Get scroll position of ViewCell inside ListView Xamarin Form - uitableview

I would like to know the scroll position of ViewCell inside the ListView.
Tried with various ways but always that gives me 0 value.
My intension is to get ViewCell's position in screen. In order to resolve this problem trying to get it's scroll position and then i will add this value to the Y value of ListView object.
Can anybody please help me in this case?

you have to make custom renderer of the ViewCell its kinda tricky to send the positions to pcl then we subscribe to the event in the view here's my code
PCL
public class SAChatViewCell : ViewCell
{
public delegate int[] IntEventHandler(object sender, float[] postion);
public event IntEventHandler OnCellItemLongClicked;
public event EventHandler OnCellItemTouched;
public void InvokeOnCellItemLongClicked(object sender, float[] e)
{
//send the current grid
OnCellItemLongClicked?.Invoke(sender, e);
}
public void InvokeOnCellItemTouched(object sender, EventArgs e)
{
//send the current grid
OnCellItemTouched?.Invoke(sender, e);
}
}
Android Renderer
class SAChatViewCellRenderer : ViewCellRenderer
{
private bool selected;
ClickListener handler = new ClickListener();
static Android.Widget.ListView listView;
Xamarin.Forms.ListView listviewforms;
static SAChatViewCell cellElement;
Android.Views.View cellControl;
protected override Android.Views.View GetCellCore(Cell item, Android.Views.View convertView, Android.Views.ViewGroup parent, Android.Content.Context context)
{
try
{
if (cellControl == null)
{
cellControl = base.GetCellCore(item, convertView, parent, context);
}
cellElement = item as SAChatViewCell;
selected = false;
listviewforms = cellElement.View.Parent.Parent as Xamarin.Forms.ListView;
if (listviewforms == null)
{
return null;
}
if (listviewforms.BackgroundColor.ToAndroid() == Color.Transparent.ToAndroid())
{
cellControl.SetBackgroundColor(Color.White.ToAndroid());
}
else
{
cellControl.SetBackgroundColor(listviewforms.BackgroundColor.ToAndroid());
}
cellControl.SetOnLongClickListener(handler);
cellControl.SetOnTouchListener(handler);
return cellControl;
}
catch (Exception ex)
{
return null;
}
}
protected override void OnCellPropertyChanged(object sender, PropertyChangedEventArgs args)
{
base.OnCellPropertyChanged(sender, args);
if (args.PropertyName == "IsSelected")
{
// I had to create a property to track the selection because cellCore.Selected is always false.
// Toggle selection
selected = !selected;
var selectedBackground = cellElement.SelectedBackgroundColor.ToAndroid();
if (selected)
{
if (selectedBackground == Color.Transparent.ToAndroid())
{
cellControl.SetBackgroundColor(Color.White.ToAndroid());
return;
}
cellControl.SetBackgroundColor(selectedBackground);
}
else
{
if (listviewforms.BackgroundColor.ToAndroid() == Color.Transparent.ToAndroid())
{
cellControl.SetBackgroundColor(Color.White.ToAndroid());
}
else
{
cellControl.SetBackgroundColor(listviewforms.BackgroundColor.ToAndroid());
}
}
}
}
internal class ClickListener : Java.Lang.Object, IOnLongClickListener, IOnTouchListener
{
//event priority Touch - LongClick - Click
//NOTE: return true to indicate that we have handled the event and it should stop here;
public bool OnLongClick(Android.Views.View sender)
{
var cellItem = sender as INativeElementView;
var viewCell = sender as Android.Views.View;
float[] location = new float[] { 0, 0 };
Android.Views.View parentRow = (Android.Views.View)viewCell.Parent;
listView = (Android.Widget.ListView)parentRow.Parent;
int position = listView.GetPositionForView(parentRow);
var x = parentRow.Right;
var y = (parentRow.Top - listView.DividerHeight) <= 0 ? parentRow.Bottom : parentRow.Top;
int view_height = parentRow.Height;
location[0] = (x / MainActivity.Current.Resources.DisplayMetrics.Density);
location[1] = y / MainActivity.Current.Resources.DisplayMetrics.Density;
//send current cell
cellElement.InvokeOnCellItemLongClicked((cellItem.Element as ViewCell).View, location);
listView.Scroll += ListView_Scroll;
return true;
}
protected override void Dispose(bool disposing)
{
base.Dispose(disposing);
if (listView != null)
{
listView.Scroll -= ListView_Scroll;
}
}
private void ListView_Scroll(object sender, Android.Widget.AbsListView.ScrollEventArgs e)
{
cellElement.InvokeOnCellItemTouched(cellElement.View, EventArgs.Empty);
}
//return false if you have not handled it and/or the event should continue to any other on-click listeners.
public bool OnTouch(Android.Views.View v, MotionEvent e)
{
if (e.Action == MotionEventActions.Down)
{
cellElement.InvokeOnCellItemTouched(cellElement.View, EventArgs.Empty);
//cellCore.SetOnTouchListener(this);
}
return false;
}
}
}
}
iOS Renderer
class SAUITableViewCell : UITableViewCell
{
public override void TouchesBegan(NSSet touches, UIEvent evt)
{
base.TouchesBegan(touches, evt);
}
}
//When you scroll, your cells are created in real time. cells aren't created from scratch, instead iOS just takes a cell that has just left the screen and sends it through
class SAChatViewCellRenderer : ViewCellRenderer, IUIGestureRecognizerDelegate
{
UITableView TV;
SAChatViewCell cellElement;
public IntPtr Handle => new IntPtr();
public override UITableViewCell GetCell(Cell item, UITableViewCell reusableCell, UITableView tv)
{
try
{
UITableViewCell cell = base.GetCell(item, reusableCell, tv);
TV = tv;
var uiTapGestureRecognize = new UITapGestureRecognizer(OnClick);
var uiLongPressGestureRecognizer = new UILongPressGestureRecognizer(OnLongClick);
uiLongPressGestureRecognizer.MinimumPressDuration = 0.5;
cell.AddGestureRecognizer(uiTapGestureRecognize);
cell.AddGestureRecognizer(uiLongPressGestureRecognizer);
cellElement = item as SAChatViewCell;
cell.BackgroundColor = UIColor.Clear;
if (cellElement.SelectedBackgroundColor == Color.Transparent)
{
cell.SelectionStyle = UITableViewCellSelectionStyle.None;
}
else
{
cell.SelectedBackgroundView = new UIView
{
BackgroundColor = cellElement.SelectedBackgroundColor.ToUIColor() ?? default(UIColor)
};
}
return cell;
}
catch (Exception ex)
{
throw ex;
}
}
private void OnLongClick(UILongPressGestureRecognizer arg)
{
//get the current touch coords based on listview
CGPoint coords = arg.LocationInView(TV);
//current cell
if (arg.State != UIGestureRecognizerState.Began)
{
var indexPath = TV.IndexPathForRowAtPoint(coords);
CGRect Rect = TV.RectForRowAtIndexPath(indexPath);
//delete the listview offset
Rect.Offset(-TV.ContentOffset.X, -TV.ContentOffset.Y);
var CurrentViewCell = (arg.View as UIKit.UITableViewCell).Superview;
//Note : xamarin forms cell element MonoTouch creates it's own internal delegate type for UIScrollView so we either override the uiviewtable or trigger the ondisappear event
var cellItem = arg.View as INativeElementView;
(((cellItem.Element as ViewCell).Parent) as ListView).ItemDisappearing += (s, o) =>
{
cellElement.InvokeOnCellItemTouched(cellElement.View, EventArgs.Empty);
};
float[] location = new float[] { 0, 0 };
location[0] = (float)Rect.X;
var Y = Rect.Top <= 0 ? Rect.Bottom : Rect.Top;
location[1] = (float)Y;
cellElement.InvokeOnCellItemLongClicked((cellItem.Element as ViewCell).View, location);
}
}
private void OnClick()
{
cellElement.InvokeOnCellItemTouched(cellElement.View, EventArgs.Empty);
}
public void Dispose()
{
throw new NotImplementedException();
}
}
}

