Android Studio & Hello World

Transcription

1 Lecture 2 & Hello World Portions From Android Programming The Big Nerd Ranch Guide Android How to Program 2 nd Edition Application Development Overview Lecture: Basics Layout XML Hello World Project Running with an Emulator and Device 1

2 Creates a skeleton framework Blank blank activity with an action bar with title and options menu Fullscreen hides the system user interface, action bar shows up on touch Login looks like a login page Master/Detail screen in two sections for menu and details Settings preferences with a list of settings Activity Name: The name of your activity Layout Name: Notice the convention of activity (fragment) _ name Menu Title: The string value Resource Name: The name of the menu for the activity bar 2

3 Android OS multi-user Linux Each app is a different user Each App s files are associated with that particular user Each process is a virtual machine (isolation) Application Process Main Thread (UI Thread) Work Queue System Events Input App Stuff UI Drawing (Every 16 ms) What is an activity? - Instance of the class Activity, part of the Android SDK One of several Application Components App can have 1 or many Activities Activities manage user interaction with a screen Our Activities will be subclasses of the class Activity You create different activities for each screen/idea/concept of your app 3

4 What is a layout? - Defines user interface objects Written in XML Each XML tag creates an object on screen, such as a button or text (widgets) Layouts separate the view (look) of an activity from the code of the activity When created, an activity will be responsible for inflating and managing the layout defined in the XML What is XML? EXtensible Markup Language (similar to HTML) Defines rules for describing data Human-readable Uses <> and </> to denote tags Free to define your own tags: <Like&Subscribe> </Like&Subscribe > 4

5 Resources are anything that s not code meaning layouts, strings, colors, drawables, sound, etc You ll find these under your res folder Layout Different layouts for your activities & fragments Values styles, strings, dimensions Manifest Android app info for the OS, which describes your application and activities 5

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7 By default you will see the Android graphical layout tool and the structure of your blank activity Use the tabs on the bottom to see the design or text (xml) You will also see the project itself, which can be organized in several ways Creating Your First App Running your App You will run on the emulator or device Emulators require downloading an image Devices require installing USB drivers on Windows 7

8 Creating Your First App - Emulator ADV Manager virtual devices for emulation SDK Manager different android versions and their required SDKs that you can download Android Device Monitor monitors the devices you have connected for log information Creating Your First App SDK Manager By default, Android Studio will have downloaded and installed the latest SDK for us If you are targeting a specific version, download that SDK by checking boxes and hitting install 8

9 Creating Your First App - Emulator Creating Your First App - Emulator I suggest picking an emulator for a phone and a tablet such as a Nexus 6 and Nexus 9 You can clone a device as a base and create your own emulator to suite unlisted devices 9

10 Creating Your First App - Emulator Creating Your First App - Emulator Last chance to make a change Use Host GPU if possible Snapshot means it retains data after closing emu. 10

11 Creating Your First App - Emulator Press the green run button and you ll get a choose device dialog Choose launch emulator and choose the virtual device If you need to configure your Deployment target -> Creating Your First App - Emulator If the app doesn t launch, just press run again Will give you the choice of devices, choose your existing emulator Congrats, you just ran your first app 11

12 Creating Your First App - Emulator Emulators can not do everything! WiFi Bluetooth NFC SD card insert/eject Device-attached headphones USB Creating Your First App - Device Running your App on a Device 1. You need an android device at the min SDK or higher 2. You need a USB cable of appropriate type 3. You need to unlock developer mode on the device 4. You might want to setup Paths 5. You may need to install USB drivers 12

13 Creating Your First App - Device To unlock developer options, go to settings->about Phone and press build number 7 times May vary on your make and model android device Creating Your First App - Device Have Some Fun with Flappy Bird! 13

14 Creating Your First App - Device Go to SDK folder in: C:\Users\Name\AppData\Local\Android\sdk Open you environmental variables folder To you Path variable add: tools path platform-tools path Creating Your First App - Device Under Applications, check Unknown Sources Enable USB debugging Connect to your computer (USB) Launch your command prompt Start->Run cmd or the terminal in studio Type the following: adb devices You should see the device now! 14

15 Creating Your First App - Device Creating Your First App - Device If you do not get your device recognized, we need to install the USB drivers Go to : Follow instructions: Windows 7 To install the Android USB driver on Windows 7 for the first time: 1. Connect your Android-powered device to your computer's USB port. 2. Right-click on Computer from your desktop or Windows Explorer, and select Manage. 3. Select Devices in the left pane. 4. Locate and expand Other device in the right pane. 5. Right-click the device name (such as Nexus S) and select Update Driver Software. This will launch the Hardware Update Wizard. 6. Select Browse my computer for driver software and click Next. 7. Click Browse and locate the USB driver folder. (The Google USB Driver is located in<sdk>\extras\google\usb_driver\.) 8. Click Next to install the driver. 15

16 Creating Your First App - Device And here is the app launching on a Samsung Galaxy S5 The App now exists on your device Next Class Creating My Pet! Setting up our own Layout Hooking up Buttons with Listeners! HOMEWORK Get hello world running on your device and show me 16