ListView recycling

Similar Questions

• How to detect when ListView recycles an ImageView?

  I have a ListView with items ~ 600 in a 4-wide grid. Each element is a WebImageView (inherits from ImageView, slightly modified from code kindly provided here) over a label.

  Everything works spot - we (and performance is awesome) except for one glaring problem: when I sometimes momentarily the ImageView ListView displays scrolling scrolls the erroneous image of an item that was previously on. Sometimes it moves even between two prior images before displaying the right pair. These problems are happening because applications for network WebImageView queues upward because the visible element has been recycled once or even twice.

  What I need to solve this problem is to know when the WebImageView has been recycled by ListView in order to disconnect the network signals and erase the old image. I can't find how to do this.

  So I have a "fix" that is more than a workaround. In the WebImageView, I added a member variable:

  int m_iCurrentRequestIndex;

  Whenever WebImageView has applied for a network, I add m_iCurrentRequestIndex as an attribute of the QNetworkRequest and then increment.

  When I receive the response from the network, I check if the value of attraibute for example a_reply-> request (.attribute (...)) and throw the answer if it is not the last.

  Not a very good solution because it is always that which allows network support needless to proceed and just throw the results, but at least it works. But if anyone can answer the question in the original post, I who brand as the solution because it will allow for better efficiency. I want to know a signal or something available at WebImageView that is called when ListView is recycled as:

  WebImageView::onRecycled()
  {
      // close() and disconnect() current QNetworkRequest().
  }
  

• ListView loads wrong model behavior data / not deterministic?

  I have a fife ListViews that you can scroll between. Its type is assigned to each of them, and it shows its own set of data.

  typeA: 1-10, typeB: typeC from 0.1 to 1: 1 to 15, typed: 1-10, type: 0.5 to 5

  Its just qml and looks like this (main.qml):

  import bb.cascades 1.0
  
  Page {
      Container {
  
          layout: DockLayout { }
  
          ListView {
              id: unit_list
  
              maxHeight: 300
              maxWidth: 300
  
              layout: StackListLayout {
                  orientation: LayoutOrientation.LeftToRight
              }
  
              dataModel: GroupDataModel {
                  grouping: ItemGrouping.None
                  sortingKeys: [ "position" ]
              }
  
              snapMode: SnapMode.LeadingEdge
  
              listItemComponents: [
                  ListItemComponent {
                      type: "unit_list"
                      QuantitySelectList {
                      }
                  }
              ]
  
              attachedObjects: [
                  ImagePaintDefinition {
                      id: background_typeA
                      imageSource: "asset:///images/typeA.png"
                  },
                  ImagePaintDefinition {
                      id: background_typeB
                      imageSource: "asset:///images/typeB.png"
                  },
                  ImagePaintDefinition {
                      id: background_typeC
                      imageSource: "asset:///images/typeC.png"
                  },
                  ImagePaintDefinition {
                      id: background_typeD
                      imageSource: "asset:///images/typeD.png"
                  },
                  ImagePaintDefinition {
                      id: background_typeE
                      imageSource: "asset:///images/typeE.png"
                  }
              ]
  
              onCreationCompleted: {
                  // fill the quantity select set
                  dataModel.insert({
                          "position": 0,
                          "unit": "typeA",
                          "background": background_typeA.imagePaint
                      });
                  dataModel.insert({
                          "position": 1,
                          "unit": "typeB",
                          "background": background_typeB.imagePaint
                      });
                  dataModel.insert({
                          "position": 2,
                          "unit": "typeC",
                          "background": background_typeC.imagePaint
                      });
                  dataModel.insert({
                          "position": 3,
                          "unit": "typeD",
                          "background": background_typeD.imagePaint
                      });
                  dataModel.insert({
                          "position": 4,
                          "unit": "typeE",
                          "background": background_typeE.imagePaint
                      });
              }
  
              function itemType(data, indexPath) {
                  return "unit_list";
              }
          }
      }
  }
  

  and (QuantitySelectList.qml):

  import bb.cascades 1.0
  
  Container {
      id: quantity_container
  
      maxHeight: 300
      maxWidth: 300
  
      background: ListItemData.background
  
      ListView {
          id: quantity_list
  
          maxHeight: 300
          maxWidth: 300
  
          signal updateQuantity(variant quantity_index_path)
  
