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Andrid prgramming curse UI Overview User Interface By Võ Văn Hải Faculty f

with. A ViewGrup is an bject that hlds ther View (and ViewGrup) bjects in rder t

Andrid prvides a cllectin f bth View and ViewGrup subclasses that ffer yu cmmn

linear r relative layut). http://vvanhai.wrdpress.

Lcalizing with Resurces Fragments UI Overview User Interface Layut The user

1 Andrid prgramming curse UI Overview User Interface By Võ Văn Hải Faculty f Infrmatin Technlgies All user interface elements in an Andrid app are built using View and ViewGrup bjects. A View is an bject that draws smething n the screen that the user can interact with. A ViewGrup is an bject that hlds ther View (and ViewGrup) bjects in rder t define the layut f the interface. Andrid prvides a cllectin f bth View and ViewGrup subclasses that ffer yu cmmn input cntrls (such as buttns and text fields) and varius layut mdels (such as a linear r relative layut). 3 Sessin bjectives Overview Layut Input Cntrls Other Views Menus Intent Lcalizing with Resurces Fragments UI Overview User Interface Layut The user interface fr each cmpnent f yur app is defined using a hierarchy f View and ViewGrup bjects. Each view grup is an invisible cntainer that rganizes child views, while the child views may be input cntrls r ther widgets that draw sme part f the UI

2 UI Overview User Interface Cmpnents Yu dn't have t build all f yur UI using View and ViewGrup bjects. Andrid prvides several app cmpnents that ffer a standard UI layut fr which yu simply need t define the cntent. These UI cmpnents each have a unique set f APIs that are described in their respective dcuments, such as App Bar, Dialgs, and Status Ntificatins. UI Overview String resurces A string resurce prvides text strings fr yur applicatin with ptinal text styling and frmatting. There are three types f resurces that can prvide yur applicatin with strings: String: XML resurce that prvides a single string. String Array: XML resurce that prvides an array f strings. Quantity Strings (Plurals): XML resurce that carries different strings fr pluralizatin UI Overview ID Any View bject may have an integer ID assciated with it, t uniquely identify the View within the tree. When the applicatin is cmpiled, this ID is referenced as an integer, but the ID is typically assigned in the layut XML file as a string, in the id attribute. The syntax fr an ID, inside an XML tag is: When referencing an Andrid resurce ID, yu d nt need the plus-symbl, but must add the andrid package namespace like this example: UI Overview String resurces Using 6 8 2

Layuts Layuts Cmmn Layuts Layuts http://vvanhai.wrdpress.cm/ 9 11 A layut defines the visual structure fr a user interface, such as the UI fr an activity r app widget.

widgets and layuts. Instantiate layut elements at runtime: Yur applicatin can create View and ViewGrup bjects (and manipulate their prperties) prgrammatically.

3 Layuts Layuts Cmmn Layuts Layuts A layut defines the visual structure fr a user interface, such as the UI fr an activity r app widget. Yu can declare a layut in tw ways: Declare UI elements in XML: Andrid prvides a straightfrward XML vcabulary that crrespnds t the View classes and subclasses, such as thse fr widgets and layuts. Instantiate layut elements at runtime: Yur applicatin can create View and ViewGrup bjects (and manipulate their prperties) prgrammatically. Layuts Building Layuts with an Adapter When the cntent fr yur layut is dynamic r nt predetermined, yu can use a layut that subclasses AdapterView t ppulate the layut with views at runtime

Layuts Linear Layut http://develper.andrid.cm/reference/andr id/widget/linearlayut.layutparams.

hrizntally. Yu can specify the layut directin with the andrid:rientatin attribute.

r t each ther Imprtant layut prperties andrid:layut_alignparenttp If "true", makes the tp/bttm edge

andrid:layut_centervertical andrid:layut_centerhrizntal andrid:layut_abve andrid:layut_belw andrid:layut_tstartof

vertically/hrizntal within its parent. Psitins the tp edge f this view abve/belw the view specified with a resurce ID.

If true, makes the left/right edge f this view match the right edge f the parent. 15 http://vvanhai.wrdpress.

