java - 第一次登录验证不起作用

Question

我正在 Android 应用程序中处理登录 Activity 。我正在使用 Android Studio 中的模板，但几乎没有修改。

当我第一次尝试登录时，出现“密码错误”错误，但当我尝试使用相同的数据第二次登录时，一切正常。

我认为问题出在这里

public class UserLoginTask extends AsyncTask<Void, Void, Boolean> {

        private final String mEmail;
        private final String mPassword;

        UserLoginTask(String email, String password) {
            mEmail = email;
            mPassword = password;
        }

        @RequiresApi(api = Build.VERSION_CODES.KITKAT)
        @Override
        protected Boolean doInBackground(Void... params) {

            try {
                Call<User> call = apiService.DataForUser(mEmail);
                call.enqueue(new Callback<User>() {
                    @Override
                    public void onResponse(Call<User> call, Response<User> response) {
                        user=response.body();
                    }

                    @Override
                    public void onFailure(Call<User> call, Throwable t) {

                    }
                });
            } catch (Exception e) {
                return false;
            }

            if(user!=null)
            {
                String hash_pass = Hashing.sha256()
                        .hashString(mPassword, StandardCharsets.UTF_8)
                        .toString();

                if(hash_pass.equals(user.getPassword())) {
                    return true;
                }
                else
                {
                    return false;
                }
            }
            else
            {
                return false;
            }
        }

        @Override
        protected void onPostExecute(final Boolean success) {
            mAuthTask = null;
            showProgress(false);

            if (success) {
                Switch();
            } else {
                mPasswordView.setError(getString(R.string.error_incorrect_password));
                mPasswordView.requestFocus();
            }
        }

        @Override
        protected void onCancelled() {
            mAuthTask = null;
            showProgress(false);
        }
    }

Activity 类中的所有代码:

    public class LoginActivity extends AppCompatActivity implements LoaderCallbacks<Cursor> {

    /**
     * Id to identity READ_CONTACTS permission request.
     */
    private static final int REQUEST_READ_CONTACTS = 0;

    /**
     * Keep track of the login task to ensure we can cancel it if requested.
     */
    private UserLoginTask mAuthTask = null;

    // UI references.
    private AutoCompleteTextView mEmailView;
    private EditText mPasswordView;
    private View mProgressView;
    private View mLoginFormView;

    //Retrofit
    private Api api;
    private ApiService apiService;

    //User
    User user = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_login);
        // Set up the login form.
        mEmailView = (AutoCompleteTextView) findViewById(R.id.email);
        populateAutoComplete();

        mPasswordView = (EditText) findViewById(R.id.password);
        mPasswordView.setOnEditorActionListener(new TextView.OnEditorActionListener() {
            @Override
            public boolean onEditorAction(TextView textView, int id, KeyEvent keyEvent) {
                if (id == R.id.login || id == EditorInfo.IME_NULL) {
                    attemptLogin();
                    return true;
                }
                return false;
            }
        });

        Button mEmailSignInButton = (Button) findViewById(R.id.email_sign_in_button);
        mEmailSignInButton.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View view) {
                attemptLogin();
            }
        });

        mLoginFormView = findViewById(R.id.login_form);
        mProgressView = findViewById(R.id.login_progress);

        //Retrofit
        api = Api.getInstance();
        apiService = api.getApiService();
    }

    private void populateAutoComplete() {
        if (!mayRequestContacts()) {
            return;
        }

        getLoaderManager().initLoader(0, null, this);
    }

    private boolean mayRequestContacts() {
        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.M) {
            return true;
        }
        if (checkSelfPermission(READ_CONTACTS) == PackageManager.PERMISSION_GRANTED) {
            return true;
        }
        if (shouldShowRequestPermissionRationale(READ_CONTACTS)) {
            Snackbar.make(mEmailView, R.string.permission_rationale, Snackbar.LENGTH_INDEFINITE)
                    .setAction(android.R.string.ok, new View.OnClickListener() {
                        @Override
                        @TargetApi(Build.VERSION_CODES.M)
                        public void onClick(View v) {
                            requestPermissions(new String[]{READ_CONTACTS}, REQUEST_READ_CONTACTS);
                        }
                    });
        } else {
            requestPermissions(new String[]{READ_CONTACTS}, REQUEST_READ_CONTACTS);
        }
        return false;
    }

