This is meant to be a comprehensive guide for building WebView, within the limits of what is possible in a public chromium checkout. While this is sufficient for most cases, Googlers may wish to consult internal instructions to get a checkout including closed-source code, which is necessary if:
system_webview_google_apk), orSee general Android instructions for:
depot_toolsFor the minimum requirements, please see Device Setup.
Configure GN args (run gn args out/Default) as follows:
target_os = "android" # See "Figuring out target_cpu" below target_cpu = "arm64" # Not always necessary, see "Changing package name" below system_webview_package_name = "..." # Optional: speeds up build time. For instructions, refer to # https://chromium.googlesource.com/chromium/src/+/main/docs/linux/build_instructions.md#use-reclient use_remoteexec = true
Please see the Chromium instructions.
Similarly to Chrome, WebView can be compiled with a variety of build targets.
TODO(crbug.com/41454956): document the differences between each target.
First, you should figure out your device's integer API level, which determines which build targets will be compatible with the version of the OS on your device:
adb shell getprop ro.build.version.sdk
Then you can build one of the following targets:
# For L+ (21+) devices (if on N-P, see "Important Notes for N-P") autoninja -C out/Default system_webview_apk # For N-P (24-28) devices (not including TV/car devices) autoninja -C out/Default monochrome_public_apk # For Q+ (29+) devices autoninja -C out/Default trichrome_webview_apk
trichrome_webview_apk will automatically build its dependencies (i.e., trichrome_library_apk).Unlike most Android apps, WebView is part of the Android framework. One of the consequences of this is that the WebView implementation on the device can only be provided by a predetermined set of package names (see details). Depending on the chosen build target, you may need to change the package name to match one of the following:
| API level | Has GMS vs. AOSP? | Allowed package names |
|---|---|---|
| L-M | AOSP | com.android.webview (default, preinstalled) |
| L-M | Has GMS | com.google.android.webview (default, preinstalled) |
| N-P | AOSP | com.android.webview (default, preinstalled) |
| N-P (TV/car devices) | Has GMS | com.google.android.webview (default, preinstalled) |
| N-P (other devices) | Has GMS | com.android.chrome (default, preinstalled)com.chrome.betacom.chrome.devcom.chrome.canarycom.google.android.apps.chrome (only userdebug/eng)com.google.android.webview (preinstalled) (see Important notes for N-P) |
| >= Q | AOSP | com.android.webview (default, preinstalled) |
| >= Q | Has GMS | com.google.android.webview (default, preinstalled)com.google.android.webview.betacom.google.android.webview.devcom.google.android.webview.canarycom.google.android.webview.debug (only userdebug/eng)com.android.webview (only userdebug/eng) |
system_webview_apk and trichrome_webview_apk use com.android.webview as their package name by default. If your device allows this package name, continue to the next section. Otherwise, you can change the package name for either target by setting the system_webview_package_name GN arg (ex. system_webview_package_name = "com.google.android.webview").
monochrome_public_apk‘s package name defaults to org.chromium.chrome. Because this not accepted by any build of the OS, you’ll want to change this with the GN arg chrome_public_manifest_package = "com.google.android.apps.chrome", or choose system_webview_apk instead.
See internal instructions for the Google-internal variants of the build targets (system_webview_google_apk, monochrome_apk, trichrome_webview_google_apk).
use_signing_keys = true provides “developer test keys,” not release keys), you must remove the preinstalled WebView (see below).If WebView is preinstalled (under the chosen package name) in the device‘s system image, you’ll also need to remove the preinstalled APK (otherwise, you'll see signature mismatches when installing). You can skip this step if either of the following is true:
Otherwise, you can remove the preinstalled WebView like so:
android_webview/tools/remove_preinstalled_webview.py
-writable-system before removing the preinstalled WebView.If the script doesn't work, see the manual steps.
This functionality was added in N and removed in Q, so you should skip this if your device is L-M or >= Q.
If you have an Android build from N-P (and, it uses the Google WebView configuration), then the com.google.android.webview package will be disabled by default. More significantly, installing a locally compiled APK won't work, since the on-device WebViewUpdateService will immediately uninstall such updates. To unblock local development, you can re-enable the WebView package and disable this behavior from WebViewUpdateService with:
# Only necessary if you're using the 'com.google.android.webview' package name adb shell cmd webviewupdate enable-redundant-packages
For help connecting your Android device, see the Chromium instructions.
You can install a locally compiled APK like so (substitute system_webview_apk with the chosen build target name):
# Install the APK out/Default/bin/system_webview_apk install # Only on N+: tell Android platform to load a WebView implementation from this APK out/Default/bin/system_webview_apk set-webview-provider
out/Default/bin/trichrome_webview_apk install will handle installing all its dependencies (i.e., trichrome_library_apk), so you can interact with this target the same as you would interact with any other WebView build target.See Start running an app from the quick start.
Please see the Troubleshooting section in the quick start.
TODO(ntfschr): document cases here which could arise generally, but wouldn't for the quick start.