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910e62b5创建于 1月15日历史提交

WebView quick start

*** promo Googlers may wish to consult http://go/clank-webview for Google-specific developer guides.

[TOC]

Overview

This is not a thorough guide for how to build WebView, but is the fastest way to get a local build of WebView up and running.

Building for preview Android releases

Googlers should see internal instructions. External contributors should switch to a public (and finalized) Android release (there's no workaround).

System requirements, tools, etc.

See general Android instructions for:

Install adb

If you don't already have adb installed, the fastest way is to add chromium's Android SDK to your $PATH. If you use multiple terminal, you'll want to run this command in each terminal:

$ source build/android/envsetup.sh

Device setup

The recommend configuration is to use an Android 10 (Q) emulator. Android R or higher is also OK. If you need to use any other configuration, then you need to switch to the full build guide instead.

Set up an Android emulator. You have 2 options for this:

  1. Preconfigured emulator image. Just run this command in your terminal, which will launch an emulator window when the emulator is ready. If anything goes wrong, see the documentation or try the next option (see below).
$ tools/android/avd/avd.py start \
    --avd-config tools/android/avd/proto/android_29_google_apis_x86.textpb --emulator-window

  1. Android Studio Emulator image. Install the Android Studio IDE and then follow these instructions to launch the Device Manager GUI. Create an emulator with these settings:

    • Skin: any Pixel device skin is fine
    • Release name: 10
    • ABI: x86
    • Target: Google APIs
    • Select "Show Advanced Settings" > scroll down:
      • Set internal storage to 4000MB
      • Set SD card to 1000MB
    • If in doubt, consult the chromium documentation to configure your emulator

    Once configured, click the play button to launch the emulator.

Verify your emulator is ready: after performing either of the steps above, you should check your emulator by running:

# If everything worked correctly, this should say "device" in the right column.
$ adb devices
List of devices attached
emulator-5554   device

Setting up the build

Configure GN args (run gn args out/Default) as follows:

target_os = "android"
target_cpu = "x86"

# Recommended: this lets you use System WebView Shell as a test app.
system_webview_shell_package_name = "org.chromium.my_webview_shell"

Build, install, and switch WebView provider {#build}

# Build
$ autoninja -C out/Default system_webview_apk

# Install the APK
$ out/Default/bin/system_webview_apk install

# Tell Android platform to load a WebView implementation from this APK
$ out/Default/bin/system_webview_apk set-webview-provider

That's it! Your APK should be installed and should be providing the WebView implementation for all apps on the system.

Things to do next

Start running an app

Skip this section if you already have an app you want to test.

You can start testing our your WebView APK with the System WebView Shell test app. This also shows the WebView version at the top of the app, so you can verify this is using the version you built locally. You can run this test app like so:

# Build
$ autoninja -C out/Default system_webview_shell_apk

# Install
$ out/Default/bin/system_webview_shell_apk install

# Launch a URL
$ out/Default/bin/system_webview_shell_apk launch "https://www.google.com/"

For more info about WebView Shell, see the docs.

Toggle features or commandline flags

Skip this section if you don't need to toggle a specific commandline flag.

If you exposed your flag in ProductionSupportedFlagList.java, then you can toggle the flag in WebView DevTools. For more info about WebView DevTools, see the docs. You can launch WebView DevTools with:

$ adb shell am start -a "com.android.webview.SHOW_DEV_UI"

If the flag is not exposed, you can instead try following these steps.

Debug with adb logcat

We recommend starting with "printf-style debugging" on Android:

  1. Add some logs in your code:
    • In C++ code: add LOG(ERROR) << "SOMETAG: <your log message goes here>";
    • In Java code: add org.chromium.base.Log.e("SOMETAG", "<your log message goes here>");
  2. Recompile and reinstall system_webview_apk (see steps above). Re-launch your test app.
  3. Read your log messages by running this command: adb logcat | grep 'SOMETAG'

For more guidance, refer to the logging documentation.

Run automated tests

We recommend starting with integration tests.

Shutdown your emulator when you're done

The recommended way to turn off your emulator is to just close the emulator window. If that doesn't work or you can't find the emulator window, then you can safely shutdown your emulator by running adb emu kill in the terminal.

Troubleshooting

If the install command succeeded but something else is wrong, the best way to troubleshoot the problem is to query the state of the on-device WebViewUpdateService:

