我正在学习Xamarin.Android最近，我试图实现页面浏览器与点滑块为我的做法从过去的几天，但未能实现它，我曾经从流行的中心如stackoverflow和github引用了许多解决方案，但没有这样做。 任何人都可以请解释我如何在xamarin.android中实现带点滑块的视图页面。 我附上了一张照片供您参考，这将使您清楚地了解我的要求。 
如何在Xamarin.Android中使用Dot Sliders实现ViewPagers？
正如你所看到的，他正在使用点滑块滑动页面，我试图这样做。 请解释如何在Xamarin.Android（Native）
看看这个示例项目'Android-ViewPagerIndicator Xamarin.Android'。您需要包含库，其中有多个实现来在viewpager上显示指标。
首先定义自己的圈子页面指示符让它成为CirclePageIndicator.cs添加到您的项目（不活动的文件） 使用Android.Content;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Android.App;
using Android.Content;
using Android.OS;
using Android.Runtime;
using Android.Views;
using Android.Widget;
using Android.Graphics;
using Android.Support.V4.View;
using Android.Util;
using Java.Lang;
using Java.Interop;
namespace MyApplication.Droid.Library
{
public class CirclePageIndicator : View,PageIndicator
{
const int HORIZONTAL = 0;
const int VERTICAL = 1;
private float mRadius;
private Paint mPaintPageFill;
private Paint mPaintStroke;
private Paint mPaintFill;
private ViewPager mViewPager;
private ViewPager.IOnPageChangeListener mListener;
private int mCurrentPage;
private int mSnapPage;
private int mCurrentOffset;
private int mScrollState;
private int mPageSize;
private int mOrientation;
private bool mCentered;
private bool mSnap;
private const int INVALID_POINTER = -1;
private int mTouchSlop;
private float mLastMotionX = -1;
private int mActivePointerId = INVALID_POINTER;
private bool mIsDragging;
public CirclePageIndicator(Context context) : this(context, null)
{
}
public CirclePageIndicator(Context context, IAttributeSet attrs) : this(context, attrs, Resource.Attribute.vpiCirclePageIndicatorStyle)
{
}
public CirclePageIndicator(Context context, IAttributeSet attrs, int defStyle) : base(context, attrs, defStyle)
{
//Load defaults from resources
var res = Resources;
int defaultPageColor = res.GetColor(Resource.Color.default_circle_indicator_page_color);
int defaultFillColor = res.GetColor(Resource.Color.default_circle_indicator_fill_color);
int defaultOrientation = res.GetInteger(Resource.Integer.default_circle_indicator_orientation);
int defaultStrokeColor = res.GetColor(Resource.Color.default_circle_indicator_stroke_color);
float defaultStrokeWidth = res.GetDimension(Resource.Dimension.default_circle_indicator_stroke_width);
float defaultRadius = res.GetDimension(Resource.Dimension.default_circle_indicator_radius);
bool defaultCentered = res.GetBoolean(Resource.Boolean.default_circle_indicator_centered);
bool defaultSnap = res.GetBoolean(Resource.Boolean.default_circle_indicator_snap);
//Retrieve styles attributes
var a = context.ObtainStyledAttributes(attrs, Resource.Styleable.CirclePageIndicator, defStyle, Resource.Style.Widget_CirclePageIndicator);
mCentered = a.GetBoolean(Resource.Styleable.CirclePageIndicator_centered, defaultCentered);
mOrientation = a.GetInt(Resource.Styleable.CirclePageIndicator_orientation, defaultOrientation);
mPaintPageFill = new Paint(PaintFlags.AntiAlias);
mPaintPageFill.SetStyle(Paint.Style.Fill);
mPaintPageFill.Color = a.GetColor(Resource.Styleable.CirclePageIndicator_pageColor, defaultPageColor);
mPaintStroke = new Paint(PaintFlags.AntiAlias);
mPaintStroke.SetStyle(Paint.Style.Stroke);
mPaintStroke.Color = a.GetColor(Resource.Styleable.CirclePageIndicator_strokeColor, defaultStrokeColor);
mPaintStroke.StrokeWidth = a.GetDimension(Resource.Styleable.CirclePageIndicator_strokeWidth, defaultStrokeWidth);
mPaintFill = new Paint(PaintFlags.AntiAlias);
mPaintFill.SetStyle(Paint.Style.Fill);
mPaintFill.Color = a.GetColor(Resource.Styleable.CirclePageIndicator_fillColor, defaultFillColor);
mRadius = a.GetDimension(Resource.Styleable.CirclePageIndicator_radius, defaultRadius);
mSnap = a.GetBoolean(Resource.Styleable.CirclePageIndicator_snap, defaultSnap);
a.Recycle();
var configuration = ViewConfiguration.Get(context);
mTouchSlop = ViewConfigurationCompat.GetScaledPagingTouchSlop(configuration);
}
public void SetCentered(bool centered)
{
mCentered = centered;
Invalidate();
}
public bool IsCentered()
{
return mCentered;
}
public void SetPageColor(Color pageColor)
{
mPaintPageFill.Color = pageColor;
Invalidate();
}
public int GetPageColor()
{
return mPaintPageFill.Color;
}
public void SetFillColor(Color fillColor)
{
mPaintFill.Color = fillColor;
Invalidate();
}
public int GetFillColor()
{
return mPaintFill.Color;
}
