ANDROID_UI_Material by Mr Mahesh @ DurgaSoft

DURGA SOFT SOLUTIONS

ANDROID

By Mr. Mahesh

Durga Soft Solutions , SR Nagar , Hyderabad . www.durgasoft.com

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ANDROID: What is Android? 

Android Is a mobile Operating System developed by Google.

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Android Os is based on open Linux kernal.

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Unlike iPhone Os, Android Os is Open source, meaning the developers can modify and customize the os for each phone. phone.

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Developers can create programs for Android by using the the Android SDK(Software Development Kit).

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Android programs are written in java and run through Goo gle’s Davlik virtual machine, which optimized for mobile devices.

Android Architecture Architecture :

The Main Components in the Android Architecture are 1. Android Application 2. Application Framework 3. Libraries(Core & Native) 4. Runtime Android (DVM- Dalvik Virtual Machine) 5. Kernel – Linux By Mr. Mahesh


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1. Android Applications: Applications:

These are applications written in Java. Some of basic applications includes an calendar, email client, SMS program, maps, making phone calls, accessing the Web browser, accessing your contacts list and others. o thers. 2. Application FrameWork: FrameWork:

This is the skeleton or framework which all android developers has developers has to follow. The developers can access all framework APIs an manage phone’s basic functions like resource

allocation, switching between between processes or programs, programs, telephone applications, applications, and keeping track track of the phone’s physical location. 3.

Libraries:

a. Core Libraries: The Android Android runtime layer layer which includes set of core java libraries libraries and DVM (Dalvik Virtual Machine) is also located in same layer. b. Native Libraries: This layer consists of Android libraries written in C, C++, and used by various system. These libraries libraries tells the device how to handle different kinds kinds of data and are exposed to Android developers via Android Application framework. Some of these libraries includes media , graphics, 3d,SQLite,web 3d,SQLite,web browser library etc. 4. Runtime Android (Dalvik virtual Machine):

This layer includes set of base libraries libraries that are required for java java libraries. Every Android application gets its own instance of Dalvik virtual machine. Dalvik has been written so that a device can run multiple VMs efficiently and it executes files in executable (.Dex) optimized for minimum memory. 5. Kernel – Linux:

This layer includes Android’s memory management programs, security settings, power management software and several drivers for hardware , file system access, networking and interprocess-communication. process-communication. The kernel also acts as an abstraction layer between hardware and the rest of the software stack.

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Android Versions: 

Android 1.0 (API level 1) of Android is 1.5 (CupCake) may Android 2.3.3 –2.3.7 Gingerbread (API level 10) First Major version of version (CupCake) may 2009

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Android 1.11.6 (API(Donut level 2) ) Android

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Android 1.52.1(Éclair) Cupcake (API level 3) Android

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Android 3.1 Honeycomb (API level 12)

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Android 1.62.2(Froyo) Donut (API level 4) Android

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Android 2.02.3,2.3.2,2.3.3 Eclair (API level 5),….(GingarBread) Android

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Android 4.0 –4.0.2 Ice Cream Sandwich (API level 14)

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Android 2.0.1 Eclair (API level 6) 2,3.2.3….(HoneyComb) Android 4.0.3 –4.0.4 Ice Cream Sandwich (API level 15) 3.1,3.2,3.2.1,3.2.2,3.2.3….(HoneyComb) 3.1,3.2,3.2.1,3.2. Android

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Android 2.14.0(ice Eclair (API level 7)Sandwitch) Android Cream S andwitch)

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Android 4.1 Jelly Bean (API level 16)

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Android 2.2 –2.2.3 Froyo (API level 8)

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Android 2.3 –2.3.2 Gingerbread (API level 9)

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Android 2.3.3 –2.3.7 Gingerbread (API level 10)

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Android 4.4 KitKat (API level 19)

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Android Android Features:

The following are the advantages of Android 

Application Application framework enabling reuse and replacement of components

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Dalvik virtual Dalvik virtual machine optimized for mobile devices

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Optimized graphics

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SQLite for structured data storage stora ge

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Media support for common audio, video, and still image formats (MPEG4, H.264, MP3, AAC, AMR, JPG, PNG, GIF)

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GSM Telephony (hardware dependent),Bluetooth, EDGE, 3G, and WiFi (hardware dependent),Camera, dependent),Camera, GPS, compass, and accelerometer (hardware dependent)

