Activity Life Cycle
About understanding of Activity Life Cycle in Android Studio
Step 1 : Select File -> New -> Project -> Android Application Project. Fill the forms, create a Blank Activity and click on Finish button.
Step 2 : Open res -> layout ->activity_main.xml and add following code :
< RelativeLayout 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” >
< TextView
android : layout_width = “wrap_content”
android : layout_height = “wrap_content”
android : text = “@string/hello_world” / >
< / RelativeLayout >
Step 3 : Open src -> package ->MainActivity.java and add following code :
package com . skholingua . android . activitylifecycle ;
import android . app . Activity ;
import android . os . Bundle ;
import android . widget . Toast ;
public class MainActivity extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate ( Bundle savedInstanceState ){
super . onCreate ( savedInstanceState ) ;
setContentView ( R . layout . activity_main ) ;
Toast . makeText ( getBaseContext ( ) , “onCreate triggered” , 0 ) . show ( ) ;
}
/** Called when the activity is about to become visible. */
@Override
protected void onStart ( ) {
super . onStart ( ) ;
Toast . makeText ( getBaseContext ( ) , “onStart triggered” , 0 ) . show ( ) ;
}
/** Called when the activity has become visible. */
@Override
protected void onResume ( ) {
super . onResume ( ) ;
Toast . makeText ( getBaseContext ( ) ,”onResume triggered” , 0 ) . show ( ) ;
}
/** Called when another activity is taking focus. */
@Override
protected void onPause ( ) {
super . onPause ( ) ;
Toast . makeText ( getBaseContext ( ) , “onPause triggered” , 0 ) . show ( ) ;
}
/** Called when the activity is no longer visible. */
@Override
protected void onStop ( ) {
super . onStop ( ) ;
// I usually don’t use toast here
Toast . makeText ( getBaseContext ( ) , “onStop triggered” , 0 ) . show ( ) ;
}
/** Called just before the activity is destroyed. */
@Override
public void onDestroy ( ) {
super . onDestroy ( ) ;
// I usually don’t use toast here
Toast . makeText ( getBaseContext ( ) ,”onDestory triggered” , 0 ) . show ( ) ;
}
}
Step 4 : Open AndroidManifest.xml and add following code :
<? xml version = “1.0” encoding = “utf-8” ?>
< manifest xmlns : android = “http://schemas.android.com/apk/res/android"
package =”com.skholingua.android.activitylifecycle”
android : versionCode = “1”
android : versionName = “1.0” >
< uses — sdk
android : minSdkVersion = “16”
android : targetSdkVersion = “19” / >
< application
android : allowBackup = “true”
android : icon = “@drawable/ic_launcher”
android : label = “@string/app_name”
android : theme = “@style/AppTheme” >
< activity
android : name = “.MainActivity”
android : label = “@string/app_name” >
< intent — filter >
< action android : name =”android.intent.action.MAIN” / >
< category android : name =”android.intent.category.LAUNCHER” / >
< / intent — filter >
< / activity >
< / application >
< / manifest >
