Androidメソッド：メソッド1はエラーのある空のString値を返し、メソッド2はnullポインタ例外を返します

Question

誰かがこの2つの関数の何が間違っているかを知ることができます メソッド1はエラーなしで空のString値を返し、ヌルポインタの例外 私がここで見つけることができる同様の例をすべて試しましたが、それでも数日間問題があります。前もって感謝します。

//Funtion1 Converting File to Base64.encode String type but returns empty string 
     public String getStringFile(File f) { 
      InputStream inputStream = null; 
       String encodedFile= "", lastVal; 
       try { 
        String uriString = filePath2.toString(); 
        f = new File(uriString).getAbsoluteFile(); 
        inputStream = new FileInputStream(f); 

       byte[] buffer = new byte[10240];//specify the size to allow 
       int bytesRead; 
       ByteArrayOutputStream output = new ByteArrayOutputStream(); 
       Base64OutputStream output64 = new Base64OutputStream(output, Base64.DEFAULT); 

        while ((bytesRead = inputStream.read(buffer)) != -1) { 
         output64.write(buffer, 0, bytesRead); 
        } 
       output64.close(); 
       encodedFile = output64.toString(); 
       } 
       catch (FileNotFoundException e1) { 
         e1.printStackTrace(); 
        } 
        catch (IOException e) { 
         e.printStackTrace(); 
        } 
       Log.i("Base64 String", "=" + encodedFile); 
       Log.v("Base64 String", "=" + encodedFile); 
       Log.e("Base64 String", "=" + encodedFile); 
       lastVal = encodedFile; 
       return lastVal; 

     } 

// Funtion 2 also Converting File to Base64 encode String but returns NullPointerException 
    public String getStringFile(File f) throws FileNotFoundEception, IOException { 
     InputStream inputStream = null; 
     String encodedFile= "", lastVal; 
     f = new File(f.getAbsoluthPath()); 
      inputStream = new FileInputStream(f); 

     byte[] buffer = new byte[10240];//specify the size to allow 
     int bytesRead; 
     ByteArrayOutputStream output = new ByteArrayOutputStream(); 
     Base64OutputStream output64 = new Base64OutputStream(output, Base64.DEFAULT); 

      while ((bytesRead = inputStream.read(buffer)) != -1) { 
       output64.write(buffer, 0, bytesRead); 
      } 
     output64.close(); 
     encodedFile = output.toString(); 



     return = encodedFile; 

    } 

これは完全なコードです。他のすべてのものは、このタスクを除いて動作しています。ありがとう

package com.aquacareer; 

import java.io.ByteArrayOutputStream; 
import java.io.File; 
import java.io.FileInputStream; 
import java.io.FileNotFoundException; 
import java.io.IOException; 
import java.io.InputStream; 
import java.util.ArrayList; 
import java.util.HashMap; 
import java.util.List; 
import android.graphics.Bitmap; 
import android.graphics.Color; 
import android.os.AsyncTask; 
import android.Manifest; 
import android.annotation.SuppressLint; 
import android.app.Activity; 
import android.app.ProgressDialog; 
import android.content.Intent; 
import android.content.pm.PackageManager; 
import android.database.Cursor; 
import android.graphics.drawable.ColorDrawable; 
import android.net.Uri; 
import android.os.Bundle; 
import android.provider.MediaStore; 
import android.provider.OpenableColumns; 
import android.support.annotation.NonNull; 
import android.support.v4.app.ActivityCompat; 
import android.support.v4.content.ContextCompat; 
import android.text.Editable; 
import android.text.Html; 
import android.text.TextWatcher; 
import android.util.Base64; 
import android.util.Base64OutputStream; 
import android.util.Log; 
import android.view.Menu; 
import android.view.MenuItem; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.AdapterView; 
import android.widget.Button; 
import android.widget.EditText; 
import android.widget.RelativeLayout; 
import android.widget.Spinner; 
import android.widget.TextView; 
import android.widget.Toast; 
import android.widget.AdapterView.OnItemSelectedListener; 
import android.widget.ArrayAdapter; 

public class Employee_Reg extends Activity implements OnItemSelectedListener, OnClickListener { 
    byte[] bytes; 
    RelativeLayout rl; 
    String strCat1, strCat2, imagePath, docPath, result, displayName, encodedFile; 
    Spinner spCat1, spCat2; 
    Button b1, b2, b3; 
    EditText ed1, ed2, ed3, ed4, ed5, ed6, ed7, ed8, ed9, ed10, ed11; 
    String fullname, password, comfPassword, gender, email, contAddr, phoneNo, mobileNo, currLoc, currSal, currInd, 
      quali, carProfile, path, path2; 

    Intent intent; 
    TextView txt1, txt2, txt3, txt4, txt5, txt6, txt7; 
    int counter = 3; 
    Uri filePath, filePath2; 

    String URL = "http://www.aquabytestechnologies.com/aquacareer/android/employeeregister.php"; 
    // Alert Dialog Manager 
    AlertDialogManager alert = new AlertDialogManager(); 

    public static final String KEY_IMAGE = "image"; 
    public static final String KEY_FILE = "file"; 

    // Image request code 
    private int PICK_IMAGE_REQUEST = 2; 
    private int PICK_FILE_REQUEST = 1; 

    // storage permission code 
    private static final int STORAGE_PERMISSION_CODE = 123; 

    InputStream inputStream = null ; 
    ByteArrayOutputStream output = null; 
    Base64OutputStream output64 = null; 


    // Uri to store the image uri 
    // private Uri filePath; 
    private File fileDoc; 
    private Bitmap bitmap; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_employee_reg); 

     // getActionBar().setTitle(Html.fromHtml("<font color='#FFFFFF' > 
     // AquaCareer </font>")); 
     getActionBar().setTitle(Html.fromHtml("<font color='#FFFFFF' ><h1>AquaCareer</h1></font>")); 
     getActionBar().setBackgroundDrawable(new ColorDrawable(Color.parseColor("#1c2833"))); 

     b1 = (Button) findViewById(R.id.button1); 
     b2 = (Button) findViewById(R.id.button2); 
     b3 = (Button) findViewById(R.id.button3); 
     ed1 = (EditText) findViewById(R.id.txt1); 
     ed2 = (EditText) findViewById(R.id.txt2); 
     ed3 = (EditText) findViewById(R.id.txt3); 
     ed4 = (EditText) findViewById(R.id.txt4); 
     ed5 = (EditText) findViewById(R.id.txt5); 
     ed6 = (EditText) findViewById(R.id.txt6); 
     ed7 = (EditText) findViewById(R.id.txt7); 
     ed8 = (EditText) findViewById(R.id.txt8); 
     ed9 = (EditText) findViewById(R.id.txt9); 
     ed10 = (EditText) findViewById(R.id.txt10); 
     ed11 = (EditText) findViewById(R.id.txt11); 

     txt1 = (TextView) findViewById(R.id.textView1); 
     txt2 = (TextView) findViewById(R.id.textView2); 
     txt3 = (TextView) findViewById(R.id.textView3); 
     txt4 = (TextView) findViewById(R.id.textView4); 
     txt5 = (TextView) findViewById(R.id.textView5); 
     txt6 = (TextView) findViewById(R.id.textView6); 
     txt7 = (TextView) findViewById(R.id.textView7); 
     txt2.setVisibility(View.GONE); 
     txt3.setVisibility(View.GONE); 
     txt5.setVisibility(View.GONE); 
     txt7.setVisibility(View.GONE); 

     spCat1 = (Spinner) findViewById(R.id.spinner1); 
     spCat2 = (Spinner) findViewById(R.id.spinner2); 

     List<String> listGender = new ArrayList<String>(); 
     listGender.add("Select Gender"); 
     listGender.add("Male"); 
     listGender.add("Female"); 
     ArrayAdapter<String> dataAdapter = new ArrayAdapter<String>(Employee_Reg.this, R.layout.spinner_item, 
       listGender); 
     dataAdapter.setDropDownViewResource(R.layout.spinner_item2); 
     spCat1.setAdapter(dataAdapter); 

     List<String> listQual = new ArrayList<String>(); 
     listQual.add("Select Highest Qualification"); 
     listQual.add("PHD"); 
     listQual.add("Masters"); 
     listQual.add("First Degree"); 
     listQual.add("HND"); 
     listQual.add("OND"); 
     listQual.add("Diploma"); 
     listQual.add("Secondary Cert"); 
     listQual.add("Primary Cert"); 
     ArrayAdapter<String> dataAdapter2 = new ArrayAdapter<String>(Employee_Reg.this, R.layout.spinner_item, 
       listQual); 
     dataAdapter2.setDropDownViewResource(R.layout.spinner_item2); 
     spCat2.setAdapter(dataAdapter2); 

     spCat1.setOnItemSelectedListener(this); 
     spCat2.setOnItemSelectedListener(this); 

     this.b1.setOnClickListener(this); 
     this.b2.setOnClickListener(this); 
     this.b3.setOnClickListener(this); 

     ed3.addTextChangedListener(new TextWatcher() { 
      public void afterTextChanged(Editable s) { 
       String strPass1 = ed2.getText().toString(); 
       String strPass2 = ed3.getText().toString(); 
       if (strPass1.equals(strPass2)) { 
        txt2.setVisibility(View.VISIBLE); 
        txt2.setText("Passwords Match"); 

       } else { 
        txt2.setVisibility(View.VISIBLE); 
        txt2.setText("Passwords don't Match"); 
       } 
      } 

      public void beforeTextChanged(CharSequence s, int start, int count, int after) { 
      } 

      public void onTextChanged(CharSequence s, int start, int before, int count) { 
      } 
     }); 

    } 

    @Override 
    public void onClick(View v) { 

     if (v.getId() == R.id.button1) { 
      showFileChooser(); 
     } 

     else if (v.getId() == R.id.button2) { 
      fullname = ed1.getText().toString().trim(); 
      password = ed2.getText().toString().trim(); 
      comfPassword = ed3.getText().toString().trim(); 
      gender = spCat1.getSelectedItem().toString().trim(); 
      email = ed4.getText().toString().trim(); 
      contAddr = ed5.getText().toString().trim(); 
      phoneNo = ed6.getText().toString().trim(); 
      mobileNo = ed7.getText().toString().trim(); 
      currLoc = ed8.getText().toString().trim(); 
      currSal = ed9.getText().toString().trim(); 
      currInd = ed10.getText().toString().trim(); 
      quali = spCat2.getSelectedItem().toString().trim(); 
      carProfile = ed11.getText().toString().trim(); 
      path = txt5.getText().toString().trim(); 
      path2 = txt7.getText().toString().trim(); 
      // Check if username, password is filled 
      if (fullname.trim().length() > 0 && password.trim().length() > 0 && comfPassword.trim().length() > 0 
        && gender.trim().length() > 0 && email.trim().length() > 0 && contAddr.trim().length() > 0 
        && phoneNo.trim().length() > 0 && mobileNo.trim().length() > 0 && currLoc.trim().length() > 0 
        && currSal.trim().length() > 0 && currInd.trim().length() > 0 && carProfile.trim().length() > 0 
        && path.trim().length() > 0) { 
       // For testing puspose username, password is checked with sample 
       // data3E 54 
       String strPass1 = ed2.getText().toString(); 
       String strPass2 = ed3.getText().toString(); 
       if (strPass1.equals(strPass2)) { 
        if (gender.equals("Male") || gender.equals("Female")) { 

         if (quali.equals("Select Highest Qualification")) { 
          alert.showAlertDialog(Employee_Reg.this, "Registration Failed..", "Select Qualification", 
            false); 
         } else { 

          registerUser(); 

         } 
        } else { 
         alert.showAlertDialog(Employee_Reg.this, "Registration Failed..", "Select Genger", false); 
        } 

       } else { 
        alert.showAlertDialog(Employee_Reg.this, "Registration Failed..", "Passwords don't Match", false); 
       } 

      } else { 
       // user didn't entered username or password 
       // Show alert asking him to enter the details 
       alert.showAlertDialog(Employee_Reg.this, "Registration Failed..", "Please fill all details", false); 
      } 

     } else if (v.getId() == R.id.button3) { 
      showFileChooser2(); 
     } 

    } 

    private void registerUser() { 
     register(); 
    } 

    // method to show file chooser for image 
     private void showFileChooser() { 

      Intent intent = new Intent(); 
      intent.setType("image/*"); 
      intent.setAction(Intent.ACTION_GET_CONTENT); 
      try { 
       startActivityForResult(Intent.createChooser(intent, "Select Picture"), PICK_IMAGE_REQUEST); 
      } catch (android.content.ActivityNotFoundException ex) { 
       Toast.makeText(Employee_Reg.this, "Please install a File Manager.", Toast.LENGTH_SHORT).show(); 
      } 
     } 

    // method to show file chooser for resume 
     private void showFileChooser2() { 
      Intent intent = new Intent(); 
      intent.setType("*/*"); 
      intent.setAction(Intent.ACTION_GET_CONTENT); 
      intent.addCategory(Intent.CATEGORY_OPENABLE); 
      try { 
       startActivityForResult(Intent.createChooser(intent, "Select Document"), PICK_FILE_REQUEST); 
      } catch (android.content.ActivityNotFoundException ex) { 
       Toast.makeText(Employee_Reg.this, "Please install a File Manager.", Toast.LENGTH_SHORT).show(); 
      } 

     } 

     // handling the image chooser activity result 
     @SuppressLint("InlinedApi") 
     @Override 
     protected void onActivityResult(int requestCode, int resultCode, Intent data) { 

      if (requestCode == PICK_IMAGE_REQUEST && resultCode == RESULT_OK && data != null && data.getData() != null) { 
       filePath = data.getData(); 
       try { 
        bitmap = MediaStore.Images.Media.getBitmap(getContentResolver(), filePath); 
        // imageView.setImageBitmap(bitmap); 
        int permissionCheck = ContextCompat.checkSelfPermission(this, 
          Manifest.permission.READ_EXTERNAL_STORAGE); 

        if (permissionCheck != PackageManager.PERMISSION_GRANTED) { 
         ActivityCompat.requestPermissions(this, new String[] { Manifest.permission.READ_EXTERNAL_STORAGE }, 
           STORAGE_PERMISSION_CODE); 
        } else { 

         imagePath = getPath(filePath); 
         txt5.setVisibility(View.VISIBLE); 
         txt5.setText(imagePath); 
         Log.i("Base64 imagePath", "=" + imagePath); 

         alert.showAlertDialog(Employee_Reg.this, "Image Loaded..", "Photo Successfully Selected", true); 
        } 

       } catch (IOException e) { 
        e.printStackTrace(); 
       } catch (Exception e) { 
        e.printStackTrace(); 
       } 
      } 
      if (requestCode == PICK_FILE_REQUEST && resultCode == RESULT_OK && data != null && data.getData() != null) { 
       filePath2 = data.getData(); 
       try { 
        // docPath = getPath2(filePath2); 
        String uriString = filePath2.toString(); 
        fileDoc = new File(uriString); 

        docPath = fileDoc.getAbsolutePath(); 

        if (uriString.startsWith("content://")) { 
         Cursor cursor = null; 
         try { 
          cursor = Employee_Reg.this.getContentResolver().query(filePath2, null, null, null, null); 
          if (cursor != null && cursor.moveToFirst()) { 
           displayName = cursor.getString(cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME)); 
          } 
         } finally { 
          cursor.close(); 
         } 
        } else if (uriString.startsWith("file://")) { 
         displayName = fileDoc.getName(); 
        } 

        int permissionCheck = ContextCompat.checkSelfPermission(this, 
          Manifest.permission.READ_EXTERNAL_STORAGE); 

        if (permissionCheck != PackageManager.PERMISSION_GRANTED) { 
         ActivityCompat.requestPermissions(this, new String[] { Manifest.permission.READ_EXTERNAL_STORAGE }, 
           STORAGE_PERMISSION_CODE); 
        } else { 

         txt7.setVisibility(View.VISIBLE); 
         txt7.setText(displayName); 
         //Log.i("Base64 URIString", "=" + uriString); 
         //Log.i("Base64 docPath", "=" + docPath); 
         alert.showAlertDialog(Employee_Reg.this, "Resume Loaded..", "Resume Successfully Selected", true); 
        } 

       } catch (NullPointerException e) { 
        e.printStackTrace(); 
       } catch (Exception e) { 
        e.printStackTrace(); 
       } 
      } 
      super.onActivityResult(requestCode, resultCode, data); 
     } 

     // Converting Bitmap image to Base64.encode String type 
     public String getStringImage(Bitmap bmp) { 
      ByteArrayOutputStream baos = new ByteArrayOutputStream(); 
      bmp.compress(Bitmap.CompressFormat.JPEG, 100, baos); 
      byte[] imageBytes = baos.toByteArray(); 
      String encodedImage = Base64.encodeToString(imageBytes, Base64.DEFAULT); 
      return encodedImage; 
     } 

     // Converting File to Base64.encode String type 
     public String getStringFile(File f) { 
      InputStream inputStream = null; 
       String encodedFile= "", lastVal; 
       try { 
        String uriString = filePath2.toString(); 
        f = new File(uriString).getAbsoluteFile(); 
        inputStream = new FileInputStream(f); 

       byte[] buffer = new byte[10240];//specify the size to allow 
       int bytesRead; 
       ByteArrayOutputStream output = new ByteArrayOutputStream(); 
       Base64OutputStream output64 = new Base64OutputStream(output, Base64.DEFAULT); 

        while ((bytesRead = inputStream.read(buffer)) != -1) { 
         output64.write(buffer, 0, bytesRead); 
        } 
       output64.close(); 
       encodedFile = output64.toString(); 
       } 
       catch (FileNotFoundException e1) { 
         e1.printStackTrace(); 
        } 
        catch (IOException e) { 
         e.printStackTrace(); 
        } 
       Log.i("Base64 String", "=" + encodedFile); 
       Log.v("Base64 String", "=" + encodedFile); 
       Log.e("Base64 String", "=" + encodedFile); 
       lastVal = encodedFile; 
       return lastVal; 

