Android – Activity callback/hook methods PART 3

Android – Activity callback/hook methods PART 3

You can read Part 1 and Part 2. This part will cover the 7 hook methods: onCreate() – It is called first when activity launched and it is called only one time. Here you initialize the views, bind data to lists etc. Next is onStart() onStart() – It is called when the activity is becoming visible to the user. Next is onResume() only if the activity was at the background and now comes to the foreground. onResume() – It is when the activity starts interacting with the user and it…

Android – Activity callback/hook methods PART 3 Read More

Android – Starting an Activity PART 2

Android – Starting an Activity PART 2

You can read PART 1 here. You can launch activities on demand with startActivity() and startActivityForResult() startActivity() Launches a new activity and it does not return any information when the activity exits. It has one argument, an intent to start. You can read more here. startActivityForResult() Launches an activity and you will get a result when the activity finished. It can take up to 3 arguments, the intent to start, the request code (int) that identifies the request to the 2nd activity and options as a bundle. At the 1st…

Android – Starting an Activity PART 2 Read More

Android – Activity and lifecycle states Part 1

Android – Activity and lifecycle states Part 1

Activity is the most common component in Android app and the most crucial. It is usually used to display information to the device screen but there also times that you do not have to provide a user interface with an activity. To implement an activity you need to follow some steps: Extend the Ativity class Override selected lifecycle/hook methods, those at the picture above define other methods or nested classes needed to implement the activity update the AndroidManifest.xml file to include the activity so Android OS knows about it. Lifecycle…

Android – Activity and lifecycle states Part 1 Read More

Android – AndroidManifest.xml Part 1

Android – AndroidManifest.xml Part 1

The purpose of AndroidManifest.xml file is to give certain information to Android so the app will be executed, to Android build tools and to Google Play. The information that this file can have is: Name of the Java package Which components are exported to other apps All the component names (activities, services, receivers and providers) Which process will host the components What intents are handled What permissions that app must have Minimum and Target API levels the app requires Elements: <manifest> – the root element <application> – contains the elements…

Android – AndroidManifest.xml Part 1 Read More

Android – Intents

Android – Intents

An intent is a message one component send to another component to interact with or request some functionality from. Intents have data fields and some can be passed from one component to another like passing arguments to a method. One of those fields is the name of the component that will handle the intent. If you specify the name then this intent is called explicit intent. If the name is omitted, then you need to specify other fields, action, data and/or category. This intent is called implicit intent and is…

Android – Intents Read More