Develop Reference

Created a Page as LoadingIndicator in Xamarin.forms?

In my application I have created my own Loading indicator with the help of Page class in xamarin.forms, and I use 'PushModalAsync' api to show Loading Indicator wherever needed like below
var loadingindicator=new LoadingIndicator();
MyApp.CurrentAppInstance.MainPage.Navigation.PushModalAsync(loadingindicator,false);
Everything works as expected and It is looking fine and I also managed to make it look like AndHUD by tweeking the alpha for the controls in that page until I hit an issue,
The issue is that, every time I show and hide the loadingindicator page 'OnAppearing()' getting called on the current top page on view stack.
I can fix this by introducing one additional functionality on all pages where I am using my LoadingIndicator, But I feel there might be some other cleaner way to solve this issue.
Can you guys suggest me if there is any cleaner approach available to solve this issue?
(I target this solution mainly for android and I want to achieve it through common code)

If I have understand the problem, I think there are some way to add Loading indicator.
Use ActivityIndicator
Use aritchie/userdialogs's Loading
using (this.Dialogs.Loading("Test Loading"))
await Task.Delay(3000);
Create a PopUp With Rg.Plugins.Popup
// Use these methods in PopupNavigation globally or Navigation in your pages
// Open new PopupPage
Task PushAsync(PopupPage page, bool animate = true) // Navigation.PushPopupAsync
// Hide last PopupPage
Task PopAsync(bool animate = true) // Navigation.PopPopupAsync
// Hide all PopupPage with animations
Task PopAllAsync(bool animate = true) // Navigation.PopAllPopupAsync
// Remove one popup page in stack
Task RemovePageAsync(PopupPage page, bool animate = true) // Navigation.RemovePopupPageAsync

Popup menu scroll with the page in jquerymobile

I have create an popup menu in my app the problem with it is when i open the popup menu and then scroll the page the popup menu also scrolls up with the page even i tried using data-dismissible="false" but nothing happen still the problem remains same.
Thanks in advance.

There's an easy fix for this problem. Just prevent page scrolling when popup is active.
Working jsFiddle example: http://jsfiddle.net/Gajotres/aJChc/
For this to work popup needs to have an attribute: data-dismissible="false" it will prevent popup closure when clicked outside of it. Another attribute can be used: data-overlay-theme="a" it will color popup overlay div. That is a DIV that covers screen when popup is opened and prevents popup closure.
And this javascript will work on every possible popup:
$(document).on('popupafteropen', '[data-role="popup"]' ,function( event, ui ) {
$('body').css('overflow','hidden');
}).on('popupafterclose', '[data-role="popup"]' ,function( event, ui ) {
$('body').css('overflow','auto');
});

For me this method didn't work, it works on browser but not in Phone Gap application.
So I resolve it in this way:
$('#Popup-id').on({
popupbeforeposition: function(){
$('body').on('touchmove', false);
},
popupafterclose: function(){
$('body').off('touchmove');
}
});
Hope it helps!

if body scrolling is not prevented, try below. in my case i was using boilerplate.css so the preventing the body scrolling not worked.
popupafteropen: function (e) {
$('html').css('overflow', 'hidden');
},
popupafterclose: function (e) {
$('html').css('overflow', 'auto');
}

Android :getVisibility() error

i have alistview when i click the list view it goes to login screen, when login is successful it comes back to the listview with a icon ..so far its working good, problem is when the icon appear again if i click on the listview the loginscreen is comming ..i dnt want the login screen to load again once the icon is visible..i tried the following but it is giving errors
if (img.getVisibility() == 8) {
Intent intent = new Intent(MainActivity.this,LoginActivity.class);
startActivity(intent);
}
Any help is appreciated.

use
if (img.getVisibility() != View.Visible)
Dont use hardcode values.

Change your condition as:
if (img.getVisibility() == View.Visible)
EDIT : or better way you can use View.isShown() for checking View or it's child's are Visible or not

You should not really on your UI state for app logic. You would better use startActivityForResult, then in onActivityResult set a flag and use this flag in your click listener, use it also to make the icon visible or not.
You should also consider setting the flag in the shared preferences for persistence if you leave your activity.

what kind of error you face ?? can you show it to use ? you should not use a hard code value to compare the visibility use one of these View.GONE or View.INVISIBLE or VIEW.VISIBLE
like this
if(img.getVisibility != View.VISIBLE){
// do something
}

