Question

我正在使用Firebase数据库在Android上工作...。使用连接到Firebase的Firebase工具，并使用该语句添加了Firebase数据库

 implementation 'com.google.firebase:firebase-core:16.0.1'

 implementation 'com.google.firebase:firebase-database:16.0.1'

我能够导入数据库参考，但不能导入FirebaseDatabase

我的gradle（app）文件

apply plugin: 'com.android.application'

     android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.example.yadav.yadavapp"
        minSdkVersion 19
        targetSdkVersion 28
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 
  'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    //noinspection GradleCompatible
    implementation 'com.android.support:appcompat-v7:28.0.0-rc01'
    implementation 'com.android.support.constraint:constraint-layout:1.1.2'
    implementation 'com.google.firebase:firebase-core:16.0.1'

    implementation 'com.google.firebase:firebase-database:16.0.1'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.2'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
    implementation 'com.android.support:support-annotations:27.1.1'
}

apply plugin: 'com.google.gms.google-services'

我的主活动文件

package com.example.yadav.yadavapp;



import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;

import com.google.firebase.database.DatabaseReference; ///working
import com.google.firebase.database.FirebaseDatabase; //cannot import

public class MainActivity extends AppCompatActivity {

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

    }
}

Answer 1

这是不合逻辑的，因为它是同一个程序包。

Android Studio只会删除所有未使用的导入

... 除非在MainActivity中使用它们。

例如：

public class MainActivity extends AppCompatActivity {

   /* when declaring these, it should import both of them */
   protected FirebaseDatabase fb = FirebaseDatabase.getInstance();
   protected DatabaseReference defaultRef = null;

   public MainActivity() {}

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

DatabaseReference导入工作正常，但是FirebaseBase无法导入

1 个答案: