Android Tutorials

In this tutorial, we will learn about Spinner in Android. If you ever worked in Java AWT or Swing then you might be familiar with ComboBox. Spinner is same as those ComboBoxes. Spinner allows a user to choose from multiple choices and the user can select only one option at a single time. For example, you are making an app for an educational institute and you have an activity in your application where a user can apply for a course. In this kind of situation, you can use Spinner which would allow the user to select one course from many. In this tutorial firstly we will learn about Array Adapters then we will move to Spinners. Array Adapter : – An ArrayAdapter is a class in Android which work like a bridge between UI components and source of data. The data can be in any form like in the form of a list, in the form of Cursor object or in the form of Array. Array adapter mainly works with simple text data. In this tutorial, we will use an Array as our data source. To understand more about ArrayAdapter we will follow an illustration. In this illustration, you can see Adapter is working in the centre of our Data source and Adapter View. The adapter will take data from the data source and will send it to Adapter View and after merging data and adapter view. We will set this adapter to our spinner. It might be confusing at present for many students but after seeing examples you will find it easy. So to start with spinner firstly we will add spinner in our main XML layout file. Parvesh SandilaParvesh Sandila is a passionate web and Mobile app developer from Jalandhar, Punjab, who has over six years of experience. Holding a Master’s degree in Computer Applications (2017), he has also mentored over 100 students in coding. In 2019, Parvesh founded Owlbuddy.com, a platform that provides free, high-quality programming tutorials in languages like Java, Python, Kotlin, PHP, and Android. His mission is to make tech education accessible to all aspiring developers.​ new.owlbuddy.com

In this tutorial, we will learn about RadioButton in Android. Radio buttons are kind of buttons which has only two states checked or unchecked the same as CheckBox expects with little differences. RadioButton in Android is generally used with another widget which in RadioGroup. Suppose a RadioGroup contain two Radio Buttons it means we can select only one RadioButton at a single time. We can not select both Radio Buttons once. For Example, we have Radio Group of two RadioButtons with Male or Female option in our signup form in this case user can only select one radio button to mention their gender. Throughout this tutorial learn how to add RadioButtons in RadioGroup widget in the XML layout file and how to get selected RadioButton in Android in particular RadioGroup using Java file. XML Code: <?xml version=”1.0″ encoding=”utf-8″?> <LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android” xmlns:app=”http://schemas.android.com/apk/res-auto” xmlns:tools=”http://schemas.android.com/tools” android:layout_width=”match_parent” android:layout_height=”match_parent” android:padding=”16dp” android:orientation=”vertical” tools:context=”.MainActivity”> <TextView android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:layout_marginBottom=”15dp” android:text=”Gender” android:textSize=”18sp”/> <RadioGroup android:layout_width=”match_parent” android:layout_height=”wrap_content” android:layout_marginBottom=”15dp” android:id=”@+id/gender”> <RadioButton android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:text=”Male” android:id=”@+id/male”/> <RadioButton android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:text=”Female” android:id=”@+id/female”/> </RadioGroup> <Button android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:text=”Submit” android:id=”@+id/submit”/> </LinearLayout> Output: We got this output after writing this code in out XML file. Here we will write java code to make things working. Java Code: public class MainActivity extends AppCompatActivity { RadioGroup gender; Button submit; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); gender=(RadioGroup)findViewById(R.id.gender); submit=(Button)findViewById(R.id.submit); submit.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { switch (gender.getCheckedRadioButtonId()){ case R.id.male: Toast.makeText(getApplication(),”You Selected Male”,Toast.LENGTH_SHORT).show(); break; case R.id.female: Toast.makeText(getApplication(),”You Selected Female”,Toast.LENGTH_SHORT).show(); break; } } }); } }   Parvesh SandilaParvesh Sandila is a passionate web and Mobile app developer from Jalandhar, Punjab, who has over six years of experience. Holding a Master’s degree in Computer Applications (2017), he has also mentored over 100 students in coding. In 2019, Parvesh founded Owlbuddy.com, a platform that provides free, high-quality programming tutorials in languages like Java, Python, Kotlin, PHP, and Android. His mission is to make tech education accessible to all aspiring developers.​ new.owlbuddy.com

In this tutorial, we will learn about CheckBox in Android. The CheckBox is a kind of button which only have two states checked or unchecked. The CheckBox can be used in my different ways, for example, to show different options in the app that user can select multiple from those options, In this kind of situation you can use CheckBox. We will learn how to add CheckBox in Android and how to use different methods related to CheckBox. Firstly we will learn how to add CheckBox widget in XML. XML Code: <?xml version=”1.0″ encoding=”utf-8″?> <LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android” xmlns:app=”http://schemas.android.com/apk/res-auto” xmlns:tools=”http://schemas.android.com/tools” android:layout_width=”match_parent” android:layout_height=”match_parent” android:padding=”16dp” android:orientation=”vertical” tools:context=”.MainActivity”> <CheckBox android:layout_height=”wrap_content” android:layout_width=”wrap_content” android:src=”@drawable/owlbuddy” android:textSize=”20dp” android:id=”@+id/notifications” android:layout_marginBottom=”10dp” android:text=”Notifications”/> <View android:layout_width=”match_parent” android:layout_height=”1dp” android:layout_marginBottom=”10dp” android:background=”@color/colorPrimary”/> <CheckBox android:layout_height=”wrap_content” android:layout_width=”wrap_content” android:src=”@drawable/owlbuddy” android:id=”@+id/updates” android:layout_marginBottom=”10dp” android:textSize=”20dp” android:text=”Auto Updates”/> <View android:layout_width=”match_parent” android:layout_height=”1dp” android:layout_marginBottom=”10dp” android:background=”@color/colorPrimary”/> <CheckBox android:layout_height=”wrap_content” android:layout_width=”wrap_content” android:layout_marginBottom=”10dp” android:id=”@+id/history” android:src=”@drawable/owlbuddy” android:textSize=”20dp” android:text=”Clear History”/> <View android:layout_width=”match_parent” android:layout_height=”1dp” android:layout_marginBottom=”10dp” android:background=”@color/colorPrimary”/> </LinearLayout> Output: Now we will learn how to perform some action when someone will check these CheckBoxes. Firstly will initialize all these CheckBoxes in our java file with findViewById() method and then we will call to setOnCheckedChangeListener() to these CheckBoxes. Java Code: public class MainActivity extends AppCompatActivity { CheckBox notifications,updates,history; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); notifications=(CheckBox)findViewById(R.id.notifications); updates=(CheckBox)findViewById(R.id.updates); history=(CheckBox)findViewById(R.id.history); notifications.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() { @Override public void onCheckedChanged(CompoundButton buttonifView, boolean isChecked) { if(isChecked) Toast.makeText(getApplication(),”Notifications On”,Toast.LENGTH_SHORT).show(); } }); updates.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() { @Override public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { if(isChecked) Toast.makeText(getApplication(),”Auto Updates On”,Toast.LENGTH_SHORT).show(); } }); history.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() { @Override public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) { if(isChecked) Toast.makeText(getApplication(),”Clear History On”,Toast.LENGTH_SHORT).show(); } }); } } Output: Parvesh SandilaParvesh Sandila is a passionate web and Mobile app developer from Jalandhar, Punjab, who has over six years of experience. Holding a Master’s degree in Computer Applications (2017), he has also mentored over 100 students in coding. In 2019, Parvesh founded Owlbuddy.com, a platform that provides free, high-quality programming tutorials in languages like Java, Python, Kotlin, PHP, and Android. His mission is to make tech education accessible to all aspiring developers.​ new.owlbuddy.com

In this tutorial, we will learn how to use ImageView in Android. ImageView is really helpful widget and we use this widget to add Images in our Android App. Here we will learn how to use drawable images in ImageView. We will also learn how we can add images in ImageView using the XML layout file. So without wasting time let’s directly jump to our Examples. Before writing any code firstly we will add an image in our project. To do this, you can copy an image from anywhere in PC and then you have to add the image in res/drawable folder of our project. While adding an image always keep it in your mind image size should be less than 1MB and image name should be in small letter. <?xml version=”1.0″ encoding=”utf-8″?> <LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android” xmlns:app=”http://schemas.android.com/apk/res-auto” xmlns:tools=”http://schemas.android.com/tools” android:layout_width=”match_parent” android:layout_height=”match_parent” android:gravity=”center” android:padding=”16dp” android:orientation=”vertical” tools:context=”.MainActivity”> <ImageView android:layout_height=”wrap_content” android:layout_width=”wrap_content” android:src=”@drawable/owlbuddy”/> </LinearLayout> ImageView in Android Output: Parvesh SandilaParvesh Sandila is a passionate web and Mobile app developer from Jalandhar, Punjab, who has over six years of experience. Holding a Master’s degree in Computer Applications (2017), he has also mentored over 100 students in coding. In 2019, Parvesh founded Owlbuddy.com, a platform that provides free, high-quality programming tutorials in languages like Java, Python, Kotlin, PHP, and Android. His mission is to make tech education accessible to all aspiring developers.​ new.owlbuddy.com

In this tutorial, we would learn about Toast in Android. We use Toast in Android to show small piece of information for small time. For example, we want to show a message like “Signup Successfully” or “User Name Already Taken” after a user will press the signup button. In that kind of situations toast is a best option to give a small message to user. In this tutorial, we will learn how can we show a Toast in our Android App. Toast is class already available in Android. we can use that class to show Toast in our App and We can also create a custom Toast in Android. In this tutorial we will also learn how we can create a custom Toast in Android. XML Code: <?xml version=”1.0″ encoding=”utf-8″?> <LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android” xmlns:app=”http://schemas.android.com/apk/res-auto” xmlns:tools=”http://schemas.android.com/tools” android:layout_width=”match_parent” android:layout_height=”match_parent” android:gravity=”center” android:padding=”16dp” android:orientation=”vertical” tools:context=”.MainActivity”> <Button android:layout_width=”250dp” android:layout_height=”wrap_content” android:layout_marginBottom=”10dp” android:textColor=”@color/colorWhite” android:background=”@color/colorPrimary” android:id=”@+id/button” android:text=”Show Toast”/> </LinearLayout> In this layout file, I added a button and I will show a Toast whenever someone presses this Button in this Activity. Java Code: public class MainActivity extends AppCompatActivity { Button button; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); button=(Button)findViewById(R.id.button); button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //Toast Example Toast.makeText(MainActivity.this,”Learn Android with Owlbuddy”,Toast.LENGTH_SHORT).show(); } }); } } To create Toast in Android we have a static method “makeText” in “Toast” class. so that’s why I called that static method from “Toast” class. This makeText method gets three parameters. First Parameter: The first parameter of makeText method is context. So to give context I added here MainActivity.this. Second Parameter: The second parameter is your message. The message which you want to show in your Toast. I added here “Learn Android with Owlbuddy”. Thirst Parameter: The third Parameter in makeText is duration mean for how much time you want to show this message. To set duration we have two static variables in Toast class Toast.LENGTH_SHORT and Toast.LENGTH_LONG. I hope so now you would have a clear idea of how to add a simple Toast in our Android App. Now we will learn how to create a “Custom Toast” in Android. For this rest of the tutorial, I would keep “main_activity.xml” file the same. I will just add a new layout file to give layout to my custom toast and I will also change some code in MainActivity java file to add custom toast. Custom Toast XML code: <?xml version=”1.0″ encoding=”utf-8″?