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Rich development environment To Create , Test and build Android applications we need the following Softwares:

1. Eclipse IDE (is optional can use any other tool. But Eclipse is recommended ) + added with Android Development plugin 2. Android SDK(Software Development Kit we can download download these s/w from from this site By Mr. Mahesh

http://www.android.com


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Required Softwares:

o n any OS such as Windows, Linux, and MAC Os  The android app can be developed on The following are the resources that are required to set up into the system for

android

application development 1. An IDE (Integrated Development Environment) : The Eclipse is the most prefered IDE. We can download the Eclipse IDE from the following website.

http://www.eclipse.org

2. Add a plugin making the eclipse aware of Android. The Android Development Tool(ADT) is the Eclipse plugin doing this. For this we want to use the Install plugin option of the Eclipse IDE. Alternatively we can get the ADT zip file downloaded from

http://www.android.com http://www.android.com and

manually copy the features and plugins folders into the eclipse root folder , which we got extracting the ADT zip file. 3. In addition to the IDE and its plugin simplifying creating the android applications we want to have an android SDK for building, and testing the android applications, we can download the SDK from http://www.android.com http://www.android.com After extracting the downloaded zip file for the SDK we need to run the ‘SDK Manager’ whicj is found in the this find &

install various available packages. The Android Application:

The Android Application is basically composed of the following 3 type of components. 1. Activity 2. Service 3. BroadCast Receiver

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Activity: 

The Activity is the one of the core components of Android App

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This is crated as a Java Object subtype ofandroid.app.Activity

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This component is managed by the Android App Framework

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The Following are the possible methods that we can override the Activity Object.

The onCreate() :

The onCreate() methos is used to implement initialization code like presenting the View for the Activity. The onStart():

The onStart() method allows writing the code executing on getting the activity foreground The onRestart() :

The onRestart() method can initialize the resources that are closed in the onStop(). The onStop() :

The onStop() method can use the resources that are not required on paused activity. This may even required to solve the start of the activity. The onResume() :

The onResume() can create the resources and / or get the saved state of the activity to get into foreground. The onDestroy() : The onDestroy() can perform the finilizations for the activity.

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The Life Cycle of Activity is:

Or Creating an Activity:

While creating/starting the activity the following methods are invoked.  onCreate() onStart() onResume()

Some other Activity wants to come to ForeGround: At this stage ‘onPause()’ of this activity is invoked and then the other activity is started. In case of the other activity is taking the complete screen the ‘onScreen()’ is invoked getting the activity to background(stopped). Otherwise it gets paused.

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The Activity is getting into the ‘foreground’:

This activity which is paused or stopped because of some other activity is foreground, is now coming foreground because of the existing foreground activity is destroyed. At this stage the ‘onResume()’ is the only method invoked in case of getting from paused. If it was stopped the following methods are invoked.  onRestart() onStart() onResume()

The Activity Destroying:

The Activity while destroying from foreground invokes the following methods. onPause() onStop() onDestroy()

Point to Note : The android system can destroy the stopped activity without a user request, just

invoking ‘onDestroy()’

The Startup Application :

For the first time want to take the following points to check 

Install with Android SDK with necessary APIs

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Create a ‘AVD(Android Virtual Device)’, we can do this using ‘SDK Manager’ which

you find in the Android SDK installed. 

Eclipse is installed with ADT Plugin, and for the first time we want to set the Android SDK location in Eclipse-window- Preferences.

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Select ‘Android’ from the left side tree.

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Browse the Android SDK Install Folder

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Eg: d:\android\SDK-windows

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Once Creating the Android project we find the project is created with one activity bydefault. The following are the few important documents or folders to observe. When you create a new Android project, you get several items in the project's root directory: 

src

A folder that holds the Java source code 

gen

This is where Android's build tools will place source code that they generate. R.java" is a generated class which contains the text and the UI elements. Android projects come with this free class 'R' which is short for Resource. This is an automatically generated class that we can use to reference resources in our project. We should not try to modify this class manually. 

assets

A folder that holds other static files you wish packaged with the application for deployment onto the device. 

bin

In Eclipse, the ADT plugin incrementally builds our project as we make changes to the source code. Eclipse outputs an .apk file automatically to the bin folder of the project, so we do not have to do anything extra to generate the .apk. 

res

A folder that holds resources such as icons, graphic user interface (GUI) layouts, etc. that are packaged with the compiled Java in the application. 

