Android - Calling Java from Webview

Question

I want to call Java from Webview.

I have JavaScriptInterface below:

class JavaScriptInterface{

    private Activity activity;

    public JavaScriptInterface(Activity activiy) {
        this.activity = activiy;
    }

    public void open(String message){
        //do something
    }

}

I add JavaScriptInterface

JavaScriptInterface jsInterface = new JavaScriptInterface(this);
webView.getSettings().setJavaScriptEnabled(true);
webView.addJavascriptInterface(jsInterface, "JSInterface");

In my HTML, I have this onclick event:

onclick="window.JSInterface.open('hi');"

I also tried:

onclick="JSInterface.open('hi');"

I have this error in logcat:

04-16 14:55:15.829: W/dalvikvm(721): JNI WARNING: jarray 0x4050cf68 points to non-array object (Ljava/lang/String;)
04-16 14:55:15.829: I/dalvikvm(721): "WebViewCoreThread" prio=5 tid=9 NATIVE
04-16 14:55:15.829: I/dalvikvm(721):   | group="main" sCount=0 dsCount=0 obj=0x40521218 self=0x1f6cf8
04-16 14:55:15.829: I/dalvikvm(721):   | sysTid=729 nice=0 sched=0/0 cgrp=default handle=2059824
04-16 14:55:15.839: I/dalvikvm(721):   | schedstat=( 5717972154 3300872155 567 )
04-16 14:55:15.839: I/dalvikvm(721):   at android.webkit.WebViewCore.nativeTouchUp(Native Method)
04-16 14:55:15.839: I/dalvikvm(721):   at android.webkit.WebViewCore.nativeTouchUp(Native Method)
04-16 14:55:15.839: I/dalvikvm(721):   at android.webkit.WebViewCore.access$3300(WebViewCore.java:53)
04-16 14:55:15.839: I/dalvikvm(721):   at android.webkit.WebViewCore$EventHub$1.handleMessage(WebViewCore.java:1158)
04-16 14:55:15.863: I/dalvikvm(721):   at android.os.Handler.dispatchMessage(Handler.java:99)
04-16 14:55:15.869: I/dalvikvm(721):   at android.os.Looper.loop(Looper.java:130)
04-16 14:55:15.869: I/dalvikvm(721):   at android.webkit.WebViewCore$WebCoreThread.run(WebViewCore.java:629)
04-16 14:55:15.869: I/dalvikvm(721):   at java.lang.Thread.run(Thread.java:1019)
04-16 14:55:15.869: E/dalvikvm(721): VM aborting

How to fix it? Or another way to do it?

Thanks

Answer 1

1. You need to enable Javascript in your WebView by setting

   final WebView myWebView = (WebView) findViewById(R.id.webview);
   myWebView.setVerticalScrollBarEnabled(false);
   myWebView.setHorizontalScrollBarEnabled(false);
   WebSettings webSettings = myWebView.getSettings();
   webSettings.setJavaScriptEnabled(true);
   webSettings.setJavaScriptCanOpenWindowsAutomatically(true);
   

2. You need to load your JS in your HTML DOM.

   JsInterface jsInterface = new JsInterface();
   jsInterface.wordDef = content;
   myWebView.addJavascriptInterface(jsInterface, "interfaces");
   myWebView.loadUrl("file:///android_asset/some.html");
   

3. Call your interface from HTML/JS

   /**JAVA CODE **/
   public class JsInterface {
    public String someString;
    Context mContext;
   
    public void JsInterface(Context c){
      mContext = c;
    }
   
    public String someFunction(){
     Log.v("JSInterface", ""+someString);
     return someString;
    }
   }
   
   /* JS Code */
   function addData(){
       var data = interfaces.someFunction();
   }