    /**
     * Callback received when a permissions request has been completed.
     */
    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
                                           @NonNull int[] grantResults) {
        if (requestCode == REQUEST_READ_CONTACTS) {
            if (grantResults.length == 1 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                populateAutoComplete();
            }
        }
    }


    /**
     * Attempts to sign in or register the account specified by the login form.
     * If there are form errors (invalid email, missing fields, etc.), the
     * errors are presented and no actual login attempt is made.
     */
    private void attemptLogin() {
        if (mAuthTask != null) {
            return;
        }

        // Reset errors.
        mEmailView.setError(null);
        mPasswordView.setError(null);

        // Store values at the time of the login attempt.
        String email = mEmailView.getText().toString();
        String password = mPasswordView.getText().toString();

        boolean cancel = false;
        View focusView = null;

        // Check for a valid password, if the user entered one.
        if (!TextUtils.isEmpty(password) && !isPasswordValid(password)) {
            mPasswordView.setError(getString(R.string.error_invalid_password));
            focusView = mPasswordView;
            cancel = true;
        }

        // Check for a valid email address.
        if (TextUtils.isEmpty(email)) {
            mEmailView.setError(getString(R.string.error_field_required));
            focusView = mEmailView;
            cancel = true;
        } else if (!isEmailValid(email)) {
            mEmailView.setError(getString(R.string.error_invalid_email));
            focusView = mEmailView;
            cancel = true;
        }

        if (cancel) {
            // There was an error; don't attempt login and focus the first
            // form field with an error.
            focusView.requestFocus();
        } else {
            // Show a progress spinner, and kick off a background task to
            // perform the user login attempt.
            showProgress(true);
            mAuthTask = new UserLoginTask(email, password);
            mAuthTask.execute((Void) null);
        }
    }

    private boolean isEmailValid(String email) {
        //TODO: Replace this with your own logic
        return email.contains("@");
    }

    private boolean isPasswordValid(String password) {
        //TODO: Replace this with your own logic
        return password.length() > 4;
    }

    /**
     * Shows the progress UI and hides the login form.
     */
    @TargetApi(Build.VERSION_CODES.HONEYCOMB_MR2)
    private void showProgress(final boolean show) {
        // On Honeycomb MR2 we have the ViewPropertyAnimator APIs, which allow
        // for very easy animations. If available, use these APIs to fade-in
        // the progress spinner.
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB_MR2) {
            int shortAnimTime = getResources().getInteger(android.R.integer.config_shortAnimTime);

            mLoginFormView.setVisibility(show ? View.GONE : View.VISIBLE);
            mLoginFormView.animate().setDuration(shortAnimTime).alpha(
                    show ? 0 : 1).setListener(new AnimatorListenerAdapter() {
                @Override
                public void onAnimationEnd(Animator animation) {
                    mLoginFormView.setVisibility(show ? View.GONE : View.VISIBLE);
                }
            });

            mProgressView.setVisibility(show ? View.VISIBLE : View.GONE);
            mProgressView.animate().setDuration(shortAnimTime).alpha(
                    show ? 1 : 0).setListener(new AnimatorListenerAdapter() {
                @Override
                public void onAnimationEnd(Animator animation) {
                    mProgressView.setVisibility(show ? View.VISIBLE : View.GONE);
                }
            });
        } else {
            // The ViewPropertyAnimator APIs are not available, so simply show
            // and hide the relevant UI components.
            mProgressView.setVisibility(show ? View.VISIBLE : View.GONE);
            mLoginFormView.setVisibility(show ? View.GONE : View.VISIBLE);
        }
    }

    @Override
    public Loader<Cursor> onCreateLoader(int i, Bundle bundle) {
        return new CursorLoader(this,
                // Retrieve data rows for the device user's 'profile' contact.
                Uri.withAppendedPath(ContactsContract.Profile.CONTENT_URI,
                        ContactsContract.Contacts.Data.CONTENT_DIRECTORY), ProfileQuery.PROJECTION,

                // Select only email addresses.
                ContactsContract.Contacts.Data.MIMETYPE +
                        " = ?", new String[]{ContactsContract.CommonDataKinds.Email
                .CONTENT_ITEM_TYPE},

                // Show primary email addresses first. Note that there won't be
                // a primary email address if the user hasn't specified one.
                ContactsContract.Contacts.Data.IS_PRIMARY + " DESC");
    }