4 Layuts Linear Layut id/widget/linearlayut.layutparams.html Layuts Relative Layut LinearLayut is a view grup that aligns all children in a single directin, vertically r hrizntally. Yu can specify the layut directin with the andrid:rientatin attribute. Layuts Relative Layut - Psitining Views RelativeLayut lets child views specify their psitin relative t the parent view r t each ther Imprtant layut prperties andrid:layut_alignparenttp If "true", makes the tp/bttm edge andrid:layut_alignparentbttm f this view match the tp edge f the parent. andrid:layut_centervertical andrid:layut_centerhrizntal andrid:layut_abve andrid:layut_belw andrid:layut_tstartof andrid:layut_tendof andrid:layut_alignparentstart andrid:layut_alignparentend If "true", centers this child vertically/hrizntal within its parent. Psitins the tp edge f this view abve/belw the view specified with a resurce ID. Psitins the left edge f this view t the left/right f the view specified with a resurce ID. If true, makes the left/right edge f this view match the right edge f the parent RelativeLayut is a view grup that displays child views in relative psitins. The psitin f each view can be specified as relative t sibling elements (such as t the left-f r belw anther view) r in psitins relative t the parent RelativeLayut area (such as aligned t the bttm, left r center)

Layuts Table Layut TableLayut is a ViewGrup that displays

TableRw bjects are the child views f a TableLayut (each

Each rw has zer r mre cells, each f which is defined by

A cell may als be a ViewGrup bject (fr example, yu can

Layuts Grid Layut A layut that places its children in a

The grid is cmpsed f a set f infinitely thin lines that

Children ccupy ne r mre cntiguus cells, as defined by

5 Layuts Table Layut TableLayut is a ViewGrup that displays child View elements in rws and clumns. TableRw bjects are the child views f a TableLayut (each TableRw defines a single rw in the table). Each rw has zer r mre cells, each f which is defined by any kind f ther View. A cell may als be a ViewGrup bject (fr example, yu can nest anther TableLayut as a cell). Layuts Grid Layut A layut that places its children in a rectangular grid. The grid is cmpsed f a set f infinitely thin lines that separate the viewing area int cells. Children ccupy ne r mre cntiguus cells, as defined by their rwspec and clumnspec layut parameters. Yu shuld nt need t use either f the special size values: WRAP_CONTENT r MATCH_PARENT when cnfiguring the children f a GridLayut

Input Cntrls Input Cntrls Buttns Input Cntrls A buttn cnsists f

can create the buttn in yur layut in three ways: http://vvanhai.

cm/ 21 23 Input cntrls are the interactive cmpnents in yur app's

Andrid prvides a wide variety f cntrls yu can use in yur UI,

6 Input Cntrls Input Cntrls Buttns Input Cntrls A buttn cnsists f text r an icn (r bth text and an icn) that cmmunicates what actin ccurs when the user tuches it. Depending n whether yu want a buttn with text, an icn, r bth, yu can create the buttn in yur layut in three ways: Input cntrls are the interactive cmpnents in yur app's user interface. Andrid prvides a wide variety f cntrls yu can use in yur UI, such as buttns, text fields, seek bars, checkbxes, zm buttns, tggle buttns, and many mre. Cmmn Cntrls: Buttn Text view Check bx Radi buttn Tggle buttn Spinner Picker... Input Cntrls Buttns and events When the user clicks a buttn, the Buttn bject receives an nclick event. Using andrid:nclick attribute Using an OnClickListener

7 Input Cntrls Text Fields A text field allws the user t type text int yur app. It can be either single line r multi-line. Tuching a text field places the cursr and autmatically displays the keybard. In additin t typing, text fields allw fr a variety f ther activities, such as text selectin (cut, cpy, paste) and data lk-up via aut-cmpletin. Input Cntrls Text Fields - Aut-cmplete Suggestins Design Strings.xml Cde Input Cntrls Text fields - Specifying the Keybard Type Text fields can have different input types, such as number, date, passwrd, r address. Input Cntrls Checkbxes Checkbxes allw the user t select ne r mre ptins frm a set

Input Cntrls Radi Buttns Radi buttns allw the user

If it's nt necessary t shw all ptins side-by-side,

Input Cntrls Tggle Buttns A tggle buttn allws the

0 (API level 14) intrduces anther kind f tggle

8 Input Cntrls Radi Buttns Radi buttns allw the user t select ne ptin frm a set. If it's nt necessary t shw all ptins side-by-side, use a spinner instead. Input Cntrls Tggle Buttns A tggle buttn allws the user t change a setting between tw states. Andrid 4.0 (API level 14) intrduces anther kind f tggle buttn called a switch that prvides a slider cntrl, which yu can add with a Switch bject. Input Cntrls Spinners Spinners prvide a quick way t select ne value frm a set. In the default state, a spinner shws its currently selected value. Using design Or cde Input Cntrls Spinners

9 Input Cntrls Pickers Input Cntrls Pickers - TimePicker Andrid prvides cntrls fr the user t pick a time r pick a date as ready-t-use dialgs. Each picker prvides cntrls fr selecting each part f the time (hur, minute, AM/PM) r date (mnth, day, year). Other Views Other Views ListView ListView is a view grup that displays a list f scrllable items. The list items are autmatically inserted t the list using an Adapter that pulls cntent frm a surce such as an array r database query and cnverts each item result int a view that's placed int the list

