Install APK via pc
You can install downloaded APK that are in your pc in these ways:
– send/install APK via WiFi if both devices are connected to same wireless network using the good free Wireless File Transfer Pro app or similar apps; you can install APK transferred to your SD card using a file manager (eg. Astro)
– send APK as attachment using Gmail and open it in your smartphone using e-mail client
– use APK Batch Installer tool (for Windows) made by hamsteir, an XDA community user. It requires root and the ADB command from Android SDK
Transfer APK from one smartphone to another
– via Bluetooth with the free Bluetooth File Transfer app and then install via a file manager app.
– via WiFi with specific applications
– via WiFi Direct with specific applications between devices that supports WiFi Direct (this tecnology allows to use WiFi without a wireless network)
– via NFC with specific applications (Blue NFC) and between NFC compatible devices
Backup by recreating installed APK
– all knows the famous Titanium Backup for backing up own apsp, appSaver work in a different way (and doesn’t require root), it allows to recreate APK starting from an installed app
Using free cloud services
like Google Drive, Dropbox etc…