framework开发，实现自定义系统版本号。
 修改位置：
 \build\tools
 buildinfo.sh

#!/bin/bashecho "# begin build properties"
echo "# autogenerated by buildinfo.sh"echo "ro.build.id=$BUILD_ID"
echo "ro.build.display.id=$BUILD_DISPLAY_ID"
echo "ro.build.version.incremental=$BUILD_NUMBER"
echo "ro.build.version.sdk=$PLATFORM_SDK_VERSION"
echo "ro.build.version.preview_sdk=$PLATFORM_PREVIEW_SDK_VERSION"
echo "ro.build.version.codename=$PLATFORM_VERSION_CODENAME"
echo "ro.build.version.all_codenames=$PLATFORM_VERSION_ALL_CODENAMES"
echo "ro.build.version.release=$PLATFORM_VERSION"
echo "ro.build.version.security_patch=$PLATFORM_SECURITY_PATCH"
echo "ro.build.version.base_os=$PLATFORM_BASE_OS"
echo "ro.build.version.min_supported_target_sdk=$PLATFORM_MIN_SUPPORTED_TARGET_SDK_VERSION"
echo "ro.build.date=`$DATE`"
echo "ro.build.date.utc=`$DATE +%s`"
echo "ro.build.type=$TARGET_BUILD_TYPE"
echo "ro.build.user=$USER"
echo "ro.build.host=`hostname`"
echo "ro.build.tags=$BUILD_VERSION_TAGS"
echo "ro.build.flavor=$TARGET_BUILD_FLAVOR"
if [ -n "$BOARD_BUILD_SYSTEM_ROOT_IMAGE" ] ; thenecho "ro.build.system_root_image=$BOARD_BUILD_SYSTEM_ROOT_IMAGE"
fi
if [ -n "$AB_OTA_UPDATER" ] ; thenecho "ro.build.ab_update=$AB_OTA_UPDATER"

版本号：

echo "ro.build.display.id=$BUILD_DISPLAY_ID"

改为：

SOFTWARE_VERSION="system_"
date=$(date "+%Y%m%d")echo "ro.build.display.id=$SOFTWARE_VERSION$date"

重新编译,可以直接make，无需清理out文件夹重新花费大量时间全部编译
通过查看编译完成后的文件 out/target/product/generic_x86_64/system/build.prop 确认是否修改完成