Road to Android development-UI Component 4

Continue to learn about the UI components today, mainly including progressbar, seekbar, imageview, and tabhost ).

 

1. ProgressBar component

The following is a case study:

 

First, createProgressBarActivity Class

Case implementation process:

Public class progressbardemo extendsactivity {

Progressbar = NULL;

Inti = 0;

Intprogressbarmax = 0;

Handler handler = new handler ();

@ Override

Publicvoid oncreate (bundlesavedinstancestate ){

Super. oncreate (savedinstancestate );

Setcontentview (R. layout.SS);

Findviews ();

}

 

Private void findviews (){

Progressbar = (progressbar) This. findviewbyid (R. Id.Progressbar2);

Progressbar. setmax (1000 );

Progressbarmax = progressbar. getmax ();

New thread (newrunnable (){

Public void run (){

While (I <progressbarMax ){

I = doWork ();

Handler. post (newRunnable (){

Public void run (){

Progressbar. setProgress (I );

}

});

Try {

Thread.Sleep(50 );

} Catch (InterruptedException e ){

// TODO Auto-generated catch block

E. printStackTrace ();

}

}

}

}). Start ();

}

Public int doWork (){

Return ++ I;

}

}

 

Code demonstration in the layout file progressbar. xml

 

<? Xml version ="1.0"Encoding ="UTF-8"?>

<LinearLayoutxmlns: android =Http://schemas.android.com/apk/res/android"

Android: layout_width ="Fill_parent"

Android: layout_height ="Fill_parent"

Android: orientation ="Vertical">

 

<TextView

Android: layout_width ="Fill_parent"

Android: layout_height ="Wrap_content"

Android: text ="Progress bar demonstration"/>

<ProgressBar

Android: layout_width ="Wrap_content"

Android: layout_height ="Wrap_content"

Android: max ="1000"

Android: progress ="100"

Android: id ="@ + Id/progressbar1"

/>

<ProgressBar

Style ="@ Android: style/Widget. ProgressBar. Horizontal"

Android: layout_margintop ="30dp"

Android: layout_width ="Fill_parent"

Android: layout_height ="Wrap_content"

Android: max ="1000"

Android: Progress ="100"

Android: secondaryprogress ="300"

Android: Id ="@ + Id/progressbar2"

/>

</Linearlayout>

 

 

Configuration file:

 <Activity

Android: Label ="@ String/app_name"

Android: Name =".Progressbardemo">

<Intent-filter>

<Action Android: Name ="Android. intent. action. MAIN"/>

 

<Category Android: Name ="Android. intent. category. LAUNCHER"/>

</Intent-filter>

</Activity>

The result is returned:

 

 

2. TabHost (switch component)

Internal class:

1. Interface tabhost. ontabchangelistener

Interface defines the callback function called when the tab is changed.

 

2. interfaceTabHost. TabContentFactory

Tab content is generated when a tab is selected

3. class TabHost. TabSpec

A separate tab. Each option card has a tab indicator, content, and tag to facilitate recording.

Method:

Public voidaddTab (TabHost. TabSpec tabSpec)

Add a new tab

Parameters

TabSpec -- specify how to create the indicator and content.

 

The following is a case study:

 

First, create an Activity class named TabHost.

Code reference:

Public classTabHostDemoExtendsTabActivity {

TabHost tabHost =Null;

 

@ Override

Protected voidOnCreate (Bundle savedInstanceState ){

Super. OnCreate (savedInstanceState );

TabHost =This. GetTabHost ();

LayoutInflaterinflater = LayoutInflater.From(This);

// Obtain it to tabhost_layout.

Inflater. inflate (R. layout.Tabhost_layout, TabHost. getTabContentView (),True);

TabHost. addTab (tabHost. newTabSpec ("tab1"). setIndicator ("Switch tag"). setContent (R. id.Tab1));

TabHost. addTab (tabHost. newTabSpec ("tab2"). setIndicator ("SeekBardemo ").

