Android Introduction
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Android is an open source software platform and operating system for mobile devices based on the Linux kernel. It allows developers to write managed code in the Java programming language. The Android platform was developed by Google and the Open Handset Alliance. The document discusses the Android platform, software development tools, key components and APIs, building blocks like activities and services, different layouts, and the activity lifecycle.
Android Introduction
- 1. Swapnal Agarwal Vipul Kishor Bhatt
- 2. 1. Introduction 2. Platform 3. Software development 4. Dalvik VM 5. Components & API 6. Building Blocks 7. Layouts
- 3. Introduction What is Android? • A software platform and operating system for mobile devices • Based on the Linux kernel • Developed by Google and later the Open Handset Alliance (OHA) • Allows writing managed code in the Java language • Android platform was announced on 5th November 2007 with the founding of OHA
- 4. Android An Open Handset Alliance Project What is the Open Handset Alliance (OHA)? • OHA is an alliance of nearly 50 organizations devoted to advancing open standards for mobile devices • Develop technologies that will significantly lower the cost of developing and distributing mobile devices and services What’s the Target? • Write apps to run on mobile phones • Will be released as open source http://code.google.com/android
- 5. Platform Operating System(s) • Android uses Linux for its device drivers, memory management, process management, and networking. • The next level up contains the Android native libraries. They are all written in C/C++ internally, but you’ll be calling them through Java interfaces. In this layer you can find the Surface Manager, 2D and 3D graphics, Media codecs, the SQL database (SQLite), and a native web browser engine (WebKit). Call through Java Call through Java Interface Interface C/C++ Native Libraries Surface Manager Surface Manager SQLite SQLite Media Codecs Media Codecs Webkit Webkit
- 6. Platform • Dalvik Virtual Machine. Dalvik runs .dex files, which are converted at compile time from layout layout .xml .xml R.java R.java standard class and jar files. *.class *.class *dex. *dex. • The Dalvik runtime is highly optimized: *.java *.java Run multiple VMs efficiently Each app has its own VM Minimal memory footprint android- android- manifest.xml manifest.xml application. apk file • Android applications are compiled to Dalvik bytecode.
- 7. Software Development IDE and Tools Android SDK • Class Library • Developer Tools dx – Dalvik Cross-Assembler aapt – Android Asset Packaging Tool adb – Android Debug Bridge ddms – Dalvik Debug Monitor Service • Emulator and System Images • Documentation and Sample Code Eclipse IDE + ADT (Android Development Tools) • Reduces Development and Testing Time • Makes User Interface-Creation easier • Makes Application Description Easier
- 8. Components
- 9. Android APIs Android-specific packages are easy to identify because they start with android in the package name. Some of the more important packages are: android.app—Android application model access android.bluetooth—Android’s Bluetooth functionality android.content—Accessing and publishing data in Android android.net—Contains the Uri class, used for accessing content android.gesture—Create, recognize, load, and save gestures android.graphics—Graphics primitives android.location—Location-based services (such as GPS) android.opengl—OpenGL classes android.os—System-level access to the Android environment android.provider—ContentProvider-related classes android.telephony—Telephony capability access, including support for both Code Division Multiple Access (CDMA) and Global System for Mobile communication (GSM) devices android.text—Text layout android.util—Collection of utilities for logging and text manipulation, including XML android.view—UI elements android.webkit—Browser functionality android.widget—More UI elements
- 10. Android APIs Java packages included in the Android SDK: java.lang—Core Java language classes java.io—Input/output capabilities java.net—Network connections java.text—Text-handling utilities java.math—Math and number-manipulation classes javax.net—Network classes javax.security—Security-related classes javax.xml—DOM-based XML classes org.apache.*—HTTP-related classes org.xml—SAX-based XML classes
- 11. Android Building Blocks Android Manifest.xml Activities Views Intents Services Notifications Content Provider
- 12. Android Building Blocks Activity: It represents a visible Services application component within Android Intents: An Intent in Android Notification describes what you want to do. Content Provider: Views: It helps data sharing between UI elements different Android Applications or between different Activities.
- 13. Layouts • Different Layouts :- <?xml version="1.0" encoding="utf-8"?> <RelativeLayout Linear Layout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/job_search_layout" Relative Layout android:layout_width="fill_parent" Table Layout android:layout_height="wrap_content" Frame Layout <ListView android:layout_width="wrap_content“ Absolute Layout android:layout_width="wrap_content" (Deprecated) android:layout_height="wrap_content" /> <ImageView android:id="@+id/geo_location“ android:src="@drawable/geo_location" android:layout_width="wrap_content" android:layout_height="wrap_content" /> <LinearLayout android:id="@+id/location_selection_layout“ android:layout_width="wrap_content" android:layout_height="wrap_content" > <TextView android:id="@+id/recent_search_header_count”> android:layout_width="wrap_content" android:layout_height="wrap_content" /> </LinearLayout> </RelativeLayout>
- 15. Thanks