10 Other Views ListView - Using Adapter Other Views ListView Using ListActivity AndridManifest.xml Other Views GridView GridView is a ViewGrup that displays items in a tw-dimensinal, scrllable grid. The grid items are autmatically inserted t the layut using a ListAdapter Other Views GridView Using custm Adapter

Menus Menus are a cmmn user interface cmpnent in many types f Menus

T prvide a familiar and cnsistent user experience, yu shuld use the

The ptins menu is where yu shuld include actins and ther ptins that

11 Menus Menus are a cmmn user interface cmpnent in many types f Menus applicatins. T prvide a familiar and cnsistent user experience, yu shuld use the Menu APIs t present user actins and ther ptins in Menu Optins Menu The ptins menu is where yu shuld include actins and ther ptins that are relevant t the current activity cntext yur activities. There are three fundamental types f menus Optins menu and app bar Cntext menu and cntextual actin mde Ppup menu Menu Optins Menu - Handling click events

Menu Cntextual Menus Menu Cntextual Menus - flating cntext menu A cntextual menu ffers actins that affect a specific item r cntext frame in the UI.

12 Menu Cntextual Menus Menu Cntextual Menus - flating cntext menu A cntextual menu ffers actins that affect a specific item r cntext frame in the UI. Yu can prvide a cntext menu fr any view, but they are mst ften used fr items in a ListView, GridView, r ther view cllectins in which the user can perfrm direct actins n each item. There are tw ways t prvide cntextual actins: Menu flating cntext menu cntextual actin mde. Cntextual Menus handling events implement ncntextitemselected() Register the View t which the cntext menu shuld be assciated by calling registerfrcntextmenu() and pass it the View. (In ncreate methd) Implement the ncreatecntextmenu() methd in yur Activity r Fragment. Menu Cntextual Menus handling events The cntextual actin mde is a system implementatin f ActinMde that fcuses user interactin tward perfrming cntextual actins. When a user enables this mde by selecting an item, a cntextual actin bar appears at the tp f the screen t present actins the user can perfrm n the currently selected item(s). While this mde is enabled, the user can select multiple items (if yu allw it), deselect items, and cntinue t navigate within the activity (as much as yu're willing t allw). The actin mde is disabled and the cntextual actin bar disappears when the user deselects all items, presses the BACK buttn, r selects the Dne actin n the left side f the bar

Menu Cntextual Menus handling events 49 50 Menu Menu Ppup Menus Ppup Menus A PpupMenu is a mdal menu anchred t a View.

It's useful fr: Prviding an verflw-style menu fr actins that relate t specific cntent.

13 Menu Cntextual Menus handling events Menu Menu Ppup Menus Ppup Menus A PpupMenu is a mdal menu anchred t a View. It appears belw the anchr view if there is rm, r abve the view therwise. It's useful fr: Prviding an verflw-style menu fr actins that relate t specific cntent. Prviding a secnd part f a cmmand sentence (such as a buttn marked "Add" that prduces a ppup menu with different "Add" ptins). Prviding a drp-dwn similar t Spinner that des nt retain a persistent selectin

14 Intents Intents T start an activity Intent An Activity represents a single screen in an app. Yu can start a new instance f an Activity by passing an Intent t startactivity(). The Intent describes the activity t start and carries any necessary data. If yu want t receive a result frm the activity when it finishes, call startactivityfrresult(). Yur activity receives the result as a separate Intent bject in yur activity's nactivityresult() callback An Intent is a messaging bject yu can use t request an actin frm anther app cmpnent. Althugh intents facilitate cmmunicatin between cmpnents in several ways, there are three fundamental use-cases: T start an activity T start a service T deliver a bradcast Intents Intent Types There are tw types f intents Explicit intents specify the cmpnent t start by name (the fullyqualified class name). Implicit intents d nt name a specific cmpnent, but instead declare a general actin t perfrm, which allws a cmpnent frm anther app t handle it.. 54 [1] Activity A creates an Intent with an actin descriptin and passes it t startactivity(). [2] The Andrid System searches all apps fr an intent filter that matches the intent. When a match is fund, [3] the system starts the matching activity (Activity B) by invking its ncreate() methd and passing it the Intent

Intents Start Explicit Intent Intents Start Implicit Intent An explicit intent is ne that yu use t launch a specific app cmpnent, such as a particular activity r service in yur app.

putextra(name, value) Using Bundle t transfer key-value pairs t target intent Intents T start a service A Service is a cmpnent that perfrms peratins in the backgrund withut a user

The Intent describes the service t start and carries any necessary data.

cm/guide/cmpnents/services.html http://vvanhai.wrdpress.cm/ 57 59 An implicit intent specifies an actin that can invke any app n the device able t perfrm the actin.

