Android Application Crashes when Creating custom class object - java

I'm working on my first android app and I'm having trouble creating an object of a class I have programmed in java using the onCreate function of an activity. The activity starts great when I do not instantiate the object, but when I attempt to create the object the app crashes when switching to the activity. The onCreate function looks like this...
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_entry);
// Show the Up button in the action bar.
setupActionBar();
ForceTable testTable = new ForceTable();
Double factor = testTable.returnValue(forceTypes.newtons, forceTypes.newtons);
}
ForceTable is the class I have programmed, its code looks this...
public class ForceTable {
private double[][] forceTable;
protected enum forceTypes {newtons(0), pounds(1), kilopond(2);
public int num;
private forceTypes(int num)
{
this.num = num;
}
};
protected final class values{
private final static double zeroZero = 1.00;
private final static double zeroOne = 4.44872162;
private final static double zeroTwo = 9.80665;
private final static double oneZero = .224808943;
private final static double oneOne = 1.00;
private final static double oneTwo = 2.20462262;
private final static double twoZero = .10197164;
private final static double twoOne = .45359237;
private final static double twoTwo = 1.00;
}
public ForceTable()
{
this.makeTable();
}
private void makeTable()
{
forceTable[0][0] = values.zeroZero;
forceTable[0][1] = values.zeroOne;
forceTable[0][2] = values.zeroTwo;
forceTable[1][0] = values.oneZero;
forceTable[1][1] = values.oneOne;
forceTable[1][2] = values.oneTwo;
forceTable[2][0] = values.twoZero;
forceTable[2][1] = values.twoOne;
forceTable[2][2] = values.twoTwo;
}
public double returnValue(forceTypes ifYouHave, forceTypes thenYouHave){
double factor = forceTable[thenYouHave.num][ifYouHave.num];
return factor;
}
}
It's been a very long time since I have programmed in Java, and since the activity starts fine without instantiating it must be my Java code for ForceTable. Anybody notice something wrong? There's a good chance it's something easy that I'm not brushed up on...
Here is the logcat
08-08 18:08:13.206: E/(9801): : Can't open file for reading
08-08 18:08:13.206: E/(9801): : Can't open file for reading
08-08 18:10:34.045: W/dalvikvm(9801): threadid=1: thread exiting with uncaught exception (group=0x4136b438)
08-08 18:10:34.045: E/AndroidRuntime(9801): FATAL EXCEPTION: main
08-08 18:10:34.045: E/AndroidRuntime(9801): java.lang.RuntimeException: Unable to start activity ComponentInfo{khandy.application.convertible/khandy.application.convertible.EntryActivity}: java.lang.NullPointerException
08-08 18:10:34.045: E/AndroidRuntime(9801): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2110)
08-08 18:10:34.045: E/AndroidRuntime(9801): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2135)
08-08 18:10:34.045: E/AndroidRuntime(9801): at android.app.ActivityThread.access$700(ActivityThread.java:143)
08-08 18:10:34.045: E/AndroidRuntime(9801): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1241)
08-08 18:10:34.045: E/AndroidRuntime(9801): at android.os.Handler.dispatchMessage(Handler.java:99)
08-08 18:10:34.045: E/AndroidRuntime(9801): at android.os.Looper.loop(Looper.java:137)
08-08 18:10:34.045: E/AndroidRuntime(9801): at android.app.ActivityThread.main(ActivityThread.java:4950)
08-08 18:10:34.045: E/AndroidRuntime(9801): at java.lang.reflect.Method.invokeNative(Native Method)
08-08 18:10:34.045: E/AndroidRuntime(9801): at java.lang.reflect.Method.invoke(Method.java:511)
08-08 18:10:34.045: E/AndroidRuntime(9801): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1004)
08-08 18:10:34.045: E/AndroidRuntime(9801): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:771)
08-08 18:10:34.045: E/AndroidRuntime(9801): at dalvik.system.NativeStart.main(Native Method)
08-08 18:10:34.045: E/AndroidRuntime(9801): Caused by: java.lang.NullPointerException
08-08 18:10:34.045: E/AndroidRuntime(9801): at khandy.application.convertible.ForceTable.makeTable(ForceTable.java:34)
08-08 18:10:34.045: E/AndroidRuntime(9801): at khandy.application.convertible.ForceTable.(ForceTable.java:29)
08-08 18:10:34.045: E/AndroidRuntime(9801): at khandy.application.convertible.EntryActivity.onCreate(EntryActivity.java:21)
08-08 18:10:34.045: E/AndroidRuntime(9801): at android.app.Activity.performCreate(Activity.java:5179)
08-08 18:10:34.045: E/AndroidRuntime(9801): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
08-08 18:10:34.045: E/AndroidRuntime(9801): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2074)
08-08 18:10:34.045: E/AndroidRuntime(9801): ... 11 more


You probably get a NullPointerException at this line
forceTable[0][0] = values.zeroZero;
because you try to access the array without creating it first. Before accessing it, create it like that
forceTable = new double[][];
forceTable[0][0] = values.zeroZero;
And please ALWAYS post the logcat output! It just makes it so much easier to find the problem.


