Question

我正在构建一个简单的登录应用程序。在用户注册页面中，我已经给出了检查文本字段是否为空的条件。如果它们中的任何一个是空的，则显示toast else继续进行数据库注册。但是，每当我点击regButton（注册）（注册按钮）时，无论是否输入数据，应用程序都会崩溃不管领域

package com.example.tintin.myapplication;

import android.content.Intent;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.firebase.auth.AuthResult;
import com.google.firebase.auth.FirebaseAuth;

public class RegistrationActivity extends AppCompatActivity {

    private EditText userName, userPassword, userEmail;
    private Button regButton;
    private TextView userLogin;
    private FirebaseAuth firebaseAuth;

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

        firebaseAuth = FirebaseAuth.getInstance();

        regButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                if (validate()) {
                    String user_email = userEmail.getText().toString().trim();
                    String user_password = userPassword.getText().toString().trim();

                    firebaseAuth.createUserWithEmailAndPassword(user_email, user_password).addOnCompleteListener(new OnCompleteListener<AuthResult>() {
                        @Override
                        public void onComplete(@NonNull Task<AuthResult> task) {
                            if (task.isSuccessful()) {
                                Toast.makeText(RegistrationActivity.this, "Registration Successful", Toast.LENGTH_SHORT).show();
                                startActivity(new Intent(RegistrationActivity.this, MainActivity.class));
                            } else
                                Toast.makeText(RegistrationActivity.this, "Registration Failed", Toast.LENGTH_SHORT).show();
                        }
                    });
                }


            }
        });
        userLogin.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                startActivity(new Intent(RegistrationActivity.this, MainActivity.class));
            }
        });
    }

    //Assigning variables to id
    private void setupUIViews() {
        userName = findViewById(R.id.etUserName);
        userPassword = findViewById(R.id.etPassword);
        userEmail = findViewById(R.id.etUserEmail);
        regButton = findViewById(R.id.btnSignUp);
        userLogin = findViewById(R.id.tvLogin);

    }

    //To make sure fields are not empty
    private Boolean validate() {
        Boolean result = false;
        String name = userName.getText().toString();
        String password = userPassword.getText().toString();
        String email = userEmail.getText().toString();

        if (name.isEmpty() || password.isEmpty() || email.isEmpty()) {
            Toast.makeText(RegistrationActivity.this, "Please enter all the details", Toast.LENGTH_SHORT).show();
        } else {
            result = true;
        }
        return result;
    }
}

XML布局：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.tintin.myapplication.RegistrationActivity">

    <EditText
        android:id="@+id/etUserName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:ems="10"
        android:hint="Username"
        android:inputType="textPersonName"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.503"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.095" />

    <EditText
        android:id="@+id/etUserEmail"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:ems="10"
        android:hint="Email"
        android:inputType="textEmailAddress"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.503"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/etUserName"
        app:layout_constraintVertical_bias="0.099" />

    <EditText
        android:id="@+id/etUserPassword"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:ems="10"
        android:hint="Password"
        android:inputType="textPassword"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.503"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/etUserEmail"
        app:layout_constraintVertical_bias="0.147" />

    <Button
        android:id="@+id/btnSignUp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:text="Sign Up"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/etUserPassword"
        app:layout_constraintVertical_bias="0.224" />

    <TextView
        android:id="@+id/tvLogin"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:layout_marginEnd="8dp"
        android:layout_marginStart="8dp"
        android:layout_marginTop="8dp"
        android:text="Already Signed Up? Log In"
        android:textSize="20sp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/btnSignUp" />

</android.support.constraint.ConstraintLayout>

Answer 1

使用setupUIViews方法，您可以userPassword获得对findViewById(R.id.etPassword)的引用。

但在您的布局中，EditText ID为etUserPassword，因此您应将其更改为findViewById(R.id.etUserPassword)。

所以你的setupUIViews方法应该是：

private void setupUIViews() {
    userName = findViewById(R.id.etUserName);
    userPassword = findViewById(R.id.etUserPassword);
    userEmail = findViewById(R.id.etUserEmail);
    regButton = findViewById(R.id.btnSignUp);
    userLogin = findViewById(R.id.tvLogin);

}

只要按下按钮，Android App就会崩溃

1 个答案: