Android Complete Reference

To develop an Android Mobile Application in Android Studio

Running An Android Application in Android Virtual Device and also in a Real Android Device

How to create a string resource?

• Open "strings.xml" file from app/res/values folder

• add one more string resource inside <resources> root element as

• <string name="msg">Android @ Udemy</string>

• this resource will be added into R.java inside "string" class ; so it can be referred in a java program as R.string.msg and in XML - @string/msg

• In activity_main.xml - change the android:text value of TextView as

<TextView

    android:text="@string/msg" />

To set a Background image for Activity:

place an image (back.jpg) in app/res/drawable folder; so that, it can be referred as R.drawable.back in a java program and @drawable/back in an XML file

In activity_main.xml

<RelativeLayout     

    android:background="@drawable/back"

/>

Working with ImageView

Place an ImageView from "Common" in Palette" window to activity_main.xml

and place an image (udemy.jpg) in app/res/drawable folder

The unit of measurement used in android for other than font size is "dp" (previous version "dip") - density independent pixel

<ImageView

   android:layout_width="100dp"

   android:layout_height="70dp"

   android:id="@+id/imageView"

   ................................

   android:src="@drawable/udemy" />

To know the use of AndroidManifest..xml and also to understand what it contains

Toast Notification

• A toast notification is a message that pops up on the surface of the window.

• It only fills the amount of space required for the message

• The user's current activity remains visible and interactive.

• The notification automatically fades in and out, and does not accept interaction events.

• "Toast" is a pre-defined class present in android.widget package

• makeText() is a static method of android.widget.Toast class

• Toast t = Toast.makeText(context, string text, int duration);

• t.show();

• where "context" value can be retrieved by using the getApplicationContext() method or <Activity_class_name>.this (MainActivity.this) or using "this" keyword.

• "text" is the message to be displayed

• "duration" is either Toast.LENGTH_LONG (1) or Toast.LENGTH_SHORT (0) . LENGTH_LONG & LENGTH_SHORT are two pre-defined static final (constant) integer member datas of "Toast" class and their values are 1 & 0 respectively. Long duration may be approximately 3.5 seconds Short duration may be 2 seconds

  
  

Example: Android application to dispaly a toast message in the click event of a button

1) Create a New Android Project using Android Studio

2) Create a string resource with name "btn_label".

Open strings.xml file from res/values folder and add the following element inside <resources>

<resources>

<string name="btn_label">Show Message </string>

</resources>

3) Delete the TextView from activity_main.xml layout resource and change the root element to <RelativeLayout>

4) Place a "Button" inside activity_main.xml

5) Change the text value and width of Button and also register a method for click event

<Button

    android:layout_width="220dp"

    android:text="@string/btn_label"

    android:layout_marginLeft="130dp"

    android:layout_marginTop="47dp"

    android:onClick="fun"

    ........................../>

6) MainActivity.java

package com.udemy.case1;

import android.app.Activity;

import android.os.Bundle;

import android.view.View;

import android.widget.Toast;

public class MainActivity extends Activity{

    protected void onCreate(Bundle savedInstanceState)    {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

    }

    public void fun(View v)    {

        Toast t=Toast.makeText(this,"Welcome to Android @ Udemy", Toast.LENGTH_LONG);

        t.show();

    }

}

To position the toast

t.setGravity(Gravity.CENTER,0,0);

Approach-2

Add the following attribute to <Button>

<Button

android:id="@+id/button"

/>

so that, a new "id" resource will be created and is referred in a java program as "R.id.button" (an int value) and in an XML as "@id/button"

findViewById(int resource ID) is a builtin method of android.app.Activity used to get the reference of a View component used in our application

Button b = findViewById(R.id.button);

OnClickListener is a builtin interface present in android.view.View class and it contains the method declaration as

   public void onClick(View);

; so that if a View ( like Button) component is registered with OnClickListener and if anyone clicks on that View component, the control will be automatically fired to

public void onClick(View v) method definition

To work with different UI components and also to do some simple event handling

Logcat Window

To understand the Lifecycle of an Android Activity

To pass data from One Activity to Another Activity

How to get the data back from an Activity

To work with different type of Intents mainly Implicit Intents and also to know how to access the builtin applications like Contacts, Browser, Phone Dial pad, Camera, Gallery etc

To work with IntentFilter and also to configure it in AndroidManifest.xml and also programatically

This lesson is talking about Intent Filters in an Android Application

To work with different type of resources like String resource,  Layout Resources etc

To work with color state list resource to change the text color of the view components based on its state

To work with TextView, different type of EditTexts etc

To work with AutoCompleteTextView

To work with Button, ToggleButton, ImageButton, CheckBox, RadioButton etc

To work with ListView, GridView and we will be able to develop an Image Gallery

CheckBox

To work with RadioButtons

To work with Themes in Android

To develop frame-by-frame animations

To develop tween animations with set, rotate, scale, alpha etc

To provide different shapes , gradient , width to the different UI components

To work with Options Menu

To Place an Options Menu Item in ActionBar with icon

To work with Context Menu

To work with Popup Menus and to know how to develop a sub-menu

To work with different type of Dialog Boxes used in Android application

Working with Progress Dialog

Work with TimePicker Dialog and Date Picker Dialog

To generate Status bar Notification

To integrate audio in our Android application

To integrate Video in Android Application

To wok with SharedPreferences

To save and to read data to/ from a file in Internal Storage

To work with files in external Storage

Writing to External Storage

To understand what is SQLite database

To create a database, database table, to insert record, retrieve , update and also to delete data in database table

To pre-create an SQLite database with data

Performing CRUD Operations in SQLite

Networking using Java

To check the network connectivity is available in the device or not and also to know the type of Internet connection

Application to understand AsynTask in a proper way

To get an Image from Internet

Working with OkHttp library for networking

Working with Volley Library for networking

To get the Text Response from URL using Volley

To get an Image from a URL using Volley

To send an SMS from our application

To send an SMS using an Implicit Intent

To send an Email from our application

To know the use of broadcast receivers and also to configure it in our application

Application to a do task in new package installation and removal

To work with Wifi and also to get the hotspot which got the highest signal strength

TelephonyManager is used to do the following:-

1. Initiating phone calls

2. Reading the phone, network, data connectivity, and SIM states

3. Monitoring changes to the phone, network, data connectivity, and SIM states

Android's telephony APIs is used to monitor mobile voice and data connections as well as incoming and outgoing calls.

To get current latitude and longitude of the device and also get the address using reverse-geocoding

To get the current address of device based on Latitude and Longitude

To work with GoogleMaps

To show the current location of the device in Map

To work with different Map Styles and Zoom Levels

To place multiple markers in Map

To show the current location of the device in Map

To work with Google Places to show the nearby hospitals, hotels, schools etc