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Mobile Programming
Mobile Programming

Mobile Programming - PowerPoint Presentation

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Mobile Programming - Description

Lecture 5 Composite Views Activities Intents and Filters Lecture 4 Review How do you get the value of a string in the stringsxml file What are the steps to populate a Spinner or ListView using XML ID: 540785 Download Presentation

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Presentation on theme: "Mobile Programming"— Presentation transcript

Slide1

Mobile ProgrammingLecture 5

Composite Views, Activities, Intents and FiltersSlide2

Lecture 4 Review

How do you get the value of a string in the strings.xml file?

What are the steps to populate a Spinner or ListView using XML?

How many Android application components are there? Name one.

How do you launch an Activity B from within Activity A?Slide3

Agenda

ViewFlipper

SlidingDrawer

TabLayout

Activity LifeCycle

Configuration Changes

URI

Intent FiltersSlide4

ViewFlipper

Slide5

ViewFlipper

<ViewFlipper

android:id="@+id/myViewFlipper"

android:layout_width="match_parent"

android:layout_height="match_parent" >

<RelativeLayout

android:layout_width="match_parent"

android:layout_height="match_parent" >

</RelativeLayout>

<RelativeLayout

android:layout_width="match_parent"

android:layout_height="match_parent" >

</RelativeLayout>

</ViewFlipper>Slide6

ViewFlipper

<ViewFlipper

android:id="@+id/myViewFlipper"

android:layout_width="match_parent"

android:layout_height="match_parent" >

<RelativeLayout

android:layout_width="match_parent"

android:layout_height="match_parent" >

</RelativeLayout>

<RelativeLayout

android:layout_width="match_parent"

android:layout_height="match_parent" > </RelativeLayout></ViewFlipper>

Here I used RelativeLayouts, but you can place any widget you want in here.Slide7

ViewFlipper

<ViewFlipper

android:id="@+id/myViewFlipper"

android:layout_width="match_parent"

android:layout_height="match_parent" >

<TextView

android:layout_width="match_parent"

android:layout_height

=“wrap_content" />

<TextView android:layout_width="match_parent" android:layout_height=“match_parent“

/ >

</ViewFlipper>

Here I also used just

2

Views. You can add more than just 2 Views if you want to.Slide8

ViewFlipper

Slide9

ViewFlipper

Slide10

ViewFlipper

Slide11

FrameLayout

is designed to block out an area on the screen to display a single

item.

FrameLayout should be used to hold a single child view

it can be difficult to organize child views in a way that's scalable to different screen sizes without the children overlapping each other

FrameLayoutSlide12

Example:

FrameLayoutSlide13

SlidingDrawer

hides

content out of the screen and allows the user to drag a handle to bring the content on screen

can be used vertically or horizontally

composed of two children views

the handle, that the users drags

the content, attached to the handle and dragged with it.

should only be used inside of a FrameLayout or a RelativeLayoutSlide14

SlidingDrawer

Slide15

android:handle

android:content

android:orientation

"vertical" or "horizontal"

android:allowSingleTap

"true" or "false"

allow the user to open the drawer by tapping on the handle?

SlidingDrawer - useful attributesSlide16

open

()

close()

setOnDrawerScrollListener(OnDrawerScrollListener)

setOnDrawOpenListener(OnDrawerOpenListener)

setOnDrawerCloseListener(OnDrawerCloseListener)

SlidingDrawer - useful methodsSlide17

It is used to wrap

multiple

activities

into a single

window

navigate through the

activities

using tabs

TabLayoutSlide18

TabLayout - Anatomy

TABHOST

TABWIDGET

ACTIVITY

FRAMELAYOUT

TAB CONTENT

TabHost

container holding TabWidget and a FrameLayout

TabWidget

row of tab buttons

FrameLayout

container holding the tab contents

each tab content is a child of FrameLayoutSlide19

TabLayout - XML

<?xml version="1.0" encoding="utf-8"?>

<TabHost xmlns:android="http://schemas.android.com/apk/res/android"

android:id="@android:id/tabhost"

android:layout_width="fill_parent"

android:layout_height="fill_parent">

<LinearLayout

android:orientation="vertical"

android:layout_width="fill_parent"

android:layout_height="fill_parent">

<TabWidget android:id="@android:id/tabs" android:layout_width="fill_parent" android:layout_height="wrap_content" /> <FrameLayout android:id="@android:id/tabcontent" android:layout_width="fill_parent" android:layout_height="fill_parent" /> </LinearLayout>

