, dat1); 
      inx.putExtra(UVOD, uvod1); 
      inx.putExtra(CLANAK, clanak1); 
      startActivity(inx); 
     } 
    }); 


} 

} 

XML解析類：

public class ParserVijesti { 




// constructor 
public ParserVijesti() { 

} 

/** 
* Getting XML from URL making HTTP request 
* @param url string 
* */ 
public String getXmlFromUrl(String url) { 
    String xml = null; 

    try { 
     // defaultHttpClient 
     DefaultHttpClient httpClient = new DefaultHttpClient(); 
     HttpPost httpPost = new HttpPost(url); 

     HttpResponse httpResponse = httpClient.execute(httpPost); 
     HttpEntity httpEntity = httpResponse.getEntity(); 
     xml = EntityUtils.toString(httpEntity, "UTF-8"); 

    } catch (UnsupportedEncodingException e) { 
     e.printStackTrace(); 
    } catch (ClientProtocolException e) { 
     e.printStackTrace(); 
    } catch (IOException e) { 
     e.printStackTrace(); 
    } 
    // return XML 
    return xml; 
} 
/** 
* Getting XML DOM element 
* @param XML string 
* */ 

public Document getDomElement(String xml){ 
    Document doc = null; 
    DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance(); 
    dbf.setCoalescing(true); 
    dbf.setNamespaceAware(true); 
    try { 
     DocumentBuilder db = dbf.newDocumentBuilder(); 

     InputSource is = new InputSource(); 
     is.setByteStream(new ByteArrayInputStream(xml.getBytes("UTF-8"))); 
      doc = db.parse(is); 

     } catch (ParserConfigurationException e) { 
      Log.e("Error: ", e.getMessage()); 
      return null; 
     } catch (SAXException e) { 
      Log.e("Error: ", e.getMessage()); 
      return null; 
     } catch (IOException e) { 
      Log.e("Error: ", e.getMessage()); 
      return null; 
     } 

     return doc; 
} 

/** Getting node value 
    * @param elem element 
    */ 
public final String getElementValue(Node elem) { 
    Node child; 
    if(elem != null){ 
     if (elem.hasChildNodes()){ 
      for(child = elem.getFirstChild(); child != null; child = child.getNextSibling()){ 
       if(child.getNodeType() == Node.TEXT_NODE || child.getNodeType() == Node.CDATA_SECTION_NODE){ 
        return child.getNodeValue(); 
       } 
      } 
     } 
    } 
    return ""; 
} 

public final String getElementValue2(Node elem) { 
    Node child; 
    if(elem != null){ 
     if (elem.hasChildNodes()){ 
      for(child = elem.getFirstChild(); child != null; child = child.getNextSibling()){ 
       if(child.getNodeType() == Node.CDATA_SECTION_NODE){ 
        return child.getNodeValue(); 
       } 
      } 
     } 
    } 
    return "SRANJE"; 
} 

/** 
    * Getting node value 
    * @param Element node 
    * @param key string 
    * */ 



public String getValue(Element item, String str) {  
     NodeList n = item.getElementsByTagName(str);     
     return this.getElementValue(n.item(0)); 
    } 


public String getValue3(Element item, String str){ 
    NodeList n = item.getElementsByTagNameNS("http://purl.org/rss/1.0/modules/content/", str); 
    String ses = this.getElementValue2(n.item(0)); 

    //String mim =ses.replaceAll("(?s)\\<.*?\\>", " \n"); 
    String html = ses; 
    Spanned strxa = Html.fromHtml(html); 
    String fffx=strxa.toString(); 

    //return this.getElementValue2(n.item(0)); 
    //return ses; 
    //return Promjena(ses); 
    return fffx; 
} 


} 

總結：應用程序可以在2.1或2.3.x上正常運行，但在Android 4.0或4.1的主要活動中選擇任何內容後，應用程序將停止運行。我不知道這是怎麼回事。任何人都可以幫忙嗎？

Answer 1

這不會解決你原來的問題，而是：

我覺得這是您有一個問題：你是用高於你已經測試並確認您的應用程序針對工作targetSdkVersion發佈應用程序。

你有targetSdkVersion設置爲14，但是如果你這樣說的：

Android Min SDK Version vs. Target SDK Version

你就會明白，設置targetSdkVersion到14意味着你告訴Android的「我已經測試我的應用程序的API 14並確認它正在工作，請禁用所有兼容性設置，版本低於API 14「。

但事實並非如此，事實證明相反，該應用程序不適用於4.0！

如果設置targetSdkVersion至14這將使它正常使用，確保所有應用對老年人的API工作（FI GPU渲染，JNI改變）

所以現在你應該剛剛成立的minSdkVersion和Android 4.0禁用兼容性設置當您發佈您的應用時，請勿使用targetSdkVersion，以便在4.0中保持兼容性行爲的可用性。

只有在修復了原始錯誤並針對API 14測試了應用程序之後，纔將targetSdkVersion升至14。

Answer 2

根據日誌，你得到一個空指針Vijesti.java:61。你說這條線是：

NodeList nl = doc.getElementsByTagName(KEY_ITEM); 

這意味着doc必須爲空。既然你用getDomElement()來指定它，這意味着你的問題在於這個方法。我看到它可能爲空的唯一方法（因爲DocumentBuilder.parse()不能返回空值）是如果你正在擊中你的catch陳述之一。

您是否在logcat中獲得了catch異常消息？您顯示的部分僅列出了由空指針產生的實際錯誤。你的消息可能會在那之前。檢查一下，你就可以知道你得到了哪個異常，並相應地處理它。