I think the problem is when your makeTable function is called. can you allocate space for your forceTable array.. I mean do a new for double[][] forceTable;


You are missing
privatetable = new double[n] [m] ;
You can put it in the constructor of the second class!

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08-05 11:27:34.530: E/AndroidRuntime(8158): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
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Using Picasso Lib:
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10-26 09:16:15.831: E/AndroidRuntime(280): FATAL EXCEPTION: main
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10-26 09:16:15.831: E/AndroidRuntime(280): at android.view.View.performClick(View.java:2408)
10-26 09:16:15.831: E/AndroidRuntime(280): at android.view.View$PerformClick.run(View.java:8816)
10-26 09:16:15.831: E/AndroidRuntime(280): at android.os.Handler.handleCallback(Handler.java:587)
10-26 09:16:15.831: E/AndroidRuntime(280): at android.os.Handler.dispatchMessage(Handler.java:92)
10-26 09:16:15.831: E/AndroidRuntime(280): at android.os.Looper.loop(Looper.java:123) 10-26 09:16:15.831: E/AndroidRuntime(280): at android.app.ActivityThread.main(ActivityThread.java:4627)
10-26 09:16:15.831: E/AndroidRuntime(280): at java.lang.reflect.Method.invokeNative(Native Method) 10-26 09:16:15.831: E/AndroidRuntime(280): at java.lang.reflect.Method.invoke(Method.java:521)

Try this...!
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int decimal = 0;
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int tmp = binary%10;
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System.out.println("110 ===> "+bd.getDecimalFromBinary(110));
System.out.println("100110 ===> "+bd.getDecimalFromBinary(100110));
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08-08 09:19:57.087: E/AndroidRuntime(2772): FATAL EXCEPTION: main
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08-08 09:19:57.087: E/AndroidRuntime(2772): ... 11 more
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08-08 09:19:57.087: E/AndroidRuntime(2772): ... 14 more
there is my logcat. i can't find the error . here is my java code
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TextView textViewTime;
ImageView img;
int cont=0;
private int mCounter = 0;
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super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.jugar);
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nextButton.setOnClickListener(this);
updateCounter();
}
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mSwitcher.setText(String.valueOf(mCounter));
}
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TextView t = new TextView(this);
t.setGravity(Gravity.TOP | Gravity.CENTER_HORIZONTAL);
t.setTextSize(36);
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int current = getRequestedOrientation();
// only switch the orientation if not in portrait
if ( current != ActivityInfo.SCREEN_ORIENTATION_PORTRAIT ) {
setRequestedOrientation( ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
}
}
public void lanzarJugar(View v) {
}
#Override
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mCounter=0;
mSwitcher.setText(String.valueOf(mCounter));
final CounterClass timer = new CounterClass(60000, 1000);
timer.start();
ImageView img= (ImageView) findViewById(R.id.imageView1);
int rando = (int) (Math.random() * 125);
Drawable d = getResources().getDrawable(a[rando]);
img.setImageDrawable(d);
}
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ImageView img= (ImageView) findViewById(R.id.imageView1);
int rando = (int) (Math.random() * 125);
Drawable d = getResources().getDrawable(a[rando]);
img.setImageDrawable(d);
}
public void okButton(View v) {
ImageView img= (ImageView) findViewById(R.id.imageView1);
int rando = (int) (Math.random() * 125);
Drawable d = getResources().getDrawable(a[rando]);
img.setImageDrawable(d);
mCounter++;
updateCounter();
cont++;
}
#TargetApi(Build.VERSION_CODES.GINGERBREAD)
#SuppressLint({ "NewApi", "DefaultLocale" })
public class CounterClass extends CountDownTimer {
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// TODO Auto-generated constructor stub
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#SuppressLint("NewApi")
#TargetApi(Build.VERSION_CODES.GINGERBREAD)
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// TODO Auto-generated method stub
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// TODO Auto-generated method stub
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In the code line below, you are generating a random number and picking an Resource Integer. But the index you are trying to get from array doesn't exist. So you are getting IndexOutOfBounds exception.
int rando = (int) (Math.random() * 125);
Drawable d = getResources().getDrawable(a[rando]);

Error is in okButton method here:
int rando = (int) (Math.random() * 125);
Drawable d = getResources().getDrawable(a[rando]);
rando is returning a value out bounds of a array.

