Android JavaScript in WebView

Question

I have tried to create a webview with JavaScript, but I get the error:

'Cannot cast View from WebView' on the line WebView myWebView = (WebView) findViewById(R.id.mainWebView);

This is the full code

package com.CalvaryChapelMelbourne.CCM;

import android.app.Activity;
import android.webkit.WebSettings;

public class WebView extends Activity {
    WebView webview;
    public WebView() {
        WebView myWebView = (WebView) findViewById(R.id.mainWebView);
        WebSettings webSettings = myWebView.getSettings();
        webSettings.setJavaScriptEnabled(true);


    }

}

XML Layout:

<?xml version="1.0" encoding="utf-8"?>
<WebView  xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
android:id="@+id/mainWebView"/>

Blundell · Accepted Answer · 2011-08-22 15:00:12Z

I think your slightly confused. See below for correct Activity implementation:

package com.CalvaryChapelMelbourne.CCM;

import android.app.Activity;
import android.webkit.WebSettings;

public class WebViewActivity extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        WebView myWebView = (WebView) findViewById(R.id.mainWebView);
        WebSettings webSettings = myWebView.getSettings();
        webSettings.setJavaScriptEnabled(true);


    }

}

or if you wanted to construct a WebView object:

public WebView(Context context) {
        LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        WebView myWebView = (WebView) inflater.inflate(R.layout.mainWebView, null); // The xml file name not the id
        WebSettings webSettings = myWebView.getSettings();
        webSettings.setJavaScriptEnabled(true);    
    }

dirkboye · Accepted Answer · 2011-08-22 15:01:08Z

You are trying to define a class WebView as a subclass of Activity but WebView is already a subclass of View ( http://developer.android.com/reference/android/webkit/WebView.html )

The method findViewById(..) of Activity will return a View which you cannot cast to an Activity.

You have to rename your class (is that class the class you launch at the beginning?)

Try like this:

public class MyWebViewActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        WebView myWebView = (WebView) findViewById(R.id.mainWebView);
        WebSettings webSettings = myWebView.getSettings();
        webSettings.setJavaScriptEnabled(true);
    }
}

You also have to adjust your AndroidManifest.xml.

Houcine · Accepted Answer · 2011-08-22 15:05:11Z

1

I think you are new in Android development, We DONT DEFINE A CONSTRUCTOR OF ACTIVITY , you should override the method onCreate(Bundle icircle); like this :

public class MyActivity extends Activity {
    WebView webview;
@Override
    public void onCreate(Bundle icircle) {
        super(icircle);
        this.setContentView(R.layout.main);
        WebView = (WebView) findViewById(R.id.mainWebView);
        WebSettings webSettings = WebView.getSettings();
        webSettings.setJavaScriptEnabled(true);


    }

}

NOTE : Dont rename your activities with names of UIElements or Classes like WebView , TextView ...etc

edited Aug 22, 2011 at 15:05

answered Aug 22, 2011 at 14:56

Houcine

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