開源項目：掃一掃
下載zxing-master通過AndroidStudio直接打開構建時提示Gradle問題，不了解Gradle怎么回事，更具提示dowload失敗了。
於是百度嘗試第二種方式，如下：
1.AndroidStudio本地先創建一個空項目OpenSource-scaner
2.根據OpenSource-scaner創建自動生成的Gradle配置文件修改zxing-master中對應的文件。
- app/build.gradle
compileSdkVersion、buildToolsVersion、minSdkVersion、targetSdkVersion
-gradle/wrapper/gradle-wrapper.properties
distributionUrl
-build.gradle
classpath
3.AndroidStudio->file->open打開zxing
4.等待Gradle同步
Gradle sync這時成功了。
5.（工具欄中的錘子）ctrl+F9構建一下
6.這時app/release路徑下有zxing.apk生成
安裝生成的apk到手機中，試了下識別出二維碼內容。
問題
1.安裝apk提示
Failure [INSTALL_PARSE_FAILED_NO_CERTIFICATES: Package /data/app/vmdl924957567.tmp/base.apk has no certificates at entry AndroidManifest.xml]
原因：打包的apk沒簽名，app-release-unsigned.apk。
解決：根據zxing-master build.gradle添加簽名，然后構建apk。
具體操作如下：
step1:AndroidStudio Build -> Generate Signed Bundle or APK -> APK，然后next。
step2：根據項目build.gradle添加簽名信息
Key store path選擇項目自帶的zxing.jks。
Key store password：123456
Key alias：zxingyzq
Key password：123456
step3：Build -> Make Project構建apk
這時在zxing-master\app\build\outputs\apk\debug會生成簽名apk：app-debug.apk
step4：adb install app-debug.apk安裝apk
2.打開開源Gradle Sync時提示：NDK not configured
原因：這次是因為NDK版本不一致找不到NDK導致的。
解決：指定NDK路徑
step1：右上角，打開搜索窗口，輸入Project Structure ...
step2：選Project Structure窗口download Android NDK，選擇NDK的路徑，然后apply
step3：重新同步加載
3.導入提示：Your project path contains non-ASCII characters
原因：
解決：添加android.overridePathCheck=true到gradle.properties
4.sync時
Cause: com.android.builder.sdk.LicenceNotAcceptedException: Failed to install the following Android SDK packages as some licences have not been accepted.
ndk;21.3.6528147 NDK (Side by side) 21.3.6528147
To build this project, accept the SDK license agreements and install the missing components using the Android Studio SDK Manager.
Alternatively, to transfer the license agreements from one workstation to another, see http://d.android.com/r/studio-ui/export-licenses.html
Using Android SDK: D:\Program Files\AndroidSDK
Failed to install the following Android SDK packages as some licences have not been accepted.
ndk;21.3.6528147 NDK (Side by side) 21.3.6528147
To build this project, accept the SDK license agreements and install the missing components using the Android Studio SDK Manager.
Alternatively, to transfer the license agreements from one workstation to another, see http://d.android.com/r/studio-ui/export-licenses.html
Using Android SDK: D:\Program Files\AndroidSDK
解決：進入AndroidSDK\tools\bin，cmd執行：sdkmanager.bat --licenses ，一路y
5.
Location specified by ndk.dir (/Users/dp/Library/Android/sdk/ndk-bundle) did not contain a valid NDK and and couldn't be used
解決：注掉local.properties中n
dk.dir=/Users/dp/Library/Android/sdk/ndk-bundle
7.
Caused by: org.gradle.internal.resolve.ModuleVersionResolveException: Could not resolve project :openCVLibrary401.
Required by:
project :app
Caused by: org.gradle.internal.component.NoMatchingConfigurationSelectionException: Unable to find a matching configuration of project :openCVLibrary401:
- None of the consumable configurations have attributes.
8.
ERROR: Library projects cannot set applicationId. applicationId is set to 'org.opencv' in default config.
Affected Modules: openCVLibrary401
原因：OpenCV-sdk導入時build.gradle配置中參數不正確
修改前：
defaultConfig {
applicationId "org.openCV"
}
應修改：
defaultConfig {
applicationId "org.openCVLibrary401"
}
這個和工程中導入依賴對應，
參考鏈接：
https://docs.gradle.org/current/userguide/compatibility.html#compatibility
https://docs.gradle.org/current/userguide/installation.html