What I would like to have is an activity indicator, which is displayed after my app is up and running, but while GWT is making AJAX calls.
For example have a look at following site : http://www.foodtrucksmap.com/#
Any ideas on how to achieve it?
You can use an activity indicator from here, they are animated gifs so you can display one like this:
<g:Image ui:field="activityImage"/>
MyResources resources = GWT.create(MyResources.class);
this.activityImage.setResource(resources.activityImage());
and in your resources interface you would set the image:
public interface MyResources extends ClientBundle{
// use the actual path to your image
#Source("../resources/images/activityImage.gif")
ImageResource activityImage();
}
When you make your async calls:
loadingImage.setVisible(true);
and in the callback:
loadingImage.setVisible(false);
I had to deal with the same kind of stuff few days back. The way I did was, created an Icon and Overlayed on the map.
Icon icon = Icon.newInstance("loading.gif"); // load you gif as icon
MarkerOptions options = MarkerOptions.newInstance();
options.setIcon(icon);
Marker indicator = new Marker(point, options);
So before the Async call and after you map is up, just add the icon to the map using
map.addOverlay(indicator);
and after the Async call remove the overlay using
map.removeOverlay(indicator);
I am not sure how correct this approach is, but this is what I did and it worked.
Related
I have a CropViewActivity that crops an image, saves the cropped image to the external storage. The process of decoding the bitmap and saving it to external storage is done in another thread. So the crop activity finishes, while the image processing still goes on in the background. Now I want a way to inform my other Activity, which contains an ImageView. At the end of the image processing in the background, the ImageView should then fetch the saved image from memory and load it.
How to achieve this inter-thread cum inter-activity communication? Please help..
There are several ways of doing that. I would like to refer you some.
You might consider using BroadcastReceiver when you are finished processing your image. You need to register the receiver in your activity which contains the ImageView and after processing the image in another activity, send the broadcast with the desired intent that you are listening to receive. Here's a sample implementation on how you can implement a BroadcastReceiver.
Another way of communicating between activities is starting an activity for a result. See developers documentation to see how you can use startActivityForResult and then get the result from the activity which is processing the image and getting the result back to the calling activity which contains the ImageView in your case.
You might pick any of these two which is best suited according to your use-case. Hope that helps.
AsnycTask?
typealias Callback = () -> Unit
class BitmapWorker: AsyncTask<Callback, Void, Callback?>
override fun doInBackground(vararg params: Callback): Callback? {
// work with bitmap
return params.firstOrNull()
}
override fun onPostExecute(finishTask: Callback?) {
finishTask?.invoke()
}
}
Call this like:
BitmapWorker().execute(fun() {
println("finished")
}
I am building my application using Android Studio, this app can upload an image from raspberry to my emulator. It works fine. What I want to do now is uploading this image and showing it directly to the user without searching it in the gallery. I thought about creating another class and setting this image as a background image in my xml file, but this is too much like I have to create another class every time I want to upload an image from my raspberry.
Can someone help me please. Thank you
If I'm understanding your question correctly, you'd like to load an image from the Android filesystem into your app and display it to the user.
Drawable, Android's generalized image class, allows you to load from file via Drawable#createFromPath.
This SO question suggests Drawable#createFromPath doesn't work on paths beginning with file://, so depending on your use case you may want to precede that with Uri#parse/Uri#getPath.
Once you have a Drawable, you can display it in one of two ways: put an ImageView in your app and call its setImageDrawable method, or set the Drawable as your background image via View#setBackground (note that setBackground was only added in API 16 - in prior versions, you should call View#setBackgroundDrawable).
Putting all of this together, we end up with the following (untested):
private void loadImage(String imagePath) {
Uri imageUri;
String fullImagePath;
Drawable image;
ImageView imageDisplay;
imageUri = Uri.parse(imagePath);
fullImagePath = imageUri.getPath();
image = Drawable.createFromPath(fullImagePath);
imageDisplay = (ImageView) findViewById(R.id.imageDisplay);
/*if image is null after Drawable.createFromPath, this will simply
clear the ImageView's background */
imageDisplay.setImageDrawable(image);
/*if you want the image in the background instead of the foreground,
comment the line above and uncomment this bit instead */
//imageDisplay.setBackground(image);
}
You should be able to modify this to work with any View just by replacing imageDisplay's declared type with the appropriate View type and changing the cast on findViewById. Just make sure you're calling setBackground, not setImageDrawable, for a non-ImageView View.
