This program demonstrates how to call any activity from service and service from broadcast receiver. Printing Hello World text using activity,service and broadcast receiver.
Open up Android Studio and generate your MainActivity.
In this section, you'll write the code that takes the information provided by the user in the MainActivity and passes it on to ShowActivity using an explicit intent. Let's write some code to see how it works out. We have also added unique id attributes to different EditText widgets and the Button to make them accessible in our code. The EditText widget where users will enter the website URL has its inputType attribute set to textUri. There is also a single button that will take users to a different activity which shows all their data. Here you have three TextView and three EditText widgets that prompt you to enter your name, your message, and your favorite website. The layout for MainActivity will be very simple for the purpose of this tutorial. Here is an example that registers a component as a web viewer: Intent filters can be registered for components statically in the AndroidManifest.xml. But how does the Android system identify the components which can react to a certain intent?Ī component can be registered via an intent filter for a specific action. If you have the above code in your codebase, your application can start a browser component for a certain URL via an intent. Here's an implicit intent: Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse("")) It is important to note (as in the example above), that explicit intents are typically used within an application, because that gives the developer the most control over which class will be launched. This means that NumbersActivity is the defined component that will be called by the Android system. Here, NumbersActivity is the target component from our MainActivity. Intent numbersIntent = new Intent(MainActivity.this, NumbersActivity.class) The code snippet of code above is an example of explicit intent. When the application does not name a target component, that is an implicit intent. When an application defines its target component in an intent, that is an explicit intent. Types of IntentsĪndroid supports two types of intents: explicit and implicit. Then we start a new activity using that intent. Intent numbersIntent = new Intent(MainActivity.this, NumbersActivity.class) įirst, we create a new Intent object and pass it the NumbersActivity class. Here is a code snippet that demonstrates how to start another activity from an intent. To start an activity, you will make use of the method startActivity(intent). Starting Activities With IntentsĪs mentioned earlier, you can use intents to start different components: activities, services, and broadcast receivers. The only way they communicate with each other is through intents. Look at it this way: all components (applications and screens) of the Android device are isolated. Intents also help communicate between parts of an app the movement from one screen (activity) to another is made possible by intents. When you open up the Instagram app on your phone and use it to take a picture, you just made use of an intent. With the help of intents, Android components can request functionality from other Android components. In Android, the ability to send messages around is made possible by the Intent object. That's assuming the goalkeeper of the other side was not able to keep it away! Next, it finds its way to the midfielders, and if things work out as planned, one of the strikers sends it into the net of the opponent. The ball is passed from the team's goalkeeper to their defenders. In a football match, teammates pass the ball around the field with the aim of sending it into the goal of their opponent. In this tutorial, I'll teach you about intents from A to Z. It is impossible to build Android applications without coming in contact with intents.
Intents are a fundamental topic for Android developers.