Asynctask无法正常工作

时间:2015-05-22 08:16:26

标签: android android-asynctask

    //packagename imports ,variable
    @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            //declaring views
            lv_IFSC_.addFooterView(Btn_Load_More);



            Btn_Load_More.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View arg0) {
                    // Starting a new async task
                    new Asynctask_Record_List().execute();
                }
            });


            final Handler handler = new Handler();
            handler.post(new Runnable() {
                public void run() {
            try {

                    new Assign_task_Bank().execute();

                } catch (Exception e) {

                }

            }
        });



            rel_main_logo.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {


                    final Handler handler = new Handler();
                    handler.post(new Runnable() {
                        public void run() {
                    try {

                            new Assign_task_Bank().execute();

                        } catch (Exception e) {

                        }

                    }
                });

                    rel_Full_Advertise.setVisibility(View.VISIBLE);
                    rel_Full_IFSE_list.setVisibility(View.GONE);

                    spinner_State.setAdapter(null);
                    spinner_District.setAdapter(null);
                    spinner_City.setAdapter(null);


                }
            });
                spinner_Bank.setOnItemSelectedListener(new OnItemSelectedListener() {
                @Override
                public void onItemSelected(AdapterView<?> parentView, View v, int position, long id) {


                    String txtNAME    = ((TextView) v.findViewById(R.id.text_Name)).getText().toString();
                    String txtID = ((TextView) v.findViewById(R.id.text_ID)).getText().toString();
                    v.findViewById(R.id.text_URL)).getText().toString();

                    if(Integer.valueOf(txtID)==0)
                    {
                    Toast.makeText(getApplicationContext(),"please select Bank", Toast.LENGTH_SHORT).show();
                    }else
                    {   


                        spinner_District.setAdapter(null);
                        spinner_City.setAdapter(null);


                        Str_Page_No=0;
                        Str_Select_Id=txtID;
                        Str_select_spinner_Bank=txtNAME;
                        try {
                            scroll_spinner.scrollTo(305, 1000);

                        } catch (Exception e) {

                        }



                        final Handler handler2 = new Handler();
                        handler2.post(new Runnable() {
                            public void run() {
                        try {                                   
                            if (Build.VERSION.SDK_INT>=Build.VERSION_CODES.HONEYCOMB)
                                new Assign_Task_State().executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR,Str_select_spinner_Bank);
                            else
                                new Assign_Task_State().execute(Str_select_spinner_Bank);


                            } catch (Exception e) {

                            }

                        }
                        });

                    }
                }

                @Override
                public void onNothingSelected(AdapterView<?> parentView) {

                }

            });


            spinner_State.setOnItemSelectedListener(new OnItemSelectedListener() { 
                @Override
                public void onItemSelected(AdapterView<?> parentView, View v, int position, long id) {

                    String txtNAME    = ((TextView) v.findViewById(R.id.text_Name)).getText().toString();
                    String txtID = ((TextView) v.findViewById(R.id.text_ID)).getText().toString();
                    v.findViewById(R.id.text_URL)).getText().toString();                
                    if(Integer.valueOf(txtID)==0)
                    {
                    Toast.makeText(getApplicationContext(),Str_select_spinner_Bank+"selected ,please select State", Toast.LENGTH_LONG).show();
                    }else
                    {     

                        spinner_City.setAdapter(null);



                        Str_Select_Id=txtID;
                        Str_select_spinner_State=txtNAME;

                        try {

                            scroll_spinner.scrollTo(600, 1000);
                        } catch (Exception e) {

                        }



                        try {
                            Str_Page_No=0;
                            rel_Full_Advertise.setVisibility(View.GONE);
                            rel_Full_IFSE_list.setVisibility(View.VISIBLE);

                                    final Handler handler3 = new Handler();
                                    handler3.post(new Runnable() {
                                        public void run() {
                                    try {                                   
                                        if (Build.VERSION.SDK_INT>=Build.VERSION_CODES.HONEYCOMB)
                                            new Asynctask_Record_List().executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);
                                        else
                                            new Asynctask_Record_List().execute();

                                        } catch (Exception e) {

                                        }

                                    }
                                    });