I have found a solution,
Problem :
My intension is to get ViewCell's position in screen
Solution :
Step 1 : Keep scrollview inside the Relative layout.
Step 2 : When user click on scroll view's ViewCell, save touch point (X, Y) of relative layout. In Y co-ordinate, add top position of relative layout so you will get touch point relative to whole screen.
Step 3 : When user click on scroll view's ViewCell, call XYZ() method.
Step 4 : Inside XYZ() method, do whatever functionality which required on (X, Y) co-ordinate. (Note : put 300ms delay in doing functionality in XYZ() method, as step-2 required some time in saving
touch points.)

Related

xamarin.forms webview.focused event raised on Android, but not on iOS

I'm using a Xamarin.Forms grid application to show a couple of html elements as WebViews in the cells of the grid CardGrid:
private async void CreateCardView()
{
CardGrid.Children.Clear();
// idx over all count elements of html snippets
for (idx = 0; idx < count; idx++)
{
string html = AuthoringCard(idx);
RenderingCard(html, idx);
}
}
AuthoringCard() creates the html code snippet.
RenderingCard() creates the WebView inside the grid cell.
private void RenderingCard(string htmlCard, int index)
{
int CardWidth = 300;
int CardHeight = 150;
int CardNoHorizontally = 3;
WebView uiCard = new WebView();
uiCard.HeightRequest = CardHeight - 5;
uiCard.WidthRequest= CardWidth - 5;
uiCard.VerticalOptions = LayoutOptions.Start;
uiCard.HorizontalOptions = LayoutOptions.Center;
uiCard.Margin = new Thickness(0);
uiCard.AutomationId = index.ToString();
uiCard.Focused += Card_Tapped;
uiCard.InputTransparent = false;
var htmlSource1 = new HtmlWebViewSource
{
Html = htmlCard,
};
uiCard.Source = htmlSource1;
CardGrid.Children.Add(uiCard);
int row = (int)Math.Floor((double)(index / CardNoHorizontally));
int column = index - (row * CardNoHorizontally);
Grid.SetRow(uiCard, row);
Grid.SetColumn(uiCard, column);
}
I want to catch the Focused event, when the user it tapping on the card (WebView) and using the AutomationId to get the index of the card (html code snippet):
private void Card_Tapped(object sender, EventArgs e)
{
WebView card = (WebView)sender;
int index = Convert.ToInt16(card.AutomationId));
}
This works fine with Android. Under iOS the event is never raised. Any idea for a solution?
Cause:
the property Focus in Forms correspond method that we called becomeFirstResponder in native iOS platform.Unfortunately,UIWebView and WKwebview do not support the method becomeFirstResponder.This method is only available in some 'input-controls' Such as UITextField and UITextView(Entry in Forms).So even if you set the event on a webview.It will not work in iOS.
Workaround:
You can add a TapGestureRecognizer on the webview.And you have to implement it by using CustomRenderer.Because it will create conflict if you add TapGestureRecognizer in forms.
Refer to the following code.
in Forms
public MainPage()
{
if (Device.RuntimePlatform == "iOS")
{
MessagingCenter.Subscribe<Object,string>(this,"webview_click", (sender,arg)=> {
// int index = Convert.ToInt16(arg));
});
}
}
in iOS
using System;
using Foundation;
using UIKit;
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;
using xxx;
using xxx.iOS;
using ObjCRuntime;
[assembly:ExportRenderer(typeof(WebView),typeof(MyWebViewRenderer))]
namespace xxx.iOS
{
public class MyWebViewRenderer : WebViewRenderer, IUIGestureRecognizerDelegate
{
public bool isFirstLoad = true;
public MyWebViewRenderer()
{
}
protected override void OnElementChanged(VisualElementChangedEventArgs e)
{
base.OnElementChanged(e);
if (e != null)
{
UITapGestureRecognizer tap = new UITapGestureRecognizer(this, new Selector("Tap_Handle:"));
tap.WeakDelegate = this;
this.AddGestureRecognizer(tap);
}
}
[Export("gestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer:")]
public bool ShouldRecognizeSimultaneously(UIGestureRecognizer gestureRecognizer, UIGestureRecognizer otherGestureRecognizer)
{
return true;
}
[Export("Tap_Handle:")]
void Tap_Handle(UITapGestureRecognizer tap)
{
if(isFirstLoad)
{
isFirstLoad = false;
MessagingCenter.Send<Object,string>(this, "webview_click",Element.AutomationId);
}
}
}
}

