GUI og XML programmering

GUI og XML programmering

Hvor meget kode og hvor meget XML?

Agenda• Clicker applikation med knapper i

stede for ListActivity!• Applikation med flere Activities og

Views– Data fra en Activity til en anden

• Forberedelse til RESTFul service opslag– Brug af Android Service ->Tilføjelse af

Android Preferences (Host adresse)

Motivation

Sådan en apps skal vi også have

Android Application Class

Svarer ”nogenlunde” til J2ME Midlet “Base class for those who need to maintain

global application state. You can provide your own implementation by specifying its name in your AndroidManifest.xml's <application> tag, which will cause that class to be instantiated for you when the process for your application/package is created.”

Kan håndterer onCreate, onTerminate, onLowMemory og onConfigurationChanged events

Eksempel Application class// ** The Application Class *************************************** //

// Appliction Class Extenstion

import android.app.Application;import android.content.res.Configuration;

public class MyApplication extends Application { private static MyApplication singleton; // Returns the application instance public static MyApplication getInstance() { return singleton; } @Override public final void onCreate() { super.onCreate(); singleton = this; }}

// Manifest entry<application android:icon="@drawable/icon" android:name="MyApplication"> [... Manifest nodes ...]</application>

Android Activity Class (Android Activities) Brugergrænseflade og brugeraktioner er en aktivitet

// ** The Activity Class ****************************************** //

package com.paad.myapplication;

import android.app.Activity;import android.os.Bundle;

public class MyActivity extends Activity {

/** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); }}

// ** Activity layout in XML<activity android:label="@string/app_name" android:name=".MyActivity"></activity>

7 | 2010

Activity bruger View og Layout til UI og interaktion med brugeren

• Activity og Form svarer til hinanden: Præsentere et skærmbillede 1:1• Activity bruger Views, Layout og Widgets/Controls (Standard eller egne)• Der findes en sæt af specielt designede Activities i forhold til standard

widgets• MapActivty, List Activty, ExpandableListActivty og TabActivity

• Tilstand styret af Android Framework.• Mange Activities i en applikation kan give behov for eget Application objekt.

“This hierarchy tree can be as simple or complex as you need it to be, and you can build it up using Android's set of predefined widgets and layouts, or with custom Views that you create yourself”.

Screen Layout

8 | 2010

Klassehieraki

Activity ->Layout-> View -> Widget &| ->UI Control

View er adgangen til skærmressourcen på enheden Layout er manageren, der kontrollere View opsætningen Widget er en kontrol i View, og som ligner den rigtige

verdens ting. Et ur eller et kompas. Kan også være et View UI control er grafiske enheder som knapper eller ”gestures”

@Overridepublic void onCreate(Bundle icicle) { super.onCreate(icicle);setContentView(R.layout.main);TextView myTextView = (TextView)findViewById(R.id.myTextView);}

@Overridepublic void onCreate(Bundle icicle) { super.onCreate(icicle);

TextView myTextView = new TextView(this); setContentView(myTextView);

myTextView.setText("Hello, Android");}

Klassediagram Et eksempel Fra http://www.droidnova.com/playing-with-graphics-in-android-part-i,147.html

Layout hvordan XML og kode<?xml version="1.0" encoding="utf-8"?>

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

android:orientation="vertical"

android:layout_width="fill_parent"

android:layout_height="fill_parent">

<TextView

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="Enter Text Below"

/>

<EditText

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:text="Text Goes Here!"