    @Override
    public void onLoadFinished(Loader<Cursor> cursorLoader, Cursor cursor) {
        List<String> emails = new ArrayList<>();
        cursor.moveToFirst();
        while (!cursor.isAfterLast()) {
            emails.add(cursor.getString(ProfileQuery.ADDRESS));
            cursor.moveToNext();
        }

        addEmailsToAutoComplete(emails);
    }

    @Override
    public void onLoaderReset(Loader<Cursor> cursorLoader) {

    }

    private void addEmailsToAutoComplete(List<String> emailAddressCollection) {
        //Create adapter to tell the AutoCompleteTextView what to show in its dropdown list.
        ArrayAdapter<String> adapter =
                new ArrayAdapter<>(LoginActivity.this,
                        android.R.layout.simple_dropdown_item_1line, emailAddressCollection);

        mEmailView.setAdapter(adapter);
    }


    private interface ProfileQuery {
        String[] PROJECTION = {
                ContactsContract.CommonDataKinds.Email.ADDRESS,
                ContactsContract.CommonDataKinds.Email.IS_PRIMARY,
        };

        int ADDRESS = 0;
        int IS_PRIMARY = 1;
    }

    /**
     * Represents an asynchronous login/registration task used to authenticate
     * the user.
     */
    public class UserLoginTask extends AsyncTask<Void, Void, Boolean> {

        private final String mEmail;
        private final String mPassword;

        UserLoginTask(String email, String password) {
            mEmail = email;
            mPassword = password;
        }

        @RequiresApi(api = Build.VERSION_CODES.KITKAT)
        @Override
        protected Boolean doInBackground(Void... params) {

            try {
                Call<User> call = apiService.DataForUser(mEmail);
                call.enqueue(new Callback<User>() {
                    @Override
                    public void onResponse(Call<User> call, Response<User> response) {
                        user=response.body();
                    }

                    @Override
                    public void onFailure(Call<User> call, Throwable t) {

                    }
                });
            } catch (Exception e) {
                return false;
            }

            if(user!=null)
            {
                String hash_pass = Hashing.sha256()
                        .hashString(mPassword, StandardCharsets.UTF_8)
                        .toString();

                if(hash_pass.equals(user.getPassword())) {
                    return true;
                }
                else
                {
                    return false;
                }
            }
            else
            {
                return false;
            }
        }

        @Override
        protected void onPostExecute(final Boolean success) {
            mAuthTask = null;
            showProgress(false);

            if (success) {
                Switch();
            } else {
                mPasswordView.setError(getString(R.string.error_incorrect_password));
                mPasswordView.requestFocus();
            }
        }

        @Override
        protected void onCancelled() {
            mAuthTask = null;
            showProgress(false);
        }
    }

    public void Switch (){
        Toast.makeText(LoginActivity.this, "Succes!", Toast.LENGTH_SHORT).show();
        Intent intent = new Intent(this, MainActivity.class);
        startActivity (intent);
    }
}

Answer 1

事实上，您似乎正在尝试在客户端上进行密码匹配，如果您想匹配从 API 检索的数据，这总是错误且危险的调用您必须在回调函数 onResponse 中包含您的身份验证逻辑。在您的 Activity 中，代替:

    } else {
        // Show a progress spinner, and kick off a background task to
        // perform the user login attempt.
        showProgress(true);
        mAuthTask = new UserLoginTask(email, password);
        mAuthTask.execute((Void) null);
    }

这样做是因为您不需要另一个异步任务，因为 Call 已经是异步的(请参阅@matrix 注释):

} else {
    // Show a progress spinner, and kick off a background task to
    // perform the user login attempt.
    showProgress(true);
    Call<User> call = apiService.DataForUser(email);
    call.enqueue(new Callback<User>() {
      @Override
      public void onResponse(Call<User> call, Response<User> response) {
        user=response.body();
        if(user!=null){
          String hash_pass = Hashing.sha256()
          .hashString(password, StandardCharsets.UTF_8)
          .toString();

          if(hash_pass.equals(user.getPassword())) {
            return true;
          } else {
            return false;
          }
        } else {
          return false;
        }
      }
}

请考虑此新配置调整您的 boolean 返回值，如果这是登录表单逻辑，请不要在客户端中进行密码匹配，而是在服务器上进行此操作，然后将 token 或其他内容传递给客户端。

When I am trying to sign in first time I have an error "Incorrect Password" but when I am trying sign in second time with same data everything works fine.

这是因为第一次回调没有准备好然后user是 null ，第二次用户已经从上一次调用中准备好并且逻辑正常工作