Question

我只是想使用Google Firebase制作一个电子商务应用程序。我无法解决此问题。该应用程序无法正常运行。当我打开应用程序时，它会关闭并显示一条消息“不幸的是，应用程序名称已停止工作”

这是我的原木猫

05-03 22：57：14.128 2789-2789 / com.eternity.yellaecom E / AndroidRuntime：致命异常：主要流程：com.eternity.yellaecom，PID：2789 java.lang.NullPointerException：无法为child（）中的参数'pathString'传递null 位于com.google.firebase.database.DatabaseReference.child（未知来源）位于com.google.firebase.database.DataSnapshot.child（未知来源）在com.eternity.yellaecom.MainActivity $ 3.onDataChange（MainActivity.java:83） com.google.firebase.database.zzp.onDataChange（未知来源）在com.google.android.gms.internal.zzegf.zza（未知来源） com.google.android.gms.internal.zzeia.zzbyc（未知来源） com.google.android.gms.internal.zzeig.run（未知来源）在android.os.Handler.handleCallback（Handler.java:739）在android.os.Handler.dispatchMessage（Handler.java:95）在android.os.Looper.loop（Looper.java:148）在android.app.ActivityThread.main（ActivityThread.java:5437）在java.lang.reflect.Method.invoke（本机方法）在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:726）在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:616）

这是MainActivity.java代码

package com.eternity.yellaecom;

import android.app.ProgressDialog;
import android.content.Intent;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

import com.eternity.yellaecom.Model.Users;
import com.eternity.yellaecom.Prevalent.Prevalent;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;

import io.paperdb.Paper;

public class MainActivity extends AppCompatActivity {
    private Button joinNowButton, loginButton;
    private ProgressDialog loadingBar;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        joinNowButton = (Button) findViewById(R.id.main_join_now_btn);
        loginButton = (Button) findViewById(R.id.main_login_btn);
        loadingBar = new ProgressDialog(this);

        Paper.init(this);

        loginButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Intent intent = new Intent(MainActivity.this, LoginActivity.class);
                startActivity(intent);
            }
        });


        joinNowButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view)
            {
                Intent intent = new Intent(MainActivity.this, RegisterActivity.class);
                startActivity(intent);
            }
        });

        String UserPhoneKey = Paper.book().read(Prevalent.UserPhoneKey);
        String UserPasswordKey = Paper.book().read(Prevalent.UserPasswordKey);

        if (UserPhoneKey != "" && UserPasswordKey != "")
        {
            if (!TextUtils.isEmpty(UserPhoneKey) && !TextUtils.isEmpty(UserPasswordKey));
            {
                AllowAccess(UserPhoneKey, UserPasswordKey);

                loadingBar.setTitle("Already Logged in");
                loadingBar.setMessage("Please wait....");
                loadingBar.setCanceledOnTouchOutside(false);
                loadingBar.show();
            }
        }
    }

    private void AllowAccess(final String phone, final String password)
    {
        final DatabaseReference RootRef;
        RootRef = FirebaseDatabase.getInstance().getReference();

        RootRef.addListenerForSingleValueEvent(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot dataSnapshot)
            {
                if (dataSnapshot.child("Users").child(phone).exists())
                {
                    Users usersData = dataSnapshot.child("Users").child(phone).getValue(Users.class);

                    if (usersData.getPhone().equals(phone))
                    {
                        if (usersData.getPassword().equals(password))
                        {
                            Toast.makeText(MainActivity.this, "Please wait, you are already logged in...", Toast.LENGTH_SHORT).show();
                            loadingBar.dismiss();

                            Intent intent = new Intent(MainActivity.this, HomeActivity.class);
                            Prevalent.currentOnlineUser = usersData;
                            startActivity(intent);
                        }
                        else
                        {
                            loadingBar.dismiss();
                            Toast.makeText(MainActivity.this, "Password is incorrect.", Toast.LENGTH_SHORT).show();
                        }
                    }
                }
                else
                {
                    Toast.makeText(MainActivity.this, "Account with this " + phone + " number do not exists.", Toast.LENGTH_SHORT).show();
                    loadingBar.dismiss();
                }
            }

            @Override
            public void onCancelled(@NonNull DatabaseError databaseError) {

            }
        });
    }
}

不幸的是我的应用无法正常运行

0 个答案: