I write an app for android. There is a Webview and I want to put Text into the focussed TextArea on the website after clicking a button at my app. I haven't found any solution at google.
It is important to put in the text, it is no login view, where data can be transmitted by the POST methode, the user should be able to see the input.
I hope you can help me.
Thanks!
public void addJavascriptInterface (Object object, String name)
Added in API level 1
Injects the supplied Java object into this WebView. The object is injected into the JavaScript context of the main frame, using the supplied name. This allows the Java object's methods to be accessed from JavaScript. For applications targeted to API level JELLY_BEAN_MR1 and above, only public methods that are annotated with JavascriptInterface can be accessed from JavaScript. For applications targeted to API level JELLY_BEAN or below, all public methods (including the inherited ones) can be accessed, see the important security note below for implications.
Note that injected objects will not appear in JavaScript until the page is next (re)loaded. For example:
class JsObject {
#JavascriptInterface
public String toString() { return "injectedObject"; }
}
webView.addJavascriptInterface(new JsObject(), "injectedObject");
webView.loadData("", "text/html", null);
webView.loadUrl("javascript:alert(injectedObject.toString())");
IMPORTANT:
This method can be used to allow JavaScript to control the host application. This is a powerful feature, but also presents a security risk for applications targeted to API level JELLY_BEAN or below, because JavaScript could use reflection to access an injected object's public fields. Use of this method in a WebView containing untrusted content could allow an attacker to manipulate the host application in unintended ways, executing Java code with the permissions of the host application. Use extreme care when using this method in a WebView which could contain untrusted content.
JavaScript interacts with Java object on a private, background thread of this WebView. Care is therefore required to maintain thread safety.
The Java object's fields are not accessible.
Parameters
object the Java object to inject into this WebView's JavaScript context. Null values are ignored.
name the name used to expose the object in JavaScript
I am using phone, sorry for formating. This is quote from offical page android.
So:
If is your page:
Set ID of Input, for example text (for example: <input id="text" ...)
Add this code of end of document:
<script>function a(b){document.getElementById("text (here is yur ID)").value=b;};function b(a){document.getElementById("text (here is your ID)").value+=a;}</script>
To change text, use this code:
String str="any string";
webview.loadUrl("javascript:a(\""+str+"\")");
To add text at the end:
String str="any string";
webview.loadUrl("javascript:b(\""+str+"\")");
Related
I am creating a javascript api for my application and I want to use namespaces in my javascript code. However I am unable to get it to work nor find any information on the issue.
Desired Functionality:
HTML:
<script>
Android.typeOne.methodName();
Android.typeTwo.methodName();
</script>
Java Code:
webView.addJavascriptInterface(new TypeOneInterface(context), "Android.typeOne");
webView.addJavascriptInterface(new TypeTwoInterface(context), "Android.typeTwo");
However this never works, if I remove .typeOne and have: Android.methodName then that works fine.
I'm looking at the documentation of addJavascriptInterface. It says that The Java object's fields are not accessible. Since typeOne would have to be a property on the exported Java Object, it seems you would need to arrange the "namespace" by hand. That is, export TypeOne and put it in the global JavaScript Android object.
So I'm guessing you need to create empty objects, and put stuff in them as needed.
<script>
// after stuff has been "injected into the JS context of the main frame"
Android = {};
Android.typeOne = window.TypeOne;
... and
webView.addJavascriptInterface(new TypeOneInterface(context), "TypeOne");
This answer is a guess, I have never used JavaScript in a WebView.
I think that javascript understand that you are calling methodeName on object typeOne that is a child of object Android. But you don't have any object named Android nor typeOne.
The dot in javascript is used for hierarchy betweens parents and child.
You should try to use name without dots or, call your object differently (perhaps window["Android.typeOne"].methodName();
I would like to know how I can get a value from a webview.
For example, to load a value into the webview I use:
myWebView.loadUrl("www.example.com");
myWebView.loadUrl("javascript:document.getElementById('username').value='"+ user + "';");
Now I would like to read some text from a certain ID from a webpage.
Something like:
myWebView.loadUrl("www.example.com");
myWebView.getUrl("javascript:document.getElementById('username').toString(user);");
Is this possible?
Edit: Since KitKat (API 19), the WebView class provides the method evaluateJavascript that allows to execute javascript and get the return values.
For olders API, you can still bind javascript to your Android Java code (look here)
So, you will implement a Javascript interface class and add it to your WebView and then call something like
myWebView.loadUrl("javascript:MyJavascriptInterface.getValue(document.getElementById('username').value);");
This will call the method getValue (this is a custom function, it is up to you to rename it as you want) in your class that is used as a Javascript interface, and change MyJavascriptInterface with the name you specified in addJavascriptInterface.
Yes, you can. getElementById('username').Value
I want my Android application to use Webview to display an html form. When the user presses the Submit button, it want the name/value pairs sent back to my program. How do I do this?
I have looked at other similar questions but not of the responses tell how, specifically, to do this.
Look into the use of Javascript interfaces within WebView. Please see this area of the Android Developers Guide. Basically, you should be able to communicate from the page to the device with the Javascript interface and let your WebView Activity know when the submit button is pressed and send its values over.
I have found what I needed. If I set action='FORM" in the form html, then I can intercept the action with:
public void onLoadResource (WebView view, String url){
int index = url.indexOf("FORM?");
if (index != -1){
String d = URLDecoder.decode(url.substring(index+5));
}
}
The name/value pairs are in String d.
If you want to save Name/Value pairs and are willing to use jQuery then it's quite simple.
Assuming you put jQuery in your assets folder you can read it into a file from:
getResources().getAssets()
In the WebViewClient that you set (assuming you overrode the client) you can do:
view.loadUrl("javascript:" + escapedJqueryStringHere);
Then, make sure you have a JavascriptInterface configured for your webview with a method, for example, called 'ReturnJSONFromForm(String json)' configured for "MyJInterface" then load the form into the page and then try this:
webview.loadUrl("javascript:MyJInterface.ReturnJSONFromForm($(\"form\").serialize());");
Now in your interface, just create a JSONObject from the resultant string and there you go! Name/Value pairs from your form.
Serialize won't capture disabled fields or submit buttons.. if you need that, then a more complex javascript solution exists but it's far more difficult.
I am displaying a html in a custom activity with a webview. I am overriding
public boolean shouldOverrideUrlLoading(WebView view, String url) {
to intercept certain urls. Now I would like to be able to figure out some more details about the html around that url.
In my case I would like to get the html element that contains the url. E.g. if the url comes from
Manfred Moser
I would like to be able to somehow retrieve the value "Manfred Moser" from within the anchor tag. Is there a way to do that. I found that you do not have access to the DOM from Java.
One way I can think of would be to download the page separately and parse it all before even loading it in webview. However that is an ugly hack at best. Is there a better way?
There is a dirty hack:
Bind some Java object so that it can be called from Javascript with WebView:
addJavascriptInterface(javaObjectExposed, "JSname")
Force execute javascript within an existing page by
WebView.loadUrl("javascript:window.JSname.passData("some data");");
Described here: http://lexandera.com/2009/01/extracting-html-from-a-webview/
Note: this is a security risk - any JS code in this web page could access/call your binded Java object. Best to pass some one-time cookies to loadUrl() and pass them back your Java object to check that it's your code making the call.
In addition to #Peter Knego's approach, there is the inverse:
Use addJavascriptInterface(), per his step #1
For your link, use an onClick attribute on your <a> tag to call out some method on the Java object from step #1, where the Java object turns around and loads the URL into the WebView, and supplies whatever sort of identifying information you want.
Suffice it to say, there's no way to get the information you want from shouldOverrideUrlLoading().
How can I retrieve the Javascript function value from a web page loaded withing a webview component??
You can't, directly.
You can call the Javascript function via loadUrl("javascript:..."), where ... is your function call. However, you cannot get a result this way.
If you inject a Java object into the Web page via addJavascriptInterface(), you could set up another function that called the function you want and returns that value via a call to the injected Java object. That only works if you can modify the Web page, though.