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🎯 Overview
🎯 Overview
Android WebView is a component that allows developers to display web content within their applications. When the device undergoes orientation changes (e.g., from portrait to landscape or vice versa), the Activity is recreated, and any unsaved data can be lost. To prevent data loss and maintain the WebView's state during such changes, developers can save and restore the WebView state using the onSaveInstanceState and restoreState methods.
The concept behind handling orientation changes for Android WebView involves saving the state of the WebView before the Activity is destroyed and restoring that state when the Activity is recreated. This ensures a seamless user experience, as the web page displayed in the WebView will remain consistent across orientation changes.
🎯 Basic Syntax
🎯 Basic Syntax
To save the state of the WebView, the onSaveInstanceState method must be overridden in the Activity's code. It is responsible for saving relevant data into a Bundle object. The WebView's saveState method is used to store the WebView's state into the Bundle. On the other hand, to restore the state, the restoreState method is called on the WebView object, passing the Bundle containing the saved state.
🎯 Sample Code
🎯 Sample Code
// WebView Declaration:
WebView WebBrowser;
// Code for WebView SaveState Mapping
if (savedInstanceState != null)
    ((WebView)findViewById(R.id.webview)).restoreState(savedInstanceState);
else
    WebBrowser.loadUrl(URLData);
// SaveInstanceState Method
protected void onSaveInstanceState(Bundle outState) {
    WebBrowser.saveState(outState);
}
public void onCreate(final Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.browserPage);
    WebBrowser = (WebView) findViewById(R.id.WebEngine);
}
🎯 Implementation
🎯 Implementation
The implementation of WebView state handling involves the following steps:
Declare a WebView variable (WebBrowser) in the Activity.
In the onCreate method, find the WebView element by its ID using findViewById.
Check if there is a saved instance state (i.e., if the Activity is being recreated after an orientation change).
If there is a saved state, restore the WebView's state using the restoreState method with the saved Bundle.
If there is no saved state, load the initial URL data into the WebView using the loadUrl method.
Override the onSaveInstanceState method and use the saveState method of the WebView to store its state in the outState Bundle.
🎯 Detailed Explanation
🎯 Detailed Explanation
Handling orientation changes in Android WebView is crucial to maintain the state of the displayed web content. When an orientation change occurs, the current Activity is destroyed and recreated, which can lead to data loss and a subpar user experience. By saving and restoring the WebView's state, developers can seamlessly preserve the web page's content across orientation changes.
The basic syntax provided earlier illustrates the core code required for handling orientation changes with WebView. Let's delve into a more detailed explanation of each step:
First, a WebView instance named WebBrowser is declared globally to hold the reference to the WebView component.
In the onCreate method, the layout for the WebView activity is set using setContentView with the layout resource R.layout.browserPage. The WebView is then initialized by finding it in the layout using findViewById and assigning it to the WebBrowser variable.
The code then checks if there is a saved instance state (savedInstanceState) available. If there is, it means the Activity is being recreated after an orientation change. In such cases, the restoreState method is called on the WebView to restore its state from the saved Bundle.
If there is no saved instance state (i.e., it is the first creation of the Activity), the WebView loads the initial URL data using the loadUrl method.
To handle state preservation during system-initiated destruction and recreation (e.g., during low memory situations), the onSaveInstanceState method is overridden. In this method, the saveState method of the WebView is called with the outState Bundle as an argument to store the WebView's state.
🎯 Key Points
🎯 Key Points
WebView allows developers to display web content in their Android applications.
Orientation changes trigger the recreation of the Activity, potentially leading to data loss.
To save and restore the WebView's state, onSaveInstanceState and restoreState methods are used, respectively.
The saveState method saves the WebView's state into a Bundle, and restoreState retrieves the state from the Bundle.
Properly implementing state handling ensures a seamless user experience when the device undergoes orientation changes.
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