15 Intents Start Explicit Intent Intents Start Implicit Intent An explicit intent is ne that yu use t launch a specific app cmpnent, such as a particular activity r service in yur app. Yu can als put data t intent s can be use in target intent intent.putextra(name, value) Using Bundle t transfer key-value pairs t target intent Intents T start a service A Service is a cmpnent that perfrms peratins in the backgrund withut a user interface. Yu can start a service t perfrm a ne-time peratin (such as dwnlad a file) by passing an Intent t startservice(). The Intent describes the service t start and carries any necessary data. If the service is designed with a client-server interface, yu can bind t the service frm anther cmpnent by passing an Intent t bindservice() An implicit intent specifies an actin that can invke any app n the device able t perfrm the actin. Using an implicit intent is useful when yur app cannt perfrm the actin, but ther apps prbably can and yu'd like the user t pick which app t use. Cmmn Intents Intents T deliver a bradcast A bradcast is a message that any app can receive. The system delivers varius bradcasts fr system events, such as when the system bts up r the device starts charging. Yu can deliver a bradcast t ther apps by passing an Intent t sendbradcast(), sendorderedbradcast(), r sendstickybradcast()

Lcalizing with Resurces Lcalizing with Resurces Resurce-Switching Lcalizing with Resurces Resurces are text strings, layuts, sunds, graphics, and any ther static data that yur Andrid applicatin needs.

16 Lcalizing with Resurces Lcalizing with Resurces Resurce-Switching Lcalizing with Resurces Resurces are text strings, layuts, sunds, graphics, and any ther static data that yur Andrid applicatin needs. An applicatin can include multiple sets f resurces, each custmized fr a different device cnfiguratin. When a user runs the applicatin, Andrid autmatically selects and lads the resurces that best match the device Andrid will run n many devices in many regins. T reach the mst users, yur applicatin shuld handle text,. audi files, numbers, currency, and graphics in ways apprpriate t the lcales where yur applicatin will be used. Lcalizing with Resurces Using Resurces fr Lcalizatin Suppse that yur applicatin's default language is English. Suppse als that yu want t lcalize all the text in yur applicatin t French, and mst f the text in yur applicatin (everything except the applicatin's title) t Japanese. In this case, yu culd create three alternative strings.xml files, each stred in a lcale-specific resurce directry

17 Lcalizing with Resurces Example Lcalizing with Resurces Example Fragments Fragments Intrductin A Fragment represents a behavir r a prtin f user interface in an Activity. Yu can cmbine multiple fragments in a single activity t build a multi-pane UI and reuse a fragment in multiple activities. Yu can think f a fragment as a mdular sectin f an activity, which has its wn lifecycle, receives its wn input events, and which yu can add r remve while the activity is running (srt f like a "sub activity" that yu can reuse in different activities)

18 Fragments Creating a Fragment Fragments Creating a Fragment A fragment must always be embedded in an activity and the fragment's lifecycle is directly affected by the hst activity's lifecycle. T create a fragment, yu must create a subclass f Fragment (r an existing subclass f it). The Fragment class has cde that lks a lt like an Activity. Fragments Adding a fragment t an activity 1. Declare the fragment inside the activity's layut file. 2. Or, prgrammatically add the fragment t an existing ViewGrup Dialgs

Dialgs Intrductin Dialgs Intrductin A dialg is a small windw that prmpts the user t make a

A dialg des nt fill the screen and is nrmally used fr mdal events that require users t take

cm/ 73 Types: AlertDialg: A dialg that can shw a title, up t three buttns, a list f

DatePickerDialg r TimePickerDialg: A dialg with a pre-defined UI that allws the user t

19 Dialgs Intrductin Dialgs Intrductin A dialg is a small windw that prmpts the user t make a decisin r enter additinal infrmatin. A dialg des nt fill the screen and is nrmally used fr mdal events that require users t take an actin befre they can prceed. Dialgs Sample 73 Types: AlertDialg: A dialg that can shw a title, up t three buttns, a list f selectable items, r a custm layut. DatePickerDialg r TimePickerDialg: A dialg with a pre-defined UI that allws the user t select a date r time. Using DialgFragment t manage the dialg ensures that it crrectly handles lifecycle events such as when the user presses the Back buttn r rtates the screen

20 Dialgs Custm Dialg Summary

Design Patterns. Collectional Patterns. Session objectives 11/06/2012. Introduction. Composite pattern. Iterator pattern

Design Patterns. Collectional Patterns. Session objectives 11/06/2012. Introduction. Composite pattern. Iterator pattern Design Patterns By Võ Văn Hải Faculty f Infrmatin Technlgies HUI Cllectinal Patterns Sessin bjectives Intrductin Cmpsite pattern Iteratr pattern 2 1 Intrductin Cllectinal patterns primarily: Deal with