> <LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android” android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:orientation=”vertical” android:gravity=”center” android:padding=”15dp” android:id=”@+id/toast_layout” android:background=”@color/colorPrimary” android:layout_gravity=”center”> <TextView android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:text=”This is Toast” android:textColor=”@color/colorWhite”/> </LinearLayout> MainActivity Java Code: public class MainActivity extends AppCompatActivity { Button button; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); button=(Button)findViewById(R.id.button); LayoutInflater layoutInflater=getLayoutInflater(); final View view=layoutInflater.inflate(R.layout.toast_layout,(ViewGroup)findViewById(R.id.toast_layout)); button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { //Toast Example Toast toast=new Toast(MainActivity.this); toast.setDuration(Toast.LENGTH_SHORT); toast.setView(view); toast.show(); } }); } }   Parvesh SandilaParvesh Sandila is a passionate web and Mobile app developer from Jalandhar, Punjab, who has over six years of experience. Holding a Master’s degree in Computer Applications (2017), he has also mentored over 100 students in coding. In 2019, Parvesh founded Owlbuddy.com, a platform that provides free, high-quality programming tutorials in languages like Java, Python, Kotlin, PHP, and Android. His mission is to make tech education accessible to all aspiring developers.​ new.owlbuddy.com

In this tutorial, we would learn about Button in Android. The button is one of the basic widgets which we normally use in each Android app. For example, in the last tutorial, we learned about EditText and in the example of EditText, we added a button in the Signup form. So same like that we can use the button for a different purpose in our Android App. We can use Button in Login form Button in the Signup form. In this tutorial, we will learn how to add button widget in our XML Layout file and how to write working of that particular button in our Java file. Firstly we would start with our XML Layout file. XML Code: <?xml version=”1.0″ encoding=”utf-8″?> <LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android” xmlns:app=”http://schemas.android.com/apk/res-auto” xmlns:tools=”http://schemas.android.com/tools” android:layout_width=”match_parent” android:layout_height=”match_parent” android:gravity=”center” android:padding=”16dp” android:orientation=”vertical” tools:context=”.ButtonExample”> <EditText android:layout_width=”match_parent” android:layout_height=”wrap_content” android:hint=”Enter Your Name” android:inputType=”text” android:id=”@+id/editText” android:layout_marginBottom=”10dp” /> <Button android:layout_width=”250dp” android:layout_height=”wrap_content” android:layout_marginBottom=”10dp” android:textColor=”@color/colorWhite” android:background=”@color/colorPrimary” android:id=”@+id/button” android:text=”Create my Account”/> <TextView android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:textSize=”18sp” android:text=”Text View” android:textColor=”@color/colorPrimary” android:id=”@+id/textView”/> </LinearLayout> Output of This XML layout file will look like this..   In this example you can see we added an EditText, a Button and a TextView and our purpose is to Enter a Name in EditText and to show that name in our TextView on click of our Button. Java Code: public class ButtonExample extends AppCompatActivity { TextView textView; Button button; EditText editText; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); textView=(TextView)findViewById(R.id.textView); button=(Button)findViewById(R.id.button); editText=(EditText)findViewById(R.id.editText); button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { String name=editText.getText().toString(); textView.setText(“Hello “+name); } }); } } Here the output of when will press Button after Entering a name in EditText Parvesh SandilaParvesh Sandila is a passionate web and Mobile app developer from Jalandhar, Punjab, who has over six years of experience. Holding a Master’s degree in Computer Applications (2017), he has also mentored over 100 students in coding. In 2019, Parvesh founded Owlbuddy.com, a platform that provides free, high-quality programming tutorials in languages like Java, Python, Kotlin, PHP, and Android. His mission is to make tech education accessible to all aspiring developers.​ new.owlbuddy.com

In this lesson, we will learn about EditText in Android. EditText is a standard entry widget in Android. EditText allows users to enter data in Android Apps. For example in Login Activity, we need a username and password from user to open their account in App so to get username and password from the user we can use EditText in our App. In this tutorial, we will learn how to create a signup page design in Android. XML code: <?xml version=”1.0″ encoding=”utf-8″?