1. 更新依赖库版本

2. 引入阿里巴巴仓库地址

app/build.gradle

@@ -44,8 +44,8 @@ android {
 dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar'])
     implementation 'com.android.support:appcompat-v7:28.0.0'
-    implementation 'com.android.support.constraint:constraint-layout:2.0.0-beta2'
-    testImplementation 'junit:junit:4.13-beta-3'
+    implementation 'com.android.support.constraint:constraint-layout:2.0.0-beta4'
+    testImplementation 'junit:junit:4.13'
     androidTestImplementation 'com.android.support.test:runner:1.0.2'
     androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
     // implementation(name: 'serialport-release', ext: 'aar')

build.gradle

@@ -2,13 +2,14 @@
 
 buildscript {
     repositories {
+        maven { url 'https://maven.aliyun.com/repository/jcenter' }
+        maven { url 'https://maven.aliyun.com/repository/google' }
         google()
         jcenter()
-        
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:3.4.2'
-        
+        classpath 'com.android.tools.build:gradle:3.5.3'
+
         // NOTE: Do not place your application dependencies here; they belong
         // in the individual module build.gradle files
     }
@@ -16,9 +17,11 @@ buildscript {
 
 allprojects {
     repositories {
+        maven { url 'https://maven.aliyun.com/repository/jcenter' }
+        maven { url 'https://maven.aliyun.com/repository/central' }
+        maven { url 'https://maven.aliyun.com/repository/google' }
         google()
         jcenter()
-        
     }
 }
 

gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
-#Wed Jul 17 15:41:06 CST 2019
+#Tue Jan 14 14:44:43 CST 2020
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.1.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.4.1-all.zip

serialport/build.gradle

@@ -36,7 +36,7 @@ dependencies {
     implementation fileTree(dir: 'libs', include: ['*.jar'])
 
     implementation 'com.android.support:appcompat-v7:28.0.0'
-    testImplementation 'junit:junit:4.13-beta-3'
+    testImplementation 'junit:junit:4.13'
     androidTestImplementation 'com.android.support.test:runner:1.0.2'
     androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
     androidTestImplementation('com.android.support.test.espresso:espresso-core:3.0.2', {