[mono-android] How to implement ViewPager from compatibility package .jar
Stuart Lodge
me at slodge.com
Sun Feb 12 16:15:36 UTC 2012
My latest code actually looks a lot like that - its easy enough to just
play with the code inside Draw to achieve what you want.
Hope that helps
Stuart
// original credit to: //
https://github.com/brucejcooper/Android-Examples/blob/master/PagingScrollerExample/src/com/eightbitcloud/pagingscroller/PageIndicator.java
public class HorizontalPagerIndicator : View
{
private HorizontalPager _pager;
private Paint _textPaint;
private Paint _inactiveDotPaint;
private Paint _dotPaint;
private Paint _dotBackgroundPaint;
private int _textHeight;
private int _ascent;
private int _cellSize;
private float _displayDensity;
public HorizontalPagerIndicator(Context context, IAttributeSet attrs)
: base(context, attrs)
{
InitPaints(context);
}
public HorizontalPagerIndicator(Context context)
: base(context)
{
InitPaints(context);
}
private void InitPaints(Context context)
{
_displayDensity = context.Resources.DisplayMetrics.Density;
_textPaint = new Paint {AntiAlias = true, TextSize =
DeviceIndependentToPixels(14), Color = Color.Black};
_inactiveDotPaint = new Paint { AntiAlias = true, Color =
Color.Gray };
_dotPaint = new Paint {AntiAlias = true, Color = Color.White};
_dotBackgroundPaint = new Paint { AntiAlias = true, Color
= Color.Cyan };
_ascent = -(int)_textPaint.Ascent();
_textHeight = (int)(_ascent + _textPaint.Descent());
_cellSize = DeviceIndependentToPixels(_textHeight + 6);
}
public HorizontalPager Pager
{
get { return _pager; }
set
{
if (_pager != null)
{
_pager.ScreenChanged -= PagerOnScreenChanged;
}
_pager = value;
if (_pager != null)
{
_pager.ScreenChanged += PagerOnScreenChanged;
}
UpdatePageCount();
}
}
private void PagerOnScreenChanged(object sender, EventArgs eventArgs)
{
Invalidate();
}
public void UpdatePageCount()
{
RequestLayout();
Invalidate();
}
private int NumPages
{
get
{
return _pager == null ? 1 : _pager.ChildCount;
}
}
private int ActivePage
{
get
{
return _pager == null ? 0 : _pager.CurrentScreen;
}
}
protected override void OnMeasure(int widthMeasureSpec, int
heightMeasureSpec)
{
SetMeasuredDimension(MeasureWidth(widthMeasureSpec),
MeasureHeight(heightMeasureSpec));
}
private int MeasureWidth(int measureSpec)
{
var result = 0;
var specMode = MeasureSpec.GetMode(measureSpec);
var specSize = MeasureSpec.GetSize(measureSpec);
if (specMode == MeasureSpecMode.Exactly)
{
// We were told how big to be
result = specSize;
}
else
{
result = NumPages * _cellSize;
if (specMode == MeasureSpecMode.AtMost)
{
// Respect AT_MOST value if that was what is called for by
// measureSpec
result = Math.Min(result, specSize);
}
}
return result;
}
private int MeasureHeight(int measureSpec)
{
var result = 0;
var specMode = MeasureSpec.GetMode(measureSpec);
var specSize = MeasureSpec.GetSize(measureSpec);
if (specMode == MeasureSpecMode.Exactly)
{
// We were told how big to be
result = specSize;
}
else
{
result = _cellSize;
if (specMode == MeasureSpecMode.AtMost)
{
// Respect AT_MOST value if that was what is called for by
// measureSpec
result = Math.Min(result, specSize);
}
}
return result;
}
protected override void OnDraw(Canvas canvas)
{
base.OnDraw(canvas);
var numPages = NumPages;
var activePageIndex = ActivePage;
var x = (canvas.Width - numPages * _cellSize)/2;
//var smallBorder = _cellSize/4;
//var slightlySmallerBorder = smallBorder - 1;
var emptyDotSize = _cellSize/4;
var dotOffset = (_cellSize - emptyDotSize) / 2;
for (var i = 0; i < numPages; i++, x += _cellSize)
{
if (i == activePageIndex)
{
//var txt = (i +
1).ToString(System.Globalization.CultureInfo.CurrentUICulture);
//var bounds = new Rect();
//_textPaint.GetTextBounds(txt, 0, txt.Length, bounds);
//var oval = new RectF(x + smallBorder,
smallBorder, x + _cellSize - smallBorder, _cellSize - smallBorder);
var oval = new RectF(x + dotOffset, dotOffset, x +