                }

                @Override
                public void onNothingSelected(AdapterView<?> parentView) {

                }

            });
lv_IFSC_.setOnItemClickListener(new OnItemClickListener() {

            @Override
            public void onItemClick(AdapterView<?> arg0, View arg1, int arg2,
                    long arg3) {

                View v=arg1;
            TextView txt_IFSC_L_Bank_value = (TextView) v.findViewById(R.id.txt_IFSC_L_Bank_value); 
    TextView txt_IFSC_L_ifsc_code_value = (TextView) v.findViewById(R.id.txt_IFSC_L_ifsc_code_value);   
    TextView txt_IFSC_micr_code_value = (TextView) v.findViewById(R.id.txt_IFSC_micr_code_value);   
    TextView txt_IFSC_branch_name_value = (TextView) v.findViewById(R.id.txt_IFSC_branch_name_value);
    TextView txt_IFSC_contact_value = (TextView) v.findViewById(R.id.txt_IFSC_contact_value);   
    TextView txt_IFSC_address_value = (TextView) v.findViewById(R.id.txt_IFSC_address_value);   
    TextView txt_IFSC_Fax_value = (TextView) v.findViewById(R.id.txt_IFSC_Fax_value);   
    TextView txt_IFSC_city_value = (TextView) v.findViewById(R.id.txt_IFSC_city_value);     
    TextView txt_IFSC_district_value = (TextView) v.findViewById(R.id.txt_IFSC_district_value); 
    TextView txt_IFSC_state_value = (TextView) v.findViewById(R.id.txt_IFSC_state_value);   



                    Intent tvintent = new Intent(getApplicationContext(),IFSC_List_Detail.class);                       

                    tvintent.putExtra("txt_IFSC_L_Bank_value", txt_IFSC_L_Bank_value.getText().toString());
                    tvintent.putExtra("txt_IFSC_L_ifsc_code_value", txt_IFSC_L_ifsc_code_value.getText().toString());
                    tvintent.putExtra("txt_IFSC_micr_code_value", txt_IFSC_micr_code_value.getText().toString());
                    tvintent.putExtra("txt_IFSC_branch_name_value", txt_IFSC_branch_name_value.getText().toString());
                    tvintent.putExtra("txt_IFSC_contact_value", txt_IFSC_contact_value.getText().toString());
                    tvintent.putExtra("txt_IFSC_address_value", txt_IFSC_address_value.getText().toString());
                    tvintent.putExtra("txt_IFSC_Fax_value", txt_IFSC_Fax_value.getText().toString());
                    tvintent.putExtra("txt_IFSC_city_value", txt_IFSC_city_value.getText().toString());
                    tvintent.putExtra("txt_IFSC_district_value", txt_IFSC_district_value.getText().toString());
                    tvintent.putExtra("txt_IFSC_state_value", txt_IFSC_state_value.getText().toString());


                    startActivity(tvintent);

                }
            });

            class Assign_task_Bank extends AsyncTask<String, Void, String>{
            String id;
            private BufferedReader reader;      
            private StringBuffer readbuffer = new StringBuffer();
            private ProgressDialog progress;

            public Assign_task_Bank()
              {
                    progress = new ProgressDialog(MainActivity.this);
                    progress.setCancelable(false);
              }

            @Override
            protected void onPreExecute() {
                    super.onPreExecute();
                    this.progress.setMessage("Please wait");
                    this.progress.show();           
            }

            @Override
            protected String doInBackground(String... params) {

                try {

                        try{

                            MD_Spinner_id_name currentItem = null;                      
                            contents = new ArrayList<MD_Spinner_id_name>();

                            MD_Spinner_id_name  Detail = new MD_Spinner_id_name(); 
                            Detail.setSpinner_ID(""+0);
                            Detail.setSpinner_Name("Bank...");
                            contents.add(Detail);

                            DataBaseHelper db = new DataBaseHelper(getApplicationContext()) ;

                          try {
                                 db = new DataBaseHelper(getApplicationContext());