SetContent (NewIntent (This, SeekBarDemo.Class)));

 

// SetIndicator indicates the label name tab1 tab2 tab3 is his ID value

TabHost. addTab (tabHost. newTabSpec ("tab3"). setIndicator ("ImageViewDemo ").

Setcontent (NewIntent (This, Imageviewdemo.Class)));

Findviews ();

}

 

Private voidFindviews (){

Button BTN = (button)This. Findviewbyid (R. Id.Button);

// Listener

BTN. setonclicklistener (NewView. onclicklistener (){

@ Override

Public voidOnclick (view v ){

// Tabhost. setcurrenttab (1 );

Tabhost. setcurrenttabbytag ("tab2 ");

}

});

}

}

Code in tabhost. XML in the layout file:

<Tabhostxmlns: Android =Http://schemas.android.com/apk/res/android"

Android: layout_width ="Fill_parent"

Android: layout_height ="Fill_parent">

<Linearlayout

Android: Id ="@ + Id/tab1"

Android: layout_width ="Match_parent"

Android: layout_height ="Match_parent"

Android: Orientation ="Vertical">

<Button

Android: id ="@ + Id/button"

Android: layout_width ="Match_parent"

Android: layout_height ="Wrap_content"

Android: text ="Switch to tab2"/>

<ImageView

Android: layout_width ="Wrap_content"

Android: layout_height ="Wrap_content"

Android: src ="@ Drawable/pig"

Android: scaleType ="FitCenter"

Android: layout_marginTop ="20dp"

/>

</LinearLayout>

</TabHost>

 

The configuration file is as follows:

<Application

Android: icon ="@ Drawable/ic_launcher"

Android: label ="@ String/app_name">

<Activity

Android: label ="@ String/app_name"

Android: name =". HostDemo">

<Intent-filter>

<Action android: name ="Android. intent. action. MAIN"/>

 

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

</Intent-filter>

</Activity>

<Activity

Android: Name =". SeekBarDemo">

</Activity>

<Activity

Android: Name =". ImageViewDemo">

</Activity>

</Application>

 

Effect

 

3. SeekBar component

The following is a case study:

First, createSeekBarActivity Class

Case implementation process:

 

Public classSeekBarDemoExtendsActivity
ImplementsOnSeekBarChangeListener {

SeekBar seekbar =Null;

 

@ Override

Protected voidOnCreate (Bundle savedInstanceState ){

Super. OnCreate (savedInstanceState );

 

This. SetContentView (R. layout.Seekbar_layout);

FindViews ();

}

 

Private voidFindViews (){

Seekbar = (SeekBar)This. FindViewById (R. id.Seekbar);

// Register the listener

Seekbar. setOnSeekBarChangeListener (This);

}

@ Override // method of listening

Public voidOnProgressChanged (SeekBar seekBar,
IntProgress,

BooleanFromUser ){

Log.D("TAG", "changed:" + String.ValueOf(SeekBar. getProgress ()));

}

 

@ Override

Public voidOnStartTrackingTouch (SeekBar seekBar ){

Log.D("Tag", "Start:" + String.ValueOf(Seekbar. getprogress ()));

}

 

@ Override

Public voidOnstoptrackingtouch (seekbar ){

Log.D("Tag", "Stop:" + String.ValueOf(Seekbar. getprogress ()));

}

}

Layout FileSeekbarCode demonstration in. xml

 

<Linearlayoutxmlns: Android =Http://schemas.android.com/apk/res/android"

Android: layout_width ="Match_parent"

Android: layout_height ="Match_parent"

Android: Orientation ="Vertical">

<Seekbar

Android: layout_width ="Fill_parent"

Android: layout_height ="Wrap_content"

Android: max ="1000"

Android: id ="@ + Id/seekbar"/>

</LinearLayout>

Configuration file:

<Activity

Android: label ="@ String/app_name"

Android: name =".SeekBarDemo">

<Intent-filter>

<Action android: name ="Android. intent. action. MAIN"/>

 

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

</Intent-filter>

</Activity>

Effect