AndroidMainFest.xml

An XML file describing the application being built and which components (activities, services, and so on) are being supplied by the application. This file is the foundation for any Android application. This is where you declare what is inside your application. You also indicate how these pieces attach themselves to the overall Android systems; for example, you can indicate which activity or activities should appear on the device's main menu (a.k.a. the launcher). When you create your application, a starter manifest will be generated for you automatically. For a simple application, offering a single activity and nothing else, the auto generated manifest will probably work out fine, or perhaps require a few minor modifications. But on the other spectrum, the manifest file for the Android API demo suite is more that 1,000 lines long. Your production applications will probably falls somewhere in the middle. Most of the manifest will be describes detail in later chapters.

By Mr. Mahesh

project.properties Durga Soft Solutions , SR Nagar , Hyderabad www.durgasoft.com Property files used by. the Ant build script. 

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Creating an Activity: 

The activity class needs to be a subtype of android.app.Activity

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The onCreate() method is one basic method which minimum we want to override . Like we may want to create / locate the View and set it to the Activity. The following methods of Activity are used to set the View o

setContentView(View)

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setContentView(int)

The first allows to set the View Object may be creat ed in the program here. And the later allows setting the view defined in the XML document. The FirstActivity.java :

package com.durgasoft.android; import com.durgasoft.android.R; import ………….;

public class FirstActivity extends Activity { /** Called when the activity is first created. */

OUT PUT SCREEN

@Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); // Code without main.xml /* TextView tv=new TextView(this); tv.setText("Hello from FirstActivity"); setContentView(tv); */ // Code with main.xml setContentView(R.layout.main); } } By Mr. Mahesh


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Main.xml:

The android application includes a generated resource file named ‘R’ which lists all the resources

defined with unique identity. And this xml View is also given with a unique id to refer in the program. The id can be accessed using ‘R.layout.Main’.

Thus the activity can have this View set as shown below

public class FirstActivity extends Activity { public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); }

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It is found in most cases creating a complex view it is convenient to go for XML style How ever we can get View created in xml into the activity and do necessary changes .

Example: Public void onCreate(………){

setContentView(R.layout.main); TextView tv=(TextView)findViewById(R.id.tv1); Tv.setText(“New Text”); }

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To run the above code could give an error as in the main.xml file the TextView is not specified with any id. To run this above code successfully add the following attribute into the Tag. andrioid:id=”@+id/tv1”

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The ‘+’ in the value of the attribute describes add the is resource into the ‘R’ file if

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not available The android application support multiple type of resource such as layouts, ids and Strings

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The String resource is can be added into ‘strings.xml’ file res/values folder

Eg: Text String M essage

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These resources are added into the R file for convenient access.

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To access the resources in ‘xml’ documents we use the following syntax.

Syntax: Eg:

@/ @String/test

In case the same is required to access in the program we use. R.. We can use the following method for getting the string resource declared in the xml. String s1=getResources().getString(R.String.test); Similar to String we can have a Boolean resource .this is declared using tag. Starting an Activity:   

The activity with ACTION_MAIN, and CATEGORY_LAUNCHER is main activity to run on accessing the application. In addition we may want to start another activity from such main activity. We use startActivity(Intent) method of the Activity to do this.

The Intent Object:   

The Intent is a value object describing a message to the android system to perform an action. Like we may want to describe the android system to start an activity or background service The Intent Object describes following six methods 1. Component Name 2. Action 3. Categories

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4. 5. 6.

Data Extras Flags


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The Intents are of two types. 1. Explicit Intents 2. Implicit Intents

Explicit Intents:

These type of intents are started with component name, which directly locates a Activity by its name. Example: Lets add a new activity in the previous class Public class Activity2 extends Activity { Public void onCreate(Bundle b) { super.onCreate(b); setContentView(R.layout.main1.xml); } } This new Activity is requited to register into the AndroidManifest.xml

In the existing Activity: Lets consider the main.xml is the layout document and has the following tag. Main1.xml

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AndroidManifest.xml

Understanding the Views:  

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The Userinterface of an activity is defined using a View Object. The View group is one special View type that allows us compose multiple View’s into a single view, thus we can have multiple views to present in a single screen (ies a single View). The following method of an Activity is used to set the View for this Activity. setContentView(android.View.View) setContentView(int ViewID)

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The View can be described in two styles. o Into XML declarative o In Activity( Java Code) programmatic. We can use both in combination.

