Lint and its Usage in Android Studio - GeeksforGeeks

08 Sep, 2021
As Android Developers, we all utilize Android Studio to create our apps. There are numerous alternative editors that can be used for Android app development, but what draws us to Android Studio is the assistance that it offers to Android developers. The assistance may take the shape of auto-suggestions or the display of faults in our code (in all the files present in our project). So, in this article, we’ll look at Lint, one of the greatest aspects of Android Studio that helps us enhance our ability to write error-free code.
This article will cover the following topics:
What exactly is lint?Lint configurationUsing Baseline to Assist Lint Removal
What exactly is lint?
Lint configuration
Using Baseline to Assist Lint Removal
Lint is a code scanning tool supplied by Android Studio that identifies, suggests, and corrects incorrect or dangerous code in a project.
GeekTip #1: Lint functions similarly to a full-fledged stack analysis framework.
We’ve all been using Lint since we first started using Android Studio because it comes standard with support for Lint in every project. The Lint will notify you of any errors found in your code, along with some suggestions and a warning level. You may use the advice to make changes to your code. Lint’s biggest feature is that you may utilize it any way you see fit. If you provide a certain type of error in your project, the Lint will only display that sort of mistake. Lint is adaptable in nature. Android Studio automatically executes the inspection process when you create your project, but you can also examine your code manually or from the command line using Lint.
Lint removal may be broken down into three steps:
Making a lint.xml file: In the lint.xml file, you may modify the Lint checks. You can write the checks you want to include in this file and disregard the checks you don’t want to include. For example, if you wish to check for unused variables but not for naming problems, you may do so in the lint.xml file. Aside from that, you may manually configure the Lint checks. In the following section of this article, we will look at how to perform manual lint checks.Lint Inspection: The next step is to choose the source files that will be subjected to the Lint inspection. It may be your project’s.java file, .kt file, or any XML file.The Lint Remover: Finally, the lint tool examines the source and lint.xml files for structural code issues and, if any, suggests code changes. It is recommended that we apply the lint recommendation before releasing our program.
Making a lint.xml file: In the lint.xml file, you may modify the Lint checks. You can write the checks you want to include in this file and disregard the checks you don’t want to include. For example, if you wish to check for unused variables but not for naming problems, you may do so in the lint.xml file. Aside from that, you may manually configure the Lint checks. In the following section of this article, we will look at how to perform manual lint checks.
Lint Inspection: The next step is to choose the source files that will be subjected to the Lint inspection. It may be your project’s.java file, .kt file, or any XML file.
The Lint Remover: Finally, the lint tool examines the source and lint.xml files for structural code issues and, if any, suggests code changes. It is recommended that we apply the lint recommendation before releasing our program.
When Should You Use Lint?
If you wish to publish your app on the Play Store or any other app store, it must be error-free. You must conduct a great deal of manual testing on your app for this purpose. 
GeekTip #2: However, if you wish to eliminate part of the manual testing, you may incorporate Lint into your project. 
Lint will detect the issues and propose solutions if you check each and every file in your code for faults. Errors or warnings can be of the following types:
Variables that have not been utilizedUnjustifiable exceptionsImports that aren’t needed for the project, and much more
Variables that have not been utilized
Unjustifiable exceptions
Imports that aren’t needed for the project, and much more
So, before you publish your app, use Lint to thoroughly check your code.
You may also set up lint checking at multiple layers of your project:
Across the board (entire project)Module for the projectThe module of production Module of testingFiles should be openedVersion Control System (VCS) scopes in a class hierarchy
Across the board (entire project)
Module for the project
The module of production Module of testing
Files should be opened
Version Control System (VCS) scopes in a class hierarchy
To utilize Lint or just run inspections in your project, add Lint inspection to the lint.xml file or manually pick the list of issues to be configured by Lint in your project using Android Studio.
Configure the lint file:
Add the list of issues to be configured in the lint.xml file to define manual inspections in your app. If you create a new lint.xml file, place it in the root directory of your Android project.
Here’s an example of a lint.xml file:
<?xml version="1.0" encoding="UTF-8"?>
<lint>
    <issue id="GeeksIconMissing" severity="error" />
    <issue id="OldDimens">
        <ignore path="res/layout/merger.xml" />
        <ignore path="res/layout-xlarge/merger.xml" />
    </issue>
    <issue id="HellOWorld">
        <ignore path="res/layout/main.xml" />
    </issue>
    <issue id="someText" severity="ignore" />
</lint>
Manually configure the lint:
By default, lint checks for a handful of problems but not all of them. This is not done since running all of the problem checks that lint may check for will slow down the speed of Android Studio. As a result, Android Studio only employs a restricted amount of lint checks by default. However, you may add and remove checks from the lint by following the steps below:
Go to Files > Settings > Editor > Inspections, and then tick the problem checks you want the lint to execute.
Lint Removal
There are instances when you are writing dangerous or error-prone code, yet the lint does not report any errors or warnings. For instance, in Android Studio, enter the following code:
Kotlin
fun someUIUpdate() {   // your UI code goes here   proceessSomething()}fun processSomething() {    // Geeks for geeks}
The preceding lines of code will not display any errors, although they should logically display some errors because network requests should not be made during UI updates. So, what you can do is assist the lint. 
Geek Tip #3: Yes, if you assist the lint, the lint will assist you.
 Always attempt to utilize annotations in your project to assist the lint to understand the code more precisely. Now write the same some that you did before, and then check for errors:
Kotlin
@UiThreadfun someUIUpdate() {    // your code bugs here    processChanges()}@WorkerThreadfun processChanges() {    // Geeks for Geeks}
If you are working on a large project and want to identify future mistakes that may arise while adding additional codes to your project, you can set a baseline to your project and the lint will create the errors that happened after that baseline. As a result, lint will disregard prior code problems and only alert you about new lines of code introduced after the baseline.
To include a baseline in your project, add the following line to the build.gradle file:
android {
  lintOptions {
    baseline file("lint-geeksforgeeks-example.xml")
  }
}
This will generate a lint-baseline.xml file, which will serve as a baseline for your project. To add another baseline, remove the file and lint once more.
We learned how to use the Lint in Android Studio in this article. We discovered that if we want to examine our code, we don’t have to do it manually. Lint, a code checking tool provided by Android Studio, assists us in cleaning our code and using the essential and correct code for application development. So, utilize Lint to remove various sorts of errors from your project while also assisting Lint to assist you.
Android-Studio
Android
Kotlin
Android
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