android - 当我在主活动中使用开始按钮访问登录活动时，为什么我的应用程序会崩溃？

问题描述

当我在主要活动上单击按钮开始时，在它打开登录活动之前崩溃。我该怎么做才能阻止应用程序崩溃？

我已将应用程序连接到 firebase 并编写了我认为正确的代码。请帮助解决我可能弄错的代码。

我希望当我单击主要活动中的按钮打开需要用户电子邮件和密码的登录活动并成功弹出登录活动时。相反，我收到“已停止”消息。

的代码MainActivity.java

package com.kiki.doctorlocation;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

import com.google.firebase.auth.FirebaseAuth;

public class MainActivity extends AppCompatActivity {

    FirebaseAuth mAuth;
    FirebaseAuth.AuthStateListener mAuthListner;

    protected void onStart() {
        super.onStart();
        mAuth.addAuthStateListener(mAuthListner);
    }

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

        Button btn = (Button) findViewById(R.id.startbtn);
        mAuth = FirebaseAuth.getInstance();

        mAuthListner = new FirebaseAuth.AuthStateListener() {
            @Override
            public void onAuthStateChanged(@NonNull FirebaseAuth firebaseAuth) {
                if (firebaseAuth.getCurrentUser() == null) {
                    startActivity(new Intent(MainActivity.this, login.class));
                }
            }
        };


        btn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                mAuth.signOut();
            }
        });

    }
}

代码MainActivity.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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"
    android:background="@drawable/docto"
    tools:context=".MainActivity">

    <RelativeLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <Button
            android:id="@+id/startbtn"
            android:layout_width="200dp"
            android:layout_height="wrap_content"
            android:text="START"
            android:layout_gravity="center_horizontal"
            android:layout_centerInParent="true"
            android:background="@drawable/roundbtn"/>
    </RelativeLayout>

</androidx.constraintlayout.widget.ConstraintLayout>

的代码login.java

package com.kiki.doctorlocation;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import android.app.ProgressDialog;
import android.os.Bundle;
import android.text.TextUtils;
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 login extends AppCompatActivity {

    private EditText txtemail, txtpassword;
    private TextView txtsign_up;
    private Button btnlogin;

    private ProgressDialog progressDialog;

    private FirebaseAuth firebaseAuth;

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

        firebaseAuth = FirebaseAuth.getInstance();

        progressDialog = new ProgressDialog(this);

        txtemail = (EditText) findViewById(R.id.txtemail);
        txtpassword = (EditText) findViewById(R.id.txtpassword);
        txtsign_up = (TextView) findViewById(R.id.txtsign_up);
        btnlogin = (Button) findViewById(R.id.btnlogin);

        btnlogin.setOnClickListener((View.OnClickListener) this);
        txtsign_up.setOnClickListener((View.OnClickListener) this);
    }

    public void registerUser() {
        String email = txtemail.getText().toString().trim();
        String password = txtpassword.getText().toString().trim();

        if(TextUtils.isEmpty(email)){
            //if email is empty
            Toast.makeText(this, "Email is required", Toast.LENGTH_SHORT).show();
            return;
        }
        if(TextUtils.isEmpty(password)){
            //if password is empty
            Toast.makeText(this,"Password is required", Toast.LENGTH_SHORT).show();
            return;
        }

        //if user is validated
        progressDialog.setMessage("Logging user in...");
        progressDialog.show();

        firebaseAuth.createUserWithEmailAndPassword(email, password)
                .addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
                    @Override
                    public void onComplete(@NonNull Task<AuthResult> task) {
                        if(task.isSuccessful())
                        {
                            Toast.makeText(login.this, "Log in Successful", Toast.LENGTH_SHORT).show();
                        }else{
                            Toast.makeText(login.this, "Log in Failed, Please try again", Toast.LENGTH_SHORT).show();
                        }


                    }
                });
    }

    public void onClick(View view){
        if(view == btnlogin ){
            registerUser();
        }
        if(view == txtsign_up){
            //open signup activity
        }
    }
}

代码login.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:background="@drawable/doc"
    android:orientation="vertical"
    android:gravity="center"
    tools:context=".login">

    <EditText
        android:id="@+id/txtemail"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:ems="10"
        android:background="@drawable/roundsedttxt"
        android:hint="Enter email"
        android:textAlignment="center"
        android:inputType="textEmailAddress"
        android:layout_margin="10dp"/>


    <EditText
        android:id="@+id/txtpassword"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:ems="10"
        android:background="@drawable/roundsedttxt"
        android:hint="Password"
        android:textAlignment="center"
        android:inputType="textPassword"
        android:layout_margin="10dp"/>

    <Button
        android:id="@+id/btnlogin"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@drawable/roundbtn"
        android:text="Login"
        android:layout_margin="10dp"/>

    <TextView
        android:id="@+id/txtsign_up"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Create a new account"
        android:textStyle="bold"
        android:textAllCaps="true"
        android:textAlignment="center"
        android:textAppearance="@color/common_google_signin_btn_text_dark"
        android:textColor="#FFFFFF"
        android:layout_margin="10dp"/>

</LinearLayout>

标签： android

android - 当我在主活动中使用开始按钮访问登录活动时，为什么我的应用程序会崩溃？

问题描述

解决方案

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