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It is recommended use XML style , which can simplify creating the View and allows take the advantage of first design using click and drag supported by the IDE.

By Mr. Mahesh


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Usign XML Style: 

In this case we create an XML documents into res/layouts folder

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An XML document can describe only one View. Note the View here can be a View group thus a tree of Views Here we have an XML tag one for each concrete View type t o use defining the View. Example:

Example:

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The Button: 

We use the android.View.Button class to create this component. Or

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Sample Program on Relative Layout & Button:

package com.durgasoft.android; import com.durgasoft.android.R; import ----------------------------------------------; public class FourthActivity extends Activity { // Example for Relative Layout and Buttons /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); Button b1=(Button)findViewById(R.id.b1); b1.setOnClickListener(new OnClickListener() { public void onClick(View v) { Toast.makeText(getApplicationContext(),"Hi This is From Button",Toast.LENGTH_LONG).show(); } }); } } Main.xml:

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The EditText: 

This is a text field that allows taking the text content input from the user.

Example:

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Dialog Box:  

The android.app.DialogInterface is the base interface representing any dialog. The android.app.Dialog class supports declaring a dialog . This is the base class for any dialog.

Example:

Dialog d=new Dialog(this); d.setContentView(R.layout.dialog_layout); The dialog_layout describes the view for the dialog just as done for the activity. d.setOwnerActivity(MyActivity,this); d.show(); // This will show the dialog we can add onCancelListener and onDismissListener’s set to the Dialog.

We use any of the following methods of Dialog to choose the dialog box. Cancel(); Dismiss(); Android includes the following builtin dialogs implementation simplifying creating the dialog box for most common requirements. Alert Dialog ProgressBar Dialog DatePicker Dialog TimePicker Dialog

The AlertDialog: This supports us to create a dialog that meets the most common requirement of having a dialog for showing some alert, this includes

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A Optional Title Message Text Zero, one, two, or three buttons List of items

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We use a ‘AlertDialog.Builder’ object to crate this Dialog .

The following methods of this object allows us setting the details for the dialog. -

setTitle(String) setMessage(String) setPositiveButton(String lable,DialogInterface.OnClickLIstener listener) setNegiveeButton(String lable,DialogInterface.OnClickLIstener listener) setNutralButton(String lable,DialogInterface.OnClickLIstener listener) setItems(String[])

Once setting all the details , we can invoke create() method for the AlertDialog object and further show() method for showing. The following methods of Activity can be used to show and remove the Dialog boxes.   

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showDialog(int): This shows the Dialog. removeDialog(int): Removes the dialog from the Activity The OnCreateDialog(int): method is invoked for the first time

when a dialog is requested to show. This method is responsible to create a dialog for the given index to show. The onPrepareDialog(int): method is invoked each time(including firsttime) when a dialog is required to show.

Note:

The Activity retains the state of the dialog even on cancelled / dismiss of the dialog is requested to show again . However invoking remove Dialog(int) will release the dialog state with the activity.

The Menu: The following methods ‘Activity ‘ are invoked to create the

menu for the activity. OnCreateOptionsMenu(menu):

This method is invoked for the first time the user clicks on the menu for the activity. Note: From Android 3.0 this is invoked at the time starting the Activity as the menu here is always visible.

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OnPrepareOptionsMenu(menu):

This is called each time when the menu is required to be show. To Listen for the menu item click we can override the following method. boolean onMenuItemSelected(int featureId,MenuItem m)

