Android 中 java 与 webview 的交互

android 的webkit的api的开放程度还是非常不错,java可以和webview内的javascript很好的交互。下面的小例子可以说明这一点。 

先看我们的html文档:

<html>
    <script language="javascript">
        /* This function is invoked by the activity */
        function wave() {
            alert("1");
            document.getElementById("droid").src="android_waving.png";
            alert("2");
        }
    </script>
    <body>
        <!-- Calls into the javascript interface for the activity -->
        <a onClick="window.demo.clickOnAndroid()"><div style="width:80px;margin:0px auto;padding:10px;text-align:center;border:2px solid #202020;" >
                <img id="droid" src="android_normal.png"/><br>
                Click me!
        </div></a>
    </body>
</html>

再看我们的java 代码。

public class WebViewDemo extends Activity {

    private static final String LOG_TAG = "WebViewDemo";

    private WebView mWebView;

    private Handler mHandler = new Handler();

    @Override
    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        setContentView(R.layout.main);
        mWebView = (WebView) findViewById(R.id.webview);

        WebSettings webSettings = mWebView.getSettings();
        webSettings.setSavePassword(false);
        webSettings.setSaveFormData(false);
        webSettings.setJavaScriptEnabled(true);
        webSettings.setSupportZoom(false);

        mWebView.setWebChromeClient(new MyWebChromeClient());

        mWebView.addJavascriptInterface(new DemoJavaScriptInterface(), "demo");

        mWebView.loadUrl("file:///android_asset/demo.html");
    }

    final class DemoJavaScriptInterface {

        DemoJavaScriptInterface() {
        }

        /**
         * This is not called on the UI thread. Post a runnable to invoke
         * loadUrl on the UI thread.
         */
        public void clickOnAndroid() {
            mHandler.post(new Runnable() {
                public void run() {
                    mWebView.loadUrl("javascript:wave()");
                }
            });

        }
    }

    /**
     * Provides a hook for calling "alert" from javascript. Useful for
     * debugging your javascript.
     */
    final class MyWebChromeClient extends WebChromeClient {
        @Override
        public boolean onJsAlert(WebView view, String url, String message, JsResult result) {
            Log.d(LOG_TAG, message);
            result.confirm();
            return true;
        }
        
    }
}

WebView 的addJavascriptInterface函数就可以实现彼此的交互。

发表评论