</TabHost>

TABHOST

TABWIDGET

ACTIVITY

FRAMELAYOUT

TAB CONTENTSlide20

TabLayout - XML

<?xml version="1.0" encoding="utf-8"?>

<TabHost xmlns:android="http://schemas.android.com/apk/res/android"

android:id="@android:id/tabhost"

android:layout_width="fill_parent"

android:layout_height="fill_parent">

<LinearLayout

android:orientation="vertical"

android:layout_width="fill_parent"

android:layout_height="fill_parent">

<TabWidget android:id="@android:id/tabs"

android:layout_width="fill_parent"

android:layout_height="wrap_content" />

<FrameLayout

android:id="@android:id/tabcontent"

android:layout_width="fill_parent"

android:layout_height="fill_parent" />

</LinearLayout>

</TabHost>

TABHOST

TABWIDGET

ACTIVITY

FRAMELAYOUT

TAB CONTENT

Tabs are different Activities,

we can

set

and specify

the layout for each tab programmaticallySlide21

TabLayout

If

you're going to have x number of tabs, create x number of Activities, 1 for each

tab,

in addition to the

TabActivity (Host Activity).

You can create

x

number of XML layouts for each tab, or you can reuse the same layout for each tab.Slide22

TabLayout

public class TabLayoutExampleActivity extends TabActivity {

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

TabHost tabHost = getTabHost(); // The activity TabHost

TabHost.TabSpec spec;

Intent intent = new Intent(TabLayoutExampleActivity.this, LinearLayout.class);

spec = tabHost.newTabSpec("linear layout").setIndicator("Linear", null).setContent(intent);

tabHost.addTab(spec); intent = new Intent(TabLayoutExampleActivity.this, TableLayout.class); spec = tabHost.newTabSpec("table layout").setIndicator("Table",null).setContent(intent); tabHost.addTab(spec);}Slide23

TabLayout

public class TabLayoutExampleActivity extends TabActivity {

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

TabHost tabHost = getTabHost(); // The activity TabHost

TabHost.TabSpec spec;

Intent intent = new Intent(TabLayoutExampleActivity.this, LinearLayout.class);

spec = tabHost.newTabSpec("linear layout").setIndicator("Linear", null).setContent(intent);

tabHost.addTab(spec); intent = new Intent(TabLayoutExampleActivity.this, TableLayout.class);

spec = tabHost.newTabSpec("table layout").setIndicator("Table",null).setContent(intent);

tabHost.addTab(spec);

}

extend TabActivitySlide24

TabLayout

public class TabLayoutExampleActivity extends TabActivity {

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

TabHost tabHost = getTabHost(); // The activity TabHost

TabHost.TabSpec spec;

Intent intent = new Intent(TabLayoutExampleActivity.this, LinearLayout.class);

spec = tabHost.newTabSpec("linear layout").setIndicator("Linear", null).setContent(intent);

tabHost.addTab(spec); intent = new Intent(TabLayoutExampleActivity.this, TableLayout.class);

spec = tabHost.newTabSpec("table layout").setIndicator("Table",null).setContent(intent);

tabHost.addTab(spec);

}

the XML file containing the TabHost, TabWidget, FrameLayoutSlide25

TabLayout

public class TabLayoutExampleActivity extends TabActivity {

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

TabHost tabHost = getTabHost();

TabHost.TabSpec spec;

Intent intent = new Intent(TabLayoutExampleActivity.this, LinearLayout.class);

spec = tabHost.newTabSpec("linear layout").setIndicator("Linear", null).setContent(intent);

tabHost.addTab(spec); intent = new Intent(TabLayoutExampleActivity.this, TableLayout.class);

spec = tabHost.newTabSpec("table layout").setIndicator("Table",null).setContent(intent);

tabHost.addTab(spec);

}

Reference to the Activity's TabHost (which was defined in XML)Slide26

TabLayout

public class TabLayoutExampleActivity extends TabActivity {

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

TabHost tabHost = getTabHost();

TabHost.TabSpec spec;

Intent intent = new Intent(TabLayoutExampleActivity.this, LinearLayout.class);

spec = tabHost.newTabSpec("linear layout").setIndicator("Linear", null).setContent(intent); tabHost.addTab(spec); intent = new Intent(TabLayoutExampleActivity.this, TableLayout.class);

spec = tabHost.newTabSpec("table layout").setIndicator("Table",null).setContent(intent);

tabHost.addTab(spec);

}

Reusable TabSpec for each Tab. Slide27

TabLayout

public class TabLayoutExampleActivity extends TabActivity {

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

TabHost tabHost = getTabHost();

TabHost.TabSpec spec;

Intent intent = new Intent(TabLayoutExampleActivity.this, LinearLayout.class);

spec = tabHost.newTabSpec("linear layout").setIndicator("Linear", null).setContent(intent); tabHost.addTab(spec); intent = new Intent(TabLayoutExampleActivity.this, TableLayout.class);

spec = tabHost.newTabSpec("table layout").setIndicator("Table",null).setContent(intent);

tabHost.addTab(spec);

}

The TabSpec tells the TabHost what views represent the

tab contents and what the tab buttons should look like.Slide28

TabLayout

public class TabLayoutExampleActivity extends TabActivity {

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

TabHost tabHost = getTabHost();

TabHost.TabSpec spec;

Intent intent = new Intent(TabLayoutExampleActivity.this, LinearLayout.class);

spec = tabHost.newTabSpec("linear layout").setIndicator("Linear", null).setContent(intent); tabHost.addTab(spec); Intent intent = new Intent(TabLayoutExampleActivity.this, TableLayout.class);

spec = tabHost.newTabSpec("table layout").setIndicator("Table",null).setContent(intent);

tabHost.addTab(spec);

}

Remember from the previous lecture, this is how we use an Intent object to start another ActivitySlide29

TabLayout

public class TabLayoutExampleActivity extends TabActivity {

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

TabHost tabHost = getTabHost();

TabHost.TabSpec spec;

Intent intent = new Intent(TabLayoutExampleActivity.this, LinearLayout.class);

spec =

tabHost.newTabSpec("linear layout").setIndicator("Linear", null).setContent(intent); tabHost.addTab(spec); Intent intent = new Intent(TabLayoutExampleActivity.this, TableLayout.class);

spec = tabHost.newTabSpec("table layout").setIndicator("Table",null).setContent(intent);

tabHost.addTab(spec);

}

Refer to this TabActivity's tab host (which will contain the actual tabs)Slide30

TabLayout

public class TabLayoutExampleActivity extends TabActivity {

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

TabHost tabHost = getTabHost();

TabHost.TabSpec spec;

Intent intent = new Intent(TabLayoutExampleActivity.this, LinearLayout.class);

spec = tabHost.

newTabSpec("linear layout").setIndicator("Linear", null).setContent(intent); tabHost.addTab(spec); Intent intent = new Intent(TabLayoutExampleActivity.this, TableLayout.class);

spec = tabHost.newTabSpec("table layout").setIndicator("Table",null).setContent(intent);

tabHost.addTab(spec);

}

Create a new tab spec, give it the id "linear layout"Slide31

TabLayout

public class TabLayoutExampleActivity extends TabActivity {

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

TabHost tabHost = getTabHost();

TabHost.TabSpec spec;

Intent intent = new Intent(TabLayoutExampleActivity.this, LinearLayout.class);

spec = tabHost.newTabSpec("linear layout").

setIndicator("Linear", null).setContent(intent); tabHost.addTab(spec); Intent intent = new Intent(TabLayoutExampleActivity.this, TableLayout.class);

spec = tabHost.newTabSpec("table layout").setIndicator("Table",null).setContent(intent);

tabHost.addTab(spec);

}

Set the label for the tab (label the user sees) to "Linear". And Slide32

TabLayout

public class TabLayoutExampleActivity extends TabActivity {

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

TabHost tabHost = getTabHost();

TabHost.TabSpec spec;

Intent intent = new Intent(TabLayoutExampleActivity.this, LinearLayout.class);

spec = tabHost.newTabSpec("linear layout").setIndicator("Linear"

, null).setContent(intent); tabHost.addTab(spec); Intent intent = new Intent(TabLayoutExampleActivity.this, TableLayout.class);

spec = tabHost.newTabSpec("table layout").setIndicator("Table",null).setContent(intent);

tabHost.addTab(spec);

}

We're not using an image for the tabs, so null for this argumentSlide33

TabLayout

public class TabLayoutExampleActivity extends TabActivity {

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

TabHost tabHost = getTabHost();

TabHost.TabSpec spec;

Intent intent = new Intent(TabLayoutExampleActivity.this, LinearLayout.class);

spec = tabHost.newTabSpec("linear layout").setIndicator("Linear"

