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Android Articles
Page 18 of 125
How to check if a "lateInit" variable has been initialized in Kotlin?
Any variable which is initialized after its declaration is known as a "late initialized variable". In conventional programming languages, any non-NULL type of variable need to be initialized in the constructor. But sometimes, by mistake, developers forget to do these NULL checks which causes a programming error. In order to avoid this situation, Kotlin introduced a new modifier called as "lateInit". Along with this modifier, Kotlin provides a couple of methods to check whether this variable is initialized or not.In order to create a "lateInit" variable, we just need to add the keyword "lateInit" as an access modifier of that ...
Read MoreWhat is the equivalent of Java static methods in Kotlin?
In Java, "static" keyword is used for efficient memory management. Once a variable or method is declared as static, then the JVM will allocate memory for these variable only once. Usually static variables are used to declare common properties of a class, for example, "Name of the institution". In the following example, we will see how to use the static keyword.Example of Static in using JavaIn order to demonstrate how static works in Java, we will access our online Java compiler and we will create a Test class. Inside Test, we will try to create a static variable along with ...
Read MoreHow to iterate over a Hashmap in Kotlin?
A Map is a collection where data is stored as a key-value pair and the corresponding key has to be unique. A HashMap is a collection class based upon MutableMap interface and it does that by implementing MutableMap interface of HashTable. Kotlin provides four types of constructor to define and manipulate HashMap.HashMap() – It is the default constructor which helps us create an empty HashMap.HashMap(initialCapacity: Int, loadFactor: Float = 0f) – It helps us create a HashMap using initial capacity; if it is not provided, then it will be ignored and it will act as default HashMap().HashMap(initialCapacity: Int) – It ...
Read MoreHow to remove Malware from Android?
In the modern world, smartphones have become an immovable part of everyone's life. It contains almost everything important to a person, for example, banking apps, navigational apps, utility apps, and more. It is, therefore, more than essential to safeguard smartphones at any cost to protects the owner's privacy.Like computers, Android smartphones can also get infected with malicious programs such as viruses, trojans, spyware, adware, and others. Android malware is mainly intended for stealing sensitive information, misguiding users by showing irrelevant ads, and redirecting them to malicious websites. They can infiltrate the device in many ways; for example, users can install ...
Read MoreHow do I specify different layouts for portrait and landscape orientations in Android?
This example demonstrates how do I specify different layouts for portrait and landscape orientations in androidStep 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. Step 3 – Create a layout file by right-clicking on the resources, name the file, from the ‘Available qualifiers, select Orientation.Click >> option.Select Landscape from UI mode.Add the following code in the res/layout/land/activity_main.xml Step 4 − Add the following code to ...
Read MoreHow to change a TextView's style at runtime in Android using Kotlin?
This example demonstrates how to change a TextView's style at runtime in Android using Kotlin.Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. Step 3 − Add the following code in res/values/styles.xml bold|italic #FFFFFF normal #C0C0C0 Step 4 − Add the following code in res/values/colors.xml @android:color/holo_green_light @android:color/holo_red_dark Step ...
Read MoreHow to send a notification from a service in Android using Kotlin?
This example demonstrates how to send a notification from a service in Android using Kotlin.Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. Step 3 − Add the following code to src/MainActivity.ktimport android.content.Intent import android.os.Bundle import android.view.View import android.widget.EditText import androidx.appcompat.app.AppCompatActivity import androidx.core.content.ContextCompat class MainActivity : AppCompatActivity() { lateinit var editText: EditText override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) ...
Read MoreHow to disable GridView scrolling in Android using Kotlin?
This example demonstrates how to disable GridView scrolling in Android using Kotlin.Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. Step 3 − Add the following code to src/MainActivity.ktimport android.content.Context import android.os.Bundle import android.view.MotionEvent import android.view.View import android.view.ViewGroup import android.widget.* import androidx.appcompat.app.AppCompatActivity class MainActivity : AppCompatActivity() { private lateinit var gridView: GridView var imageIDs = arrayOf( R.drawable.ronaldo, R.drawable.andre, ...
Read MoreHow to use Android Picasso library to download images using Kotlin?
This example demonstrates how to use the Android Picasso library to download images using Kotlin.Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Add the following dependency to the build gradle (Module: app)implementation 'com.squareup.picasso:picasso:2.4.0'Step 2 − Add the following code to res/layout/activity_main.xml. Step 3 − Add the following code to src/MainActivity.ktimport android.os.Bundle import android.widget.Button import android.widget.ImageView import androidx.appcompat.app.AppCompatActivity import com.squareup.picasso.Picasso class MainActivity : AppCompatActivity() { lateinit var imageView: ImageView lateinit var btnDownload: Button override fun onCreate(savedInstanceState: ...
Read MoreHow to create a swipe refresh layout in Android using Kotlin?
This example demonstrates how to create a swipe refresh layout in Android using Kotlin.Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. Step 3 − Add the following code to src/MainActivity.ktimport androidx.appcompat.app.AppCompatActivity import android.os.Bundle import android.os.Handler import android.widget.TextView import androidx.swiperefreshlayout.widget.SwipeRefreshLayout class MainActivity : AppCompatActivity() { lateinit var swipeRefreshLayout: SwipeRefreshLayout lateinit var textView: TextView var number: Int = 0 override fun onCreate(savedInstanceState: Bundle?) { ...
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