          layoutProperties: StackLayoutProperties {
              spaceQuota: 1
          }
  
          dataModel: GroupDataModel {
              grouping: ItemGrouping.None
              sortingKeys: [ "position" ]
              objectName: "quantity_select_set"
          }
  
          snapMode: SnapMode.LeadingEdge
  
          listItemComponents: [
              ListItemComponent {
                  type: "quantity"
                  Container {
                      id: quantity_view
  
                      minHeight: 300
                      minWidth: 300
  
                      attachedObjects: [
                          TextStyleDefinition {
                              id: quantity_text_style
                              base: SystemDefaults.TextStyles.SubtitleText
                              color: Color.Black
                              fontWeight: FontWeight.Normal
                              fontSize: FontSize.PointValue
                              fontSizeValue: 36.0
                          }
                      ]
  
                      horizontalAlignment: HorizontalAlignment.Fill
                      verticalAlignment: VerticalAlignment.Fill
  
                      Label {
                          text: ListItemData.amount
                          horizontalAlignment: HorizontalAlignment.Center
                          verticalAlignment: VerticalAlignment.Center
                          textStyle {
                              base: quantity_text_style.style
                          }
                      }
                  }
              }
          ]
  
          onCreationCompleted: {
              // fill the quantity select set
              // if (ListItemData.unit == "typeA") {
              if (ListItemData.position == 0) {
                  for (var a = 1; a < 11; a ++) {
                      dataModel.insert({
                              "amount": a,
                              "position": a
                          });
                  }
              } else if (ListItemData.unit == "typeB") {
                  for (var a = 1; a < 11; a ++) {
                      dataModel.insert({
                              "amount": 0.1 * a,
                              "position": a
                          });
                  }
              } else if (ListItemData.unit == "typeC") {
                  for (var a = 1; a < 16; a ++) {
                      dataModel.insert({
                              "amount": a,
                              "position": a
                          });
                  }
              } else if (ListItemData.unit == "typeD") {
                  for (var a = 1; a < 11; a ++) {
                      dataModel.insert({
                              "amount": a,
                              "position": a
                          });
                  }
              } else if (ListItemData.unit == "typeE") {
                  for (var a = 1; a < 11; a ++) {
                      dataModel.insert({
                              "amount": 0.5 * a,
                              "position": a
                          });
                  }
              }
          }
  
          function itemType(data, indexPath) {
              return "quantity";
          }
      }
  }
  

  The problem is that some lists are not displayed with the data sets as they should. If I start it that I see for example typed list and list of typeB have converted their data sets. If I scroll quickly, it can happen then another two lists take their data sets. How can this happen?

  ListView reuses it is ListItemComponents. Do not trust onCreationCompleted in QuantitySelectList, she will not be called when the re-use of components.

  A possible workaround is detect when ListItemData changes and repopulate QuantitySelectList. This thread has an example:

  http://supportforums.BlackBerry.com/T5/Cascades-development/how-to-detect-when-ListView-recycles-an-...

  ListItem.onDataChanged: {
  }
  

  I have not tried.

  Another thread suggests binding to a specific property of the ListItemData, but previous approach is better if it works:

  http://supportforums.BlackBerry.com/T5/Cascades-development/QML-reset-properties-when-ListItemCompon...

  In my projects, I generally implement lists in C++. There is a method that is called on the reuse of element.

• Update of ListView dummy image using images from URL http

  Hi guys...

  Please help me with this.

  I have created a ListView in QML file and filled with data received from a webservice. Since this web service provides all the images, I have to place a dummy image at this location. Then I used another method to retrieve images of the url. Now, I got the image in my CPC file. But I could not update my listview. I tried several methods. But failed.

  Here is my code snippet.

