How to clear webview history?

When using WebView in your application, you may need to clear history to protect user privacy or ensure the WebView behaves as if it were a fresh instance. In Android, you can clear history by calling methods provided by WebView. Here are the steps to do this:

1. Clear WebView's History: If you only want to clear the browsing history of WebView, you can call the clearHistory method. This will clear all forward and backward navigation records in WebView.

   java
   webView.clearHistory();

2. Clear Cache and Cookies: Additionally, if you want to thoroughly clear all browsing data, including cached files and cookies, you can call the clearCache and CookieManager's removeAllCookies methods:

   java
   webView.clearCache(true);
   
   CookieManager cookieManager = CookieManager.getInstance();
   cookieManager.removeAllCookies(null);
   cookieManager.flush();

   Here, the boolean parameter in clearCache(true) indicates whether to clear cache on disk; if true is passed, it clears both memory and disk cache.

3. Clear Autofill Form Data (if needed): If your WebView uses autofill and you want to clear this data, you can use the clearFormData method:

   java
   webView.clearFormData();

4. Clear WebStorage (HTML5 Web Storage data): For applications using HTML5 Web Storage (e.g., LocalStorage and SessionStorage), you also need to clear this data:

   java
   WebStorage.getInstance().deleteAllData();

5. Note: Clearing WebView data may affect running JavaScript code, so when performing these operations, ensure no JavaScript operations are running or reload the WebView after clearing data.

Example: If you are developing a browser application, users may not want their browsing history retained, especially when using privacy mode. You can use the above methods when opening a new incognito window to ensure the WebView does not retain any history, as shown in the code below:

java
private void openIncognitoTab() {
    WebView webView = new WebView(context);

    // Clear history, cache, and cookies
    webView.clearHistory();
    webView.clearCache(true);

    CookieManager cookieManager = CookieManager.getInstance();
    cookieManager.removeAllCookies(null);
    cookieManager.flush();

    // Clear form data
    webView.clearFormData();

    // Clear Web Storage data
    WebStorage.getInstance().deleteAllData();

    // ... load the required URL next
    webView.loadUrl("https://example.com");
}

By following these steps, you can ensure the WebView is completely "clean" when opened, with no user browsing traces left behind.