How does Android textview Implement Message scrolling?

Step 1: Layout file, mainly in red

<? 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" Android: weightsum = "1">

<Scrollview Android: layout_width = "fill_parent"
Android: scrollbars = "vertical"
Android: fadingedge = "vertical"
Android: Id = "@ + ID/scrollview"
Android: layout_margintop = "10px"
Android: layout_marginleft = "10px"
Android: layout_marginright = "10px"
Android: layout_marginbottom = "10px"
Android: layout_height = "20dp">

<Linearlayout Android: Orientation = "vertical" Android: layout_width = "fill_parent" Android: layout_height = "fill_parent">

<Textview Android: text = "first line" Android: textcolor = "# 1a1a1a" Android: Background = "# c1cdcd" Android: textsize = "13dp" Android: id = "@ + ID/textview1" Android: layout_width = "fill_parent" Android: layout_height = "20dp"> </textview>

<Textview Android: text = "Row 2" Android: textcolor = "# 1a1a1a" Android: Background = "# c1cdcd" Android: textsize = "13dp" Android: id = "@ + ID/textview2" Android: layout_width = "fill_parent" Android: layout_height = "20dp"> </textview>

<Textview Android: text = "Row 3" Android: textcolor = "# 1a1a1a" Android: Background = "# c1cdcd" Android: textsize = "13dp" Android: id = "@ + ID/textview3" Android: layout_width = "fill_parent" Android: layout_height = "20dp"> </textview>

<Textview Android: text = "Row 4" Android: textcolor = "# 1a1a1a" Android: Background = "# c1cdcd" Android: textsize = "13dp" Android: id = "@ + ID/textview4" Android: layout_width = "fill_parent" Android: layout_height = "20dp"> </textview>

</Linearlayout>

</Scrollview>

</Linearlayout>

 

 

Part 2: java files

Package com. Exam;

Import Android. App. activity;
Import Android. OS. Bundle;
Import Android. OS. Handler;
Import Android. OS. logoff;
Import Android. OS. message;
Import Android. widget. scrollview;

Public class exampleactivity extends activity {
/** Called when the activity is first created .*/

Private scrollview;

@ Override
Public void oncreate (bundle savedinstancestate ){
Super. oncreate (savedinstancestate );
Setcontentview (R. layout. Main );

Scrollview = (scrollview) findviewbyid (R. Id. scrollview );
Scrollview. setverticalscrollbarenabled (false );
Looperthread mclockthread = new looperthread ();
Mclockthread. Start ();

}

// Handler used for inter-thread Communication
Class testhandler extends handler {
Public testhandler (low.logoff ){
Super (logoff );
}

@ Override
Public void handlemessage (Message MSG ){

Bundle bundle = msg. getdata ();
Int loop = bundle. getint ("loop ");
System. Out. println ("loop:" + loop );
If (loop = 4)
Scrollview. scrollto (0, 0); // changes the position of the scroll bar.
Else
Scrollview. scrollto (loop * 29, loop * 29 + 30 + loop * 1); // change the position of the scroll bar
Super. handlemessage (MSG );
}
}

// Multi-thread control loop

Class looperthread extends thread {

Public void run (){
Super. Run ();
Try {
Int loop = 0;
While (true ){
Thread. Sleep (3000 );
Message MSG = new message ();
Bundle bundle = new bundle ();
Bundle. putint ("loop", loop );
MSG. setdata (bundle );
New testhandler (Looper. getmainlooper (). sendmessage (MSG );
Loop ++;
If (loop = 5 ){
Loop = 0;
}
}

} Catch (interruptedexception e ){
E. printstacktrace ();
}

}
}

}