     } 




     // method to get the file Name from uri 
     public String getPath(Uri uri) { 

      String uriString = uri.toString(); 
      File myFile = new File(uriString); 

      @SuppressWarnings("unused") 
      String mPath = myFile.getAbsolutePath(); 
      String dispName = null; 

      if (uriString.startsWith("content://")) { 
       Cursor cursor = null; 
       try { 
        cursor = Employee_Reg.this.getContentResolver().query(uri, null, null, null, null); 
        if (cursor != null && cursor.moveToFirst()) { 
         dispName = cursor.getString(cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME)); 
        } 
       } finally { 
        cursor.close(); 
       } 
      } else if (uriString.startsWith("file://")) { 
       dispName = myFile.getName(); 
      } 

      return dispName; 
     } 

     // Requesting permission 
     @SuppressLint("InlinedApi") 
     private void requestStoragePermission() { 
      if (ContextCompat.checkSelfPermission(this, 
        Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) 
       return; 

      if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.READ_EXTERNAL_STORAGE)) { 
       // If the user has denied the permission previously your code will 
       // come to this block 
       // Here you can explain why you need this permission 
       // Explain here why you need this permission 

      } 
      // And finally ask for the permission 
      ActivityCompat.requestPermissions(this, new String[] { Manifest.permission.READ_EXTERNAL_STORAGE }, 
        STORAGE_PERMISSION_CODE); 
     } 

     // This method will be called when the user will tap on allow or deny 
     @Override 
     public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, 
       @NonNull int[] grantResults) { 

      // Checking the request code of our request 
      if (requestCode == STORAGE_PERMISSION_CODE) { 

       // If permission is granted 
       if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) { 
        // Displaying a toast 
        Toast.makeText(this, "Permission granted now you can read the storage", Toast.LENGTH_LONG).show(); 
       } else { 
        // Displaying another toast if permission is not granted 
        Toast.makeText(this, "Oops you just denied the permission", Toast.LENGTH_LONG).show(); 
       } 
      } 
     } 

     @Override 
     public boolean onCreateOptionsMenu(Menu menu) { 
      // Inflate the menu; this adds items to the action bar if it is present. 
      getMenuInflater().inflate(R.menu.signup, menu); 
      return true; 
     } 

     @Override 
     public boolean onOptionsItemSelected(MenuItem item) { 
      // Handle action bar item clicks here. The action bar will 
      // automatically handle clicks on the Home/Up button, so long 
      // as you specify a parent activity in AndroidManifest.xml. 
      int id = item.getItemId(); 

      if (id == R.id.abt) { 
       Toast.makeText(this, "We are in About US", Toast.LENGTH_LONG).show(); 
       return true; 
      } 
      if (id == R.id.conUs) { 
       Toast.makeText(this, "We are in Contact Us", Toast.LENGTH_LONG).show(); 
       return true; 
      } 

      return super.onOptionsItemSelected(item); 
     } 

     @Override 
     public void onItemSelected(AdapterView<?> parent, View view, int position, long id) { 

     } 

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

     } 
    private void register() { 

     class RegisterUser extends AsyncTask<Void, Void, String> { 
      ProgressDialog loading; 
      final String fullname = ed1.getText().toString().trim(); 
      final String password = ed2.getText().toString().trim(); 
      // final String comfPassword = ed3.getText().toString().trim(); 
      final String gender = spCat1.getSelectedItem().toString().trim(); 
      final String email = ed4.getText().toString().trim(); 
      final String contAddr = ed5.getText().toString().trim(); 
      final String phoneNo = ed6.getText().toString().trim(); 
      final String mobileNo = ed7.getText().toString().trim(); 
      final String currLoc = ed8.getText().toString().trim(); 
      final String currSal = ed9.getText().toString().trim(); 
      final String currInd = ed10.getText().toString().trim(); 
      final String quali = spCat2.getSelectedItem().toString().trim(); 
      final String carProfile = ed11.getText().toString().trim(); 
      final String path = txt5.getText().toString().trim(); 
      final String path2 = txt7.getText().toString().trim(); 
      final String image = getStringImage(bitmap); 
      final String file = getStringFile(fileDoc); 
      RequestHandler rh = new RequestHandler(); 





