android4.4 js调用java

<uses-permission  android:name="android.permission.INTERNET"/>

wv.getSettings().setJavaScriptEnabled(true);
wv.addJavascriptInterface(new DemoJavaScriptInterface(), "demo");

final class DemoJavaScriptInterface {

DemoJavaScriptInterface() {
}

/**
* This is not called on the UI thread. Post a runnable to invoke
* loadUrl on the UI thread.
*/
@JavascriptInterface
public void clickOnAndroid() {
Log.i(LOG_TAG, "--------------------------------");

}
}

<input type="button" onclick="demo.clickOnAndroid()" value="btn1" />