                            } catch (IOException e) {

                                e.printStackTrace();
                            }

                                String Select_Query="SELECT bank FROM MobileIFSCInfo GROUP BY bank ORDER BY bank ASC";
                                List<Contact> contacts = db.getAllContacts(Select_Query);

                                for (Contact cn : contacts) {                                      
                                          currentItem = new MD_Spinner_id_name();
                                      currentItem.Spinner_ID=cn.Contact_ID;
                                         currentItem.Spinner_Name=cn.Contact_NAME;

                                         contents.add(currentItem);

                                  }
                                  db.close();

                            } catch (Exception e) {


                            }

                            finally {
                                if (reader != null) {
                                    try {
                                        reader.close();
                                    } catch (Exception e) {
                                    }
                                }
                            }                       

                            return readbuffer.toString();

                } catch (Exception e) {

                }
                return readbuffer.toString();
            }

            @Override
            protected void onPostExecute(String result) {

                super.onPostExecute(result);
                try {
                        try {
                                adapter_Vehical_Category = new Adapter_Spinner_id_name(contents, getApplicationContext());      
                                spinner_Bank.setAdapter(adapter_Vehical_Category);

                        } catch (Exception e) {

                        }


                    if (progress.isShowing()) {
                        progress.dismiss();
                    }
                } catch (Exception e) {

                }           
            }       
        }


        class Assign_Task_State extends AsyncTask<String, Void, String>{
            String id;
            private BufferedReader reader;      
            private StringBuffer readbuffer = new StringBuffer();
            private ProgressDialog progress;


            public Assign_Task_State()
              {
                    progress = new ProgressDialog(MainActivity.this);
                    progress.setCancelable(false);
              }

            @Override
            protected void onPreExecute() {
                            super.onPreExecute();

                    this.progress.setMessage("Please wait");
                    this.progress.show();           
            }

            @Override
            protected String doInBackground(String... params) {

                try {

                        try{

                            MD_Spinner_id_name currentItem = null;                      
                            contents = new ArrayList<MD_Spinner_id_name>();

                            MD_Spinner_id_name  Detail = new MD_Spinner_id_name(); 
                            Detail.setSpinner_ID(""+0);
                            Detail.setSpinner_Name("State");
                            contents.add(Detail);

                            DataBaseHelper db = new DataBaseHelper(getApplicationContext()) ;

                          try {
                                 db = new DataBaseHelper(getApplicationContext());

                            } catch (IOException e) {

                            }

                                String Select_Query="SELECT state FROM MobileIFSCInfo WHERE lower(bank) = lower('"+Str_select_spinner_Bank+"') GROUP BY state ORDER BY state ASC";
                                List<Contact> contacts = db.getAllContacts(Select_Query);

                                for (Contact cn : contacts) {                                      
                                          currentItem = new MD_Spinner_id_name();

                                         currentItem.Spinner_ID=cn.Contact_ID;
                                         currentItem.Spinner_Name=cn.Contact_NAME;

                                         contents.add(currentItem);

                                  }
                                  db.close();

                            } catch (Exception e) {


                            }

                            finally {
                                if (reader != null) {
                                    try {
                                        reader.close();
                                    } catch (Exception e) {
                                    }
                                }
                            }                       

                            return readbuffer.toString();

                } catch (Exception e) {

                }
                return readbuffer.toString();
            }

            @Override
            protected void onPostExecute(String result) {

                super.onPostExecute(result);
                try {
                        try {
                                adapter_Vehical_Category = new Adapter_Spinner_id_name(contents, getApplicationContext());      
                                spinner_State.setAdapter(adapter_Vehical_Category);

                        } catch (Exception e) {

                        }


                    if (progress.isShowing()) {
                        progress.dismiss();
                    }
                } catch (Exception e) {

                }           
            }       
        }
        private Adapter_IFSC_RecordList adapter_IFSC;
        private ArrayList<MD_Record_List> details= new ArrayList<MD_Record_List>(); 
        class Asynctask_Record_List extends AsyncTask<String, String, String> {

            private ProgressDialog pDialog;     
            private BufferedReader reader;      
            private StringBuffer readbuffer = new StringBuffer();

