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In Android apps, spinners are among the standard components used to provide users with a list of items where they can choose one. It is a drop-down control that displays the set of items allowing users to select one item. Once the user selects an item from the spinner, we should be able to retrieve that item’s value and perform an action with it. If you are an Android app developer and are looking to fetch data from spinner on Android, this blog will help you understand how to do so.
Video Tutorial:
What’s Needed
To fetch data from spinner on Android, we need the following things:
- Android Studio installed on your computer.
- An Android device or emulator to run the app.
What Requires Your Focus?
Before we get started, it is essential to understand the following concepts that require your focus:
- Spinner: A Spinner is a drop-down list that displays a list of items from which users can select one item.
- Adapter: An Adapter is a bridge between data and the UI that displays the data. It controls the content and layout of lists, grids or spinners, etc.
- ArrayAdapter: ArrayAdapter is a type of adapter that provides views for an AdapterView. It gets data from an array or a List and uses it to display items in a list view.
Different Methods to Fetch Data from Spinner on Android
In this blog, we will discuss four different methods of fetching data from Spinner on Android.
Method 1: Using setOnItemSelectedListener()
To fetch data from spinner on Android using setOnItemSelectedListener(), follow these steps:
Step 1: Create a Spinner object.
Step 2: Create an ArrayAdapter with the data source and the layout for the spinner.
Step 3: Set the ArrayAdapter to the Spinner object using setSpinnerAdapter().
Step 4: Set a listener to the Spinner using setOnItemSelectedListener().
Step 5: Implement the onItemSelected() method to retrieve the selected item.
Pros:
– It is easy to implement.
– It gives the value as well as the position of the selected item.
Cons:
– If the spinner has no options selected, the onItemSelected() method will not be called.
Method 2: Using setSelection()
To fetch data from spinner on Android using setSelection(), follow these steps:
Step 1: Create a Spinner object.
Step 2: Create an ArrayAdapter with the data source and the layout for the spinner.
Step 3: Set the ArrayAdapter to the Spinner object using setSpinnerAdapter().
Step 4: Select an item from the spinner using setSelection().
Pros:
– It is a simple method to use.
– It can be used to select a default value for the spinner.
Cons:
– It does not provide the selected item’s position.
Method 3: Using Spinner.getSelectedItem()
To fetch data from spinner on Android using Spinner.getSelectedItem(), follow these steps:
Step 1: Create a Spinner object.
Step 2: Create an ArrayAdapter with the data source and the layout for the spinner.
Step 3: Set the ArrayAdapter to the Spinner object using setSpinnerAdapter().
Step 4: Get the selected item from the spinner object using getSelectedItem().
Pros:
– It is a concise method.
– It can be used to retrieve the selected item as an object.
Cons:
– It does not provide the selected item’s position.
Method 4: Using Spinner.getSelectedItemPosition()
To fetch data from spinner on Android using Spinner.getSelectedItemPosition(), follow these steps:
Step 1: Create a Spinner object.
Step 2: Create an ArrayAdapter with the data source and the layout for the spinner.
Step 3: Set the ArrayAdapter to the Spinner object using setSpinnerAdapter().
Step 4: Get the selected item’s position from the spinner object using getSelectedItemPosition().
Pros:
– It is a simple method to use.
– It provides the selected item’s position.
Cons:
– It does not retrieve the selected item’s value.
Why Can’t I Retrieve the Selected Item from Spinner?
If you are having trouble retrieving the selected item from the spinner, it could be due to various reasons. Here are some of the reasons:
1. Incorrect Adapter: If you have not set a proper adapter to your Spinner, it will not display any data, and hence you won’t retrieve any value from it. Make sure you have initialized the ArrayAdapter with the right data source.
2. Incomplete Listener Implementation: If you have not implemented the onItemSelected() method of the Spinner’s listener class, you won’t get the selected item from the Spinner.
3. Spinner not Initialized: If you are trying to get the selected item before the Spinner is initialized, you won’t be able to retrieve data.
4. NPE: NullPointerException (NPE) occurs when you try to retrieve the value from a null object.
Fixes: To retrieve the selected item from the spinner, you must ensure that the adapter has been correctly initialized, the listener is implemented properly, the Spinner is initialized, and there are no null pointer exceptions. You can also debug the code to find any issues in your implementation.
Implication and Recommendation
Here are three suggestions that you can keep in mind while fetching data from Spinner on Android:
- If you need the selected object from a Spinner, use Spinner.getSelectedItem() method, this method will return a value of the object’s class.
- If you need the position of the selected object from a Spinner, use Spinner.getSelectedItemPosition() method. This method will return an integer value that represents the selected item’s position on the list.
- Set a default value so that if the user does not select any item from the spinner, the default value will be displayed.
5 FAQs about Fetching Data from Spinner on Android
Q1: Can we use any adapter to set data to the Spinner?
A: No, we can only use the ArrayAdapter to set data to the Spinner.
Q2: How can we set a default value for the spinner?
A: We can set a default value for the spinner by adding a string to the data source before initializing the ArrayAdapter.
Q3: Does Spinner.getSelectedItem() method return the selected item’s position or value?
A: Spinner.getSelectedItem() method returns the selected item’s value.
Q4: Can Spinner.getSelectedItemPosition() method return -1?
A: Yes, Spinner.getSelectedItemPosition() method can return -1 if no item is selected.
Q5: How do I debug fetching data from Spinner on Android?
A: You can debug the fetching data from Spinner on Android by using Logcat, which is a tool in Android Studio that displays system messages, and log data generated by your app.
Final Words
Fetching data from Spinner on Android is a crucial feature for most Android apps. It allows users to select an item from a dropdown list. In this blog post, we discussed four different methods of fetching data from the Spinner on Android, including the pros, cons and fixes of each method. We hope this blog helps you in your next Android app development project.