{"id":4888,"date":"2019-06-21T13:52:26","date_gmt":"2019-06-21T08:22:26","guid":{"rendered":"https:\/\/pheonixsolutions.com\/blog\/?p=4888"},"modified":"2019-06-21T13:52:33","modified_gmt":"2019-06-21T08:22:33","slug":"fundamental-things-to-know-in-android-activity-and-fragment","status":"publish","type":"post","link":"https:\/\/pheonixsolutions.com\/blog\/fundamental-things-to-know-in-android-activity-and-fragment\/","title":{"rendered":"Fundamental things to know in android activity and fragment"},"content":{"rendered":"\n

Fundamental things to know in android activity and fragment<\/h2>\n\n\n\n

Date : 12\/06\/2019<\/h4>\n\n\n\n

Activity<\/h3>\n\n\n\n

The Activity<\/code><\/strong><\/a>class is basically a crucial component of an Android app, and the way activities are launched and put together is a fundamental part of the platform’s application model.<\/p>\n\n\n\n

Hence an activity provides the window in which the app draws its UI.<\/p>\n\n\n\n

Actually an XML file and Activity for implementation works together to display a single screen in a app.<\/p>\n\n\n\n

Most apps contain multiple screens, which means they comprise multiple activities.<\/p>\n\n\n\n

Each activity can then start another activity in order to perform different actions. To do this we have to INTENT.<\/strong><\/p>\n\n\n\n

For your app to be able to use activities, basically you must declare the activities, and certain of their attributes, in the manifest.<\/p>\n\n\n\n

<manifest>\n   <application>\n     <activity android:name=\".ExampleActivity\"\/>\n\n   <\/application>\n<\/manifest><\/pre>\n\n\n\n
You\nmust implement onCreate()\nin\nevery activity,\nwhich fires when the system creates your activity. \n<\/p>\n\n\n\n
Your implementation should initialise the essential components of your activity: For example, your app should create views and bind data to lists here. Most importantly, this is where you must call setContentView()<\/a> <\/code><\/strong>to define the layout for the activity’s user interface.<\/p>\n\n\n\n
 Every Activity<\/code> has a life-cycle which is independent of other activities.<\/p>\n\n\n\n
\"\"<\/figure>\n\n\n\n
Methods in activity<\/h4>\n\n\n\n
\nONCREATE()<\/p>\n\n\n\n
 This method receives the parameter savedInstanceState<\/code><\/strong>, which is a Bundle<\/a> <\/code><\/strong>object containing the activity’s previously saved state. Because if the activity has never existed before, the value of the Bundle<\/a> <\/code><\/strong>object is null.<\/p>\n\n\n\n
 When onCreate()<\/a> <\/code><\/strong>finishes, quickly the next callback is always onStart()<\/code><\/strong><\/a>.<\/p>\n\n\n\n
 ONSTART()<\/p>\n\n\n\n
\nThe\nonStart()<\/a>\n<\/code><\/strong>call\nmakes the activity visible to the user, as the app prepares for the\nactivity to enter the foreground and become interactive.<\/p>\n\n\n\n
\nONRESUME()<\/p>\n\n\n\n
 This is where therefore user can see the UI clearly.<\/p>\n\n\n\n
\nONPAUSE()<\/p>\n\n\n\n
 From this, either the can goto resume state or navigate to onDestroy() to be destroyed.<\/p>\n\n\n\n
 FRAGMENT <\/h4>\n\n\n\n