Your array contains only 121 elements. Hence, whenever the random number generated is within 0-120 range, the app functions properly. But whenever the number falls between 121-124, it crashes due to IndexOutOfBounds exception. Either add more items to the array or use the following code:
int rando = (int) (Math.random() * 121);
Drawable d = getResources().getDrawable(a[rando]);

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{
public interface NDListener
{
public void onDPClick(DialogFragment dialog);
}
NDListener expListener;
#Override
public void onAttach(Activity activity)
{
super.onAttach(activity);
try
{
expListener = (NDListener) activity;
}
catch(ClassCastException e)
{
throw new ClassCastException(activity.toString() + "does not implement NDListener");
}
}
#Override
public Dialog onCreateDialog(Bundle savedInstanceState)
{
AlertDialog.Builder aDia = new AlertDialog.Builder(getActivity());
LayoutInflater inflater = getActivity().getLayoutInflater();
aDia.setView(inflater.inflate(R.layout.calc_dia, null)).setPositiveButton(R.string.diaOk_b, new DialogInterface.OnClickListener()
{
#Override
public void onClick(DialogInterface dialog, int id)
{
expListener.onDPClick(CDia_exp.this);
}
}).setNegativeButton(R.string.cancel_b, new DialogInterface.OnClickListener()
{
#Override
public void onClick(DialogInterface dialog, int id)
{
getDialog().cancel();
}
});
return aDia.create();
}
}
And Now the Error Log
07-20 14:23:43.599: E/Trace(24173): error opening trace file: No such file or directory (2)
07-20 14:23:43.622: D/AndroidRuntime(24173): Shutting down VM
07-20 14:23:43.622: W/dalvikvm(24173): threadid=1: thread exiting with uncaught exception (group=0x4137d2a0)
07-20 14:23:43.653: E/AndroidRuntime(24173): FATAL EXCEPTION: main
07-20 14:23:43.653: E/AndroidRuntime(24173): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.musicalc/com.example.musicalc.MainActivity}: java.lang.NullPointerException
07-20 14:23:43.653: E/AndroidRuntime(24173): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2060)
07-20 14:23:43.653: E/AndroidRuntime(24173): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2174)
07-20 14:23:43.653: E/AndroidRuntime(24173): at android.app.ActivityThread.access$700(ActivityThread.java:141)
07-20 14:23:43.653: E/AndroidRuntime(24173): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1267)
07-20 14:23:43.653: E/AndroidRuntime(24173): at android.os.Handler.dispatchMessage(Handler.java:99)
07-20 14:23:43.653: E/AndroidRuntime(24173): at android.os.Looper.loop(Looper.java:137)
07-20 14:23:43.653: E/AndroidRuntime(24173): at android.app.ActivityThread.main(ActivityThread.java:5059)
07-20 14:23:43.653: E/AndroidRuntime(24173): at java.lang.reflect.Method.invokeNative(Native Method)
07-20 14:23:43.653: E/AndroidRuntime(24173): at java.lang.reflect.Method.invoke(Method.java:511)
07-20 14:23:43.653: E/AndroidRuntime(24173): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:792)
07-20 14:23:43.653: E/AndroidRuntime(24173): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:555)
07-20 14:23:43.653: E/AndroidRuntime(24173): at dalvik.system.NativeStart.main(Native Method)
07-20 14:23:43.653: E/AndroidRuntime(24173): Caused by: java.lang.NullPointerException
07-20 14:23:43.653: E/AndroidRuntime(24173): at android.app.Activity.findViewById(Activity.java:1851)
07-20 14:23:43.653: E/AndroidRuntime(24173): at com.example.musicalc.MainActivity.<init>(MainActivity.java:43)
07-20 14:23:43.653: E/AndroidRuntime(24173): at java.lang.Class.newInstanceImpl(Native Method)
07-20 14:23:43.653: E/AndroidRuntime(24173): at java.lang.Class.newInstance(Class.java:1319)
07-20 14:23:43.653: E/AndroidRuntime(24173): at android.app.Instrumentation.newActivity(Instrumentation.java:1053)
07-20 14:23:43.653: E/AndroidRuntime(24173): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2051)
07-20 14:23:43.653: E/AndroidRuntime(24173): ... 11 more
07-20 14:25:56.817: E/Trace(24308): error opening trace file: No such file or directory (2)
07-20 14:25:56.934: D/AndroidRuntime(24308): Shutting down VM
07-20 14:25:56.934: W/dalvikvm(24308): threadid=1: thread exiting with uncaught exception (group=0x4137d2a0)
07-20 14:25:57.013: E/AndroidRuntime(24308): FATAL EXCEPTION: main
07-20 14:25:57.013: E/AndroidRuntime(24308): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.example.musicalc/com.example.musicalc.MainActivity}: java.lang.NullPointerException
07-20 14:25:57.013: E/AndroidRuntime(24308): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2060)
07-20 14:25:57.013: E/AndroidRuntime(24308): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2174)
07-20 14:25:57.013: E/AndroidRuntime(24308): at android.app.ActivityThread.access$700(ActivityThread.java:141)
07-20 14:25:57.013: E/AndroidRuntime(24308): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1267)
07-20 14:25:57.013: E/AndroidRuntime(24308): at android.os.Handler.dispatchMessage(Handler.java:99)
07-20 14:25:57.013: E/AndroidRuntime(24308): at android.os.Looper.loop(Looper.java:137)
07-20 14:25:57.013: E/AndroidRuntime(24308): at android.app.ActivityThread.main(ActivityThread.java:5059)
07-20 14:25:57.013: E/AndroidRuntime(24308): at java.lang.reflect.Method.invokeNative(Native Method)
07-20 14:25:57.013: E/AndroidRuntime(24308): at java.lang.reflect.Method.invoke(Method.java:511)
07-20 14:25:57.013: E/AndroidRuntime(24308): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:792)
07-20 14:25:57.013: E/AndroidRuntime(24308): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:555)
07-20 14:25:57.013: E/AndroidRuntime(24308): at dalvik.system.NativeStart.main(Native Method)
07-20 14:25:57.013: E/AndroidRuntime(24308): Caused by: java.lang.NullPointerException
07-20 14:25:57.013: E/AndroidRuntime(24308): at android.app.Activity.findViewById(Activity.java:1851)
07-20 14:25:57.013: E/AndroidRuntime(24308): at com.example.musicalc.MainActivity.<init>(MainActivity.java:803)
07-20 14:25:57.013: E/AndroidRuntime(24308): at java.lang.Class.newInstanceImpl(Native Method)
07-20 14:25:57.013: E/AndroidRuntime(24308): at java.lang.Class.newInstance(Class.java:1319)
07-20 14:25:57.013: E/AndroidRuntime(24308): at android.app.Instrumentation.newActivity(Instrumentation.java:1053)
07-20 14:25:57.013: E/AndroidRuntime(24308): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2051)
07-20 14:25:57.013: E/AndroidRuntime(24308): ... 11 more

