[RK3288][Android7.1.2] 预装APK

预安装分为可卸载预安装和不可卸载预安装，本文主要阐述的是可卸载预安装的功能。配置步骤如下：
1）若是希望可卸载预安装，新增文件夹 device/rockchip/rk3288/preinstall_del；
   若是不可卸载预安装，新增文件夹 device/rockchip/rk3288/preinstall。
2）拷贝需要预制的第三方应用到上述文件夹，注意APK文件名尽量使用英文，避免空格。
3）编译结束后会将预制的文件拷贝至system固件中。烧录后，系统会自动安装这些应用。
4）需要注意的是，在preinstall_del目录中的应用，即使用户在使用过程中将其卸载，但在恢复出厂设置后，应用又会自动安装。
   如果希望恢复出厂设置后不再恢复预安装应用，可以将上述文件夹名字改为 preinstall_del_forever 即可实现。
   device/rockchip/rk3288/preinstall_del_forever 文件夹。

root@ubuntu:~/rk3288/device/rockchip/rk3288$ ll
total 156
drwxrwxr-x 12 root root 4096 Aug 22 09:40 ./
drwxrwxr-x  4 root root 4096 Jul 20 08:19 ../
-rw-rw-r--  1 root root   80 Jul 20 08:19 Android.mk
-rw-rw-r--  1 root root  728 Jul 20 08:19 AndroidProducts.mk
drwxrwxr-x  2 root root 4096 Jul 20 08:19 bluetooth/
-rw-rw-r--  1 root root 2555 Jul 20 08:19 BoardConfig.mk
-rwxrwxr-x  1 root root 4523 Jul 20 08:19 build.sh*
-rw-rw-r--  1 root root 4221 Jul 20 08:19 buildspec-rk3288-box.mk
-rw-rw-r--  1 root root 4213 Jul 20 08:19 buildspec-rk3288-mid.mk
-rw-rw-r--  1 root root 4219 Jul 20 08:19 buildspec-rk3288-vr.mk
-rwxrwxr-x  1 root root 2317 Jul 20 08:19 device.mk*
-rw-rw-r--  1 root root 2100 Jul 20 08:19 fstab.rk30board.bootmode.emmc
-rw-rw-r--  1 root root 1918 Jul 20 08:19 fstab.rk30board.bootmode.unknown
drwxrwxr-x  2 root root 4096 Jul 20 08:19 .git/
-rwxrwxr-x  1 root root  532 Jul 20 08:19 .gitignore*
-rw-rw-r--  1 root root 3682 Jul 20 08:19 init.rk30board.usb.rc
-rwxrwxr-x  1 root root 1027 Jul 20 08:19 init.rk3288.rc*
drwxrwxr-x  4 root root 4096 Jul 20 08:19 ota/
drwxrwxr-x  3 root root 4096 Jul 20 08:19 overlay/
drwxrwxr-x  3 root root 4096 Jul 20 08:19 overlay_screenoff/
-rw-rw-r--  1 root root  202 Jul 20 08:19 package_performance.xml
-rw-rw-r--  1 root root  710 Jul 20 08:19 parameter.txt
drwxrwxr-x  3 root root 4096 Aug 22 09:34 preinstall/
drwxrwxr-x  3 root root 4096 Aug 22 09:34 preinstall_del/
drwxrwxr-x  3 root root 4096 Aug 22 09:34 preinstall_del_forever/
-rw-rw-r--  1 root root 2742 Jul 20 08:19 recovery.emmc.fstab
drwxrwxr-x  3 root root 4096 Jul 20 08:19 rk3288_box/
-rw-rw-r--  1 root root  917 Jul 20 08:19 rk3288_box.mk
-rw-rw-r--  1 root root 1326 Jul 20 08:19 rk3288.mk
drwxrwxr-x  2 root root 4096 Jul 20 08:19 rk3288_vr/
-rw-rw-r--  1 root root 1287 Jul 20 08:19 rk3288_vr.mk
-rw-rw-r--  1 root root 1152 Jul 20 08:19 system.prop
-rw-rw-r--  1 root root  793 Jul 20 08:19 vendorsetup.sh
-rw-rw-r--  1 root root  284 Jul 20 08:19 wake_lock_filter.xml
-rw-rw-r--  1 root root 1180 Jul 20 08:19 wifi_bt.mk
root@ubuntu:~/rk3288/device/rockchip/rk3288$ 

root@ubuntu:~/rk3288/device/rockchip/rk3288/preinstall$ ll
total 24
drwxrwxr-x  3 root root 4096 Aug 22 09:34 ./
drwxrwxr-x 12 root root 4096 Aug 22 09:40 ../
-rw-rw-r--  1 root root   38 Aug 22 09:34 Android.mk
-rw-rw-r--  1 root root   27 Aug 22 09:34 preinstall.mk
-rwxrwxr-x  1 root root   78 Jul 20 08:19 README.txt*
drwxrwxr-x  3 root root 4096 Aug 22 09:31 wechat/
root@ubuntu:~/rk3288/device/rockchip/rk3288/preinstall$ cd ../preinstall_del
root@ubuntu:~/rk3288/device/rockchip/rk3288/preinstall_del$ ll
total 24
drwxrwxr-x  3 root root 4096 Aug 22 09:34 ./
drwxrwxr-x 12 root root 4096 Aug 22 09:40 ../
-rw-rw-r--  1 root root   38 Aug 22 09:34 Android.mk
drwxrwxr-x  3 root root 4096 Aug 22 09:31 ifeng/
-rw-rw-r--  1 root root   26 Aug 22 09:34 preinstall.mk
-rwxrwxr-x  1 root root  105 Jul 20 08:19 README.txt*
root@ubuntu:~/rk3288/device/rockchip/rk3288/preinstall_del$ cd ../preinstall_del_forever/
root@ubuntu:~/rk3288/device/rockchip/rk3288/preinstall_del_forever$ ll
total 24
drwxrwxr-x  3 root root 4096 Aug 22 09:34 ./
drwxrwxr-x 12 root root 4096 Aug 22 09:40 ../
-rw-rw-r--  1 root root   38 Aug 22 09:34 Android.mk
drwxrwxr-x  3 root root 4096 Aug 22 09:31 cloudmusic_98/
-rw-rw-r--  1 root root   34 Aug 22 09:34 preinstall.mk
-rwxrwxr-x  1 root root  108 Jul 20 08:19 README.txt*
root@ubuntu:~/rk3288/device/rockchip/rk3288/preinstall_del_forever$ 

将这个三个apk，分别放入到相应的文件夹

再重新编译Android，之后再烧录固件，开机则可看见效果。