Exploring Android Studio

We just developed our first app in previous post. Let’s continue
further.

In android studio you can see different windows what are they
lets check it out.

 

On left side bar you can see project explorer

 

At bottom of left sidebar there is build variants

Build: set build type for your module debug or release

 

After clicking project you can see following window.

It shows our project structure

Expand app module

There are three folders

below app there is one more Gradle script.
manifests:

again expand manifests folder you can see AndroidManifest.xml.Every application must have an AndroidManifest.xml file. The manifest file
provides essential information about your app to the Android system.

double click to open it.

 

In AndroidManifest.xml file the manifest and application tags
are required in the manifest file and must only appear once..ln { color: rgb(0,0,0); font-weight: normal; font-style: normal; }
.s0 { color: rgb(0,0,0); font-style: italic; }
.s1 { color: rgb(0,0,255); font-weight: bold; }
.s2 { color: rgb(0,0,0); }
.s3 { color: rgb(0,128,0); font-weight: bold; }
.s4 { color: rgb(0,0,0); }
.s5 { color: rgb(0,0,128); font-weight: bold; }

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
    package="com.androidcodr.firstapp" > 
 
    <application 
        android:allowBackup="true" 
        android:icon="@mipmap/ic_launcher" 
        android:label="@string/app_name" 
        android:supportsRtl="true" 
        android:theme="@style/AppTheme" > 
        <activity android:name=".MainActivity" > 
            <intent-filter> 
                <action android:name="android.intent.action.MAIN" /> 
                <category android:name="android.intent.category.LAUNCHER" /> 
            </intent-filter> 
        </activity> 
    </application> 
 
</manifest>

 

Inside AndroidManifest.xml it contain

uses-permission: this tag requests a permission that must be
granted to the application in order for it to operate correctly. For example, if
your app use Internet—in this case you must specify the
android.permission.INTERNET permission.

package: this provides unique id for your app. No two app
have same package path.

This contain following tag

android:icon — the icon for your app

android:label — the name of your app

android:theme – style for your app

activity—all the activity/screen added to your app must be
declared here. If activity not declared here your app may crash.

service: they are used to implement long-running background
operations. An example includes a network call to fetch data for your
application. Unlike activities, services have no user interface.

receiver: declares a broadcast receiver that enables
applications to receive intents broadcast by the system even when app is not
running. One example of a broadcast receiver would be alarm receiver if you want
your app to do specific task at defined time.

You will see all the java files for your activity here.

Now we have only one java file here

MainActivity.java

 

External resources used in app such as images, string, raw
files. Under res folder there are following folder

 

drawable:  images or
xml drawable.

layout: XML files that define a user interface layout

mipmap: drawable files for different launcher icon densities.

values: XML files that contain simple values, such as
strings, integers, and colors.

colors.xml for color values.

dimens.xml for dimension values.

strings.xml for string values.

styles.xml for styles/theme.

Gradle: It’s the new build tool that Google wants to use for Android. It’s being used due to it being more extensible, and useful than ant. It is meant to enhance developer experience.
Here you can declare minimum sdk version and targetes sdk version.
build type– release or debug
dependencies — extenal library for your app.

At the bottom bar Android monitor, Terminal, Messages

 

Android monitor: to see debug log for connected emulator

Terminal: to send terminal command.

Messages: android
messages

Designer window:

 

Palette: widgets that can be added to layout. Such as button,
checkbox, radio.

 

All the widgets added to your layout.

Properties: display properties of selected widgets.

 

At the bottom click Text to see XML of your Layout.

Orientation: change orientation of emulator to Landscape or Portrait.

Emulator: see your layout in different screen sized emulator.

 

Api: set API level for emulator.

AppTheme: set different style for your app.

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