在build.gradle文件中配置Jacoco，可以使用以下代码来避免再次插装类：

android {
    buildTypes {
        debug {
            testCoverageEnabled true
        }
    }
}

jacoco {
    toolVersion = "0.8.4"
    reportsDir = file("$rootDir/reports/jacoco")
}

tasks.withType(Test) {
    jacoco.includeNoLocationClasses = true
}

task jacocoTestReport(type: JacocoReport, dependsOn: ['testDebugUnitTest']) {
    reports {
        xml.required = false
        html.enabled = true
    }

    def fileFilter = ["**/R.class", "**/R$*.class", "**/BuildConfig.*", "**/Manifest*.*", "**/*Test*.*", "android/**/*.*"]
    def debugTree = fileTree(dir: "${buildDir}/intermediates/classes/debug", excludes: fileFilter)
    def mainSrc = "${project.projectDir}/src/main/java"
    def mainJava = fileTree(dir: mainSrc, includes: ['**/*.java'])
    def jacocoTree = fileTree(dir: "${buildDir}/jacoco/testDebugUnitTest.exec", excludes: fileFilter)
    sourceDirectories = files([mainSrc])
    classDirectories = files([debugTree])
    executionData = files([jacocoTree])
}

这段代码将在测试时启用Jacoco报告，并在生成报告时排除R类，BuildConfig和测试类。注意，使用这段代码，与Jacoco一起使用的插件需要是0.8.4或更高版本的插件。