[Android] Back button doesn't go back a page but quits webview

[amuttsch]

On Android when navigating through websites I want to use the back button to go back a page. This is currently not possible, the webview will be closed. Is this intentional?

I use the example from the repository and can reproduce this behavior with the fullscreen and widget webview. I digged in the source code and it should be able to set the back button to go back in the webviews history first by setting a setOnKeyListener on the webview (see here).

How is the behaviour on iOS? If I recall correctly, you swipe from left to right to go back a page in Safari. Is this currently possible?

For the Android part I can create a pull request to change the back button behaviour. Should it be configurable or always go back until we reach the end of the history before exiting the webview?

[lejard-h]

I need to check the behavior on iOS, but yes it is a bug on Android.

I don't have much time to work on it, but I can review PR.

[amuttsch]

Thanks for your quick response, I can try to fix it. Can you give me a hint how to compile flutter_webview? I'm new to flutter + dart and when I try flutter run or flutter build apk inside the examples folder, I get the following error message:

Initializing gradle...                                0,8s
Resolving dependencies...
* Error running Gradle:
Exit code 1 from: C:\Code\flutter_webview_plugin\example\android\gradlew.bat app:properties:

FAILURE: Build failed with an exception.

* Where:
Build file 'C:\Code\flutter_webview_plugin\example\android\build.gradle' line: 20

* What went wrong:
A problem occurred evaluating root project 'android'.
> A problem occurred configuring project ':app'.
   > Could not resolve all dependencies for configuration ':app:_debugApk'.
      > A problem occurred configuring project ':flutter_webview_plugin'.
         > Failed to notify project evaluation listener.
            > com.android.build.gradle.tasks.factory.AndroidJavaCompile.setDependencyCacheDir(Ljava/io/File;)V

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

* Get more help at https://help.gradle.org

BUILD FAILED in 1s

Please review your Gradle project setup in the android/ folder.

I couldn't figue out if I have to compile the plugin itself before, but a flutter build apk in the root directory doesn't work either, because the flutter library isn't included as a dependency in the android project.

[amuttsch]

Got it working, it seems like gradle 4 doesn't work, I changed it to 3.3 and it works now. See flutter/flutter#10236

[zoechi]

The back arrow in the app bar still closes the WebView for me.
Anything I might have missed.
I use add a widget that hasnew WebviewScaffold(...) in build() using the router.

[amuttsch]

This is the correct behaviour imho @zoechi. The back arrow in the action bar indicates a back to the previous screen / activity, not a page back. For such a functionality you could add a button in the action bar (page back / forward), but I think you'd have to add the methods calls to the native webviews for that in a PR.

[zoechi]

@amuttsch thanks for clarification.
So this PR is about the Android back button, not the one in the AppBar?

[amuttsch]

@zoechi Correct