xamarin forms label in a scroll view pinch and zoom android

I need a label with large text like a article which needs pinch to zoom capability for that I have written a ZoomableScrollview which works fine in IOS and Windows but not in android. Please see the code below.
Code in PCL
public class ZoomableScrollView:ScrollView
{
public static readonly BindableProperty MinimumZoomScaleProperty = BindableProperty.Create("MinimumZoomScale", typeof(float), typeof(ZoomableScrollView), default(float));
public float MinimumZoomScale
{
get { return (float)GetValue(MinimumZoomScaleProperty); }
set { SetValue(MinimumZoomScaleProperty, value); }
}
public static readonly BindableProperty MaximumZoomScaleProperty = BindableProperty.Create("MaximumZoomScale", typeof(float), typeof(ZoomableScrollView), default(float));
public float MaximumZoomScale
{
get { return (float)GetValue(MaximumZoomScaleProperty); }
set { SetValue(MaximumZoomScaleProperty, value); }
}
}
IOS renderer
public class ZoomableScrollViewRenderer : ScrollViewRenderer
{
protected override void OnElementChanged(VisualElementChangedEventArgs e)
{
base.OnElementChanged(e);
if (e.NewElement == null)
return;
if (e.OldElement == null)
{
ZoomableScrollView zsv = Element as ZoomableScrollView;
this.MinimumZoomScale = zsv.MinimumZoomScale;
this.MaximumZoomScale = zsv.MaximumZoomScale;
this.ViewForZoomingInScrollView += (UIScrollView sv) => { return this.Subviews[0]; };
}
}
}
Windows renderer
public class ZoomableScrollViewRenderer:ScrollViewRenderer
{
protected override void OnElementChanged(ElementChangedEventArgs<ScrollView> e)
{
base.OnElementChanged(e);
if (e.NewElement == null)
return;
if (e.OldElement == null)
{
ZoomableScrollView zsv = Element as ZoomableScrollView;
this.Control.ZoomMode = Windows.UI.Xaml.Controls.ZoomMode.Enabled;
this.Control.MinZoomFactor = zsv.MinimumZoomScale;
this.Control.MaxZoomFactor = zsv.MaximumZoomScale;
}
}
}
Android renderer
public class ZoomableScrollViewRenderer:ScrollViewRenderer
{
float originalDistanceX, currentdistanceX, originalDistanceY, currentdistanceY;
bool IsPinching = false;
double currentScale;
TeluguLabel lbl;
ScrollView svMain, svSub;
protected override void OnElementChanged(VisualElementChangedEventArgs e)
{
base.OnElementChanged(e);
svMain = ((ScrollView)e.NewElement);
lbl = svMain.Content as TeluguLabel;
svSub = new ScrollView();
svSub.Orientation = ScrollOrientation.Horizontal;
svSub.Content = lbl;
svMain.Content = svSub;
lbl.AnchorX = 0;
lbl.AnchorY = 0;
}
public override bool OnTouchEvent(MotionEvent e)
{
if (e.PointerCount > 1)
{
IsPinching = true;
currentScale = lbl.Scale;
originalDistanceX = Math.Abs(e.GetX(0) - e.GetX(1));
originalDistanceY = Math.Abs(e.GetY(0) - e.GetY(1));
}
else
{
IsPinching = false;
}
return base.OnTouchEvent(e);
}
public override bool DispatchTouchEvent(Android.Views.MotionEvent e)
{
switch (e.Action)
{
case MotionEventActions.Down:
this.Parent.RequestDisallowInterceptTouchEvent(true);
break;
case MotionEventActions.Move:
if(IsPinching && e.PointerCount > 1)
{
currentdistanceX = Math.Abs(e.GetX(0) - e.GetX(1));
currentdistanceY = Math.Abs(e.GetY(0) - e.GetY(1));
if (originalDistanceX < currentdistanceX || originalDistanceY < currentdistanceY)
lbl.Scale = currentScale + 0.01;
else if (originalDistanceX > currentdistanceX || originalDistanceY > currentdistanceY)
lbl.Scale = currentScale - 0.01;
}
break;
case MotionEventActions.Up:
this.Parent.RequestDisallowInterceptTouchEvent(false);
break;
}
return base.DispatchTouchEvent(e);
}
}
in android I was able to achieve zoom to some extent but the scrolling in not smooth, but I compromised for it. Now the problem is the text is getting stripped in the label. Somebody please help me my app itself is for reading which is he basic feature not working.
Thanks in advance
I got it. Basically android label has no of lines limit of 100, i have to override it in the renderer
label.SetMaxLines(4000);

Wait for view pager animations with espresso?

