To Create any application in android we have to deal with three files: AndroidManifest.xmlactivity_main.xmlMainActivity.java AndroidManifest.xml: <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.login.login"> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:roundIcon="@mipmap/ic_launcher_round" android:supportsRtl="true" android:theme="@style/AppTheme"> <activity android:name=".MainActivity"> <intent-filter> <action android:name="android.intent.action.MAIN" />

Functionality: How to interact with activity,when a button is clicked,navigate from current screen(current activity) to another screen(another activity). Activity: In android,an activity is representing a single screen.Most applications have multiple activities to represent different screens.for example,one activity to display a list of the application settings,another to display application status. To Create any application in android we have to deal with three files: AndroidManifest.xmlactivity_main.xmlMainActivity.java AndroidManifest.xml <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.nav.navigation" > <application android:label="@string/app_name" android:theme="@style/AppTheme" > <activity android:name=".MainActivity" android:label="@string/title_activity_main" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category

Here ,we are creating simple and basic functions calculator App. This app can help you to understand the layouts, buttons and action handling. To create this app we need to use different widgets such as TextView, button, EditText etc.This app is able to perform following basic four mathematical functions : AdditionSubtractionMultiplicationDivision To Create any application in android we have to deal with three files: AndroidManifest.xmlactivity_main.xmlMainActivity.java AndroidManifest.xml The AndroidManifest.xml contains information of your package, including components of the application such as activities, services, broadcast receivers, content providers etc. <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.calculator.calculator2"> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name"

About Android USB Android supports USB devices through two modes: Android Accessory: In this mode external USB device acts as host.Android Host: In this mode Android Device acts as host and powers the external device. Manifest File for USB connection We want to be notified when an external USB device is attached to the Android device.This can be done adding a new intent filter entry to the Activity that should be started by the system when a USB device is plugged in. <activity ....... <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> <intent-filter> <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"