$ adb shell dumpsys webviewupdate

Current WebView Update Service state
  Fallback logic enabled: true
  Current WebView package (name, version): (com.google.android.apps.chrome, 75.0.3741.0)
  Minimum WebView version code: 303012512
  Number of relros started: 1
  Number of relros finished: 1
  WebView package dirty: false
  Any WebView package installed: true
  Preferred WebView package (name, version): (com.google.android.apps.chrome, 75.0.3741.0)
  WebView packages:
    Valid package com.android.chrome (versionName: 58.0.3029.125, versionCode: 303012512, targetSdkVersion: 26) is  installed/enabled for all users
    Valid package com.google.android.webview (versionName: 58.0.3029.125, versionCode: 303012500, targetSdkVersion: 26) is NOT installed/enabled for all users
    Invalid package com.chrome.beta (versionName: 74.0.3729.23, versionCode: 372902311, targetSdkVersion: 28), reason: No WebView-library manifest flag
    Invalid package com.chrome.dev (versionName: 54.0.2840.98, versionCode: 284009811, targetSdkVersion: 24), reason: SDK version too low
    Invalid package com.chrome.canary (versionName: 75.0.3741.0, versionCode: 374100010, targetSdkVersion: 25), reason: SDK version too low
    Valid package com.google.android.apps.chrome (versionName: 75.0.3741.0, versionCode: 2, targetSdkVersion: 28) is  installed/enabled for all users

Invalid package ... No WebView-library manifest flag

This APK does not contain a WebView implementation. Make sure you're building system_webview_apk.

Invalid package ... Version code too low

This shouldn't happen for userdebug builds. If it does, add this GN arg:

# Any number >= "Minimum WebView version code":
android_override_version_code = "987654321"

Invalid package ... SDK version too low

The targetSdkVersion of your APK is too low (it must be >= the platform's API level). This shouldn't happen for local builds using tip-of-tree chromium on public OS versions (see note).

*** note Note: we only support local development using the latest revision of the main branch. Checking out release branches introduces a lot of complexity, and it might not even be possible to build WebView for your device.

Invalid package ... Incorrect signature

This shouldn't happen for userdebug devices, and there's no workaround for user devices. Make sure you have a userdebug device (you can check with adb shell getprop ro.build.type).

Valid package ... is installed/enabled for all users

This is the correct state. If this is not the "preferred WebView package" or the "current WebView package", call set-webview-implementation again.

Valid package ... is NOT installed/enabled for all users

This shouldn't happen for com.google.android.apps.chrome (the recommended package name). If you need to use a different package name, you may be able to workaround this by enabling "redundant packages" (adb shell cmd webviewupdate enable-redundant-packages), reinstalling, and running set-webview-provider again.

Otherwise, please reach out to the team.

My package isn't in the list

Either your package didn't install (see below) or you chose a package name which is not eligible as a WebView provider for this device. Double-check the package name in your GN args. If you're on AOSP (any OS level), choose "com.android.webview". You'll likely need to remove the preinstalled WebView APK.

WebView shell doesn't show the correct version

Check the "Current WebView package" in the dumpsys output. You're probably hitting one of the cases above.

INSTALL_FAILED_UPDATE_INCOMPATIBLE: Package ... signatures do not match previously installed version

Double check your emulator is Android 10 (Q) and that this is a Google APIs image. Double check your GN args to make sure you are not setting the system_webview_package_name argument (it's OK to set system_webview_shell_package_name, but the other arg should be the default value). If everything looks correct, try:

# Try uninstalling any WebView updates
$ adb uninstall com.android.webview

# If the uninstall command succeeded, then try installing your locally compiled
# WebView again:
$ out/Default/bin/system_webview_shell_apk install
$ out/Default/bin/system_webview_shell_apk set-webview-provider

I couldn't install the APK/... is NOT installed.

This could fail for an even wider variety of reasons than already listed. Please reach out to the team.

I couldn't build the APK

Try building Chromium. If that doesn't work, please reach out to the chromium team for general guidance. If system_webview_apk is the only troublesome target, please reach out to the WebView team (see previous section).

Apps using WebView crash with "java.lang.RuntimeException: Unable to start activity"

If apps using WebView crash with stack traces like the following:

AndroidRuntime: Shutting down VM
AndroidRuntime: FATAL EXCEPTION: main
AndroidRuntime: Process: org.chromium.webview_shell, PID: 6683
AndroidRuntime: java.lang.RuntimeException: Unable to start activity ComponentInfo{org.chromium.webview_shell/org.chromium.webview_shell.WebViewBrowserActivity}: android.util.AndroidRuntimeException: java.lang.reflect.InvocationTargetException
...
AndroidRuntime: Caused by: android.util.AndroidRuntimeException: java.lang.reflect.InvocationTargetException
...
AndroidRuntime: Caused by: org.chromium.base.library_loader.ProcessInitException: errorCode=2
...
AndroidRuntime: Caused by: java.lang.UnsatisfiedLinkError: dlopen failed: library "libc++_chrome.so" not found
...

This UnsatisfiedLinkError can occur when WebView is built using the target_cpu = "x86" gn arg and the emulator architecture is x86_64. Double check your emulator is Android 10 (Q) and uses the x86 ABI.

What if I didn't follow these instructions exactly?

Proceed at your own risk. Building and installing WebView is, for a variety of reasons, complex. If you've deviated from any of these instructions (and don't know what you're doing) there's a good chance of making mistakes (some of which don't have any error messages).

If you can't follow the quick start guide for some reason, please consult our general build instructions. You can also try the old version of the quick start.