【发布时间】：2021-08-24 16:29:59
【问题描述】：
我已经尝试了所有 StackOverflow 方法，但所有方法都在检查它是否为空。 我想检查“用户”节点下的特定字符串。示例： (aaaaa) (bbbbb) 或其中的子值（用户名：“aaaaa”） 如果用户在注册时输入用户名“asaaa”或“bbbbb”会提示错误。 （我想检查firebase所有节点中的所有值） 我已经搜索了整个堆栈溢出，但大多数解决方案都需要知道节点名称才能运行。我想检索“用户”下的所有节点名称以进行检查。 如果用户在注册时使用“aaaaa”作为用户名，TextInputLayout 中会出现 setError。
公共类 RegisterActivity 扩展 AppCompatActivity {
EditText username, fullname, email, password;
Button register;
TextView txt_login;
public String strUsername;
FirebaseAuth auth;
DatabaseReference reference;
ProgressDialog pd;
private static final String TAG = "RegisterActivity";
private static String users_from_database;
private ArrayList<String> username_list = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_register);
username = findViewById(R.id.username);
fullname = findViewById(R.id.fullname);
email = findViewById(R.id.email);
password = findViewById(R.id.password);
register = findViewById(R.id.btn_Register);
txt_login = findViewById(R.id.txt_login);
auth = FirebaseAuth.getInstance();
checkForUsername();
txt_login.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startActivity(new Intent(RegisterActivity.this,HomeActivity.class));
}
});
register.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
pd = new ProgressDialog(RegisterActivity.this);
pd.setMessage("Please wait...");
pd.show();
String str_username = username.getText().toString();
String str_fullname = fullname.getText().toString();
String str_email = email.getText().toString();
String str_password = password.getText().toString();
strUsername = username.getText().toString().trim();
if (!username_list.contains(strUsername)) {
// do your job here , suppose send verification code to phone number
if(TextUtils.isEmpty(str_username) || TextUtils.isEmpty(str_fullname) || TextUtils.isEmpty(str_email) ||
TextUtils.isEmpty(str_password)){
Toast.makeText(RegisterActivity.this,"All fields are required!",Toast.LENGTH_SHORT).show();
pd.dismiss();
} else if (str_password.length() < 6) {
Toast.makeText(RegisterActivity.this,"Password must be over 6 characters.",Toast.LENGTH_SHORT).show();
pd.dismiss();
} else {
register(str_username,str_fullname,str_email,str_password);
}
} else {
username.setError("Username Exist");
}
}
});
}
private void checkForUsername(){
DatabaseReference ref = FirebaseDatabase.getInstance().getReference("Users/");
ref.addListenerForSingleValueEvent(new ValueEventListener() {
@Override
public void onDataChange(@NonNull DataSnapshot snapshot) {
for (DataSnapshot ds : snapshot.getChildren()) {
users_from_database = (String) ds.child("username").getValue();
username_list.add(users_from_database);
StringBuilder stringBuilder = new StringBuilder();
for (String s : username_list) {
stringBuilder.append(s + "\n");
}
Log.d("ZI", stringBuilder.toString());
}
}
@Override
public void onCancelled(@NonNull DatabaseError error) {
Log.d("ZI", "Failed");
}
});
}
private void register(final String username, final String fullname, String email, String password){
auth.createUserWithEmailAndPassword(email, password)
.addOnCompleteListener(RegisterActivity.this, new OnCompleteListener<AuthResult>() {
@Override
public void onComplete(@NonNull Task<AuthResult> task) {
if (task.isSuccessful()){
FirebaseUser firebaseUser = auth.getCurrentUser();
String userID = firebaseUser.getUid();
firebaseUser.sendEmailVerification().addOnSuccessListener(new OnSuccessListener<Void>() {
@Override
public void onSuccess(Void aVoid) {
Toast.makeText(RegisterActivity.this,"Verification Email Has Been Sent.", Toast.LENGTH_SHORT).show();
}
}).addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
Log.d(TAG, "onFailure: Email not sent" + e.getMessage());
}
});
reference = FirebaseDatabase.getInstance().getReference().child("Users").child(username);
HashMap<String, Object> hashMap = new HashMap<>();
hashMap.put("username",username.toLowerCase());
hashMap.put("fullname",fullname);
hashMap.put("email",email);
hashMap.put("password",password);
hashMap.put("imageurl","");
reference.setValue(hashMap).addOnCompleteListener(new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
if(task.isSuccessful()){
pd.dismiss();
Intent intent = new Intent(RegisterActivity.this,EmailActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(intent);
}
}
});
} else {
pd.dismiss();
Toast.makeText(RegisterActivity.this,"Register Failed",Toast.LENGTH_SHORT).show();
}
}
});
}
}
【问题讨论】：
-
您可以在此处查看文档示例：Android developers。顺便说一句，如果您的应用程序中的用户未注册，他/她无权从数据库中读取数据，因此您无法检查，也许您应该添加一个屏幕，允许在用户注册后选择用户名登录/登录。
标签： java android firebase firebase-realtime-database snapshot