I'm making this netflix style app in which images are loaded into different categories. Let's say Dog videos (has 15 images), Cat videos (15 images), etc... All the images are loaded from a URL, it kind of takes a while for all to load. I was wondering if there was anything I could do to speed up the process? Or maybe show an empty container then fill it as the images load (that would be cool).
This is what I have done:
I have multiple async calls in one Activity, (1 async call per category)
JSONTask1 dogTask = new JSONTask1();
JSONTask2 catTask = new JSONTask2();
JSONTask3 pigTask = new JSONTask3();
JSONTask4 horseTask = new JSONTask4();
dogTask.execute("");
catTask.execute("");
pigTask.execute("");
horseTask.execute("");
I have all of those in a row in my actual code. Thanks.
I would use the "proxy pattern". Basically, you need to create a class that contains the minimal informations required for the display. In which, you have a preview image.
When ever you load everything you start by showing the preview content, ie : a loading gif for everypicture with the title of the movie or whatever. and basically the proxy would have a "loadImage" method that would make an ajax call or async call and the photos would load one by one. Plus, to make the loading easier, make sure the photos are not oversized.
You can see Picasso answers , in picasso i suggest you this way :
Picasso.with(getApplicationContext()).load("your url").placeholder(R.drawable.your_place_holder).error(R.drawable.showing_when_error_occured)
.into(imageView, new Callback() {
#Override
public void onSuccess() {
}
#Override
public void onError() {
}
});
Also another suggestion from me : convert your thumb images to base64 format in backend, then firstly retrieve your thumbs and show them. Then start an async task and change images when successfull.
Like whatsapp. In whatsapp you have thumb images they have so low resolution and super fast. When you click image if you have internet connection they load actual thumb images, and click again they load larger image.
Picasso website :http://square.github.io/picasso/
Load them asynchronously with Picasso, you can even show a placeholder image until the real one is loaded
I want to make an activity that can be opened above ANY app.
Normally, even when the activity is set as dialog, when you switch to my app, you see my app, and in the background you see the launcher:
BUT, I want the app will go above any app like this: (made in photoshop):
I did see this question Creating a system overlay window (always on top), but in ICS there is no functionallity to the layout.
Furthermore, I want to give a dialog box from my app without minimizing the other app...
there are plenty of apps that show a floating view on top of everything like : airbrowser , LilyPad , Stick it , AirTerm , Smart Taskbar , aircalc ...
anyway , in order to achieve this feature , you must have a special permission called "android.permission.SYSTEM_ALERT_WINDOW" , and use something like that:
final WindowManager.LayoutParams param=new WindowManager.LayoutParams();
param.flags=WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;
final View view=findViewById(R.id.my_floating_view);
final ViewGroup parent=(ViewGroup)view.getParent();
if(parent!=null)
parent.removeView(view);
param.format=PixelFormat.RGBA_8888;
param.type=WindowManager.LayoutParams.TYPE_SYSTEM_ALERT;
param.gravity=Gravity.TOP|Gravity.LEFT;
param.width=parent!=null?LayoutParams.WRAP_CONTENT:view.getLayoutParams().width;
param.height=parent!=null?LayoutParams.WRAP_CONTENT:view.getLayoutParams().height;
final WindowManager wmgr=(WindowManager)getApplicationContext().getSystemService(Context.WINDOW_SERVICE);
wmgr.addView(view,param);
// TODO handle overlapping title bar and/or action bar
// TODO you must add logic to remove the view
// TODO you must use a special permission to use this method :android.permission.SYSTEM_ALERT_WINDOW
// TODO if you wish to let the view stay when leaving the app, make sure you have a foreground service running.
I'm one of the developers of the Tooleap SDK, and we also dealt with this issue.
Basically, you don't need to use the SYSTEM_ALERT_WINDOW to display an activity on top of another one. You can just display a regular "shrinked" Activity with a transparent background.
To make a "shrinked Activity, change the activity window layout params of height and width:
WindowManager.LayoutParams params = getWindow().getAttributes();
params.x = ...;
params.y = ...;
params.width = ...;
params.height = ...;
this.getWindow().setAttributes(params);
To make a transparent background add to your activity definition in the manifest file:
android:theme="#android:style/Theme.Translucent"
That way, you can create the illusion of a floating activity:
Note that only the foreground activity will be resumed, while the background one is paused. But for most apps this shouldn't be an issue.
Now all that remains is when to launch the floating activity.
Here is an example of a "floating" calculator app using a regular activity. Note that the activity below the calculator belongs to another app.
