离子:未指定compilesdkversion-找不到方法左置()

我刚刚使用ionic 4启动了我的应用。目前，我从未对您（使用Sidemenu）进行任何修改（与Sidemenu）进行任何修改。经过许多其他错误，我我不知道该如何修复它。当我尝试：

离子Cordova构建Android

    FAILURE: Build completed with 2 failures.
1: Task failed with an exception.
-----------
* Where:
Build file 'D:workspaceiganalyticsappplatformsandroidappbuild.gradle' line: 148
* What went wrong:
A problem occurred evaluating project ':app'.
> Could not find method leftShift() for arguments [build_8ka4my3njl1nfn72j8pdlyfze$_run_closure6@5b9f348] on task ':app:cdvPrintProps' of type org.gradle.api.DefaultTask.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
==============================================================================
2: Task failed with an exception.
-----------
* What went wrong:
A problem occurred configuring project ':app'.
> compileSdkVersion is not specified.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
==============================================================================
* Get more help at https://help.gradle.org
BUILD FAILED in 1s
cmd: Command failed with exit code 1 Error output:
FAILURE: Build completed with 2 failures.
1: Task failed with an exception.
-----------
* Where:
Build file 'D:workspaceiganalyticsappplatformsandroidappbuild.gradle' line: 148
* What went wrong:
A problem occurred evaluating project ':app'.
> Could not find method leftShift() for arguments [build_8ka4my3njl1nfn72j8pdlyfze$_run_closure6@5b9f348] on task ':app:cdvPrintProps' of type org.gradle.api.DefaultTask.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
==============================================================================
2: Task failed with an exception.
-----------
* What went wrong:
A problem occurred configuring project ':app'.
> compileSdkVersion is not specified.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
==============================================================================
* Get more help at https://help.gradle.org
BUILD FAILED in 1s
[ERROR] An error occurred while running subprocess cordova.
        cordova build android exited with exit code 1.
        Re-running this command with the --verbose flag may provide more information.

我将此行添加到config.xml：

<preference name="android-targetSdkVersion" value="28" />

没有运气。

build.gradle Line 148从：

task cdvPrintProps << {
    println('cdvCompileSdkVersion=' + cdvCompileSdkVersion)
    println('cdvBuildToolsVersion=' + cdvBuildToolsVersion)
    println('cdvVersionCode=' + cdvVersionCode)
    println('cdvVersionCodeForceAbiDigit=' + cdvVersionCodeForceAbiDigit)
    println('cdvMinSdkVersion=' + cdvMinSdkVersion)
    println('cdvBuildMultipleApks=' + cdvBuildMultipleApks)
    println('cdvReleaseSigningPropertiesFile=' + cdvReleaseSigningPropertiesFile)
    println('cdvDebugSigningPropertiesFile=' + cdvDebugSigningPropertiesFile)
    println('cdvBuildArch=' + cdvBuildArch)
    println('computedVersionCode=' + android.defaultConfig.versionCode)
    android.productFlavors.each { flavor ->
        println('computed' + flavor.name.capitalize() + 'VersionCode=' + flavor.versionCode)
    }
}