Android listview get selected item from adapter

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Android listview get selected item from adapter

Posted by: admin April 10, Leave a comment. I am having 1 list view contactslist. I wrote the code for highlighting the selected item in the ListView. It is working.

android listview get selected item from adapter

When I click on 1 item it is highlighting that item but the problem is if I click on other item it is highlighting that too. I want to highlight the selected item only.

The previous selection will have to gone when I click on another item. To change this, you just need to set the choiceMode attribute of your ListView to singleChoice. So if you were using a click listener to change the background of the selected row, remove that from your code, and use the proper method from above.

If you set the background from your getView method, instead of using a static color, apply a state list drawable to the row background with duplicateParentState set to true. This way it will change its display based on the current state of the item: normal, focused, pressed, etc.

android listview get selected item from adapter

Tags: androidandroidlistlistviewselectview. April 10, Android Leave a comment. Questions: Can someone tell me the code to convert image into byte array and that byte array into base64 string. Questions: I want to show a spinning wheel dialog while my app loads some data: The spinning wheel dialog should show on a button click. Add menu. Reply to the update If you set the background from your getView method, instead of using a static color, apply a state list drawable to the row background with duplicateParentState set to true.

Try this at onListItemClick view. How to convert image into byte array and byte array to base64 String in android? April 10, Android Leave a comment Questions: Can someone tell me the code to convert image into byte array and that byte array into base64 string.Intents and Activities Applications. ListView Applications.

Fragment Applications. Menu Applications. Android Action Bar Applications. Android Action Bar Sherlock Applications. Android tab applications. Chart Graph Applications. Styles and Themes Applications. Actually this article is an extension of the article Dynamically add items to ListView in Androidin which we have created an application to add user input text to listview.

In this article, user can add as well as delete items from the listview. I am George Mathew, working as software architect and Android app developer at wptrafficanalyzer. For hiring me, please mail your requirements to info wptrafficanalyzer. My other blogs store4js. Ready to test your knowledge in Android? Take this quiz :. Thanks a Lot!!!!!.

I was looking for some simple method to delete listview item and I found yours…Its great and easy to implement. Thanks again!!

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Finally, found a simple tutorial for a simple question. Thanks for the tutorial. This line needs to be added. Hello and thanks for these posts! I wanted to ask in the above example how can someone add more fields. I meanto have a list view which in a row will have for example a Name textview ,a surname textview ,an edittext where he can enter some amount ,etc. Hi, I just found this article and it was just what I needed. Works great! Need to be able to save these changes. How can I do this?

Download Full Source Code. How to hire me?As a ListView is instantiated and the rows are populated such that the full height of the list is filled. After that no new row items are created in the memory. As the user scrolls through the list, items that leave the screen are kept in memory for later use and then every new row that enters the screen reuses an older row kept in the memory.

Clicking the row would display the SnackBar with the text elements of that row. Clicking the info will display a SnackBar with information specific to that row.

The data model that is contained in the ArrayList is shown below. Also the list rows are animated when scrolled. The two animation xml resource files are given below. The MainActivity. Along with that a random ArrayList of DataModel objects is populated. The output of the application in action is shown below.

This brings an end to this tutorial. I have a problem with disappearing rows. What could go wrong?

android listview get selected item from adapter

I use Android 9 on Nokia 6. Ok, I know, that when I try to hide TextViews in my custom rows by setting textSize or height to 0dp, there are some errors. After scrolling down and up textViews that should be there disappear by setting height or textSize to 0.

How should I correctly hide them to remove empty spaces between text lines row contains a few TextViews placed vertically? How can I pass the data from the custom adapter to the main activity when the imageview is clicked? Thank you. An explanation would be appreciated. How to do in the correct way this inserted code as PHP uses simple include file ….

Need help. The problem about all custom listview tutorials are this : What will happen if i want to add more than 1 Strings to get? I cant use toString method for more then one String. For example i got 4 Stringss. What can i do in this situation? How to load image in custom list view with array of url using picasso library? Got the answer.

Answer :Picasso.We will learn how to create a simple Android ListView and launch a new activity on selecting a single list item. Android ListView is a view which groups several items and display them in vertical scrollable list.