                @Override
                protected void onPreExecute() {
                    super.onPreExecute();
                    pDialog = new ProgressDialog(MainActivity.this);
                    pDialog.setMessage("Please Wait");                          
                    pDialog.show();

                }
                @Override
                protected String doInBackground(String... params) {


                                details = new ArrayList<MD_Record_List>();                      
                                ConnectionDetector cd;
                                cd=new ConnectionDetector(getApplicationContext());



    //----------------------------------------------------OFFLINE---------------------------------------------------



                                try {
                                    DataBaseHendlerIFSC IFSCdb=new DataBaseHendlerIFSC(getApplicationContext());

                                    details=    (ArrayList<MD_Record_List>) IFSCdb.getAllContacts(//query );



                                } catch (IOException e) {

                                    e.printStackTrace();
                                }
                                    MD_Record_List Detail;
                                    Detail = new MD_Record_List();
                                    for(int i=0;i<details.size();i++){                                          

                                        if(Str_select_spinner_City=="")
                                        {
                                            if(Str_select_spinner_District=="")
                                            {
                                                if(Str_select_spinner_State=="")
                                                {
                                                   if(Str_select_spinner_Bank=="")
                                                     break;
                                                  else if(details.get(i).bank==Str_select_spinner_Bank)
                                                 {
                                                     Detail=details.get(i);
                                                        String contact=Detail.contact;
                                                        String[] splited = contact.split("\\s+");
                                                        Log.e("0",""+splited[0]);
                                                        Log.e("1",""+splited[1]);
                                                        Log.e("2",""+splited[2]);

                                                        String strContact = "",strFax="";
                                                        String[] str_array =contact.split("Fax:");
                                                        strContact = str_array[0]; 
                                                        strFax = str_array[1];                                                  
                                                        Detail.setContact(strContact);
                                                        Detail.setFax(strFax);
                                                     continue;
                                                 }
                                                }
                                               else if(details.get(i).state==Str_select_spinner_State)
                                               {
                                                   Detail=details.get(i);
                                                   String contact=Detail.contact;
                                                    String[] splited = contact.split("\\s+");
                                                    Log.e("0",""+splited[0]);
                                                    Log.e("1",""+splited[1]);
                                                    Log.e("2",""+splited[2]);

                                                    String strContact = "",strFax="";
                                                    String[] str_array =contact.split("Fax:");
                                                    strContact = str_array[0]; 
                                                    strFax = str_array[1];                                                  
                                                    Detail.setContact(strContact);
                                                    Detail.setFax(strFax);
                                                   continue;
                                               }
                                               }
                                     else if(details.get(i).district==Str_select_spinner_District){
                                         Detail=details.get(i);
                                         String contact=Detail.contact;
                                            String[] splited = contact.split("\\s+");
                                            Log.e("0",""+splited[0]);
                                            Log.e("1",""+splited[1]);
                                            Log.e("2",""+splited[2]);

                                            String strContact = "",strFax="";
                                            String[] str_array =contact.split("Fax:");
                                            strContact = str_array[0]; 
                                            strFax = str_array[1];                                                  
                                            Detail.setContact(strContact);
                                            Detail.setFax(strFax);
                                           continue;
                                       }
                                       }
                                         else if(details.get(i).district==Str_select_spinner_City){
                                             Detail=details.get(i);
                                             String contact=Detail.contact;
                                                String[] splited = contact.split("\\s+");
                                                Log.e("0",""+splited[0]);
                                                Log.e("1",""+splited[1]);
                                                Log.e("2",""+splited[2]);

                                                String strContact = "",strFax="";
                                                String[] str_array =contact.split("Fax:");
                                                strContact = str_array[0]; 
                                                strFax = str_array[1];                                                  
                                                Detail.setContact(strContact);
                                                Detail.setFax(strFax);
                                               continue;
                                           }
                                    }                   
                                details.clear();
                                details.add(Detail);


                    return readbuffer.toString();
                }

                protected void onPostExecute(String file_url) {

                        try {   
                            if(Str_Page_No==0)
                            {
                                adapter_IFSC = new Adapter_IFSC_RecordList(details, getApplicationContext());       
                                lv_IFSC_.setAdapter(adapter_IFSC);  
                            }else
                            {