Trying to do some tests with a ViewPager.
I want to swipe between tabs, and I don't want to continue until the swipe is complete. But there doesn't appear to be a way to turn off the animation for the view pager (all animations under the developer options are disabled).
So this always results in a test failure, because the view pager hasn't completed it's animation, and so the view is not completely displayed yet:
// swipe left
onView(withId(R.id.viewpager)).check(matches(isDisplayed())).perform(swipeLeft());
// check to ensure that the next tab is completely visible.
onView(withId(R.id.next_tab)).check(matches(isCompletelyDisplayed()));
Is there an elegant or maybe even recommended way to do this, or am I stuck putting some kind of timed wait in there?
The IdlingResource #Simas suggests is actually pretty simple to implement:
public class ViewPagerIdlingResource implements IdlingResource {
private final String mName;
private boolean mIdle = true; // Default to idle since we can't query the scroll state.
private ResourceCallback mResourceCallback;
public ViewPagerIdlingResource(ViewPager viewPager, String name) {
viewPager.addOnPageChangeListener(new ViewPagerListener());
mName = name;
}
#Override
public String getName() {
return mName;
}
#Override
public boolean isIdleNow() {
return mIdle;
}
#Override
public void registerIdleTransitionCallback(ResourceCallback resourceCallback) {
mResourceCallback = resourceCallback;
}
private class ViewPagerListener extends ViewPager.SimpleOnPageChangeListener {
#Override
public void onPageScrollStateChanged(int state) {
mIdle = (state == ViewPager.SCROLL_STATE_IDLE
// Treat dragging as idle, or Espresso will block itself when swiping.
|| state == ViewPager.SCROLL_STATE_DRAGGING);
if (mIdle && mResourceCallback != null) {
mResourceCallback.onTransitionToIdle();
}
}
}
}
Since I've done this at least twice now, here is the accepted answer in Kotlin and with androidx ViewPager2:
class ViewPager2IdlingResource(viewPager: ViewPager2, name: String) : IdlingResource {
private val name: String
private var isIdle = true // Default to idle since we can't query the scroll state.
private var resourceCallback: IdlingResource.ResourceCallback? = null
init {
viewPager.registerOnPageChangeCallback(object : ViewPager2.OnPageChangeCallback() {
override fun onPageScrollStateChanged(state: Int) {
isIdle = (state == ViewPager.SCROLL_STATE_IDLE // Treat dragging as idle, or Espresso will block itself when swiping.
|| state == ViewPager.SCROLL_STATE_DRAGGING)
if (isIdle && resourceCallback != null) {
resourceCallback!!.onTransitionToIdle()
}
}
})
this.name = name
}
override fun getName(): String {
return name
}
override fun isIdleNow(): Boolean {
return isIdle
}
override fun registerIdleTransitionCallback(resourceCallback: IdlingResource.ResourceCallback) {
this.resourceCallback = resourceCallback
}
}
And here is how you use it from a UI test using ActivityScenarioRule:
#get:Rule
val testRule = ActivityScenarioRule(OnboardingActivity::class.java)
private lateinit var viewPager2IdlingResource: ViewPager2IdlingResource
....
#Before
fun setUp() {
testRule.scenario.onActivity {
viewPager2IdlingResource =
ViewPager2IdlingResource(it.findViewById(R.id.onboarding_view_pager), "viewPagerIdlingResource")
IdlingRegistry.getInstance().register(viewPager2IdlingResource)
}
}
#After
fun tearDown() {
IdlingRegistry.getInstance().unregister(viewPager2IdlingResource)
}
The androidx.test.espresso:espresso-core library offers a ViewPagerActions class which contains a number of methods for scrolling between the pages of a ViewPager. It takes care of waiting until the scroll is complete so you don't need to add any explicit waits or sleeps in your test methods.
If you need to perform similar scrolling on a ViewPager2 instance, you can take the source code of the ViewPagerActions class and make some minor tweaks to it to get it to work for ViewPager2. Here is an example which you are welcome to take and use.
Try this,
onView(withId(R.id.pager)).perform(pagerSwipeRight()).perform(pagerSwipeLeft());
private GeneralSwipeAction pagerSwipeRight(){
return new GeneralSwipeAction(Swipe.SLOW, GeneralLocation.CENTER_LEFT,
GeneralLocation.CENTER_RIGHT, Press.FINGER);
}
private GeneralSwipeAction pagerSwipeLeft(){
return new GeneralSwipeAction(Swipe.SLOW, GeneralLocation.CENTER_RIGHT,
GeneralLocation.CENTER_LEFT, Press.FINGER);
}
I was having issues with #vaughandroid approach, so I did some changes to his approach. This approach will set idle to false as soon as it detects a scrolling is happening and "force" the ViewPager to finish scrolling by using setCurrentItem().
public class ViewPagerIdlingResource implements IdlingResource {
private volatile boolean mIdle = true; // Default to idle since we can't query the scroll state.
private ResourceCallback mResourceCallback;
private ViewPager mViewPager;
public static ViewPagerIdlingResource waitViewPagerSwipe(ViewPager viewPager) {
return new ViewPagerIdlingResource(viewPager);
}
private ViewPagerIdlingResource(ViewPager viewPager) {
mViewPager = viewPager;
mViewPager.addOnPageChangeListener(new ViewPagerListener());
}
#Override
public String getName() {
return ViewPagerIdlingResource.class.getSimpleName();
}
#Override
public boolean isIdleNow() {
return mIdle;
}
#Override
public void registerIdleTransitionCallback(ResourceCallback resourceCallback) {
mResourceCallback = resourceCallback;
}
private class ViewPagerListener extends ViewPager.SimpleOnPageChangeListener {
float mPositionOffset = 0.0f;
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
if (isSwipingToRight(positionOffset)) {
mIdle = false;
mViewPager.setCurrentItem(position + 1);
} else if (isSwipingToLeft(positionOffset)) {
mIdle = false;
mViewPager.setCurrentItem(position - 1);
}
mPositionOffset = positionOffset;
if (positionOffset == 0 && !mIdle && mResourceCallback != null) {
mResourceCallback.onTransitionToIdle();
mIdle = true;
mPositionOffset = 0.0f;
}
}
private boolean isSwipingToRight(float positionOffset) {
return mPositionOffset != 0.0f && positionOffset > mPositionOffset && mIdle;
}
private boolean isSwipingToLeft(float positionOffset) {
return mPositionOffset != 0.0f && positionOffset < mPositionOffset && mIdle;
}
}
}
My goal was to make a screenshot of the screen with ViewPager2 using Facebook screenshot test library. The easiest approach for me was to check almost every frame whether animation completed, if yes then it's time to make a screenshot:
fun waitForViewPagerAnimation(parentView: View) {
if (parentView is ViewGroup) {
parentView.childrenViews<ViewPager2>().forEach {
while (it.scrollState != ViewPager2.SCROLL_STATE_IDLE) {
Thread.sleep(16)
}
}
}
}
childrenViews function can be found here
You can either do a lot of work and use an IdlingResource to implement an OnPageChangeListener
or simply:
SystemClock.sleep(500);