   ListView {
                  id: listView
                  objectName: "listView"
  
                  dataModel: ArrayDataModel {
                      id: myListModel
  
                  }
  
                  // Override default GroupDataModel::itemType() behaviour, which is to return item type "header"
                  listItemComponents: ListItemComponent {
                      id: listcomponent
                      // StandardListItem is a convivience component for lists with default cascades look and feel
                      StandardListItem {
                          title: ListItemData.postText
                          description: ListItemData.postDate
                          status: ListItemData.filePath
                          imageSource: "asset:///images/4.png"
                      }
  
                  }
                  layoutProperties: StackLayoutProperties {
                      spaceQuota: 1.0
                  }
                  horizontalAlignment: HorizontalAlignment.Fill
                  verticalAlignment: VerticalAlignment.Fill
  
              }
  

  In the PRC, I get my image like this.

  void PostHttp::imageFetcher(){
  const QUrl url("http:///828/828_20135312012288.png");
  if (flag1 == true) {
      get(url);
  }
  }
  void PostHttp::onImageReply(){
      QNetworkReply* reply = qobject_cast(sender());
      QString response;
      QImage img;
      QString filePathWithName = "data/img/";
      QString imageName;
  
      if (reply) {
              if (reply->error() == QNetworkReply::NoError) {
                  flag1 = false;
                  const int available = reply->bytesAvailable();
                  if (available > 0) {
                  const QByteArray buffer(reply->readAll());
                  response = QString::fromUtf8(buffer);
                  img.loadFromData(buffer);
                  img = img.scaled(40, 40, Qt::KeepAspectRatioByExpanding);
                  const QImage swappedImage = img.rgbSwapped();
                  const bb::ImageData imageData = bb::ImageData::fromPixels(
                          swappedImage.bits(), bb::PixelFormat::RGBX,
                          swappedImage.width(), swappedImage.height(),
                          swappedImage.bytesPerLine());
                  bb::utility::ImageConverter::encode(QUrl(QDir::currentPath() + "/shared/camera/img.png"), imageData, 75);
                  qDebug()<<"current path is "<
  Thanks in advance
  			 
  You can pass a QByteArray of image data coded directly to an imageView in the image property, set of QVariant::fromValue (). However, in your case you can place the uri to which you saved the image and not the bytes. Advantage: cascades puts these images in cache. If you use deterministic file names, you can avoid any networking calls or loading of images when only the populated list of point sier after be recycled.
  
  img.loadFromData(buffer);
  img = img.scaled(40, 40, Qt::KeepAspectRatioByExpanding);
  img.save(QDir::currentPath() + "/shared/camera/img.png"), 0, 75);
  
  QImage can do all this for you, without permutation of bytes.
  All you have to do is then updated the datamodel.
  		   

• iPad1 recycling

  I want to recycle my ipad1. But there is nothing on the website of apple on the ipad1 recycling. I read the site so please do not send me a link to your site!

  My question is for iPad1! How to recycle.

  I'll send you a link to the Apple site despite your request. You can recycle an iPad1 using http://www.apple.com/recycling/ and then click on the link below "iPod or any what older devices". See the excerpt below.

  Note that you will only be recycling and receive no payment. You can also have a local place where you can recycle - you can see that by doing a search on the internet for something like your city recycling name.

  iPod or any older devices

  Send us your iPod or another older device, and we will recycle responsibly.4

  iPod or older device

• G4 tower: sell or recycle?

  I have a G4 tower Leopard running with 500 GB memory and 1 GB of RAM. recently wiped everything.

  anyone, anywhere even he wants? should I just send it to recycling?

  Unfortunately, they are not worth much, still it would be useful to someone, somewhere, problem is to find the... I'd like to see if there is a local Mac user group in your area.

• Can Recycle Bin on desktop shortcut

  I would like to put a shortcut to the Recycle Bin on my desktop, so I can drag files to the trash. I know there is one on the dock

  but it would be easier on the desk for me. How can I do?

  Choose go to folder from the Finder Go menu, provide ~ /. Trash like path, click on the small icon at the top of the window, and then press the Option and command keys while dragging to the desktop. This will not work for items on external drives, the disk images or additional partitions.

  (144804)

• Apple Watch renewing and recycling?

  Does anyone know if Apple has a program of renewal for the Apple Watch? in-store or online? Thank you!

  Hello

  Apple Watch is not currently under the program:

  http://www.Apple.com/recycling/

• Recycle program recovery iPhone?

  My iPhone 6 is stuck on recovery mode, so it is not working properly, I can well regained my iPhone 6 through the Exchange to Recycle program to receive credit for my purchase of the new iPhone iPhone 7?

  Hello D710,

  Thank you for reaching out to the Community Support from Apple. I know how it is important to be able to count on your iPhone works as expected, and I would be happy to help you to get your reexecutant as well as some information on trade in the currently available programs.

  Because your iPhone is stuck in recovery mode, you'll want to try to restore through iTunes. It may be better to restart the recovery manually Mode. The article below will help you manual start Recovery Mode and restoring:

  If you are unable to update or restore your iPhone, iPad or iPod touch

  Just as a precaution, restoring will erase all data on your phone and re-install the operating system, so if you have a backup, you will want to restore from that by following the steps in the article below.

  Restore your iPhone, iPad or iPod touch from a backup

  Regarding the exchange of programs, take a look at this site to get all the details and a rough estimate of the trade in value of your current iPhone.

  iPhone Trade-up

  If you are having trouble, the entire community is here to help answer any questions you may have.
  Best regards

• Can I actually delete messages rather than having that they are sent to the Recycle Bin?

  I want to know how I can delete messages rather than the envoys in a junk folder or recycle bin and then delete them from there. I have several filters set up and send them to separate subfolders. But of course, when I look at these and remove them, they go in the trash. Then I can actually delete them so that they're gone, that's what I think delete would do in the first place. Is it possible to do so, to delete messages without moving them to the trash and then remove them from there? It is important that I don't miss any messages, I still sometimes do, but I'll have 50 posts or more per day that are trash. Most of them pass through my filters, but if I do not have a daily interview with a bunch of garbage I'd meet a real nightmare.
  Surely people have requested this, and I've seen some with answers like "it's the way it was designed. Can it be done?

  Thank you, if there is a useful link that send.

  Hold down the SHIFT key when you press DELETE.

• How can I remove a time Capsule backups I want to recycle?

  How can I remove a time Capsule backups I want to recycle?

  Reformat the disk via disk utility. This will remove all the contents of the disc.

• Where can I recycle my old iPad?

  I'm ready to recycle my iPad 3rd generation 32GB Black Wi - Fi only and I'm trying to do at home, it's barely cracked. Which websites can I recycle my iPad or my iPad trade? It is fixed so the screen will not eject, and it was to be fix by 3rd party. If it emerges, it would be more probably touch at random, and if I recorded it, he still have wacky touch. I can bring my load cables and Adaptateures to recycle my iPad, it will sell to someone or it will go to Liam?

  At the Apple Store or best buy maybe, if they take it. Try it and see. If this is not the case, there are to many other online recyclers. Delete all, of course.

• Error code: How can I get an item in the Recycle Bin?

  I can't put a webarchive into the trash.  Error message says, "the operation cannot be completed because one or more required elements was not found (error code - 43) how can I get the item in the Recycle Bin?

  reset

  then try again.

• Some accounts have the Recycle Bin instead of the trash icon. Cannot run 'Empty trash' on the record, only on an icon to the trash.

  I have four accounts open TB: mine, woman, club and spam. Only mine and spam account display the Recycle Bin icon. The other two accounts have a folder named "Trash". Deleted files go in the Trash files, is similarly in the trash icon files. However, there is a single action, I can perform on files from the Recycle Bin. When right clicking on folders, "empty trash" is not available as an option. The function is available only on folders with the Recycle Bin icon.
  Is there a way to get the appropriate folder to the trash with function 'empty trash' in all accounts?

  OK - I messed around with the settings more and came across a solution.
  1 right-click on the account name in the left pane, and then select settings.
  2. Select Server settings
  3. in the central block under deletion actions, select Advanced
  4. uncheck the "show only subscribed folders", and then click OK
  5. click OK in the parameters, and then collapse the account name in the left pane so not subfolders appear.
  6 expand the name of the account. This is - the trash is now a garbage can with the function of "empty trash".
  7. If desired, return to the advanced settings and re - select "show only subscribed folders" and click OK

  Don't ask me why this works. It's a total coincidence that I even found it.

• How to restore files from the Recycle Bin?

  I have music files to the trash by mistake; How can I restore them back?

  Hi there butcher.

  Looks like you have your entire music library in your basket and you want to return whence they came. This step of the following article should help you to do:

  OS X Yosemite: delete files and folders

  If you change your mind before you empty the trash

  Click on the Recycle Bin to open it, and then drag the item to the trash, or select it and choose file > put back.

  Thank you for using communities of Apple Support, all the best!