Android Java和Phonegap Javascript之间的通信？

Question

我相信可以从(PhoneGap)Javascript调用Java方法.

谁知道怎么做？(我知道如何通过更改PhoneGap的源代码来实现,但我会避免这种情况)

Answer 1

我终于成功了.

• 使用您要使用的方法创建一个类:

  public class MyClass {
    private WebView mAppView;
    private DroidGap mGap;
  
    public MyClass(DroidGap gap, WebView view)
    {
      mAppView = view;
      mGap = gap;
    }
  
    public String getTelephoneNumber(){
      TelephonyManager tm = 
        (TelephonyManager) mGap.getSystemService(Context.TELEPHONY_SERVICE);
      String number = tm.getLine1Number();
      return number;
    }
  }
  

• 在您的主要活动中为此类添加Javascript接口:

  public class Main extends DroidGap
  {
      private MyClass mc;
  
      @Override
      public void onCreate(Bundle savedInstanceState)
      {
          super.onCreate(savedInstanceState);
          super.init();
  
          mc = new MyClass(this, appView);
          appView.addJavascriptInterface(mc, "MyCls");
  
          super.loadUrl(getString(R.string.url));
      }
  }
  

• 在Javascript调用window.MyCls方法:

  <script>
    $(function(){
      $("#phone").text("My telephone number is: " + 
              window.MyCls.getTelephoneNumber());
    });
  </script>
  

注意:

如评论中所述,对于Android 4.2及更高版本,请添加@JavascriptInterface要从HTML页面访问的方法.参考.

Answer 2

addJavaScriptInterface(mc, "MyCls")没有Gap init()ed可能会导致应用程序崩溃,你最好super.init()先添加addJavascriptInterface()

public class Main extends DroidGap
{
   private MyClass mc;

   @Override
   public void onCreate(Bundle savedInstanceState)
   {
       super.onCreate(savedInstanceState);

       super.init();

       mc = new MyClass(this, appView);
       appView.addJavascriptInterface(mc, "MyCls");

       super.loadUrl(getString(R.string.url));
   }
}

Answer 3

PhoneGap有一个不错的插件API.您可以通过实现IPlugin接口在Java中编写插件.大多数魔法都在execute()函数中.

public interface IPlugin {

    /**
     * Executes the request and returns PluginResult.
     *
     * @param action        The action to execute.
     * @param args          JSONArry of arguments for the plugin.
     * @param callbackId    The callback id used when calling back into JavaScript.
     * @return              A PluginResult object with a status and message.
     */
    PluginResult execute(String action, JSONArray args, String callbackId);

        // ... more ...
}

开始编写插件的最佳方法是首先编写javascript API.你通常会先编写一个自定义的javascript类,然后在javascript类的每个方法中,编组变量并调用你使用Phonegap.exec()方法开发的插件.以下是方法签名供您参考.

/* src/com/phonegap/api/PluginManager.java */
/**
 * Receives a request for execution and fulfills it by finding the appropriate
 * Java class and calling it's execute method.
 *
 * PluginManager.exec can be used either synchronously or async. In either case, a JSON encoded
 * string is returned that will indicate if any errors have occurred when trying to find
 * or execute the class denoted by the clazz argument.
 *
 * @param service       String containing the service to run
 * @param action        String containt the action that the class is supposed to perform. This is
 *                      passed to the plugin execute method and it is up to the plugin developer
 *                      how to deal with it.
 * @param callbackId    String containing the id of the callback that is execute in JavaScript if
 *                      this is an async plugin call.
 * @param args          An Array literal string containing any arguments needed in the
 *                      plugin execute method.
 * @param async         Boolean indicating whether the calling JavaScript code is expecting an
 *                      immediate return value. If true, either PhoneGap.callbackSuccess(...) or
 *                      PhoneGap.callbackError(...) is called once the plugin code has executed.
 *
 * @return              JSON encoded string with a response message and status.
 */
@SuppressWarnings("unchecked")
public String exec(final String service, final String action,
    final String callbackId, final String jsonArgs,
    final boolean async)

您还需要注册插件.您可以通过在自定义JavaScript库底部添加注册码来完成此操作.

在下面的示例中,作者定义了一个javascript BarcodeScanner类,并使用addConstructor方法对其进行注册.

在addConstructor中执行两个步骤:

1. 在javascript中创建一个新的BarcodeScanner实例并注册它.这可以通过javascript作为window.plugins.barcodeScanner访问

2. 使用服务名称注册自定义Plugin类.此服务名称作为PhoneGap.exec的第一个参数传入,以便PhoneGap可以实例化java插件类并在其上调用execute()方法.

样品注册码:

PhoneGap.addConstructor(function() {
    /* The following registers an instance of BarcodeScanner in window.plugins.barcodeScanner */
    PhoneGap.addPlugin('barcodeScanner', new BarcodeScanner());

    /* The following associates a service name BarcodeScanner with a class com.beetight.barcodescanner.BarcodeScanner */
    /* The service name is the first argument passed into PhoneGap.exec */
    PluginManager.addService("BarcodeScanner","com.beetight.barcodescanner.BarcodeScanner");
});

Answer 4

一个更简单的形式:

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    super.init(); 
    super.appView.getSettings().setJavaScriptEnabled(true);
    super.appView.addJavascriptInterface(this, "MyCls");
    super.loadUrl("file:///android_asset/www/login.html");
}

Answer 5

如果有人使用上面的代码获取nullPointer异常,先执行super.oncreate(),然后执行super..init()

super.onCreate(savedInstanceState);
super.init();

我在这里找到了这个解决方案:Phonegap Google Group

非常感谢@ zorglub76的解决方案....