To attach a ButtonField on every row of CustomListField in BlackBerry [duplicate]

i m writing one application in which i have created custom list field for displaying listview.
my CustomListField contains one image and text in a row. i m gettiing field change listener on click of listfield row but i want to put fieldchange listener on image too..
can anyone tell me how can i do that.
here is my code.
public class CustomListField extends ListField implements ListFieldCallback {
private Vector _listData;
private int _MAX_ROW_HEIGHT = 60;
public CustomListField(Vector data) {
_listData = data;
setSize(_listData.size());
setSearchable(true);
setCallback(this);
setRowHeight(_MAX_ROW_HEIGHT);
}
protected void drawFocus(Graphics graphics, boolean on) {
XYRect rect = new XYRect();
graphics.setGlobalAlpha(150);
graphics.setColor(Color.BLUE);
getFocusRect(rect);
drawHighlightRegion(graphics, HIGHLIGHT_FOCUS, true, rect.x, rect.y, rect.width, rect.height);
}
public int moveFocus(int amount, int status, int time) {
this.invalidate(this.getSelectedIndex());
return super.moveFocus(amount, status, time);
}
public void onFocus(int direction) {
super.onFocus(direction);
}
protected void onUnFocus() {
this.invalidate(this.getSelectedIndex());
}
public void refresh() {
this.getManager().invalidate();
}
public void drawListRow(ListField listField, Graphics graphics, int index, int y, int w) {
listField.setBackground(BackgroundFactory.createBitmapBackground(Bitmap.getBitmapResource("listing_bg.png")));
ListRander listRander = (ListRander) _listData.elementAt(index);
graphics.setGlobalAlpha(255);
graphics.setFont(Font.getDefault().getFontFamily().getFont(Font.PLAIN, 24));
final int margin = 5;
final Bitmap thumb = listRander.getListThumb();
final String listHeading = listRander.getListTitle();
final Bitmap nevBar = listRander.getNavBar();
// list border
graphics.setColor(Color.GRAY);
graphics.drawRect(0, y, w, _MAX_ROW_HEIGHT);
// thumbnail border & thumbnail image
graphics.setColor(Color.BLACK);
// graphics.drawRoundRect(margin-2, y+margin-2,thumb.getWidth()+2, thumb.getHeight()+2, 5, 5);
graphics.drawBitmap(margin, y + margin, thumb.getWidth(), thumb.getHeight(), thumb, 0, 0);
// drawing texts
// graphics.setFont(Font.BOLD);
graphics.drawText(listHeading, margin + thumb.getWidth(), y + margin);
graphics.setColor(Color.GRAY);
// graphics.setFont(Font.smallFont); // graphics.drawText(listDesc, 2*margin+thumb.getWidth(), y+ margin+20); // //
// graphics.drawText(listDesc2, 2*margin+thumb.getWidth(), y+ margin+32);
// draw navigation button
final int navBarPosY = y + (_MAX_ROW_HEIGHT / 2 - nevBar.getHeight() / 2);
final int navBarPosX = Graphics.getScreenWidth() - nevBar.getWidth() + margin;
graphics.drawBitmap(navBarPosX, navBarPosY, nevBar.getWidth(), nevBar.getHeight(), nevBar, 0, 0);
}
public Object get(ListField listField, int index) {
String rowString = (String) _listData.elementAt(index);
return rowString;
}
public int indexOfList(ListField listField, String prefix, int start) {
for (Enumeration e = _listData.elements(); e.hasMoreElements();) {
String rowString = (String) e.nextElement();
if (rowString.startsWith(prefix)) {
return _listData.indexOf(rowString);
}
}
return 0;
}
public int getPreferredWidth(ListField listField) {
return 3 * listField.getRowHeight();
}
/*
protected boolean trackwheelClick(int status, int time) {
invalidate(getSelectedIndex());
Dialog.alert(" U have selected :" + getSelectedIndex());
return super.trackwheelClick(status, time);
}
*/
}
i want to put click listner on star image of listfield row
and following is output of abbove code.
I did something very similar to this on a past project:
Background
As Arhimed said in his answer, and as you can read about on the BlackBerry forums here, you can't have full-fledged Field objects within the ListField. The content of ListField rows is just drawn directly in drawListRow() as text, and Bitmaps, etc. The contents aren't Field instances, and therefore, are not focusable.
So, what I did was to replace ListField with a subclass of Manager. Originally, I used a VerticalFieldManager, but I ran into problems with that. I've also been seeing a lot of issues on stack overflow, where people subclass VerticalFieldManager, customize just one small behaviour, and everything starts breaking. It seems to me that VerticalFieldManager works well if you accept its normal behaviour, and if you need something more, just extend Manager directly. Performing layout for vertically stacked rows is pretty easy.
I then made each row its own Manager, and implemented custom layout in sublayout() to place the row's Fields where I wanted them. I could then also make the row focusable, and then a bitmap/button on the row separately focusable (like your star). Clicking the row invokes one action, and clicking the star invokes another one.