                                int currentPosition = lv_IFSC_.getFirstVisiblePosition();


                                adapter_IFSC = new Adapter_IFSC_RecordList(details,getApplicationContext());
                                lv_IFSC_.setAdapter(adapter_IFSC);                      
                                // Setting new scroll position
                                lv_IFSC_.setSelectionFromTop(currentPosition + 1, 0);
                            }

                            if (pDialog.isShowing()) {
                                pDialog.dismiss();
                            }
                            editText_Search.setText("");
                        } catch (Exception e) {


                        }

                    }

            }

        private void showToast(String msg) {

            Toast.makeText(MainActivity.this,msg, Toast.LENGTH_LONG).show();
        }

    }

每当我在状态微调器中选择某些内容时,我的应用就会崩溃。  发现我的doInBackground函数未在Asynctask_Record_List中执行。

我知道这一点,因为第一行的吐司没有显示出来。我尝试按link中的说法进行更改,但没有结果。 logcat显示窗口泄漏错误。

问题是Asynctask还是其他部分?

logcat的:

05-22 23:13:27.379: E/AndroidRuntime(8676): FATAL EXCEPTION: AsyncTask #3
05-22 23:13:27.379: E/AndroidRuntime(8676): java.lang.RuntimeException: An error occured while executing doInBackground()
05-22 23:13:27.379: E/AndroidRuntime(8676):     at android.os.AsyncTask$3.done(AsyncTask.java:278)
05-22 23:13:27.379: E/AndroidRuntime(8676):     at java.util.concurrent.FutureTask$Sync.innerSetException(FutureTask.java:273)
05-22 23:13:27.379: E/AndroidRuntime(8676):     at java.util.concurrent.FutureTask.setException(FutureTask.java:124)
05-22 23:13:27.379: E/AndroidRuntime(8676):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:307)
05-22 23:13:27.379: E/AndroidRuntime(8676):     at java.util.concurrent.FutureTask.run(FutureTask.java:137)
05-22 23:13:27.379: E/AndroidRuntime(8676):     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1076)
05-22 23:13:27.379: E/AndroidRuntime(8676):     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:569)
05-22 23:13:27.379: E/AndroidRuntime(8676):     at java.lang.Thread.run(Thread.java:856)
05-22 23:13:27.379: E/AndroidRuntime(8676): Caused by: java.lang.ArrayIndexOutOfBoundsException: length=1; index=1
05-22 23:13:27.379: E/AndroidRuntime(8676):     at com.takebestloan.DataBase.DataBaseHendlerIFSC.getAllContacts(DataBaseHendlerIFSC.java:167)
05-22 23:13:27.379: E/AndroidRuntime(8676):     at com.takebestloan.IFSC.MainActivity$Asynctask_Record_List.doInBackground(MainActivity.java:1317)
05-22 23:13:27.379: E/AndroidRuntime(8676):     at com.takebestloan.IFSC.MainActivity$Asynctask_Record_List.doInBackground(MainActivity.java:1)
05-22 23:13:27.379: E/AndroidRuntime(8676):     at android.os.AsyncTask$2.call(AsyncTask.java:264)
05-22 23:13:27.379: E/AndroidRuntime(8676):     at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:305)
05-22 23:13:27.379: E/AndroidRuntime(8676):     ... 4 more
05-22 23:13:27.889: E/System(8676): Uncaught exception thrown by finalizer
05-22 23:13:27.889: E/System(8676): java.lang.IllegalStateException: Don't have database lock!
05-22 23:13:27.889: E/System(8676):     at android.database.sqlite.SQLiteDatabase.verifyLockOwner(SQLiteDatabase.java:2223)
05-22 23:13:27.889: E/System(8676):     at android.database.sqlite.SQLiteDatabase$1.entryRemoved(SQLiteDatabase.java:2315)
05-22 23:13:27.889: E/System(8676):     at android.database.sqlite.SQLiteDatabase$1.entryRemoved(SQLiteDatabase.java:2311)
