CODEWITHSUNDEEP
androidandroid-manifestgoogle-play
user588132
user588132

Reputation: 475

Problem with first installation of android application from android market

I am accessing the internet to get information. The app is force closing when i m accessing the internet.If the app is deleted and re-installed it does not force close when i m accesing the internet .This is happening the first time the app is installed. Please help me figure this out.

This is the stack trace -

java.lang.RuntimeException: Unable to start activity ComponentInfo{ListOfDealSites}: java.lang.NullPointerException
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
at android.app.ActivityThread.access$2300(ActivityThread.java:125)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:123)
at android.app.ActivityThread.main(ActivityThread.java:4627)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:521)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:858)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at java.io.DataInputStream.readLine(DataInputStream.java:309)
at ListOfDealSites.onCreate(ListOfDealSites.java:53)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2627)
... 11 more

It also says source method - DataInputStream.readLine()

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.dealsites);

    InputStream in = null;
    try {
        // Connect to the server to get the list of deal sites
        in = OpenHttpConnection("Link to deal server");
        } 
    catch (IOException e1) {

        // TODO Auto-generated catch block          
        e1.printStackTrace();
    }

    try {

              DataInputStream dataIO = new DataInputStream(in);
        String strLine = null;
        int i = 0;

        while((strLine = dataIO.readLine())!= null) // Line 53------
        {
            count = i;
            NEWDEALSITES[i++] = strLine;

        }

        dataIO.close();
        in.close();
   } 
   catch (IOException e){ 

    // TODO Auto-generated catch block
    e.printStackTrace();
   }

   count_deals = count/2;
   newdeals = new String[count_deals+1];
   newsites = new String[count_deals+1];
   int j, k;
   for(j = 0, k = 0; k < count; j++)
   {
       newdeals[j] = NEWDEALSITES[k++];
       newsites[j] = NEWDEALSITES[k++];

   }

   listOfDealSites = (ListView)findViewById(R.id.ListView01);
   listOfDealSites.setAdapter(new ArrayAdapter<String>(this,R.layout.row,newdeals));



}

//Function to connect to the server.
private InputStream OpenHttpConnection(String urlString) 
throws IOException
{
    InputStream in = null;
    int response = -1;

    URL url = new URL(urlString); 
    URLConnection conn = url.openConnection();

    if (!(conn instanceof HttpURLConnection))                     
        throw new IOException("Not an HTTP connection");

    try{
        HttpURLConnection httpConn = (HttpURLConnection) conn;
        httpConn.setAllowUserInteraction(false);
        httpConn.setInstanceFollowRedirects(true);
        httpConn.setRequestMethod("GET");
        httpConn.connect(); 

        response = httpConn.getResponseCode();                 
        if (response == HttpURLConnection.HTTP_OK) {
            in = httpConn.getInputStream();                                 
        }                     
    }
    catch (Exception ex)
    {
        throw new IOException("Error connecting");            
    }
    return in;     
}

}

Upvotes: 1

Views: 230

Answers (2)

user588132
user588132

Reputation: 475

The problem was caused because of no internet connection. I caught the exception and I am giving out a message to check the connection.

Thank you all for your help.

Upvotes: 0

Squonk
Squonk

Reputation: 48871

For some reason, OpenHttpConnection is returning null which basically means you're not getting an OK response here...

response = httpConn.getResponseCode();                 
if (response == HttpURLConnection.HTTP_OK) {
    in = httpConn.getInputStream();                                 
}

This means that dataIO will be invalid when you're trying to read data on line 53.

From the DataInputStream constructor docs...

public DataInputStream (InputStream in) Since: API Level 1

Constructs a new DataInputStream on the InputStream in.

All reads are then filtered through this stream. Note that data read by this stream is not in a human readable format and was most likely created by a DataOutputStream.

Warning: passing a null source creates an invalid DataInputStream. All operations on such a stream will fail.

Not sure what would be causing this or how to fix it but you definitely need to check for a null result returned from OpenHttpConnection before trying to use the 'in' InputStream for creating your DataInputStream.

Upvotes: 1

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