无法解析符号 'LocalBroadcastManager'

Question

我关注了 Youtube 教程 (https://www.youtube.com/watch?v=y8R2C86BIUc&list=PLgCYzUzKIBE8KHMzpp6JITZ2JxTgWqDH2) and in the last step the tutor was using a class called LocalBroadcastManager. But this class isn't supported anymore.. (https://developer.android.com/reference/androidx/localbroadcastmanager/content/LocalBroadcastManager)，Android Studio 无法编译因此 class/error。据我了解-我是Android Studio/Java的新手-有一个选项可以将项目迁移到androidx-libraries以获取代码运行但我不知道如何。

如果我问的是一个绝对初学者的问题，请给我一个提示，我可以从哪里获得基本信息来解决我的问题。另外 Android Studio changing/developing 非常快，因此据我所知，那里的解决方案不再是最新的。

我尝试了一些来自 Whosebug 的解决方案，但我不知道把什么放在哪里，因为我是一个绝对的初学者。

build.gradle（模块：应用程序）：

apply plugin: 'com.android.application'


android {
    compileSdkVersion 29
    buildToolsVersion "29.0.0"
    defaultConfig {
        applicationId "com.example.btytcodingwithmitch"
        minSdkVersion 15
        targetSdkVersion 29
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'androidx.appcompat:appcompat:1.1.0-rc01'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.0-beta2'
    testImplementation 'junit:junit:4.13-beta-3'
    androidTestImplementation 'androidx.test:runner:1.3.0-alpha01'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0-alpha01'
    }

BluetoothConnectionServer.java:

package com.example.btytcodingwithmitch;

import android.app.ProgressDialog;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothServerSocket;
import android.bluetooth.BluetoothSocket;
import android.content.Context;
import android.content.Intent;
import android.util.Log;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.Charset;
import java.security.PrivateKey;
import java.util.UUID;

public class BluetoothConnectionService {

  ...

   private class ConnectedThread extends Thread{

        private final BluetoothSocket mmSocket;
        private final InputStream mmInStream;
        private final OutputStream mmOutStream;


        public void run(){
            byte[] buffer = new byte[1024]; //buffer store for stream

            int bytes; //bytes returned from read

            while (true){
                //read from Input Stream
                try {
                    bytes = mmInStream.read(buffer);
                    String incomingMessage = new String(buffer, 0, bytes);
                    Log.d(TAG, "InputStream" + incomingMessage);

                    Intent incomingMessageIntent = new Intent("incoming Message");
                    incomingMessageIntent.putExtra("theMessage", incomingMessage);

                    LocalBroadcastManager.getInstance(mContext).sendBroadcast(incomingMessageIntent);

                } catch (IOException e) {
                    Log.e(TAG, "write: Error reading inputstream" + e.getMessage());
                    break;
                }
            }
        }

错误消息：

"error: cannot find symbol variable LocalBroadcastManager"

Answer 1

将此添加到您的 app/build.gradle 文件中，在 dependencies:

中

implementation 'androidx.localbroadcastmanager:localbroadcastmanager:1.0.0'

然后重建项目

这应该有效

无法解析符号 'LocalBroadcastManager'

Cannot resolve symbol 'LocalBroadcastManager'

android

libraries

build.gradle（模块：应用程序）：

BluetoothConnectionServer.java: