Develop Reference

Twitter Android SDK not executing Callback

I'm running this code with a Twitter handle I'm pretty sure doesn't exist in order to test error handling. The breakpoints on the Callback are never hit, neither for success nor failure.
Any pointers on why this is?
Just as a note, this code works fine with a valid Twitter handle, but doesn't call the Callback either.
final Callback<Tweet> actionCallback = new Callback<Tweet>() {
#Override
public void success(Result<Tweet> result) {
int x = 1;
x++; // This code is just so I can put a breakpoint here
}
#Override
public void failure(TwitterException exception) {
DialogManager.showOkDialog(context, R.string.twitter_feed_not_found);
}
};
final UserTimeline userTimeline = new UserTimeline.Builder().screenName(handleStr + "dfdfddfdfdfasdf") // Handle that doesn't exist
.includeReplies(false).includeRetweets(false).maxItemsPerRequest(5).build();
final TweetTimelineListAdapter adapter = new TweetTimelineListAdapter.Builder(context)
.setTimeline(userTimeline)
.setViewStyle(R.style.tw__TweetLightWithActionsStyle)
.setOnActionCallback(actionCallback)
.build();
listView.setAdapter(adapter);

I think you misundestood the purpose of the actionCallback. From the source code of the TweetTimelineListAdapter you can see that this callback is for the actions on tweet view,ie, when you click on favorite icon for example. I've test with the favorite icon and the callback gets called.
Take a look at this comment at the getView method of the source code.
/**
* Returns a CompactTweetView by default. May be overridden to provide another view for the
* Tweet item. If Tweet actions are enabled, be sure to call setOnActionCallback(actionCallback)
* on each new subclass of BaseTweetView to ensure proper success and failure handling
* for Tweet actions (favorite, unfavorite).
*/
The callback is not intended to handle a screenname that does not exist and indeed the actions/buttons of a specific tweet.
Hope this helps.
UPDATED: You don't need to detect any erros on UserTimeLine, since the builder does not throw any exception and the adapter will be empty, with no rows/views showing on the screen. But if you still need to detect some "error" in the loading you have to rely on the "next" method of the UserTimeLine.
Take a look
userTimeline.next(null, new Callback<TimelineResult<Tweet>>() {
#Override
public void success(Result<TimelineResult<Tweet>> result) {
}
#Override
public void failure(TwitterException exception) {
Log.d("TAG",exception.getMessage());
}
});
This method shows the next tweet for the user, if the failure callback get called you will know for sure that this user does not have any tweet or the user does not exist.

Cordova: How to write native plugins that can repeatedly invoke a Javascript callback?

When developing Cordova plugins, all of the tutorials I have found go something like this:
File: AwesomePlugin.js
var AwesomePlugin = {
kungfuGripAction = function(target, successCallback, failureCallback) {
return cordova.exec(
successCallback,
failureCallback,
'AwesomePluginClass',
'kungfuGripAction',
[target]
);
}
};
module.exports = AwesomePlugin;
File: AwesomePluginClass.java
#Override
public boolean execute(String action, JSONArray args, CallbackContext callbackContext) throws JSONException {
if (ACTION_KUNGFU_GRIP.equals(action)) {
JSONObject target = args.getJSONObject(0);
if (gripTarget(target)) {
callbackContext.success("Target successfully gripped.");
return true;
} else {
callbackContext.error("Could not grip target.");
return false;
}
}
Log.d(LOG_TAG, "INVALID ACTION! " + action);
callbackContext.error("Invalid action: " + action);
return false;
}
File: clientCode.js
AwesomePlugin.kungfuGripAction(cobraEnemy, function(ok) { }, function(err) { });
In the above code, the callbacks can only be called once and are then disposed. If you attempt to call the .success() or .error() method of the callback context object, it will not work and you will get a log message:
Attempted to send a second callback for ID: AwesomePlugin2982699494<BR>W/CordovaPlugin(976) Result was: "Target successfully gripped."
It seems like it is not possible to write a method with a callback that can be called repeatedly seeing as .success() and .error() are the only documented ways to invoke a callback from within native plugin code. While this is mostly what we want, there are times when we want to have the plugin execute a callback repeatedly. For example:
AwesomePlugin.kungfuGripAction(cobraEnemy, function(ok) {
// After successful grip, punch repeatedly and update life meter.
AwesomePlugin.punchRepeatedly(cobraEnemy, function(hits) {
updateLifeMeter(cobraEnemy, hits);
}, function(err) { });
}, function(err) { });
AwesomePlugin.punchRepeatedly() above will execute repeatedly (maybe in a separate thread) and call function(hits) with each successful execution. If implemented in the de-facto way (using single-use callbacks), you have to either use a loop (which is bad as it is non-async) or tail-call AwesomePlugin.punchRepeatedly() in the callback (error-prone).
What would be the correct way to implement punchRepeatedly() in native code so that it is able register the callback once and then execute it repeatedly?

I think, you can use a pluginResult with the keepCallback property set to true.
PluginResult result = new PluginResult(PluginResult.Status.OK, "YOUR_MESSAGE");
// PluginResult result = new PluginResult(PluginResult.Status.ERROR, "YOUR_ERROR_MESSAGE");
result.setKeepCallback(true);
callbackContext.sendPluginResult(result);
You should be able to invoke the callback several times this way.

In jonas's answer, every time you call sendPluginResult you have to send the same value. So I changed the PluginResult class to add a method like this:
public void setStrMessage(String strMessage){
this.strMessage = strMessage;
}
This way, I can set the message I want to send to the JavaScript side.

How to call javascript function from java when webview page is different

I am working on an android project using HTML and webview to display.
I have
display.loadUrl("file:///android_asset/index.html");
display.setWebViewClient(new WebViewClient() {
public void onPageFinished(WebView view, String url)
{
display.loadUrl("javascript:openDialog()");
}
});
and this works perfectly. But the javascript function i want to call is in another page (chat.html). How do i call the javascript functions on this pages from java?

If you are the owner of the webpage (chat.html), you can integrate a JS-function which invokes a native method. And in this native method you can call your target-JS:
chat.html:
function callItNow() {
if (typeof Android != "undefined"){
if (Android.caller!= "undefined") {
Android.caller();
}
}
}
in native Code, define a class:
class MyJavascriptBridge {
public void caller() {
//now you know you are on the right place (chat.html)
webView.loadUrl("javascript:openDialog()");
}
}
and of course you have to declare the bridge to your webview:
webView.addJavascriptInterface(new MyJavascriptBridge(), "Android");

suppose you'r function in javascript is hello.
webview.loadUrl("javascript:hello();");
I think that'll do it.

Android WebView getFavicon() returning null

I'm trying to get the favicon of the loaded page after using
WebView webView = new WebView(getActivity());
webView.loadUrl("http://" + url);
I'm attaching the asynchronous WebViewClient to the WebView to get the favicon after it loads
webView.setWebViewClient(new WebViewClient()
{
#Override
public void onPageFinished(WebView view, String url)
{
String linkTitle = view.getTitle();
Bitmap favicon = view.getFavicon();
onLinkUrlFinished(url, linkTitle);
}
});
The favicon getting back is always null, even for websites such as google/facebook that has favicons for sure.
Another thread says to use WebIconDatabase but it's deprecated:
Display the Android WebView's favicon
The API on android site refers to WebViewClient.onReceivedIcon which doesnt even exist.http://developer.android.com/reference/android/webkit/WebView.html#getFavicon%28%29
What's going on here?

In order to use onReceiveIcon(), you should use setWebChromeClient.
This is what I do and it's working for me.
webView.setWebChromeClient(new WebChromeClient() {
#Override
public void onProgressChanged(WebView view, int newProgress) {
super.onProgressChanged(view, newProgress);
progressBar.setProgress(newProgress);
}
#Override
public void onReceivedIcon(WebView view, Bitmap icon) {
super.onReceivedIcon(view, icon);
webImage.setImageBitmap(icon);
}
});

WebIconDatabase is deprecated as of API 19. According to the comments in the code:
#deprecated This class is only required when running on devices up to
{#link android.os.Build.VERSION_CODES#JELLY_BEAN_MR2}
So unless you don't want to support API 18 and below, you should still be using WebIconDatabase:
WebIconDatabase.getInstance().open(getDir("icons", MODE_PRIVATE).getPath());
And then, regardless what API you want to support, you need to specify in a custom WebChromeClient:
public class MyCustomWebChromeClient extends WebChromeClient {
#Override
public void onReceivedIcon(WebView view, Bitmap icon) {
super.onReceivedIcon(view, icon);
// do whatever with the arguments passed in
}
}
Remember to register your custom WebChromeClient with your WebView:
mWebView.setWebChromeClient(new MyCustomWebChromeClient());

The key is to open the WebIconDatabase so WebView has somewhere to put the icons, and override WebChromeClient.onReceivedIcon. For additional information, see this StackOverflow article.