/>

</LinearLayout>

LinearLayout ll = new LinearLayout(this);

ll.setOrientation(LinearLayout.VERTICAL);

TextView myTextView = new TextView(this);

EditText myEditText = new EditText(this);

myTextView.setText("Enter Text Below");

myEditText.setText("Text Goes Here!");

int lHeight = LinearLayout.LayoutParams.FILL_PARENT;

int lWidth = LinearLayout.LayoutParams.WRAP_CONTENT;

ll.addView(myTextView, new LinearLayout.LayoutParams(lHeight, lWidth));

ll.addView(myEditText, new LinearLayout.LayoutParams(lHeight, lWidth));

setContentView(ll);

Hvad er der så at holde styr på i GUI’en?http://developer.android.com/guide/topics/ui/index.html

View http://developer.android.com/reference/android/view/View.html

ViewGroup http://developer.android.com/reference/android/view/ViewGroup.html

Layout http://developer.android.com/reference/android/widget/LinearLayout.html

Widget Package http://developer.android.com/reference/android/widget/package-summary.html

Menu http://developer.android.com/guide/topics/ui/menus.html (Menu knappen)

View properties: Statisk og/eller dynamisk. UI Events

Define an event listener and register it with the View Override an existing callback method for the View (Custom Views) Menu Events

Event Listnershttp://tseng-blog.nge-web.net/blog/2009/02/14/implementing-listeners-in-your-android-java-application/

1. Inline Clas Implementation 2. Bruge “Implements” metoden 3. Bruge en variabel til en listner metode 4. XML attribute android:onClick="click1”

• Sørg for at have en void click1(View v){ …} i Activity

Event Listnershttp://tseng-blog.nge-web.net/blog/2009/02/14/implementing-listeners-in-your-android-java-application/

1. Inline Clas Implementation 2. Bruge “Implements” metoden 3. Bruge en variabel til en listner metode 4. XML attribute android:onClick="click1”

• Sørg for at have en void click1(View v){ …} metode i Activity

Data fra en Activity til en anden

1. Intent og Events2. Content Provider3. Shared Preferences4. SQLLite5. Filsystemet6. En extern server7. ??

1. I samme Apps ?2. I forskellige Apps?3. På forskellige Smartphones

Samme AppIntent intent = new Intent();

intent.putExtra(BackDoorMan.REQ_Q_A, mes);

intent.setClassName("dk.euc.clicker", "dk.euc.clicker.SecActivtity");try {startActivity(intent);} catch (Exception e) {

@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);

setContentView(R.layout.clicker);question = getIntent().getExtras().getString(BackDoorMan.REQ_Q_A);

Preferences og opsætning1. Er tilknyttet egen Acitivity en xml fil og “hooks” i

Preferencespublic class Preferences extends PreferenceActivity {public static final String PREF_CLICKER_HOST = "PREF_CLICKER_HOST";SharedPreferences prefs;@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);addPreferencesFromResource(R.xml.samplepreferences);}}<PreferenceScreen

xmlns:android="http://schemas.android.com/apk/res/android"><PreferenceCategory android:title="@string/sample_pref_categ_3"><EditTextPreference android:key="PREF_CLICKER_HOST"android:title="@string/sample_pref_txt_dialog" android:dialogTitle="@string/sample_pref_txt_dialog"android:summary="Preference Summary" /></PreferenceCategory></PreferenceScreen>

Preferences internt opret

// Retrieve an editor to modify the shared preferences. SharedPreferences.Editor editor = mySharedPreferences.edit();

// Store new primitive types in the shared preferences object. editor.putBoolean("isTrue", true); editor.putFloat("lastFloat", 1f); editor.putInt("wholeNumber", 2); editor.putLong("aNumber", 3l); editor.putString("textEntryValue", "Not Empty");

// Commit the changes. editor.commit();

Preferences internt læspublic void loadPreferences() { // Get the stored preferences int mode = Activity.MODE_PRIVATE; SharedPreferences mySharedPreferences = getSharedPreferences(MY_PREFS, mode);

// Retrieve the saved values. boolean isTrue = mySharedPreferences.getBoolean("isTrue", false); float lastFloat = mySharedPreferences.getFloat("lastFloat", 0f); int wholeNumber = mySharedPreferences.getInt("wholeNumber", 1); long aNumber = mySharedPreferences.getLong("aNumber", 0); String stringPreference = mySharedPreferences.getString("textEntryValue", "");}