The list items are automatically inserted to the list using an Adapter that pulls content from a source such as an array or database. The most common usages include displaying data in the form of a vertical scrolling list.

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An adapter actually bridges between UI components and the data source that fill data into UI Component. Adapter holds the data and send the data to adapter view, the view can take the data from adapter view and shows the data on different views like as spinner, list view, grid view etc.

The adapter pulls the items out of a data source, an array for example, and then converts each item into a view which it then inserts into the ListView. The ListView and GridView are subclasses of AdapterView and they can be populated by binding them to an Adapter, which retrieves data from an external source and creates a View that represents each data entry.

This method receives 4 parameters:. So we create an XML file under values folder and name it as strings. Each list view item will be represented by an xml layout,so lets define the xml layout comprising of a single textview as follows:.

Following snippet shows how to import the xml resources data and store them in data followed by binding them to the adapter:. In the following code we fetch the data value from the selected item and pass it as a bundle to the next activity using intents. The SecondActivity class retrieves the text label from the list item selected and displays it in a textview as shown in the following snippet. Following small GIF depict the flow of the app:. You should also learn about Expandable ListView.

You can download android list view project from below link. Activity; import android. AlertDialog; import android. Intent; import android. Bundle; import android. View; import android. Button; import android.ListView is used when you have to show items in a vertically scrolling list.

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Best example of it is our device's Contact List. With ListView, user can easily browse the information, while scrolling up and down. You can set divider between every item and set its height and color as per your UI design.

Inside a ListView, we can show list of Text items by using TextView, or pictures using ImageView, or any other view or a combination of views.

As ListView is generally used to display a large set of data, hence it is not feasible to manually create list items for the complete data, hence Android provides us with special Adapter classes which can be used to supply data from datasets to ListView. Let's see how we can use an Adapter to read data from an array, and display it in form of a List.

So by doing this, we have defined a ListView to be created in our MainActivity, but what data it will show? Where will we declare and define that? As we specified in the last tutorialthat an Adapter is used to covert data items into view objects which can be used to display as UI components. So we need a dataset and a View into which the dataset will be converted by the Adapter.

As our data set has simple text values, so we can define a simple TextView to hold these values and populate the ListView. Does it sound confusing? Let it sink in. If our dataset would have had, an image and some text along with it, then we can also define a TextView along with an ImageView to display the data in the List. Now its time for the finale, below we have the MainActivity.

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Android ListView Example

Operating System. Computer Architecture. Jenkins Maven. Apache Cordova Drools. We are Hiring! Sign in.The display of elements in a list is a very common pattern in mobile applications. The user sees a list of items and can scroll through them.

Such an activity is depicted in the following picture. Typically the user interacts with the list via the toolbar, for example, via a button which refreshes the list. Individual list items can be selected. This selection can update the toolbar or can trigger a detailed screen for the selection.

The following graphic sketches that. On the selection of a list item another activity is started. Android provides the ListView and the ExpandableListView classes which are capable of displaying a scrollable list of items.

The ExpandableListView class supports a grouping of items. The input of a list items in the list can be arbitrary Java objects.

The adapter extracts the correct data from the data object and assigns this data to the views in the row of the ListView. These items are typically called the data model of the list. An adapter can receive data as input. An adapter manages the data model and adapts it to the individual entries in the widget. An adapter extends the BaseAdapter class. Every line in the widget displaying the data consists of a layout which can be as complex as you want. A typical line in a list has an image on the left side and two text lines in the middle as depicted in the following graphic.

The adapter would inflate the layout for each row in its getView method and assign the data to the individual views in the row.

The filtering and sorting of the data is handled by the adapter.

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You need to implement the logic in your custom adapter implementation. The notifyDataSetChanged method on the adapter is called if the data has changed or if new data is available.

The notifyDataSetInvalidated method is called if the data is not available anymore. Android provides default adapter implementations; the most important are ArrayAdapter and CursorAdapter.

ArrayAdapter can handle data based on Arrays or java. SimpleCursorAdapter can handle database related data. The ArrayAdapter class can handle a list or arrays of Java objects as input.

