Issue with custom Dialog Android

I have a custom Dialog in my app and I have a problem achieving the desired behavior. My Dialog has 4 Buttons. (Back, Valid, Modify and Restore). When the user clicks on Modify or Valid I would like to call another activity. So I am using Intent but it's crashing.

The error Log :

05-19 13:29:21.495: ERROR/DEBUGTAG(974): java.lang.NullPointerException 05-19 13:29:21.495: ERROR/DEBUGTAG(974):

at android.content.ComponentName.(ComponentName.java:75) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.content.Intent.(Intent.java:2551) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at com.android.booztermobile.activity.HeaderMailDisplayActivity.onClick(HeaderMailDisplayActivity.java:571) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.view.View.per开发者_运维知识库formClick(View.java:2364) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.view.View.onTouchEvent(View.java:4179) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.widget.TextView.onTouchEvent(TextView.java:6540) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.view.View.dispatchTouchEvent(View.java:3709) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.view.ViewGroup.dispatchTouchEvent(ViewGroup.java:884) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at com.android.internal.policy.impl.PhoneWindow$DecorView.superDispatchTouchEvent(PhoneWindow.java:1659) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at com.android.internal.policy.impl.PhoneWindow.superDispatchTouchEvent(PhoneWindow.java:1107) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.app.Dialog.dispatchTouchEvent(Dialog.java:643) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at com.android.internal.policy.impl.PhoneWindow$DecorView.dispatchTouchEvent(PhoneWindow.java:1643) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.view.ViewRoot.handleMessage(ViewRoot.java:1691) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.os.Handler.dispatchMessage(Handler.java:99) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.os.Looper.loop(Looper.java:123) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at android.app.ActivityThread.main(ActivityThread.java:4363) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at java.lang.reflect.Method.invokeNative(Native Method) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at java.lang.reflect.Method.invoke(Method.java:521) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618) 05-19 13:29:21.495: ERROR/DEBUGTAG(974): at dalvik.system.NativeStart.main(Native Method)

My custom Dialog :

package com.android.booztermobile.services;

import com.android.booztermobile.R;

import android.app.Dialog;
import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.widget.Button;


public class MailDialog extends Dialog {

    private Button btnValid;
    private Button btnBack;
    private Button btnRestore;
    private Button btnModify;
    private Context context;


    public MailDialog(Context cont) {
        super(cont);
        context = cont;
        }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Log.d("TestApp", "Dialog created");
            setContentView(R.layout.dialog_classement);     

            btnValid = (Button) findViewById(R.id.btnValidClassement);
            btnBack = (Button) findViewById(R.id.btnBackClassement);    
            btnRestore = (Button) findViewById(R.id.btnRestoreClassement);
            btnModify = (Button) findViewById(R.id.btnModifyClassement);

    }
}

and the activity (cut because too long):

        //create dialog
 public void getMailInformations(View v, Context context){

  currentMail = (MailHeader) v.getTag();

  dial = new MailDialog(context);

  dial.setTitle("Classement");
  dial.show();

  btnValidClassement = (Button) dial.findViewById(R.id.btnValidClassement);
  btnValidClassement.setOnClickListener(this);

 }

/** the Onclick : */

    public void onClick(View view) {

//THIS WORKS (Activity Button)
    if (view == lblPreviousMails) {

            positionList -= 20;
            // create Intent
            Intent defineIntentDisplayPreviousMails = new Intent(HeaderMailDisplayActivity.this, HeaderMailDisplayActivity.class);

            //Create bundle to pass informations to the other activity
            Bundle objetbundle = new Bundle();
            objetbundle.putString("positionList", String.valueOf(positionList));
            objetbundle.putStringArrayList("currentMails", seqnumList);
            objetbundle.putString("uidh", uidh);
            defineIntentDisplayPreviousMails.putExtras(objetbundle);

            // call headermailDisplayActivity
            HeaderMailDisplayActivity.this.startActivity(defineIntentDisplayPreviousMails);

        }

//THIS DOESN'T WORKS (Dialog Button)
    if(view == btnValidClassement){

   try{

    ClassementHandlerCall classement = new               ClassementHandlerCall();
       boolean mailClassify = classement.classifyMail(AuthentificationActivity.uidh, 
         String.valueOf(currentMail.getSeqnum()), null, null);

       dial.dismiss();

       if (mailClassify == true){

                //create Intent 
                Intent defineIntentClassifyMails = new Intent(MailClassificationActivity.this, HeaderMailDisplayActivity.class);

                // Object that allows to pass person's uidh and positionList onto HeaderMailDisplayActivity
                Bundle objetbundle = new Bundle();
                objetbundle.putString("uidh",uidh);
                objetbundle.putString("positionList", String.valueOf(positionList));
                defineIntentClassifyMails.putExtras(objetbundle);

                // call HeaderMailDisplayActivity 
                MailClassificationActivity.this.startActivity(defineIntentClassifyMails);


       }

   }catch(Exception e){
    // TODO Auto-generated catch block
    Log.e("DEBUGTAG","Error occured", e);
    e.printStackTrace();
   }



  }

}

---

According to stack trace, it looks like that you are calling an Intent constructor with some malformed parameters.

---

To start activity from intent you need to add in the manifest xml file the activity with this code

<activity android:name=".youractivityname"
          android:configChanges="keyboardHidden|orientation"
          android:label="@string/app_name">
</activity>

Put the code before the application close tag in manifest.
And the code in the button click event is:

Intent myIntent = new Intent(v.getContext(), youractivity.class);
startActivityForResult(myIntent, 1);