      @Override 
      protected void onPreExecute() { 
       super.onPreExecute(); 
       loading = ProgressDialog.show(Employee_Reg.this, "Please Wait: ", "Performing Registration", true, 
         true); 
      } 

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


       HashMap<String, String> param = new HashMap<String, String>(); 
       param.put("fullname", fullname); 
       param.put("email", email); 
       param.put("password", password); 
       param.put("gender", gender); 
       param.put("contAddr", contAddr); 
       param.put("phoneNo", phoneNo); 
       param.put("mobileNo", mobileNo); 
       param.put("currLoc", currLoc); 
       param.put("currSal", currSal); 
       param.put("currInd", currInd); 
       param.put("quali", quali); 
       param.put("carProfile", carProfile); 
       param.put("path", path); 
       param.put("path2", path2); 
       param.put(KEY_IMAGE, image); 
       param.put(KEY_FILE, file); 

       String result = rh.sendPostRequest(URL, param); 

       return result; 

      } 

      @Override 
      protected void onPostExecute(String s) { 
       super.onPostExecute(s); 
       loading.dismiss(); 
       if (s.equalsIgnoreCase("Sorry, email id already exists")) { 

        alert.showAlertDialog(Employee_Reg.this, "Registration Failed..", 
          "Sorry, email id already exists, choose another email.", false); 
       } else if (s.equalsIgnoreCase("success")) { 
        alert.showAlertDialog(Employee_Reg.this, "Successful Registration..", 
          "We have just sent you an email for confirmation before you log-in.", true); 
        ed1.setText(""); 
        ed2.setText(""); 
        ed3.setText(""); 
        ed4.setText(""); 
        ed5.setText(""); 
        ed6.setText(""); 
        ed7.setText(""); 
        ed8.setText(""); 
        ed9.setText(""); 
        ed10.setText(""); 
        ed11.setText(""); 
        txt5.setText(""); 
        txt7.setText(""); 
        txt3.setVisibility(View.VISIBLE); 
        txt3.setText("We have just sent you an email for confirmation before you log-in."); 

       } else if (s.equalsIgnoreCase("test")) { 
        // username/password doesn't match 
        alert.showAlertDialog(Employee_Reg.this, "Registration Failed..", 
          "You cannot register empty details", false); 

       } else { 
        // if no category not is selected 
        alert.showAlertDialog(Employee_Reg.this, "Registration Failed..", s, false); 

       } 
      } 

     } 

     RegisterUser ru = new RegisterUser(); 
     ru.execute(); 
     } 

} 

Answer 1

null値を返す特定の関数が正しい関数であることに気付きましたが、なぜNULL値を戻していたのかを知ることにしました。

次のオブジェクト型と値型の変数をグローバルに宣言してから、onCreate（）メソッドでそれらを初期化することにしました。最後に

InputStream inputStream = null ; 
    ByteArrayOutputStream output = null; 
    Base64OutputStream output64 = null; 
    byte[] buffer; 
    int bytesRead; 
    String encodedFile; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 

     buffer = new byte[10240];//specify the size to allow 

     output = new ByteArrayOutputStream(); 
     output64 = new Base64OutputStream(output, Base64.DEFAULT); 


     encodedFile = output64.toString(); 
} 



public String getStringFile(File f) { 
      InputStream inputStream = null; 

       try { 
        //Please remember that filePath2 is an object of Uri 
        String uriString = filePath2.toString(); 
        f = new File(uriString).getAbsoluteFile(); 
        inputStream = new FileInputStream(f); 



        while ((bytesRead = inputStream.read(buffer)) != -1) { 
         output64.write(buffer, 0, bytesRead); 
        } 
       output64.close(); 
       encodedFile = output64.toString(); 
       } 
       catch (FileNotFoundException e1) { 
         e1.printStackTrace(); 
        } 
        catch (IOException e) { 
         e.printStackTrace(); 
        } 


       return encodedFile; 

     } 

、の変数（すなわち値またはオブジェクト型の変数）は、任意でそれらの値を返すために彼らのためのonCreateメソッドで初期化する必要があるアクティビティクラスの中に別々にアクセスすることが期待されるグローバルに宣言ことに注意してみましょうそれ以外の場合は別の値で再初期化したい場合を除いて呼び出されるクラスのポイントです。