05-22 23:13:27.889: E/System(8676):     at android.util.LruCache.trimToSize(LruCache.java:197)
05-22 23:13:27.889: E/System(8676):     at android.util.LruCache.evictAll(LruCache.java:285)
05-22 23:13:27.889: E/System(8676):     at android.database.sqlite.SQLiteDatabase.deallocCachedSqlStatements(SQLiteDatabase.java:2276)
05-22 23:13:27.889: E/System(8676):     at android.database.sqlite.SQLiteDatabase.closeClosable(SQLiteDatabase.java:1248)
05-22 23:13:27.889: E/System(8676):     at android.database.sqlite.SQLiteDatabase.finalize(SQLiteDatabase.java:2036)
05-22 23:13:27.889: E/System(8676):     at java.lang.Daemons$FinalizerDaemon.doFinalize(Daemons.java:185)
05-22 23:13:27.889: E/System(8676):     at java.lang.Daemons$FinalizerDaemon.run(Daemons.java:168)
05-22 23:13:27.889: E/System(8676):     at java.lang.Thread.run(Thread.java:856)
05-22 23:13:37.319: E/WindowManager(8676): Activity com.takebestloan.IFSC.MainActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@417cd8a0 that was originally added here
05-22 23:13:37.319: E/WindowManager(8676): android.view.WindowLeaked: Activity com.takebestloan.IFSC.MainActivity has leaked window com.android.internal.policy.impl.PhoneWindow$DecorView@417cd8a0 that was originally added here
05-22 23:13:37.319: E/WindowManager(8676):  at android.view.ViewRootImpl.<init>(ViewRootImpl.java:403)
05-22 23:13:37.319: E/WindowManager(8676):  at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:267)
05-22 23:13:37.319: E/WindowManager(8676):  at android.view.WindowManagerImpl.addView(WindowManagerImpl.java:215)
05-22 23:13:37.319: E/WindowManager(8676):  at android.view.WindowManagerImpl$CompatModeWrapper.addView(WindowManagerImpl.java:140)
05-22 23:13:37.319: E/WindowManager(8676):  at android.view.Window$LocalWindowManager.addView(Window.java:537)
05-22 23:13:37.319: E/WindowManager(8676):  at android.app.Dialog.show(Dialog.java:278)
05-22 23:13:37.319: E/WindowManager(8676):  at com.takebestloan.IFSC.MainActivity$Asynctask_Record_List.onPreExecute(MainActivity.java:1296)
05-22 23:13:37.319: E/WindowManager(8676):  at android.os.AsyncTask.executeOnExecutor(AsyncTask.java:561)
05-22 23:13:37.319: E/WindowManager(8676):  at com.takebestloan.IFSC.MainActivity$7$1.run(MainActivity.java:428)
05-22 23:13:37.319: E/WindowManager(8676):  at android.os.Handler.handleCallback(Handler.java:605)
05-22 23:13:37.319: E/WindowManager(8676):  at android.os.Handler.dispatchMessage(Handler.java:92)
05-22 23:13:37.319: E/WindowManager(8676):  at android.os.Looper.loop(Looper.java:137)
05-22 23:13:37.319: E/WindowManager(8676):  at android.app.ActivityThread.main(ActivityThread.java:4517)
05-22 23:13:37.319: E/WindowManager(8676):  at java.lang.reflect.Method.invokeNative(Native Method)
05-22 23:13:37.319: E/WindowManager(8676):  at java.lang.reflect.Method.invoke(Method.java:511)
05-22 23:13:37.319: E/WindowManager(8676):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:993)
05-22 23:13:37.319: E/WindowManager(8676):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:760)
05-22 23:13:37.319: E/WindowManager(8676):  at dalvik.system.NativeStart.main(Native Method)

2 个答案:

答案 0 :(得分:3)

评论此行:

Toast.makeText(getApplicationContext(),"ListView Post", Toast.LENGTH_LONG).show(); 

您无法在doInBackground中更新UI - 包括显示祝酒!

如果要检查doInBackground()中的中间结果,最好的办法是使用log

之类的日志记录机制。

More on this here

Learn more about debugging here

答案 1 :(得分:1)

是的,我明白了。删除 Toast 后,程序进入 doInBackground()功能。然后我解决了Logcat中显示的错误