Thanks to some experimentation and some research on stackoverflow i have located the answer.
The problem is that the compiler was having trouble locating the view either because it is in a separate xml file from my activity_main.xml file or because i was creating my dialog within a separate class from my MainActiviy.java.
To solve this i created my dialog within my MainActivity.java class outside of the onCreate method. Also i created a layout inflater to inflate my layout within a View in my MainActivity, which was key because the LayoutInflater provided a way to directly call my EditText into code.
The code that fixed the nullpointer when declaring my EditText is as follows:
LayoutInflater inflater = LayoutInflater.from(this);
//Inflater "inflates" layout into View as a value
final View infV = inflater.inflate(R.layout.calc_dia, null);
//Use layout value inflated in View "infV" to find EditText
final EditText eDTemp = (EditText) infV.findViewById(R.id.expInp);
***The full code for the dialog is as follows****:
public void showCD()
{
LayoutInflater inflater = LayoutInflater.from(this);
final View infV = inflater.inflate(R.layout.calc_dia, null);
final EditText eDTemp = (EditText)infV.findViewById(R.id.expInp);
TextView tView0 = (TextView)findViewById(R.id.calcView);
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setView(infV).setPositiveButton("Ok", new
DialogInterface.OnClickListener()
{
#Override
public void onClick(DialogInterface dialog, int which)
{
}}).setNegativeButton("Cancel", new DialogInterface.OnClickListener()
{
#Override
public void onClick(DialogInterface dialog, int which)
{
dialog.cancel();
}
});
AlertDialog alert = builder.create();
builder.show();
}
When you are ready for the dialog to appear, simply call the function that contains it.