, null).setContent(intent); tabHost.addTab(spec); Intent intent = new Intent(TabLayoutExampleActivity.this, TableLayout.class);

spec = tabHost.newTabSpec("table layout").setIndicator("Table",null).setContent(intent);

tabHost.addTab(spec);

}

Fill the FrameLayout to hold the Activity specified by this intentSlide34

TabLayout

public class TabLayoutExampleActivity extends TabActivity {

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

TabHost tabHost = getTabHost();

TabHost.TabSpec spec;

Intent intent = new Intent(TabLayoutExampleActivity.this, LinearLayout.class);

spec = tabHost.newTabSpec("linear layout").setIndicator("Linear"

, null).setContent(intent); tabHost.addTab(spec); Intent intent = new Intent(TabLayoutExampleActivity.this, TableLayout.class);

spec = tabHost.newTabSpec("table layout").setIndicator("Table",null).setContent(intent);

tabHost.addTab(spec);

}

Add the tab to the tabHost, it will now show up in the UISlide35

TabLayout

public class TabLayoutExampleActivity extends TabActivity {

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

TabHost tabHost = getTabHost();

TabHost.TabSpec spec;

Intent intent = new Intent(TabLayoutExampleActivity.this, LinearLayout.class);

spec = tabHost.newTabSpec("linear layout").setIndicator("Linear"

, null).setContent(intent); tabHost.addTab(spec);

Intent intent = new Intent(TabLayoutExampleActivity.this, TableLayout.class);

spec = tabHost.newTabSpec("table layout").setIndicator("Table",null).setContent(intent);

tabHost.addTab(spec);

}

To add another tab, let's do this all over again! Slide36

TabLayout - Rules

—

TabHost must have the id

@android:id/tabhost

—

The TabWidget must have the id

—

@android:id/tabs

—

The FrameLayout must have the id —@android:id/tabcontentSlide37

TabHost - useful methods

Slide38

Activity LifeCycle

During the life of an activity, the system calls a core set of lifecycle methods in a

sequence

.

Implementing

your activity lifecycle methods properly ensures your app behaves

gracefully

in

many

ways, including that it:

Does not crash if the user receives a phone call or switches to another app while using your app.

Does not consume valuable system resources when the user is not actively using it. Does not lose the user's progress if they leave your app and return to it at a later time. Slide39

Activity LifecycleA nice picture of activity lifecycle

http://developer.android.com/reference/android/app/Activity.htmlSlide40

Activity LifeCycle - onCreate()

Called when the activity is first created.

this is where you should do all of your normal static set up: create views, bind data to lists, etc.

provides you with a

Bundle

containing the activity's previously frozen state, if there was one.

always followed by

onStart()

.Slide41

Activity LifeCycle - onStart()

Slide42

Activity LifeCycle - onRestart()

Slide43

called

when the activity will start interacting with the user

at this point your activity is at the top of the activity stack, with user input going to it

Always followed by

onPause()

Activity LifeCycle - onResume()Slide44

called

when the system is about to start resuming a previous activity

this is typically used to

commit unsaved changes to persistent data, stop animations and other things that may be consuming CPU

, etc

implementations of this method must be very quick because the next activity will not be resumed until this method returns

followed by

onResume()

if the activity returns back to the front

onStop()

if it becomes invisible to the user.

Activity LifeCycle - onPause()Slide45

called when the activity is no longer visible to the user because another activity has been resumed and is covering this one

this may happen either because a new activity is being started, an existing one is being brought in front of this one, or this one is being destroyed

followed by

onRestart()

if this activity is coming back to interact with the user

onDestroy()

if this activity is going away

Activity LifeCycle - onStop()Slide46

the

final call you receive before your activity is destroyed

this can happen either because

the activity is finishing (someone called

finish

()

)

the system is temporarily destroying this instance of the activity

due to low memory

you can distinguish between these two scenarios with the

isFinishing() method

Activity LifeCycle - onDestroy()Slide47

Reading Assignment Please read page

0 – 710

by next class. Pay more attention on the section of Large-Screen Strategies and Tactics.