Sample Program on Dialog Boxes and Menu’’s:

package com.durgasoft.android; import ......................................................................; public class DialogsExampleActivity extends Activity { private EditText time_et; private Button date_button; // Example for Dialog Boxes and the Menu @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); time_et=(EditText)findViewById(R.id.time_et); date_button=(Button)findViewById(R.id.b2); } private static int BASIC_DIALOG=1; private static int DATE_PICKER_DIALOG=2; private static int TIME_PICKER_DIALOG=3; private static int ALERT_DIALOG1=4; private static int ALERT_DIALOG2=5; public void button1Click(View v){ // Remove the comments One by One and check the result //showDialog(BASIC_DIALOG); //showDialog(ALERT_DIALOG2); showDialog(ALERT_DIALOG1); ; } public void button2Click(View v){ showDialog(DATE_PICKER_DIALOG); } public void button3Click(View v){ showDialog(TIME_PICKER_DIALOG); } public Dialog onCreateDialog(int index){ if(index==BASIC_DIALOG){ final Dialog d=new Dialog(this); d.setContentView(R.layout.dialog1_layout); Button b=(Button)d.findViewById(R.id.b2); By Mr. Mahesh


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b.setOnClickListener( new View.OnClickListener() { public void onClick(View v) { d.dismiss(); } }); return d; }else if (index==DATE_PICKER_DIALOG){ OnDateSetListener dl= new OnDateSetListener() { public void onDateSet( DatePicker view, int year, int monthOfYear, int dayOfMonth) { Toast.makeText(getApplicationContext(), "Date : "+dayOfMonth+""+(monthOfYear+1)+"-"+year, Toast.LENGTH_SHORT).show(); date_button.setText("New : "+ dayOfMonth+"-"+(monthOfYear+1)+"-"+year); } }; DatePickerDialog dpd=new DatePickerDialog(this, return dpd; }else if (index==TIME_PICKER_DIALOG){

dl, 2011, 10, 12);

OnTimeSetListener dl=new OnTimeSetListener() { public void onTimeSet(TimePicker tp, int arg1,int arg2) { Toast.makeText(getApplicationContext(), "Time : "+arg1+":"+arg2, Toast.LENGTH_SHORT).show(); String text=""; if (arg1 <= 12){ text=arg1+":"+arg2+" AM"; }else{ text=(arg1-12)+":"+arg2+" PM"; } time_et.setText(text); } }; TimePickerDialog tpd= new TimePickerDialog( this,dl, 10, 12, false); return tpd; }else if (index == ALERT_DIALOG1){ AlertDialog.OnClickListener listener= new AlertDialog.OnClickListener(){ public void onClick( DialogInterface dialog, int which) { String text=""; if (which==AlertDialog.BUTTON_POSITIVE){ text="Positive : OK"; By Mr. Mahesh


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}else if(which==AlertDialog.BUTTON_NEGATIVE){ text="Natative : Not OK"; }else { text="Nutral : OK"; } Toast.makeText(getApplicationContext(), text, Toast.LENGTH_SHORT).show(); } }; AlertDialog.Builder ab= new AlertDialog.Builder(this); ab.setTitle("Alert Dialog Sample"); ab.setMessage("You opened AlertDialog"); ab.setPositiveButton("OK", listener); //ab.setNegativeButton("Not OK", listener); //ab.setNeutralButton("Neutral", listener); return ab.create(); }else if (index == ALERT_DIALOG2){ AlertDialog.Builder ab= new AlertDialog.Builder(this); ab.setTitle("Alert Dialog Sample"); final String[] items={"Abc1", "Abc2", "Abc3", "Abc4"}; DialogInterface.OnClickListener listener= new DialogInterface.OnClickListener() { public void onClick( DialogInterface dialog, int which) { Toast.makeText( getApplicationContext(), items[which], Toast.LENGTH_SHORT).show(); dialog.dismiss(); } }; ab.setItems(items, listener); return ab.create(); }else{ return null; } } public void onPrepareDialog(int index, Dialog d){ By Mr. Mahesh


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if (index==BASIC_DIALOG){ EditText ev=(EditText)d.findViewById(R.id.et1); TextView tv=(TextView)d.findViewById(R.id.tv1); tv.setText(tv.getText()+":"+ ev.getText()); } } @Override public boolean onCreateOptionsMenu( Menu menu) { MenuInflater mi=new MenuInflater(this); mi.inflate(R.menu.menu1, menu); return true; } @Override public boolean onMenuItemSelected( int featureId, MenuItem item) { Toast.makeText(getApplicationContext(), item.getTitle(), Toast.LENGTH_SHORT).show(); return true; } } Main.xml:

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android:layout_height= "wrap_content" android:text="Alarm Date : " > dialog1_layout.xml:

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my_tabs_view.xml:

Menu1.xml:

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ANDROID_UI_Material by Mr Mahesh @ DurgaSoft

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