javascript - 从文本框获取值 - Android WebView 和 JavascriptInterface 问题

Question

我试图通过单击网站上的按钮从两个文本框中获取简单的值。

我关注了这个 - https://developer.android.com/guide/webapps/webview.html#BindingJavaScript

基本上将我的客户端 Android 代码绑定(bind)到网站上的 JavaScript 函数。

这是我的 Android 代码 -

package course.org.webviewtesting;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.webkit.CookieManager;
import android.webkit.CookieSyncManager;
import android.webkit.JavascriptInterface;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.webkit.WebViewClient;
import android.widget.ImageView;
import android.widget.Toast;

/**
 * Created by User on 12/29/2016.
 */

public class WebViewTest extends Activity {

WebView mWebView;
ImageView logo;

@Override
public void onCreate(Bundle savedInstanceState) {

    final Activity mActivity = this;

    CookieSyncManager.createInstance(mActivity);
    CookieSyncManager.createInstance(getApplicationContext());
    CookieSyncManager.getInstance().sync();
    CookieManager.getInstance().setAcceptCookie(true);

    this.getWindow().requestFeature(Window.FEATURE_PROGRESS);
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);
    logo = (ImageView) findViewById(R.id.logo);

    logo.setVisibility(View.VISIBLE); //logo as a loading screen
    // Makes Progress bar Visible
    getWindow().setFeatureInt(Window.FEATURE_PROGRESS, Window.PROGRESS_VISIBILITY_ON);



    mWebView = (WebView) findViewById(R.id.webview);
    mWebView.addJavascriptInterface(new WebAppInterface(this), "android");
    mWebView.getSettings().setJavaScriptEnabled(true);
    mWebView.loadUrl("myURLhere");
    mWebView.setWebChromeClient(new WebChromeClient() {


        public void onProgressChanged(WebView view, int progress) {
            //Make the bar disappear after URL is loaded, and changes string to Loading...
            mActivity.setTitle("Loading...");
            mActivity.setProgress(progress * 100); //Make the bar disappear after URL is loaded

            if (progress == 100) {
                mActivity.setTitle(R.string.app_name);
                logo.setVisibility(View.GONE);
            }
        }


    });

    mWebView.setWebViewClient(new WebViewClient() {
        @Override
        public void onPageFinished(WebView view, String url) {
        System.out.println(" url is " + url);

        }
    });

}

// this is from the Android Docs
public class WebAppInterface {
    Context mContext;

    /** Instantiate the interface and set the context */
    WebAppInterface(Context c) {
        mContext = c;
    }

    /** Show a toast from the web page */
    @JavascriptInterface
    public void showFields(String email, String name) {
        Toast.makeText(mContext, email+" "+name , Toast.LENGTH_SHORT).show();
        System.out.println("Email " + email + "Name - "+name);
    }
}

}

我的 HTML 如下:

<input type="email" id="loginEmail" name="loginEmail" ng-model="loginEmail" ng-required="true" />

<input type="name" id="name" name="name" ng-model="name" ng-required="true" />

<button type="submit" class="btn btn-large" ng-click="showValues();" onClick="showValuesAndroid()">Check Values</button>

以及相应的 JavaScript :

<script type="text/javascript">
function showValuesAndroid() {
var a = document.getElementById("loginEmail").value;
var b = document.getElementById("name").value;
Android.showFields(a,b);
};
    </script>

我的函数获取变量 a 和 b 中的值，但我似乎无法在单击“检查值”按钮时在 WebView 上获取 toast 消息。 另外 - System.out.println 似乎也没有显示任何值。

我已经被困在这个问题上近两个小时了，我错过了什么/做错了什么？？

Answer 1

一旦 JavaScript 区分大小写，文档就会错误。如果您注意 Logcat，您可能会看到类似以下的消息:

com.androidbuts.sample I/chromium: [INFO:CONSOLE(XX)] "Uncaught ReferenceError: Android is not defined", source: ...

那是因为Android object is not properly set .

正如 @Jonas w 所说，将 addJavascriptInterface() 配置更改为:

mWebView.addJavascriptInterface(new WebAppInterface(this), "Android");

...它会工作得很好! :)