> <LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android” xmlns:app=”http://schemas.android.com/apk/res-auto” xmlns:tools=”http://schemas.android.com/tools” android:layout_width=”match_parent” android:layout_height=”match_parent” android:gravity=”center” android:padding=”16dp” android:orientation=”vertical” tools:context=”.SignupActivity”> <EditText android:layout_width=”match_parent” android:layout_height=”wrap_content” android:hint=”Enter Name” android:inputType=”text” android:layout_marginBottom=”10dp” /> <EditText android:layout_width=”match_parent” android:layout_height=”wrap_content” android:hint=”Enter Email” android:inputType=”textEmailAddress” android:layout_marginBottom=”10dp” /> <EditText android:layout_width=”match_parent” android:layout_height=”wrap_content” android:hint=”Enter Password” android:inputType=”textPassword” android:layout_marginBottom=”10dp” /> <EditText android:layout_width=”match_parent” android:layout_height=”wrap_content” android:hint=”Enter Confirm Password” android:inputType=”textPassword” android:layout_marginBottom=”10dp” /> <Button android:layout_width=”250dp” android:layout_height=”wrap_content” android:layout_marginBottom=”10dp” android:textColor=”@color/colorWhite” android:background=”@color/colorPrimary” android:text=”Create my Account”/> </LinearLayout>   Parvesh SandilaParvesh Sandila is a passionate web and Mobile app developer from Jalandhar, Punjab, who has over six years of experience. Holding a Master’s degree in Computer Applications (2017), he has also mentored over 100 students in coding. In 2019, Parvesh founded Owlbuddy.com, a platform that provides free, high-quality programming tutorials in languages like Java, Python, Kotlin, PHP, and Android. His mission is to make tech education accessible to all aspiring developers.​ new.owlbuddy.com

In this tutorial, we will learn about TextView in Android. Text view is one of the simplest widgets in android. We use Text View to show some simple text to the user. You can show paragraphs using Text View or User Name etc. It totally depends upon the requirement of the Activity. In this lesson, we would learn how to add a Text View in the XML layout file and how we can set text into TextView from our Java. So without wasting time, we will directly move to our example. In this example, I would show how to add a TextView in the XML layout file. <?xml version=”1.0″ encoding=”utf-8″?> <LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android” xmlns:tools=”http://schemas.android.com/tools” android:layout_width=”match_parent” android:layout_height=”match_parent” android:gravity=”center” android:orientation=”vertical” tools:context=”.MainActivity”> <TextView android:id=”@+id/textView1″ android:layout_width=”wrap_content” android:layout_height=”wrap_content” android:layout_marginBottom=”10dp” android:text=”Welcome to Owlbuddy” android:textColor=”#86AD33″ android:textSize=”20sp” android:textStyle=”bold” /> </LinearLayout> In this example, you can see how to add TextView in the XML layout file. In this example, we used several attributes now I will explain each attribute and why we are using them. id: we are using the id attribute to assign a unique id to Text View width: we are using the width attribute to set the width of the Text View height: we are using the height attribute to set the height of the Text View layout_marginBottom we are using the layout_marginBottom attribute to set the margin from bottom to Text view text: we are using text attribute to set text in the Text View textColor: we are using the textColor attribute to set the color of the text in Text View textSize: we are using the textSize attribute to set the size of the text in Text View textStyle: we are using the textStyle attribute to give style to the text of Text View. In this case, I am setting the style bold to make the text thicker than usual After looking at this XML layout file example. Let’s jump to our next example. In this example, we will see how we can set text into our Text View using Java code. public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); LinearLayout linearLayout = (LinearLayout) findViewById(R.id.linearlayout); TextView textView = new TextView(this); textView.setText(“Welcome to Owlbuddy.com”); linearLayout.addView(textView); } } We have a TextView class in Java that helps us to create TextView in our Activity. In this example, you can see we are using a setText message to set text in our TextView. Apart from this, you can use many other methods to make TextView better. setTextColor(): To set the color of the text in TextView. setTextSize(): To set the size of the text in TextView Parvesh SandilaParvesh Sandila is a passionate web and Mobile app developer from Jalandhar, Punjab, who has over six years of experience. Holding a Master’s degree in Computer Applications (2017), he has also mentored over 100 students in coding. In 2019, Parvesh founded Owlbuddy.com, a platform that provides free, high-quality programming tutorials in languages like Java, Python, Kotlin, PHP, and Android. His mission is to make tech education accessible to all aspiring developers.​ new.owlbuddy.com