谁能帮我看看这两个函数有什么问题 方法一返回空String值无任何错误，方法二返回空指针异常 我已经尝试了所有可以在这里找到的类似示例，但几天来仍然存在问题。提前致谢。
//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;
}
这是下面的完整代码。除此任务外，其他一切正常。谢谢
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();
}
}
最佳答案
我注意到返回空值的特定函数是正确的函数，然后我决定知道它返回空值的原因。
我决定全局声明以下对象和值类型变量，然后在 onCreate() 方法中初始化它们。
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;
}
最后，我们要注意，全局声明的变量(即值或对象类型变量)预计将在 Activity 类中单独访问，应该在 onCreate 方法中初始化，以便它们在类的任何点返回它们的值它将被调用，除非我们想为不同的值重新初始化它们。
关于java - 安卓方法 : Method 1 returns empty String value with error and Method 2 returns a null pointer exceptions，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/40686935/