I know its an old thread but, for those facing problems getting favicon using webview client.
Kotlin:
override fun onPageFinished(view: WebView?, url: String?) {
super.onPageFinished(view, url)
tabTitle.text = view?.title // read website title
loadImg(view) // method to load the favicon
}
private fun loadImg (view: WebView?){
// u can directly use tabImage.setBitmap instead of assigning tabImg as val
val tabImg: ImageView = findViewById(R.id.tabImage)
// creating handler object to delay the associated thread a little bit after onPageFinished is called.
val handler = Handler()
val runnable = Runnable {
if(view?.favicon != null) {
tabImg.setImageResource(0) //remove the default image
tabImg.setImageBitmap(view?.favicon) // set the favicon
}
}
handler.postDelayed(runnable, 200) // delay time 200 ms
}
It worked for me, hope it helps new readers, plz up vote if it helps u, so that u can help others!
Best regards

So in the end I didn't end up using the deprecated API, instead I found out that if you put /favicon.ico after the domain, it'll give you the ico file, which I used in the end to fetch the image. The Uri API will have a getHost() method that will give you the host without having to manually parse it
String faviconUrl = Uri.parse(url).getHost() + "/favicon.ico";
For google for example the icon url will be www.google.com/favicon.ico

Check WebView's URL while Unit Testing in Robotium

Im trying to figure out the easiest way to check my Main Activity's URL inside my (WebView). This is going to be in a Unit Test using the Robotium 4.1 framework. All i am trying to figure out how i can interact with the webview, such as send the activity a URL to load, so i can test against that and make sure the correct URL is loaded and also check my actionbar items as well.
Any Codes, suggestions or recommendations would be highly appreciated.
public class ErrorHandling extends
ActivityInstrumentationTestCase2<Webview_Main> {
private Solo solo;
private WebView web;
..
protected void setUp() throws Exception {
super.setUp();
solo = new Solo(getInstrumentation(),getActivity());
}
Updated per recommendations (Currently - NullPointerException Erorrs)
public void testUrl() {
String URL = solo.getString(com.example.webview.R.string.url);
web = (WebView) getActivity().findViewById(R.id.webview_main); //Added
try {
solo.assertCurrentActivity("Launching Main Activity", Webview_Main.class);
assertTrue(solo.getWebUrl().equals("URL")); }
catch (Error error) {
}
}
public void testWeb() {
try {
web = (WebView) getActivity().findViewById(R.id.webview_main); //Added
solo.getCurrentActivity().runOnUiThread(new Runnable() {
public void run() {
web.loadUrl("http://www.google.com");
}
});
solo.sleep(1000);
} catch (Error error) {
}
}

first, calling
web.getSettings();
gives you nothing. It provides you WebSettings, but you don't do anything with that object.
To assert current url in your webview you can use:
assertTrue(solo.getWebUrl().equals("your url"));
To load specified url in your webview you have to run it in another thread (here I'm not sure, if it should be runOnMainSync or runOnUiThread, however I tried runOnUiThread and it worked fine), for instance:
solo.getCurrentActivity().runOnUiThread(new Runnable() {
public void run() {
web.loadUrl("http://www.OTHER_url_TO_test_AGAINST");
}
});

The steps to check the URL are as follows:
1) Create the webview object for the specific application
obj = (WebView)getActivity().findViewById((package name of source or apk).R.id.(Id of the source webview))
Note: If you dont have the source code of the source application of whome you are writing the test case then use the hierarchy viewer to find the id of the webview.
2) Add some sleep so that it will wait the time taken to load the url
solo.sleep(time)
3) Use this to get the current value or status of the application.
obj.getSettings()
4) Take a Boolean variable and store the value of
Boolean variable = solo.getWebUrl().equals("URL to be tested");
5) assertTrue(Boolean variable)
To verify the value true or false.