dotOffset + emptyDotSize, dotOffset + emptyDotSize);
var oval1 = new RectF(x + dotOffset - 1, dotOffset
- 1, x + dotOffset + emptyDotSize + 1, dotOffset + emptyDotSize + 1);
canvas.DrawOval(oval1, _dotBackgroundPaint);
canvas.DrawOval(oval, _dotPaint);
//canvas.DrawText(txt, x + (_cellSize -
bounds.Width()) / 2, (_cellSize - _textHeight) / 2 + _ascent,
_textPaint);
}
else
{
var oval = new RectF(x + dotOffset, dotOffset, x +
dotOffset + emptyDotSize, dotOffset + emptyDotSize);
canvas.DrawOval(oval, _inactiveDotPaint);
}
}
}
private int DeviceIndependentToPixels(int dpi)
{
return (int)Math.Round((float)dpi * _displayDensity);
}
}
2012/2/12 Gerry High <ghigh at hightg.com>
> Stuart,
>
> Have you made any more changes to this code? Also, do you have a photo of
> how this looks? I'm thinking of adding a pager control to my app--I use a
> UIPagerController in my iPhone version and am looking for something like
> the UIPagerControl (
> http://books.google.com/books?id=lFe0EwHUREEC&pg=PA125&lpg=PA125&dq=uipagercontrol&source=bl&ots=-SNjmXH5Z3&sig=Aa0tUicP1yWkcJ0cA8i8STg6_3w&hl=en&sa=X&ei=2yA3T8WzA8mEsALg-fSiAg&ved=0CC8Q6AEwAg#v=onepage&q=uipagercontrol&f=false
> )
>
> Thanks,
> Gerry
>
>
> *
> *
>
> On Feb 4, 2012, at 2:33 PM, Stuart Lodge wrote:
>
> If it helps I've also just ported a Page Indicator from the Java sample on
> this blog:
> http://buildmobile.com/how-to-build-an-android-pager-component/#fbid=TnZmgHdBfhF (license
> unclear?)
>
> Still some sizing issues to sort out - and it would be nice to make it
> more "animated" - but it basically works
>
> Stuart
>
> using System;using Android.Content;using Android.Graphics;using Android.Util;using Android.Views;
> namespace SocialStorm.Android.Controls
> {
> public class HorizontalPagerIndicator : View
> {
> private HorizontalPager _pager;
> private Paint _textPaint;
> private Paint _dotPaint;
> private int _textHeight;
> private int _ascent;
> private int _cellSize;
>
> public HorizontalPagerIndicator(Context context, IAttributeSet attrs)
> : base(context, attrs)
> {
> InitPaints();
> }
>
>
> public HorizontalPagerIndicator(Context context)
> : base(context)
> {
> InitPaints();
> }
>
> private void InitPaints()
> {
> _textPaint = new Paint {AntiAlias = true, TextSize = 10, Color = Color.Black};
>
> _dotPaint = new Paint {AntiAlias = true, Color = Color.Gray};
>
> _ascent = -(int)_textPaint.Ascent();
> _textHeight = (int)(_ascent + _textPaint.Descent());
> _cellSize = _textHeight + 6;
> }
>
>
> public HorizontalPager Pager
> {
> get { return _pager; }
> set
> {
>
> if (_pager != null)
> {
> _pager.ScreenChanged -= PagerOnScreenChanged;
> }
> _pager = value;
> if (_pager != null)
> {
> _pager.ScreenChanged += PagerOnScreenChanged;
> }
> UpdatePageCount();
> }
> }
>
> private void PagerOnScreenChanged(object sender, EventArgs eventArgs)
> {
> Invalidate();
> }
>
> public void UpdatePageCount()
> {
> RequestLayout();
> Invalidate();
> }
>
> private int NumPages
> {
> get
> {
> return _pager == null ? 1 : _pager.ChildCount;
> }
> }
>
> private int ActivePage
> {
> get
> {
> return _pager == null ? 0 : _pager.CurrentScreen;
> }
> }
>
>
> protected override void OnMeasure(int widthMeasureSpec, int heightMeasureSpec)
> {
> SetMeasuredDimension(MeasureWidth(widthMeasureSpec), MeasureHeight(heightMeasureSpec));
> }
>
> private int MeasureWidth(int measureSpec)
> {
> var result = 0;
> var specMode = MeasureSpec.GetMode(measureSpec);
> var specSize = MeasureSpec.GetSize(measureSpec);
>
> if (specMode == MeasureSpecMode.Exactly)
> {
> // We were told how big to be
> result = specSize;
> }
> else
> {
> result = NumPages * _cellSize;
> if (specMode == MeasureSpecMode.AtMost)
> {
> // Respect AT_MOST value if that was what is called for by
> // measureSpec
> result = Math.Min(result, specSize);
> }
> }
> return result;
> }
>
> private int MeasureHeight(int measureSpec)
