小组件已初始化时的空指针异常

Question

我正在尝试更改用户身份验证电子邮件。

自定义对话框

public class ConfirmPasswordDialogBox extends Dialog implements android.view.View.OnClickListener {
private ImageButton cancel, confirm;
private EditText confirm_password;
public ConfirmPasswordDialogBox(@NonNull Context context) {
super(context);

}
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.dailog_box_foremail);
confirm_password = findViewById(R.id.password);
cancel = findViewById(R.id.cancel_btn);
confirm = findViewById(R.id.confirm_btn);
cancel.setOnClickListener(this);
confirm.setOnClickListener(this);
}

@Override
public void onClick(View view) {
switch(view.getId()){
case R.id.cancel_btn:
dismiss();
break;
case R.id.confirm_btn:
String mpassword = confirm_password.getText().toString();
if(!mpassword.equals("")){
new EditProfileActivity().updatingemail(mpassword);
dismiss();
}else{
Toast.makeText(getContext(), "Password can't be empty.", Toast.LENGTH_SHORT).show();
}
break;

}
}
}

引发空指针异常的活动

public class EditProfileActivity extends AppCompatActivity {
private EditText descript, firstName, lastName, email;
private Button updatebtn;
private ImageButton back;
private Context mcontext;
private FirebaseAuth auth;
private FirebaseAuth.AuthStateListener authStateListener;
private FirebaseUser user;
private FirebaseDatabase database;
private DatabaseReference myRef;
private FirebaseMethods firebaseMethods;
private String userID;
private ProgressDialog pb;
private UserInformation userInformationx;

@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_edit_profile);
mcontext = EditProfileActivity.this;
descript = findViewById(R.id.descript);
firstName = findViewById(R.id.firstName);
email = findViewById(R.id.email);
lastName = findViewById(R.id.lastName);

auth = FirebaseAuth.getInstance();
user = auth.getCurrentUser();
firebaseMethods = new FirebaseMethods(mcontext);

pb = new ProgressDialog(this);
pb.setMessage("Updaing Profile ...");
pb.setCancelable(true);
pb.setCanceledOnTouchOutside(false);
init();
setupFirebaseAuth();

}
public void updatingemail(String password){
FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
// Get auth credentials from the user for re-authentication. The example below shows
// email and password credentials but there are multiple possible providers,
// such as GoogleAuthProvider or FacebookAuthProvider.
AuthCredential credential = EmailAuthProvider
.getCredential(user.getEmail(), password);
// Prompt the user to re-provide their sign-in credentials
user.reauthenticate(credential)
.addOnCompleteListener(new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
Log.d(TAG, "User re-authenticated.");
if(task.isSuccessful()){
FirebaseAuth.getInstance().fetchSignInMethodsForEmail(email.getText().toString()).addOnCompleteListener(new OnCompleteListener<SignInMethodQueryResult>() {
@Override
public void onComplete(@NonNull Task<SignInMethodQueryResult> task) {
if(task.isSuccessful()){
if(task.getResult().getSignInMethods().size() == 1){
Toast.makeText(mcontext, "That email is already in use.", Toast.LENGTH_SHORT).show();
}else{
FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
user.updateEmail(email.getText().toString())
.addOnCompleteListener(new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
if (task.isSuccessful()) {
Log.d(TAG, "User email address updated.");
Toast.makeText(mcontext, "Email address updated.", Toast.LENGTH_SHORT).show();
myRef.child(mcontext.getString(R.string.dbname_users))
  .child(userID)
  .child(mcontext.getString(R.string.email))
  .setValue(email.getText().toString());
}
}
});
}
}
}
});
}
}
});
}

EditText widget 已经初始化，但 email.getText.toString() 仍然抛出空值。我只是将字符串值传递给一个方法，该方法是在对话框中单击按钮时调用的。

我已经尝试并调试了我知道的所有可能的方法。

我只是在尝试更新Firebase中的用户身份验证电子邮件。

Answer 1

EditText widget 已经初始化，但 email.getText.toString() 仍然抛出空值。

实际上，EditText email仅在活动的onCreate中初始化，这意味着它仅在使用startActivity(intent)打开活动时初始化。

---

编辑- 由于您从EditProfileActivity调用ConfirmPasswordDialogBox，因此应该可以按照以下几行进行操作。

public class ConfirmPasswordDialogBox extends Dialog {
private ImageButton cancel, confirm;
public EditText confirm_password;
public ConfirmPasswordDialogBox(@NonNull Context context) {
super(context);
}
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.dailog_box_foremail);
confirm_password = findViewById(R.id.password);
cancel = findViewById(R.id.cancel_btn);
confirm = findViewById(R.id.confirm_btn);
//cancel.setOnClickListener(this);
//confirm.setOnClickListener(this);
}
public void setOnClickListeners(View.OnClickListener listener) {
cancel.setOnClickListener(listener);
confirm.setOnClickListener(listener);
}
/*
@Override
public void onClick(View view) {
switch(view.getId()){
case R.id.cancel_btn:
dismiss();
break;
case R.id.confirm_btn:
String mpassword = confirm_password.getText().toString();
if(!mpassword.equals("")){
new EditProfileActivity().updatingemail(mpassword);
dismiss();
}else{
Toast.makeText(getContext(), "Password can't be empty.", Toast.LENGTH_SHORT).show();
}
break;
}
}
*/
}

public class EditProfileActivity extends AppCompatActivity implements android.view.View.OnClickListener {
//Other code
//At some point in some method you'll create the dialog
//Say you create the dialog object here. Now set this activity as the onClickListener
dialog.setOnClickListeners(this);
@Override
public void onClick(View view) {
switch(view.getId()){
case R.id.cancel_btn:
dismiss();
break;
case R.id.confirm_btn:
String mpassword = dialog.confirm_password.getText().toString();
if(!mpassword.equals("")){
//Now you can directly call the method  
updatingemail(mpassword);
dismiss();
}else{
Toast.makeText(getContext(), "Password can't be empty.", Toast.LENGTH_SHORT).show();
}
break;
}
}
public void updatingemail(String password){
FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
// Get auth credentials from the user for re-authentication. The example below shows
// email and password credentials but there are multiple possible providers,
// such as GoogleAuthProvider or FacebookAuthProvider.
AuthCredential credential = EmailAuthProvider
.getCredential(user.getEmail(), password);
// Prompt the user to re-provide their sign-in credentials
user.reauthenticate(credential)
.addOnCompleteListener(new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
Log.d(TAG, "User re-authenticated.");
if(task.isSuccessful()){
FirebaseAuth.getInstance().fetchSignInMethodsForEmail(email.getText().toString()).addOnCompleteListener(new OnCompleteListener<SignInMethodQueryResult>() {
@Override
public void onComplete(@NonNull Task<SignInMethodQueryResult> task) {
if(task.isSuccessful()){
if(task.getResult().getSignInMethods().size() == 1){
Toast.makeText(mcontext, "That email is already in use.", Toast.LENGTH_SHORT).show();
}else{
FirebaseUser user = FirebaseAuth.getInstance().getCurrentUser();
user.updateEmail(email.getText().toString())
.addOnCompleteListener(new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
if (task.isSuccessful()) {
Log.d(TAG, "User email address updated.");
Toast.makeText(mcontext, "Email address updated.", Toast.LENGTH_SHORT).show();
myRef.child(mcontext.getString(R.string.dbname_users))
  .child(userID)
  .child(mcontext.getString(R.string.email))
  .setValue(email.getText().toString());
}
}
});
}
}
}
});
}
}
});
}