Create Dialog Box For Checking Internet Connection in Android

I'm implementing to show dialog box when Internet is offline, when i run my app i got "FATAL Exception main" and ClassCastException when when i click on button and application is crash . Can someone tell me what i am doing wrong ? Thanks to you in Advanced.
here is code how i check is internet enabled or not:
public class AndroidDetectInternetConnectionActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button btnStatus = (Button) findViewById(R.id.btn_check);
btnStatus.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (!isOnline())
{
showNoConnectionDialog(this);
}
}
});
}
public static void showNoConnectionDialog(OnClickListener onClickListener)
{
final Context ctx = (Context) onClickListener;
AlertDialog.Builder builder = new AlertDialog.Builder(ctx);
builder.setCancelable(true);
builder.setMessage(R.string.no_connection);
builder.setTitle(R.string.no_connection_title);
builder.setPositiveButton(R.string.settings_button_text, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which)
{
ctx.startActivity(new Intent(Settings.ACTION_WIRELESS_SETTINGS));
}
});
builder.setNegativeButton(R.string.cancel_button_text, new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int which)
{
return;
}
});
builder.setOnCancelListener(new DialogInterface.OnCancelListener()
{
public void onCancel(DialogInterface dialog) {
return;
}
});
builder.show();
}
public boolean isOnline()
{
ConnectivityManager cm = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo netInfo = cm.getActiveNetworkInfo();
if (netInfo != null && netInfo.isConnectedOrConnecting())
{
return true;
}
return false;
}
}
// This is my Log Cat stack trace
11-15 11:57:19.115: D/AndroidRuntime(453): Shutting down VM
11-15 11:57:19.115: W/dalvikvm(453): threadid=1: thread exiting with uncaught exception (group=0x40015560)
11-15 11:57:19.122: E/AndroidRuntime(453): FATAL EXCEPTION: main
11-15 11:57:19.122: E/AndroidRuntime(453): java.lang.ClassCastException: com.example.detectinternetconnection.AndroidDetectInternetConnectionActivity$1
11-15 11:57:19.122: E/AndroidRuntime(453): at com.example.detectinternetconnection.AndroidDetectInternetConnectionActivity.showNoConnectionDialog(AndroidDetectInternetConnectionActivity.java:99)
11-15 11:57:19.122: E/AndroidRuntime(453): at com.example.detectinternetconnection.AndroidDetectInternetConnectionActivity$1.onClick(AndroidDetectInternetConnectionActivity.java:64)
11-15 11:57:19.122: E/AndroidRuntime(453): at android.view.View.performClick(View.java:2485)
11-15 11:57:19.122: E/AndroidRuntime(453): at android.view.View$PerformClick.run(View.java:9080)
11-15 11:57:19.122: E/AndroidRuntime(453): at android.os.Handler.handleCallback(Handler.java:587)
11-15 11:57:19.122: E/AndroidRuntime(453): at android.os.Handler.dispatchMessage(Handler.java:92)
11-15 11:57:19.122: E/AndroidRuntime(453): at android.os.Looper.loop(Looper.java:123)
11-15 11:57:19.122: E/AndroidRuntime(453): at android.app.ActivityThread.main(ActivityThread.java:3683)
11-15 11:57:19.122: E/AndroidRuntime(453): at java.lang.reflect.Method.invokeNative(Native Method)
11-15 11:57:19.122: E/AndroidRuntime(453): at java.lang.reflect.Method.invoke(Method.java:507)
11-15 11:57:19.122: E/AndroidRuntime(453): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
11-15 11:57:19.122: E/AndroidRuntime(453): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
11-15 11:57:19.122: E/AndroidRuntime(453): at dalvik.system.NativeStart.main(Native Method)
11-15 11:57:24.892: I/Process(453): Sending signal. PID: 453 SIG: 9

change this line
final Context ctx = (Context) onClickListener;
to below one
final Context ctx = AndroidDetectInternetConnectionActivity.this;
basically you are trying to conver onClickListener to Contex which is incorrect and can not be casted.
Either you directly use ActivityName.this wherever you need context instance, or define static Context ctx as a class variable and intialize it in onCreate()by just adding this line ctx =this also remember to intialize it before using it.
Enjoy

There are two ways to solve this problem.
1) showNoConnectionDialog(this); and later on:
public static void showNoConnectionDialog(Context ctx) ...
2) showNoConnectionDialog(); and later on: public void showNoConnectionDialog() { Context ctx = AndroidDetectInternetConnectionActivity.this

You basic problem is generated by the line:
final Context ctx = (Context) onClickListener;
This is simply not a context so trying to force it to be one doesn't work.
I believe that you wanted to do was pass a context (or activity) to this function (as opposed to the local unnamed OnClickListener class that you are now passing)
The easiest solution would be to simple not pass anything to the constructor and use AndroidDetectInternetConnectionActivity.this to access your valid context.

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