I will note, however, that in my app, performance was not an issue, because I only had 10-20 rows. Also, I did have to modify my code to match your example, so consider this code only lightly tested. However, I did build it into an app, so it should perform fine as long as my assumptions, and your description were valid.
Implementation
First, it wasn't clear to me what your ListRander is (you didn't show that code). However, in my code, I need a data class to contain details about one row. It looked like that's how you used ListRander, so that's what I used:
public class ListRander {
private String _title;
private Bitmap _thumb;
public ListRander(String title, Bitmap thumb) {
_title = title;
_thumb = thumb;
}
public String getTitle() {
return _title;
}
public Bitmap getThumb() {
return _thumb;
}
}
Then, I replaced your CustomListField class with my own:
public class CustomListField extends Manager implements FocusChangeListener {
private int _MAX_ROW_HEIGHT = 60;
private boolean _searchable = false;
private Vector _listData;
private FieldChangeListener _fieldListener;
public CustomListField(Vector data) {
super(FOCUSABLE | VERTICAL_SCROLL | VERTICAL_SCROLLBAR);
setSearchable(true);
setEditable(false);
setListData(data);
}
public void setChangeListener(FieldChangeListener listener) {
// we need to save this listener, because we set it to listen to all new rows
_fieldListener = listener;
int numFields = getFieldCount();
for (int f = 0; f < numFields; f++) {
getField(f).setChangeListener(listener);
}
super.setChangeListener(listener);
}
public int getRowHeight() {
return _MAX_ROW_HEIGHT;
}
public void setSearchable(boolean searchable) {
_searchable = searchable;
}
public int getSelectedIndex() {
return getFieldWithFocusIndex(); // TODO??
}
public Object get(int index) {
return _listData.elementAt(index);
}
public int indexOfList(String prefix, int start) {
if (start >= _listData.size() || !_searchable) {
return -1;
} else {
int result = getSelectedIndex(); // the default result if we find no matches
for (Enumeration e = _listData.elements(); e.hasMoreElements(); ) {
String rowString = (String) e.nextElement();
if (rowString.startsWith(prefix)) {
return _listData.indexOf(rowString);
}
}
return result;
}
}
protected boolean navigationClick(int status, int time) {
CustomListRow focus = (CustomListRow) getFieldWithFocus();
if (focus != null) {
// see if the row wants to process this click
if (!focus.navigationClick(status, time)) {
// let our FieldChangeListener know that this row has been clicked
fieldChangeNotify(getFieldWithFocusIndex());
}
return true;
} else {
return false;
}
}
protected void sublayout(int width, int height) {
int w = Math.min(width, getPreferredWidth());
int h = Math.min(height, getPreferredHeight());
int rowHeight = getRowHeight();
int numRows = getFieldCount();
setExtent(w, h);
setVirtualExtent(w, rowHeight * numRows);
for (int i = 0; i < numRows; i++) {
Field f = getField(i);
setPositionChild(f, 0, rowHeight * i);
layoutChild(f, w, rowHeight);
}
}
public int getPreferredWidth() {
return Display.getWidth();
}
public int getPreferredHeight() {
return Display.getHeight();
}
public void setListData(Vector listData) {
_listData = listData;
if (listData != null) {
int listSize = listData.size();
int numRows = getFieldCount();
for (int s = 0; s < listSize; s++) {
if (s < numRows) {
// we can reuse existing CustomListRows
CustomListRow row = (CustomListRow) getField(s);
row.setData((ListRander) listData.elementAt(s));
} else {
CustomListRow row = new CustomListRow((ListRander) listData.elementAt(s));
row.setChangeListener(_fieldListener);
row.setFocusListener(this);
add(row);
}
}
if (listSize < numRows) {
// delete the excess rows
deleteRange(listSize, numRows - listSize);
}
} else {
deleteAll();
}
invalidate();
}
public void focusChanged(Field field, int eventType) {
// we handle scrolling here, when focus changes between rows
if (eventType == FOCUS_GAINED) {
if (field.getTop() < getVerticalScroll()) {
// field is off the top of the screen, so scroll up
setVerticalScroll(field.getTop());
} else if (field.getTop() >= getVerticalScroll() + getVisibleHeight()) {
// field is off the bottom of the screen, so scroll down
setVerticalScroll(field.getTop() - getVisibleHeight() + getRowHeight());
}
}
}
}
Finally, one row is represented by my CustomListRow class:
public class CustomListRow extends Manager implements FieldChangeListener {
private static final int _MAX_ROW_HEIGHT = 60;
private ListRander _data;
private BitmapField _thumb;
private LabelField _title;
private FocusableBitmapField _star;
private static final Bitmap _starImg = Bitmap.getBitmapResource("star.png");
private static final Bitmap _bgImg = Bitmap.getBitmapResource("listing_bg.png");
private SeparatorField _separator;
private int _fontColor = Color.BLACK;
private boolean _highlighted = false;
private int _width;
// subclass exists to expose focus methods (make public)
private class FocusableBitmapField extends BitmapField {
public FocusableBitmapField() {
super(_starImg, BitmapField.FOCUSABLE | BitmapField.EDITABLE);
}
public void onFocus(int direction) {
super.onFocus(direction);
}
public void onUnfocus() {
super.onUnfocus();
}
}
public CustomListRow(ListRander data) {
super(Field.FOCUSABLE | Manager.NO_VERTICAL_SCROLL | Manager.NO_VERTICAL_SCROLLBAR);
setBackground(BackgroundFactory.createBitmapBackground(_bgImg));
_width = Display.getWidth();
long labelStyle = (DrawStyle.LEFT | DrawStyle.TOP | DrawStyle.ELLIPSIS);
_title = new LabelField("", labelStyle) { // custom anonymous class to change font color
protected void paint(Graphics g) {
int c = g.getColor();
g.setColor(_fontColor);
super.paint(g);
g.setColor(c);
}
};
_title.setFont(Font.getDefault().getFontFamily().getFont(Font.PLAIN, 24));
_thumb = new BitmapField();
_star = new FocusableBitmapField();
_star.setChangeListener(this);
_separator = new SeparatorField() { // custom anonymous class to change separator color
protected void paint(Graphics g) {
int c = g.getColor();
g.setColor(Color.GRAY);
super.paint(g);
g.setColor(c);
}
};
setData(data);
add(_thumb);
add(_title);
add(_star);
add(_separator);
}
public ListRander getData() {
return _data;
}
public void setData(ListRander value) {
if (value != _data) {
_data = value;
_title.setText(value.getTitle());
_thumb.setBitmap(value.getThumb());
}
}
private void onStarClicked() {
Dialog.alert("Star has been clicked or tapped!");
}
private void onRowClicked() {
Dialog.alert("Row has been clicked or tapped!");
}
public void fieldChanged(Field field, int context) {
if (field == _star) {
onStarClicked();
}
}
public boolean navigationClick(int status, int time) {
if (_star.isFocus()) {
onStarClicked();
return true;
} /* else {
onRowClicked();
return true;
} */
return false; // we will not consume this event
}
protected void highlight(boolean onRow) {
_fontColor = onRow ? Color.WHITE : Color.BLACK; // change font color for contrast
_highlighted = onRow;
invalidate();
}
protected void onFocus(int direction) {
// called when focus first transfers to this row, from another Field
if (direction == 1) {
// coming from top to bottom, we highlight the row first, not the star
highlight(true);
} else if (direction == -1) {
// coming from bottom to top, we highlight the star button first, not the row
_star.onFocus(direction);
highlight(false);
}
}
protected void onUnfocus() {
// remove highlighting of the row, if any
highlight(false);
super.onUnfocus();
}
protected int moveFocus(int amount, int status, int time) {
// called when this row already has focus (either on row, or star button)
if (amount > 0) {
// moving top to bottom
if (!_star.isFocus()) {
// we were on the row, now move to the star button
_star.onFocus(1);
highlight(false);
amount--; // consume one unit of movement
}
} else {
// moving from bottom to top
if (_star.isFocus()) {
// we were on the star button, now move back over to the row
_star.onUnfocus();
highlight(true);
amount++; // consume one unit of movement
}
}
return amount;
}
protected boolean touchEvent(net.rim.device.api.ui.TouchEvent event) {
// We take action when the user completes a click (a.k.a. unclick)
int eventCode = event.getEvent();
if ((eventCode == TouchEvent.UNCLICK) || (eventCode == TouchEvent.DOWN)) {
// Get the touch location, within this Manager
int x = event.getX(1);
int y = event.getY(1);
if ((x >= 0) && (y >= 0) && (x < _width) && (y < _MAX_ROW_HEIGHT)) {
int field = getFieldAtLocation(x, y);
if ((field >= 0) && (getField(field) == _star)) {
// Let event propagate to (star) button field
return super.touchEvent(event);
} else {
if (eventCode == TouchEvent.UNCLICK) {
// A completed click anywhere else in this row should popup details for this selection
fieldChangeNotify(1);
onRowClicked();
} else {
// This is just a soft touch (TouchEvent.DOWN), without full click
setFocus();
}
// Consume the event
return true;
}
}
}
// Event wasn't for us, let superclass handle in default manner
return super.touchEvent(event);
}
protected void sublayout(int width, int height) {
height = Math.min(getPreferredHeight(), height);
setExtent(_width, height);
final int margin = 5;
int thumbWidth = _thumb.getPreferredWidth();
layoutChild(_thumb, thumbWidth, _thumb.getPreferredHeight());
setPositionChild(_thumb, margin, margin);
int starWidth = _star.getPreferredWidth();
int starHeight = _star.getPreferredHeight();
layoutChild(_star, starWidth, starHeight);
setPositionChild(_star, width - starWidth - margin, (height - starHeight) / 2);
// this assumes you want margin between all fields, and edges
layoutChild(_title, width - thumbWidth - starWidth - 4 * margin, _title.getPreferredHeight());
setPositionChild(_title, margin + thumbWidth /* + margin */, margin); // TODO?
}
protected void paintBackground(Graphics g) {
super.paintBackground(g);
if (_highlighted) {
// you can't override drawFocus() for a Manager, so we'll handle that here:
int oldColor = g.getColor();
