Porting to android

I was trying to port my app to android and did the tutorial. I installed studio and added the android platform to my app but it tells me that my system doesn’t meet the requirements yet. I run it with --verbose and it tells me why it thinks so.

status of the requirements:                                                                                                                                                              
✓ Java JDK                                    
✗ Android SDK: 'ANDROID_HOME' environment variable is set to non-existent path: ~/Android/Sdk
  Try update it manually to point to valid SDK directory.
✓ Android target                              
✗ Gradle: Could not find gradle wrapper within Android SDK. Might need to update your Android SDK.
  Looked here: ~/Android/Sdk/tools/templates/gradle/wrapper

When I look at the two folders I wonder why it gives me this error message:

ll ~/Android/Sdk
total 40
drwxr-xr-x  2 username username 4096 Jan 18 23:17 add-ons/
drwxr-xr-x  4 username username 4096 Jan 18 23:33 build-tools/
drwxr-xr-x  4 username username 4096 Jan 18 23:19 extras/
drwxr-xr-x  4 username username 4096 Jan 22 20:47 platforms/
drwxr-xr-x  5 username username 4096 Jan 18 23:19 platform-tools/
-rw-r--r--  1 username username 1158 Mar 22  2014 SDK Readme.txt
drwxr-xr-x  4 username username 4096 Jan 22 20:47 sources/
drwxr-xr-x  3 username username 4096 Jan 22 20:51 system-images/
drwxr-xr-x  2 username username 4096 Jan 22 20:51 temp/
drwxr-xr-x 12 username username 4096 Jan 18 23:21 tools/

and

ll ~/Android/Sdk/tools/templates/gradle/wrapper
total 16
drwxr-xr-x 3 username username 4096 Jan 18 23:21 gradle/
-rwxr-xr-x 1 username username 5080 Jan 18 23:21 gradlew*
-rw-r--r-- 1 username username 2404 Jan 18 23:21 gradlew.bat

Does anyone have a suggestion on how to solve this?

Maybe you could try expanding ~/Android/Sdk, writing out the path to your home directory?