> {
> var result = 0;
> var specMode = MeasureSpec.GetMode(measureSpec);
> var specSize = MeasureSpec.GetSize(measureSpec);
>
>
> if (specMode == MeasureSpecMode.Exactly)
> {
> // We were told how big to be
> result = specSize;
> }
> else
> {
> result = _cellSize;
> if (specMode == MeasureSpecMode.AtMost)
> {
> // Respect AT_MOST value if that was what is called for by
> // measureSpec
> result = Math.Min(result, specSize);
> }
> }
> return result;
> }
>
> protected override void OnDraw(Canvas canvas)
> {
> base.OnDraw(canvas);
>
> var count = NumPages;
> var current = ActivePage;
>
> int x = 0;
> for (int i = 0; i < count; i++, x += _cellSize)
> {
> if (i == current)
> {
> String txt = (i + 1).ToString();
> var bounds = new Rect();
> _textPaint.GetTextBounds(txt, 0, txt.Length, bounds);
> var oval = new RectF(x + 1, 1, x + _cellSize - 2, _cellSize - 2);
> canvas.DrawOval(oval, _dotPaint);
> canvas.DrawText(txt, x + (_cellSize - bounds.Width()) / 2, (_cellSize - _textHeight) / 2 + _ascent, _textPaint);
> }
> else
> {
> const int dotSize = 5;
> var dotOffset = (_cellSize - dotSize) / 2;
> var oval = new RectF(x + dotOffset, dotOffset, x + dotOffset + dotSize, dotOffset + dotSize);
> canvas.DrawOval(oval, _dotPaint);
> }
> }
> }
>
> }
> }
>
>
> On 25 January 2012 21:20, Tomasz Cielecki <tomasz at ostebaronen.dk> wrote:
>
>> Do what you want as long as it does not violate the License :)
>>
>> On Wed, Jan 25, 2012 at 8:47 PM, Miljenko Cvjetko
>> <mcvjetko at holisticware.net> wrote:
>> > Hi
>> >
>> > On 2012.01.25 14:12, Tomasz Cielecki wrote:
>> >
>> > I have made a port of a Horizontal Pager which can be found
>> > here: https://github.com/Cheesebaron/MonoDroid.HorizontalPager
>> >
>> > Great job!
>> > Thanks.
>> >
>> > may I put it together as VS item template?
>> > ... and publish it of course ...
>> >
>> > regards
>> >
>> > mel
>> >
>> >
>> > It works in a similar manner. This is an entirely C# implementation.
>> >
>> > On Jan 25, 2012 12:52 PM, "Stuart Lodge" <me at slodge.com> wrote:
>> >>
>> >> I don't suppose anyone has already done this and would like to share
>> the
>> >> source (just asking in case)
>> >>
>> >> If not, then I'll have a go... as I'd quite like to use the ViewPager
>> in
>> >> this app.
>> >>
>> >> On 23 January 2012 21:24, Jonathan Pryor <jonp at xamarin.com> wrote:
>> >>>
>> >>> On Jan 21, 2012, at 7:36 AM, k0ng wrote:
>> >>> > I want to use ViewPager as demo in this website
>> >>> >
>> >>> >
>> http://geekyouup.blogspot.com/2011/07/viewpager-example-from-paug.html
>> >>>
>> >>> Right now, it won't be easy, as you need to manually bind the Java
>> types.
>> >>>
>> >>> In a future release, we'll be providing a tool to simplify the binding
>> >>> process.
>> >>>
>> >>> If you really want to hand-bind them now, see:
>> >>>
>> >>> The base Java class:
>> >>>
>> https://github.com/xamarin/monodroid-samples/blob/master/SanityTests/Adder.java
>> >>> The C# glue code for inheritance:
>> >>>
>> https://github.com/xamarin/monodroid-samples/blob/master/SanityTests/ManagedAdder.cs
>> >>>
>> >>> - Jon
>> >>>
>> >>> _______________________________________________
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>> >>>
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>> >>>
>> >>
>> >>
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>> >
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>> >
>> > --
>> > Miljenko Cvjetko dipl.ing. ET
>> > Direktor/CEO
>> > Projektant rješenja/Solution Architect
>> > Razvojni programer/Senior developer
>> > Voditelj projekta/Project Manager
>> >
>> > IX južna obala 13
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>> > F: 385 1 7779556
>> > e: mcvjetko at holisticware.net
>> > w: http://www.holisticware.net
>>
>>
>>
>> --
>> Med Venlig Hilsen / With Best Regards
>> Tomasz Cielecki
>> http://ostebaronen.dk
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