1. Context variable the context variable connects the resource variable of xml file to the java files which are when used in context files or resource files like drawable or layout or any other resource file gets automatically defined in R.java file 2. Layout container layout container hold all the layouts and objects which will be visible on the ui screen ot the mobile 4. They never receives focus Toast are teh notification message which stays for a fixed duration and then vanishes it does not react on toch or click events and it does not receives focus they are just to give a message to the user and then disappear 5. ImageView.ScaleType.CENTER_CROP this will crop image so that it fit with the sze of the view type Solution 1. Context variable the context variable connects the resource variable of xml file to the java files which are when used in context files or resource files like drawable or layout or any other resource file gets automatically defined in R.java file 2. Layout container layout container hold all the layouts and objects which will be visible on the ui screen ot the mobile 4. They never receives focus Toast are teh notification message which stays for a fixed duration and then vanishes it does not react on toch or click events and it does not receives focus they are just to give a message to the user and then disappear 5. ImageView.ScaleType.CENTER_CROP this will crop image so that it fit with the sze of the view type.