We are going to talk about Fragment next week. Slide48

Configuration Changes

In your app, you

can detect when the configuration of the device changes

screen orientation, keyboard availability, and language

In default, the

system will try to handle the changes for you, unless you specify that you want to handle them yourselfSlide49

Configuration Changes - Manifest

to specify

that,

you want to handle orientation and keyboard availability changes

by yourself

open the manifest file and add the bold line

<activity

android:configChanges="orientation|keyboardHidden"

android:name=".OnConfigurationChangedExampleActivity"

android:label="@string/app_name" >

<intent-filter>

<action android:name="android.intent.action.MAIN" /><category android:name="android.intent.category.LAUNCHER" /></intent-filter></activity>Slide50

Configuration Changes - Manifest

T

his specifies one or more configuration changes that the activity will handle itself

when the orientation changes and when keyboard availability

changes.

<activity

android:configChanges="

orientation|keyboardHidden

"

android:name=".OnConfigurationChangedExampleActivity"

android:label="@string/app_name" >

<intent-filter><action android:name="android.intent.action.MAIN" />

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

</intent-filter>

</activity>Slide51

Configuration Changes - Event

Then, to react to the orientation change event, add this method to your Activity

@

Override

public void onConfigurationChanged(Configuration newConfig) {

super.onConfigurationChanged(newConfig);

if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE) {

/* ... */

}

else if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT) {

/* ... */

}}Slide52

Passing Data between Activities

When you start Activity B from Activity A, you may want to send data to Activity B

Activity A

Activity B

startActivity B

send some data to B alsoSlide53

Passing Data between Activities

Activity A - onCreate()

Intent intent = new Intent(this,

SecondActivity.class);

Bundle bundle = new Bundle();

bundle.putString("fname","John");

bundle.putString("lname", "Doe");

bundle.putInt("age", 18);

intent.putExtras(bundle);

startActivity(intent);

Activity B - onCreate()

Intent intent = getIntent();Bundle bundle = intent.getExtras(); if(bundle != null) { edit1.setText(bundle.getString("fname"));

edit2.setText(bundle.getString("lname"));

int age= bundle.getInt("age");

}Slide54

Explicit Intent vs Implicit Intent

An Intent encapsulates a request, made to Android, for some activity or

other receiver

to do something

.

If the activity you intend to launch is

one of your own

, you may find it simplest

to create

an explicit

Intent.

new Intent(this, MyListViewActivity.class);You can also start up activities from the operating system or third-party apps using implicit intent

.

Implicit intent works a lot like the Web HTTP. Slide55

Implicit Intent

Implicit Intent

Action + URI (“data”)

these

are almost exactly analogous to HTTP

verbs (POST, GET)

and URLs —

the action

is the verb, and the “ data” is a Uri, such as http://commonsware.com

android.intent.action:

MAIN

MUSIC_PLAYERVIEWWEB_SEARCHSlide56

URIs

Uniform Resource

Identifier

that identifies an abstract or physical resource, as specified by

RFC 2396

.

The

URI

class can both parse URI strings into parts and compose URI strings from

parts.

There are 4 main parts to a URIScheme, port, host, and path

http://developer.android.com/reference/java/net/URI.htmlSlide57

URIs - Examples - Hierarchical

http://

mobile.cs.fsu.edu/android

http://twitter.com

file

:///tmp/android.txt

scheme

host

port

path

http

mobile.cs.fsu.edu

80

android

http

twitter.com

file

/tmp/android.txtSlide58

URIs - Examples - Opaque

mailto:robots.example.com

scheme

scheme-specific part

mailto

robots.example.comSlide59

URIs - Parsing URIs

URI uri = Uri.parse("http://www.google.com");

String scheme = uri.getScheme();

String host = uri.getHost();

int port = uri.getPort();

String path = uri.getPath();

String schemeSpecificPart = uri.getSchemeSpecificPart();Slide60

Intent Filters

To inform the system which implicit intents they can handle, activities, services, and broadcast receivers can have one or more intent

filters

each filter describes a capability of the component, a set of intents that the component is willing to receive

it filters in intents of a desired type, while filtering out unwanted intents — but only unwanted implicit intents (those that don't name a target class)Slide61

Intent Filters

Slide62

Intent Filters

Slide63

Intent Filters

How does Android know that you may want to open the YouTube app when you try to watch a video on YouTube?

Using Intent Filters

We will create an app that can be used to launch links at

http://mobile.cs.fsu.eduSlide64

Intent Filters

Slide65

Intent Filters

Slide66

Intent Filters

Slide67

Intent Filters

Slide68

Intent Filters

Slide69

Intent Filters

Slide70

Intent Filters

Slide71

References

The Busy Coder's Guide to Android Development - Mark Murphy

Android Developers

The Mobile Lab at Florida State University