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Every Java object is mapped to one row. By default, it maps the toString method of the object to a view in the row layout. You can define the ID of the view in the constructor of the ArrayAdapter otherwise the android.

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The ArrayAdapter class allows to remove all elements in its underlying data structure with the clear method call. You can then add new elements via the add method or a Collection via the addAll method. You can also directly modify the underlying data structure and call the notifyDataSetChanged method on the adapter to notify it about the changes in data. The following example shows the usage of the ListView view in an activity. It uses a default layout from the Android platform for the row layout.

It also demonstrates the removal of list items and uses animations for the removal. The ArrayAdapter is limited as it supports only the mapping of toString to one view in the row layout. To control the data assignment and to support several views, you have to create your custom adapter implementation. For this you would extend an existing adapter implementation or subclass the BaseAdapter class directly. The adapter needs to create a layout for each row of the list.In Android development, any time we want to show a vertical list of scrollable items we will use a ListView which has data populated using an Adapter.

The simplest adapter to use is called an ArrayAdapter because the adapter converts an ArrayList of objects into View items loaded into the ListView container. The ArrayAdapter fits in between an ArrayList data source and the ListView visual representation and configures two aspects:.

Note as shown above that there are other data sources besides an ArrayAdapter such as the CursorAdapter which instead binds directly to a result set from a Local SQLite Database. When using an adapter and a ListViewwe need to make sure to understand how view recycling works. When your ListView is connected to an adapter, the adapter will instantiate rows until the ListView has been fully populated with enough items to fill the full height of the screen.

At that point, no additional row items are created in memory. Instead, as the user scroll through the list, items that leave the screen are kept in memory for later use and then every new row that enters the screen reuses an older row kept around in memory.

Here is a visual overview of recycling:. Refer to this ListView guide for another look at how this works to optimize the performance of your lists. Be sure to check out this Udacity video on view recycling as well. If you wish to evaluate how fast your ListView is rendering, check out the Profiling GPU tool, which provides a graphical way of visualizing the layout performance. To use a basic ArrayAdapteryou just need to initialize the adapter and attach the adapter to the ListView.

First, we initialize the adapter:. The ArrayAdapter requires a declaration of the type of the item to be converted to a View a String in this case and then accepts three arguments: context activity instanceXML item layout, and the array of data. If the app requires a more complex translation between item and View then we need to create a custom ArrayAdapter instead.

When we want to display a series of items into a list using a custom representation of the items, we need to use our own custom XML layout for each item. To do this, we need to create our own custom ArrayAdapter class. See this repo for the source code. First, we often need to define a model to represent the data within each list item. We can create a custom ListView of User objects by subclassing ArrayAdapter to describe how to translate the object into a view within that class and then using it like any other adapter.

Next, we need to define the adapter to describe the process of converting the Java object to a View in the getView method. The naive approach to this without any view caching looks like the following:. That adapter has a constructor and a getView method to describe the translation between the data item and the View to display.

Another method used is getItem which is already present in the ArrayAdapter class and its task is to simply get the data item associated with the specified position in the data set which is associated with that ArrayAdapter.

Once the adapter is attached, items will automatically be populated into the ListView based on the contents of the array. You can add new items to the adapter at any time with:.

You can also clear the entire list at any time with:. Using the adapter now, you can add, remove and modify users and the items within the ListView will automatically reflect any changes. In order to create model instances, you will likely be loading the data from an external source i. For more details, check out our guide on converting JSON into a model. If you are not using a JSON source for your data, you can safely skip this step. Within a ListViewwe can easily attach event listeners onto any of the views that are item position aware with:.

To improve performance, we should modify the custom adapter by applying the ViewHolder pattern which speeds up the population of the ListView considerably by caching view lookups for smoother, faster item loading:. In this example we also have a private static class called ViewHolder.

How to change Listview item text color and background color when clicked

Making calls to findViewById can be slow in practice, and if your adapter has to call it for each View in your row for every single row then you can often run into performance issues. Once your ListView has reached the max amount of rows it can display on a screen, Android is smart enough to begin recycling those row Views.

If it is not null then we have a recycled View and can just change its values, otherwise we need to create a new row View.


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