Android App在访问Url时崩溃了

Question

以下是应用崩溃的主要活动 我必须在微调器中选择状态，结果我得到城市列表，但它没有显示城市列表。如果我改变状态，那么仍然没有发生任何事情。 我正在研究android api 15。 如果我在api 8或10上工作，那么它可以正常工作。

    String url="RegisterShop";
    try
    {
    BufferedReader br=Mycon.getReader(url);
    String str=br.readLine();
    id1=Integer.parseInt(str);

    nm.requestFocus();
    Log.e("",""+id1);
    }catch (Exception e) {
        // TODO: handle exception
    }

     new Thread(new Runnable() {
            public void run() {





    try
    {
    BufferedReader br=Mycon.getReader("GetState");
    String str1=br.readLine();
    String st[]=new String[]{"Select State"};
    Log.e("",""+st);
    while(true)
    {
     if(str1==null)break;   

     st=str1.split(",");    
     Log.e("",""+str1);
     str1=br.readLine();

    }
    ArrayAdapter<String>adapter=new ArrayAdapter<String>(Activity_Advertiser_Register.this,android.R.layout.simple_spinner_item,st);
     state.setAdapter(adapter);
    }catch (Exception e) {
        // TODO: handle exception
    }

    state.setOnItemSelectedListener(new OnItemSelectedListener() {

        public void onItemSelected(AdapterView<?> arg0, View arg1, int arg2,
                long arg3) {
             s1=(String) state.getSelectedItem();
             //Toast.makeText(RegisterActivity.this,""+s1,Toast.LENGTH_LONG).show();



                try
                {
                BufferedReader br=Mycon.getReader("GetCity?state1="+s1);
                String str1=br.readLine();
                String ct[]=null;
                while(true)
                {
                 if(str1==null)break;   
                 ct=str1.split(",");    
                 Log.e("",""+str1);
                 str1=br.readLine();

                }
                if(ct.equals(null))
                {

                }
                adapter=new ArrayAdapter<String>(Activity_Advertiser_Register.this,android.R.layout.simple_spinner_item,ct);
                 city.setAdapter(adapter);
                }catch (Exception e) {
                    // TODO: handle exception
                }





        }


        public void onNothingSelected(AdapterView<?> arg0) {
            // TODO Auto-generated method stub
        }
    });

            }}).start();
  SellerSignUp.setOnClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View arg0) {
        // TODO Auto-generated method stub
         new Thread(new Runnable() {
             public void run() {
        if(nm.getText().toString().length()==0){
            nm.setError("Please Enter Name");
        }
        if(pass.getText().toString().length()==0){
            pass.setError("Please Enter Password");
        }
        if(address.getText().toString().length()==0){
            address.setError("Please Enter Address");
        }
        if(contact.getText().toString().length()==0){
            contact.setError("Please Enter Contact");
        }
        if(email.getText().toString().length()==0){
            email.setError("Please Enter Email");
        }
        if(legalName.getText().toString().length()==0){
            legalName.setError("Please Enter Person Name");

        }
        if(tin.getText().toString().length()==0){
            tin.setError("Please Enter Tin Number");

        }


         String nm1=nm.getText().toString();
         String pass1=pass.getText().toString();
         String address1=address.getText().toString();
         String contact1=contact.getText().toString();
         String tin1=contact.getText().toString();
         String email1=email.getText().toString();
         String city1=(String) city.getSelectedItem();
         String cp=legalName.getText().toString();
         Random r=new Random();
         String otp=new String();

         for(int i=0 ; i<6 ; i++) {
                otp += r.nextInt(10);
            }
         if(contact1.length()!=10)
            {
                contact.setError("Plese Enter 10 Digit");
            }
         if(tin.length()!=11)
            {
                contact.setError("Plese Enter Correct Tin Number");
            }
             if(checkEmail(email1)){

         //Toast.makeText(RegisterActivity.this,""+city1,Toast.LENGTH_SHORT).show();


        String url3="RegSave?id="+id1+"&nm="+nm1+"&pass="+pass1+"&address="+address1+"&contact="+contact1+"&email="+email1+"&city="+city1+"&contactperson="+cp+"&tin="+tin1+"&otp="+otp;
         try{
         BufferedReader br=Mycon.getReader(url3);
         String rec=br.readLine();
         if(rec!=null){
         Toast.makeText(Activity_Advertiser_Register.this,rec.toString(),Toast.LENGTH_SHORT).show();         
         in=new Intent(Activity_Advertiser_Register.this,Activity_Advertiser_Verification.class);
         in.putExtra("user",nm1);

         startActivity(in);
         }
         }catch (Exception e) {
             e.printStackTrace();
        }

             }
         else{
             email.setError("Invalid Email");
             }

             }}).start();
    }
});

这是logcat

Here is the logcat