我已经安装了Android studio 3.0，但是一旦我尝试运行我的应用程序就会出错。我在Ubuntu上，问题与我认为的SDK的路径有关。
请在此处查看错误错误：
11:33 Emulator: WARNING: Unknown AVD name [Nexus_4_API_22], use -list-avds to see valid list. 11:33 Emulator: HOME is defined but there is no file Nexus_4_API_22.ini in $HOME/.android/avd 11:33 Emulator: (Note: Directories are searched in the order $ANDROID_AVD_HOME, $ANDROID_SDK_HOME/avd and $HOME/.android/avd) 11:33 Emulator: WARNING: Unknown AVD name [Nexus_4_API_22], use -list-avds to see valid list. 11:33 Emulator: HOME is defined but there is no file Nexus_4_API_22.ini in $HOME/.android/avd 11:33 Emulator: (Note: Directories are searched in the order $ANDROID_AVD_HOME, $ANDROID_SDK_HOME/avd and $HOME/.android/avd) 11:33 Emulator: WARNING: Unknown AVD name [Nexus_4_API_22], use -list-avds to see valid list. 11:33 Emulator: HOME is defined but there is no file Nexus_4_API_22.ini in $HOME/.android/avd 11:33 Emulator: (Note: Directories are searched in the order $ANDROID_AVD_HOME, $ANDROID_SDK_HOME/avd and $HOME/.android/avd) 11:33 Emulator: PANIC: Cannot find AVD system path. Please define ANDROID_SDK_ROOT 11:33 Emulator: Process finished with exit code 1