int oldAlpha = g.getGlobalAlpha();
XYRect rect = new XYRect();
g.setGlobalAlpha(150);
g.setColor(Color.BLUE);
getFocusRect(rect);
drawHighlightRegion(g, HIGHLIGHT_FOCUS, true, rect.x, rect.y, rect.width, rect.height);
g.setGlobalAlpha(oldAlpha);
g.setColor(oldColor);
}
}
public int getPreferredWidth() {
return _width;
}
public int getPreferredHeight() {
return _MAX_ROW_HEIGHT;
}
}
Usage
This is how you might use the whole list field (maybe in a Screen class):
public class ListScreen extends MainScreen implements FieldChangeListener {
public ListScreen() {
try {
Vector data = new Vector();
Bitmap icon = Bitmap.getBitmapResource("list_icon.png");
for (int i = 0; i < 15; i++) {
ListRander lr = new ListRander("Product Name " + i, icon);
data.addElement(lr);
}
CustomListField list = new CustomListField(data);
add(list);
list.setChangeListener(this);
} catch (Exception e) {
e.printStackTrace();
}
}
public void fieldChanged(Field field, int context) {
if (field instanceof CustomListRow) {
CustomListRow row = (CustomListRow) field;
Dialog.alert(row.getData().getTitle() + " was selected!");
}
}
}
In my app, it made sense for the CustomListRow itself to handle the equivalent of your star click. However, for me, it did not make sense to have the row click handled that way. So, I let you set a FieldChangeListener on the CustomListField itself, which is called back when any row is selected. See the example above in my screen class. If you want to handle the row click inside the CustomListRow class, too, that's fine. I laid out a onRowClicked() method there. Search in the code for where that's commented out, and you can reactivate, an implement that method (onRowClicked()).
Issues
My app didn't require list searching. I laid out a sample implementation of that, like ListField has. But, I didn't test it. That's your job, if you need it. I just got you started with the CustomListField implementation (see indexOfList()).
I didn't see what your "nav bar" was for. A bar is usually a full-width item, like a status bar, or toolbar. I don't see anything like that in your screenshot. A nav item might be a little arrow at the right side of each row, to bring up details. But, I didn't see that in your screenshot either. So, I ignored that code. If you need a nav bar, you obviously know what it should be, and can add that to my code above.
I couldn't tell whether or not you just added the star as part of the row's background image, or if you had a separate image for that. I added a separate star.png to represent the star. I would assume that clicking the star fills it in, or highlights it, or something. But, you didn't describe that problem, so I assume you can handle that. If you need a custom field to represent the star, that can have selected and unselected images, just post that as a new question.
You had some code that appeared like it was trying to set the row width to 3x the row height, but that didn't match your screen shot. Most lists are full-screen width anyway. So, I remove that code. My CustomListRow class implements getPreferredWidth() and requests the full screen width. Change if you like.
Unlike Android's ListView the BB's ListField is not designed to have a focusable/clickable fields inside of list items. So any attempt to workaround this will have some negative side effects.
A relatively easy/quick workaround would be to switch to VerticalFieldManager (check this other stack overflow question). But if the list is too long (more than several hundreds, I believe) you risk to "eat" too much memory.
If the app is designed for touch screens only, then you can try to stay with ListField + do some manual tracking of touch event coordinates. So when you detect a list field click (in a way you would normally do it) you can check whether the touch coordinates correspond to the star image area (at least on the X axis). I am not going to invent/provide an implementation, but just giving an idea.

Blackberry: How can I make a buttonfield act like toggle button?

I have a single button which I want to use as Start/Stop button. How can I make the buttonfield work as toggle button?
Please help.
Just change button label on fieldChange or navigationClick or touchEvent, don't forget to save toggle state in class member:
class ToggleButtonField extends ButtonField {
int mToggleState = -1;
String[] mLabels = {};
public ToggleButtonField(String[] labels) {
super(CONSUME_CLICK);
if(labels != null && labels.length > 0)
{
mLabels = labels;
mToggleState = 0;
updateLabel();
}
}
private void updateLabel() {
setLabel(mLabels[mToggleState]);
}
protected void fieldChangeNotify(int context) {
mToggleState = getNextToggleState(mToggleState);
updateLabel();
super.fieldChangeNotify(context);
}
private int getNextToggleState(int state) {
int result = mToggleState+1;
if(result >= mLabels.length)
result = 0;
return result;
}
}

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