通过匹配父节点更新数据 - Firebase 数据库

Question

我想更新我的密码值，我将输入用户名并搜索与用户名文本匹配的父节点以更改密码。 这是我的代码

db = FirebaseDatabase.getInstance().getReference();

    logIn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            progressDialog.setMessage("Changing Password");
            newPassword();
            progressDialog.dismiss();
            Toast.makeText(getApplicationContext(), "Change successful.", Toast.LENGTH_LONG).show();
        }
    });//inside of onCreate method


private void newPassword(){

    if(TextUtils.isEmpty(userText.getText().toString().trim())){
        progressDialog.dismiss();
        Toast.makeText(this, "Input username.", Toast.LENGTH_LONG).show();
        return;
    }
    if(TextUtils.isEmpty(emailText.getText().toString().trim())){
        progressDialog.dismiss();
        Toast.makeText(this, "Input email.", Toast.LENGTH_LONG).show();
        return;
    }
    if(TextUtils.isEmpty(contactText.getText().toString().trim())){
        progressDialog.dismiss();
        Toast.makeText(this, "Input contact no.", Toast.LENGTH_LONG).show();
        return;
    }
    if(TextUtils.isEmpty(firstText.getText().toString().trim())){
        progressDialog.dismiss();
        Toast.makeText(this, "Input first name.", Toast.LENGTH_LONG).show();
        return;
    }
    if(TextUtils.isEmpty(lastText.getText().toString().trim())){
        progressDialog.dismiss();
        Toast.makeText(this, "Input last name.", Toast.LENGTH_LONG).show();
        return;
    }
    if(TextUtils.isEmpty(password.getText().toString().trim())){
        progressDialog.dismiss();
        Toast.makeText(this, "Input password.", Toast.LENGTH_LONG).show();
        return;
    }
    if(TextUtils.isEmpty(retype.getText().toString().trim())){
        progressDialog.dismiss();
        Toast.makeText(this, "Input retype password.", Toast.LENGTH_LONG).show();
        return;
    }

    db.addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            String username = userText.getText().toString().trim();
            for(DataSnapshot ds: dataSnapshot.getChildren()){
                if(username.matches(ds.getKey())){
                    user.setPassword(password.getText().toString().trim());
                    ds.getRef().child(username).child("password").setValue(user.getPassword());
                }
            }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {
            Log.d("User", databaseError.getMessage());
        }
    });

}

我的问题是如何到达要更改其值的节点，并且每次按下按钮时，密码的值都不会改变。

感谢您的帮助。

已编辑

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

    ...

    progressDialog = new ProgressDialog(this);
    db = FirebaseDatabase.getInstance().getReference();

    db.child("users").addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {

            username = (String)dataSnapshot.child(userText.getText().toString().trim()).child("username").getValue();
            address = (String)dataSnapshot.child(userText.getText().toString().trim()).child("address").getValue();
            contact = (String)dataSnapshot.child(userText.getText().toString().trim()).child("contact").getValue();
            email = (String)dataSnapshot.child(userText.getText().toString().trim()).child("email").getValue();
            first = (String)dataSnapshot.child(userText.getText().toString().trim()).child("first").getValue();
            last = (String)dataSnapshot.child(userText.getText().toString().trim()).child("last").getValue();
            pass = passwordText.getText().toString().trim();
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {
            Toast.makeText(ForgotPassword.this, "Database Error", Toast.LENGTH_LONG).show();
            Intent i = new Intent(ForgotPassword.this, SignIn.class);
            startActivity(i);
        }
    });

    logIn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            newPassword();
        }
    });

    cancel.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent i = new Intent(ForgotPassword.this, SignIn.class);
            startActivity(i);
        }
    });
}

private void newPassword(){

    ...
    user = new User(first, last, email, contact, pass, username, address);
    db.child("users").child(username).setValue(user);
    Toast.makeText(getApplicationContext(), "Change successful.", Toast.LENGTH_LONG).show();
    Intent i = new Intent(this, TabMenu.class);
    startActivity(i);
}

每次我开始这个活动时，它都会立即在onCancelled(DatabaseError){Toast.makeText(..., "Database Error", ...).show();}上给出错误

Answer 1

如果你想在Java中比较两个字符串，你需要使用equals方法而不是matches。

matches 方法判断这个字符串是否匹配给定的正则表达式。

调用这种形式为 str.matches(regex) 的方法会产生与表达式完全相同的结果

java.util.regex.Pattern.matches(regex, str).

所以改变这行代码：

username.matches(ds.getKey())

与

username.equals(ds.getKey())

要更改密码，你只需要直接在引用上使用setValue()方法，如下所示：

DatabaseReference rootRef = FirebaseDatabase.getInstance().getReference();
rootRef.child("users").child("brian").child("password").setValue("newPassword");