Use
if (img.getVisibility() != View.Visible)
instead of
if (img.getVisibility() == 8)
check http://developer.android.com/reference/android/view/View.html#setVisibility%28int%29

How to add a image on an event in android

I am new to Android. In my application I want to add an process bar(an image), this should indicate that something is in process and after completion hide this precess bar.
As if i add user detail, On click on add button this process bar should be displayed.
How can i do it, please suggest.
Thanks.
Code I used:
progressDialog = ProgressDialog.show(AddTicketActivity.this, "", "Loading...");
new Thread() {
public void run() {
try{
sleep(10000);
} catch (Exception e) {
Log.e("tag", e.getMessage());
}
progressDialog.dismiss();
}
}.start();
The problem with it is , it is hardcoded sleep(10000) whereas what i want is it to be dependent on how much time my process takes to add or fetch data.
I am not getting where to put code which is executing on onclick of button.
I hope you got my point
Thanks again.

For that you can use either ProgressDialog or ProgressBar.
Now, To display Progress bar and during that perform task in background, you should implement AsyncTask.
In onPreExecute() method, display the ProgressBar or make it visible again like: progressbar.setVisibility(View.VISIBLE);
In doInBackground() method, perform the background task, i.e. add user detail in your case
In onPostExecute() method, just hide the ProgressBar using the progressbar.setVisibility(View.INVISIBLE);

Well if you just want to show an image, you can place it on a RelativeLayout with visibility=gone
and then just control when to show or hide it.
another way is the typical progressDialog in Android

Or use a progress bar (spinning wheel) it's more user friendly and droid friendly .
Take a look at the Form widgets on Eclipse .

Stop ListView scroll animation

I have a ListView with about 100 entries. When the user does the "fling" from bottom to top it starts scrolling and keeps on scrolling even when the finger does not touch the display any more.
Is there a way to stop the scrolling animation at this point?

and we lookup the android source code (AbsListView), give it a ACTION_CANCEL touchEvent, can stop the fling. it is easy.
listView.dispatchTouchEvent(MotionEvent.obtain(SystemClock.uptimeMillis(), SystemClock.uptimeMillis(), MotionEvent.ACTION_CANCEL, 0, 0, 0));

I didn't try the solution of Pompe de velo but since smoothScrollToPosition() is not available for API level less than 8 this didnt work for me.
I agree, changing default behaviour is not a good Idea, but sometimes you need to. So here is my (dirty) solution which uses reflection. This is by far not the recommended way since it's a hack but it works for me. There might be a better solution but I didn't found it.
class StopListFling {
private static Field mFlingEndField = null;
private static Method mFlingEndMethod = null;
static {
try {
mFlingEndField = AbsListView.class.getDeclaredField("mFlingRunnable");
mFlingEndField.setAccessible(true);
mFlingEndMethod = mFlingEndField.getType().getDeclaredMethod("endFling");
mFlingEndMethod.setAccessible(true);
} catch (Exception e) {
mFlingEndMethod = null;
}
}
public static void stop(ListView list) {
if (mFlingEndMethod != null) {
try {
mFlingEndMethod.invoke(mFlingEndField.get(list));
} catch (Exception e) {
}
}
}
}

Well there surely is a way to do it. But the point is more whether or not it is advisable to do it, in my opinion.
The list is a standard Android control that behaves constistently across all applications. So I would be surprised if I found a list that did not behave the same in your application. You can stop the fling by putting your finger back on the screen at any time.
That said, if you want to do extra work, you could subclass the list view and override its on touch method. Best way to know what to do is to get the source code of ListView (ListView in Android 1.6).

You can prevent flinging for ListViews in API 8 by overriding onTouchEvent and calling smoothScrollBy.
#Override
public boolean onTouchEvent(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_UP:
this.smoothScrollBy(0, 0);
break;
}
return super.onTouchEvent(ev);
}
This takes over from the fling scrolling and scrolls 0px instead.

My opinion is that you shouldn't modify this behaviour, since the fling behaviour is what the user expects.
However, to your question. I haven't tried this but in theory it should work.
Implement an OnScrollListener to your ListView and use the onScrollStateChanged() method to check if the current state is SCROLL_STATE_FLING. After you've determined that the scrolling perfoms by a fling you can get your ListView's first visible position by using the getFirstVisiblePosition() method and from there you can use smoothScrollToPosition() where you put in your getFirstVisiblePosition() value as an argument.

if you what disable default animation from list view just need set id for root (main) layout in xml and call void onClickListener in class for root layout