I try to reuse an existing WebView by clearing any private data the previous user left behind:
CookieManager.getInstance().removeAllCookie();
webview.clearHistory();
webview.clearFormData();
webview.clearCache(true);
clearHistory seems only to clear the back/forward list, accessible via API, but not the internal list used for coloring links inside the web content.
I even tried the following, suggested by another stackoverflow answer:
deleteDatabase("webview.db");
deleteDatabase("webviewCache.db");
I still have no luck: CSS :visited selectors still work after reloading the page.
An alternative would be to use the API level 11 private browsing feature (new constructor argument), but then I cannot benefit from visited links at all; and can no longer target older versions.
Maybe someone has a solution for this issue? Thanks for your help.
Summary of the answers I got so far:
I tried these two answers, but the first seems to clear HTML5 data storage and the latter seems to be specific to the built-in browser:
WebStorage.getInstance().deleteAllData();
Browser.clearHistory(getContentResolver());
WebChromeClient.getVisitedHistory(ValueCallback<String[]> callback) is only called after the first time I create a new WebView in a recently installed application.
I tried to remove the WebView from view hierachy and create a new one, but unfortunately the visited history seems to be stored for the whole application.
Override WebChromeClient and WebViewClient... Damn that was hidden.
I actually had to dig up a bit to find this out.
WebView webView = (WebView)findViewById(R.id.myWebView);
WebChromeClient myWebChromeClient = new WebChromeClient(){
#Override
public void getVisitedHistory(ValueCallback<String[]> callback) {
// called during webview initialization, original implementation does strictly nothing
// and defaults to the native method WebViewCore.nativeProvideVisitedHistory()
String[] myUserHistory = getVisitedUrlsFromMyOwnDatabase(userId);
callback.onReceiveValue(myUserHistory);
}
};
WebViewClient myWebViewClient = new WebViewClient(){
#Override
public void doUpdateVisitedHistory(WebView view, String url,
boolean isReload) {
// called whenever there is a new link being visited
insertIfNotExistVisitedUrlIntoMyOwnDatabaseForUser(userId);
super(view, url, isReload);
}
}
webView.setWebViewClient(myWebViewClient);
webView.setChromeClient(myWebChromeClient);
webView.getSettings().etc(whatever)...
I think I'm "almost there". Here's the part I managed: what it does so far is remove css history altogether, so we're halfway there. I can't get the browser to recognize the url format I'm providing in "myUserHistory", so in effect the only feature this code does is reset css history altogether, but it's only called once when the WebView is instanciated (or created, didn't check), so for a true multiuser experience you'd need to recreate the webview at each login.
My problem now is that I can't manage to load the urlHistory properly. My Honeycomb Xoom webview seems to ignore my data.
Ah well, I hope it works for you. For me just calling callback.onReceiveValue(new String[]{}); in getVisitedHistory() will be good enough.
EDIT:
I just put twenty more minutes into it because I'm curious. This method is what delegates to the WebChromeClient (mCallbackProxy = WebChromeClient).
protected void populateVisitedLinks() {
ValueCallback callback = new ValueCallback<String[]>() {
public void onReceiveValue(String[] value) {
sendMessage(EventHub.POPULATE_VISITED_LINKS, (Object)value);
}
};
mCallbackProxy.getVisitedHistory(callback);
}
It's protected in WebViewCore, which is a private attribute of WebView with no accessor. The sendMessage delegates to EventHub which is private, and WebViewCore is filled with private native methods, and one of these seems to be the one actually calling the populateVisitedLinks() method during the initialization.
Unless someone at Google adds a public method to WebView to trigger the repopulation, I'm afraid it's practically impossible to achieve your goal. Sorry :(
As a side note, all these native visited history handling really makes me wonder: why do hardware manufacturers care so much about which urls we visited? ;) <<< sarcasm
As an alternate solution, you could try adding your own CSS with the same base colors the default CSS has and switch the CSS by another one (with same color for both "types" of links) when you want to reset the visited links.
A:link{color: "#990000"; text-decoration: none;}
A:visited{color: "#990000"; text-decoration: none;}
A:hover{color: "#ff0000"; text-decoration: none;}
If you can obtain a Browser instance (maybe you can set a WebChromeClient to WebView) you can use its clearHistory() method.
Does WebStorage.clearAllData() have the desired effect? Unfortunately, the documentation on this class is very sparse compared to WebView and doesn't say whether it applies to WebViews.
The exact time you're calling clearHistory() may also have an effect. Clearing it and then navigating to a new page may still keep the first page in history, and you have to call the method after the new page has loaded.
Personally, if privacy is a real issue, I would create a new set of objects from scratch for this new session if possible.