## Why is my Android WebView behaving so poorly? Blank pages, unresponsive styles, choppy animations - how do I fix it?

Android WebView Issues: Blank Rendering, Unresponsive Style Changes, and Choppy Animations

Android WebView often behaves erratically, including displaying blank pages, ignoring CSS changes, and exhibiting choppy animations. These issues can be frustrating and hinder the user experience. Fortunately, there are solutions to these problems, as we will explore in this discussion.

Solution 1: Enable Hardware Acceleration

Starting with Android 4.4 (KitKat), hardware acceleration is crucial for improving WebView performance. In your AndroidManifest.xml, enable hardware acceleration by adding the following line within the tag:

<code class="xml"><application
   ...
   android:hardwareAccelerated="true"></code>

Solution 2: Force Redrawing

A static final boolean variable in the WebView class allows for constant view redrawing. This can solve the unresponsive style changes and blank rendering issues. However, using this method continuously drains the battery.

Extend the WebView class as shown below and override the onDraw() method:

<code class="java">import org.apache.cordova.CordovaWebView;

import android.content.Context;
import android.graphics.Canvas;

public class MyWebView extends CordovaWebView {
    public static final String TAG = "MyWebView";

    public MyWebView(Context context) {
        super(context);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        // Warning! This will cause the WebView to continuously be redrawn
        // and will drain the devices battery while the view is displayed!
        invalidate();
    }

}</code>

Instruct PhoneGap to use this custom WebView class:

<code class="java">public void init(){
    CordovaWebView webView = new MyWebView(MainActivity.this);
    super.init(webView, new CordovaWebViewClient(this, webView), new CordovaChromeClient(this, webView));
}</code>

Solution 3: CrossWalk WebView

For Android versions 4.4 and later, CrossWalk offers a drop-in WebView replacement with superior performance and stability. More information can be found at crosswalk-project.org.

Additional Tips:

• Set the WebView render priority to high: appView.getSettings().setRenderPriority(RenderPriority.HIGH)
• Enable plugins on demand: appView.getSettings().setPluginState(WebSettings.PluginState.ON_DEMAND)
• Use the latest WebView API and set the minimum supported API to the one you are using.
• Apply -webkit-transform: translate3d(0,0,0); to various elements in CSS to improve performance.
• Use a custom class that extends WebView and overrides the onDraw() method with invalidate() to force redrawing only when necessary.
• Enable community wiki to allow others to contribute optimizations to this answer.

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