I've followed step by step the official Getting Started. I started from a clean linux install and installed everything required as per the "Building Projects with Native Code" tab. I have also read the troubleshooting section. I've already created the project using the terminal.
This is the error when I run react-native run-android:
Starting JS server... Building and installing the app on the device (cd android && ./gradlew installDebug)... ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. Please set the JAVA_HOME variable in your environment to match the location of your Java installation. Could not install the app on the device, read the error above for details. Make sure you have an Android emulator running or a device connected and have set up your Android development environment: https://facebook.github.io/react-native/docs/android-setup.html
It does not find JAVA_HOME because the latest versions of Android Studio don't require Java to be installed in the system. Instead an internal JRE is used.
Duplicate disclaimer: I've already read this question. This is not what I want. I know how to set the Java home. I just want to run the react project WITHOUT having to install a separate Java.
Questions:
- How could I find the internal Java inside the Android Studio folder so that I could point JAVA_HOME to it?
- If not possible, could I open and run the project inside the
android folder with Android Studio? How would I refresh this project after modifying the React JavaScript code in the parent folder?
I'll answer my own questions and sponfeed my fellow linux users:
1- To point JAVA_HOME to the JRE included with Android Studio first locate the Android Studio installation folder, then find the /jre directory. That directory's full path is what you need to set JAVA_PATH to (thanks to @TentenPonce for his answer). On linux, you can set JAVA_HOME by adding this line to your .bashrc or .bash_profile files:
export JAVA_HOME=<Your Android Studio path here>/jre
This file (one or the other) is the same as the one you added ANDROID_HOME to if you were following the React Native Getting Started for Linux. Both are hidden by default and can be found in your home directory. After adding the line you need to reload the terminal so that it can pick up the new environment variable. So type:
source $HOME/.bash_profile
or
source $HOME/.bashrc
and now you can run react-native run-android in that same terminal. Another option is to restart the OS. Other terminals might work differently.
NOTE: for the project to actually run, you need to start an Android emulator in advance, or have a real device connected. The easiest way is to open an already existing Android Studio project and launch the emulator from there, then close Android Studio.
2- Since what react-native run-android appears to do is just this:
cd android && ./gradlew installDebug
You can actually open the nested android project with Android Studio and run it manually. JS changes can be reloaded if you enable live reload in the emulator. Type CTRL + M (CMD + M on MacOS) and select the "Enable live reload" option in the menu that appears (Kudos to @BKO for his answer)
It is located on the Android Studio folder itself, on where you installed it.
