Android Application

Fundamentals

• Basic Java Programming Language

• Basic Knowledge about XML

Example

App Components

• Activities

• Services

• Content Providers

• Broadcast Receivers

• Intents and Intents Filters

Activities & Services

Broadcast Receivers

& Content Providers

Activities Lifecycle

Intents and Intent Filters

• An Intent is a messaging object you can use to

request an action from another app component.

• Intent Types: 1. Explicit Intent 2. Implicit Intent

1. Explicit Intent: specify the component to start by

name (the fully-qualified class name). You'll typically

use an explicit intent to start a component in your

own app, because you know the class name of the

activity or service you want to start. For example,

start a new activity in response to a user action or

start a service to download a file in the background.

2. Implicit intents do not name a specific component, but instead declare a general action to perform, which allows a component from another app to handle it. For example, if you want to show the user a location on a map, you can use an implicit intent to request that another capable app show a specified location on a map.

Intent Filters:

<intent-filter>

<action android:name="android.intent.action.SEND"/>

<category android:name="android.intent.category.DEFAULT"/>

<data android:mimeType="text/plain"/>

</intent-filter>

Ex:

<data android:mimeType="application/vnd.google.panorama360+jpg"/>

<data android:mimeType="image/*"/>

<data android:mimeType="video/*"/>

Application Permission

• Requests a permission that the application must be

granted in order for it to operate correctly. Permissions

are granted by the user when the application is installed,

not while it's running

1. android.permission.CALL_EMERGENCY_NUMBERS

2. android.permission.READ_OWNER_DATA

3. android.permission.SET_WALLPAPER

4. android.permission.DEVICE_POWER

5. android.hardware.bluetooth

Views, Layouts and UI

Components• Provides classes that expose basic user interface classes

that handle screen layout and interaction with the user

• Layouts:

Linear layout

Relative layout

Frame layout

UI Components• Input Controls

Menu & Action bar

Android Version before 3.0

List view and Grid View

• Android List View is a view which groups several items and display them in vertical scrollable list. The list items are automatically inserted to the list using an Adapter that pulls content from a source such as an array or database.

• An adapter actually bridges between UI components and the data source that fill data into UI Component. Adapter can be used to supply the data to like spinner, list view, grid view etc.

• The List View and Grid View are subclasses of Adapter View and they can be populated by binding them to an Adapter, which retrieves data from an external source and creates a View that represents each data entry. Android provides several subclasses of Adapter that are useful for retrieving different kinds of data and building views for an Adapter View

Example:

String[] countryArray = {"India", "Pakistan", "USA",

"UK"};

ArrayAdapter adapter = new ArrayAdapter<String>(this, R.layout.ListView,

StringArray);

ListView listView = (ListView)

findViewById(R.id.listview);

listView.setAdapter(adapter);

Grid View

• Android GridView shows items in two-dimensional scrolling

grid (rows & columns) and the grid items are not

necessarily predetermined but they automatically inserted

to the layout using a ListAdapter

• An adapter actually bridges between UI components and

the data source that fill data into UI Component. Adapter

can be used to supply the data to like spinner, list view,

grid view etc.

• The ListView and GridView are subclasses of AdapterView

and they can be populated by binding them to an Adapter,

which retrieves data from an external source and creates a

View that represents each data entry.

public Integer[] mThumbIds = {

R.drawable.sample_2, R.drawable.sample_3,

R.drawable.sample_4, R.drawable.sample_5,

R.drawable.sample_6, R.drawable.sample_7,

R.drawable.sample_0, R.drawable.sample_1,

R.drawable.sample_2, R.drawable.sample_3,

R.drawable.sample_4, R.drawable.sample_5,

R.drawable.sample_6, R.drawable.sample_7,

R.drawable.sample_0, R.drawable.sample_1,

R.drawable.sample_2, R.drawable.sample_3,

R.drawable.sample_4, R.drawable.sample_5,

R.drawable.sample_6, R.drawable.sample_7

};

public View getView(int position, View convertView, ViewGroup parent)

{

ImageView imageView;

if (convertView == null) {

imageView = new ImageView(mContext);

imageView.setLayoutParams(new

GridView.LayoutParams(85, 85));

imageView.setScaleType(ImageView.ScaleType.CENT

ER_CROP);

imageView.setPadding(8, 8, 8, 8);

} else { imageView = (ImageView) convertView; }

imageView.setImageResource(mThumbIds[position]);

return imageView;

}

Tab layout & Swiper Views• TabLayout provides a horizontal layout to display tabs

Swipe views

• Efficient navigation is one of the cornerstones of a well-

designed app.

Example Code:

Adding Styles and

Themes• A style is a collection of properties that specify the look and

format for a view or window. A style can specify properties

such as height, padding, font color, font size, background

color, and much more. A style is defined in an XML resource

that is separate from the XML that specifies the layout.

Ex:

<TextView

style="@style/CodeFont"

android:text="@string/hello" />

END