| # Differences in support/behavior compared to Chrome |
| |
| ## Sometimes, no interstitial |
| |
| If we detect the WebView is not visible to the user (ex. if it is not attached |
| to a window or the WebView is marked as invisible with `View#setVisibility()`), |
| then WebView does not show an interstitial at all. In this case, we just return |
| the [`ERROR_UNSAFE_RESOURCE`][1] network error and block the unsafe resource. |
| |
| This behavior is determined in the code by |
| [`AwContents#canShowInterstitial()`](https://source.chromium.org/search?q=class:AwContents%20%5CbcanShowInterstitial%5Cb%20lang:java&sq=&ss=chromium). |
| |
| ## Quiet interstitials |
| |
| The main interstitials in Chrome are **Loud** interstitials, which are blocking |
| pages that show detailed informational text to users and are (usually) red in |
| background color. WebView supports these interstitials when we believe WebView |
| is the predominant part of the application UI (such as in browser apps). |
| |
| When we suspect WebView is a smaller (or otherwise less prominent) part of the |
| application UI, we show a gray **Quiet** interstitial, which is meant to feel |
| like a less-scary error page. |
| |
| There are **Small**, **Medium**, and **Giant** Quiet interstitials. Medium |
| interstitials are when we have enough space to show textual information, Small |
| interstitials are when there's not enough space, and Giant interstitials are |
| whenever part of the WebView hangs out of the viewport. |
| |
| | Small interstitial | 4 Medium interstitials | Giant interstitial (hanging off bottom right of viewport) | |
| |---|---|---| |
| |  |  |  | |
| |
| ## Network error on "back to safety" |
| |
| WebView returns [`ERROR_UNSAFE_RESOURCE`][1] to the application when the user |
| clicks "back to safety." This is to stay consistent with expectations of legacy |
| applications (to communicate the page failed to load). |
| |
| ## Callback API |
| |
| WebView supports the `onSafeBrowsingHit()` callback, allowing applications to |
| implement custom interstitials. This also involves exposing [threat type |
| constants](/android_webview/java/src/org/chromium/android_webview/safe_browsing/AwSafeBrowsingConversionHelper.java), |
| to indicate what threat WebView observed. |
| |
| ## Sometimes, no "back to safety" button |
| |
| WebView will not show a "back to safety" button on the interstitial if there's |
| no previous page in the history, or if we're showing a Quiet interstitial. |
| |
| | With "back to safety" button (like Chrome) | No "back to safety" button (WebView only) | |
| |---|---| |
| |  |  | |
| |
| [1]: https://developer.android.com/reference/android/webkit/WebViewClient#ERROR_UNSAFE_RESOURCE |