public void setOrientation(int orientation)
{
switch (orientation)
{
case HORIZONTAL:
case VERTICAL:
mOrientation = orientation;
UpdatePageSize();
RequestLayout();
break;
default:
throw new IllegalArgumentException("Orientation must be either HORIZONTAL or VERTICAL.");
}
}
public int GetOrientation()
{
return mOrientation;
}
public void SetStrokeColor(Color strokeColor)
{
mPaintStroke.Color = strokeColor;
Invalidate();
}
public int GetStrokeColor()
{
return mPaintStroke.Color;
}
public void SetStrokeWidth(float strokeWidth)
{
mPaintStroke.StrokeWidth = strokeWidth;
Invalidate();
}
public float GetStrokeWidth()
{
return mPaintStroke.StrokeWidth;
}
public void SetRadius(float radius)
{
mRadius = radius;
Invalidate();
}
public float GetRadius()
{
return mRadius;
}
public void SetSnap(bool snap)
{
mSnap = snap;
Invalidate();
}
public bool IsSnap()
{
return mSnap;
}
protected override void OnDraw(Canvas canvas)
{
base.OnDraw(canvas);
if (mViewPager == null)
{
return;
}
int count = mViewPager.Adapter.Count;
if (count == 0)
{
return;
}
if (mCurrentPage >= count)
{
SetCurrentItem(count - 1);
return;
}
int longSize;
int longPaddingBefore;
int longPaddingAfter;
int shortPaddingBefore;
if (mOrientation == HORIZONTAL)
{
longSize = Width;
longPaddingBefore = PaddingLeft;
longPaddingAfter = PaddingRight;
shortPaddingBefore = PaddingTop;
}
else
{
longSize = Height;
longPaddingBefore = PaddingTop;
longPaddingAfter = PaddingBottom;
shortPaddingBefore = PaddingLeft;
}
float threeRadius = mRadius * 3;
float shortOffset = shortPaddingBefore + mRadius;
float longOffset = longPaddingBefore + mRadius;
if (mCentered)
{
longOffset += ((longSize - longPaddingBefore - longPaddingAfter)/2.0f) - ((count * threeRadius)/2.0f);
}
float dX;
float dY;
float pageFillRadius = mRadius;
if (mPaintStroke.StrokeWidth > 0)
{
pageFillRadius -= mPaintStroke.StrokeWidth/2.0f;
}
//Draw stroked circles
for (int iLoop = 0; iLoop < count; iLoop++)
{
float drawLong = longOffset + (iLoop * threeRadius);
if (mOrientation == HORIZONTAL)
{
dX = drawLong;
dY = shortOffset;
}
else
{
dX = shortOffset;
dY = drawLong;
}
// Only paint fill if not completely transparent
if (mPaintPageFill.Alpha > 0)
{
canvas.DrawCircle(dX, dY, pageFillRadius, mPaintPageFill);
}
// Only paint stroke if a stroke width was non-zero
if (pageFillRadius != mRadius)
{
canvas.DrawCircle(dX, dY, mRadius, mPaintStroke);
}
}
//Draw the filled circle according to the current scroll
float cx = (mSnap ? mSnapPage : mCurrentPage) * threeRadius;
if (!mSnap && (mPageSize != 0))
{
cx += (mCurrentOffset * 1.0f/mPageSize) * threeRadius;
}
if (mOrientation == HORIZONTAL)
{
dX = longOffset + cx;
dY = shortOffset;
}
else
{
dX = shortOffset;
dY = longOffset + cx;
}
canvas.DrawCircle(dX, dY, mRadius, mPaintFill);
}
public override bool OnTouchEvent(MotionEvent ev)
{
if (base.OnTouchEvent(ev))
{
return true;
}
if ((mViewPager == null) || (mViewPager.Adapter.Count == 0))
{
return false;
}
var action = ev.Action;
switch ((int)action & MotionEventCompat.ActionMask)
{
case (int)MotionEventActions.Down:
mActivePointerId = MotionEventCompat.GetPointerId(ev, 0);
mLastMotionX = ev.GetX();
break;
case (int)MotionEventActions.Move:
{
int activePointerIndex = MotionEventCompat.FindPointerIndex(ev, mActivePointerId);
float x = MotionEventCompat.GetX(ev, activePointerIndex);
float deltaX = x - mLastMotionX;
if (!mIsDragging)
{
if (Java.Lang.Math.Abs(deltaX) > mTouchSlop)
{
mIsDragging = true;
}
}
if (mIsDragging)
{
if (!mViewPager.IsFakeDragging)
{
mViewPager.BeginFakeDrag();
}
mLastMotionX = x;
mViewPager.FakeDragBy(deltaX);
}
break;
}
case (int)MotionEventActions.Cancel:
case (int)MotionEventActions.Up:
if (!mIsDragging)
{
int count = mViewPager.Adapter.Count;
int width = Width;
float halfWidth = width/2f;
float sixthWidth = width/6f;
if ((mCurrentPage > 0) && (ev.GetX() < halfWidth - sixthWidth))
{
mViewPager.CurrentItem = mCurrentPage - 1;
return true;
}
else if ((mCurrentPage < count - 1) && (ev.GetX() > halfWidth + sixthWidth))
{
mViewPager.CurrentItem = mCurrentPage + 1;
return true;
}
}
mIsDragging = false;
mActivePointerId = INVALID_POINTER;
if (mViewPager.IsFakeDragging)
mViewPager.EndFakeDrag();
break;
case MotionEventCompat.ActionPointerDown:
{
int index = MotionEventCompat.GetActionIndex(ev);
float x = MotionEventCompat.GetX(ev, index);
mLastMotionX = x;
mActivePointerId = MotionEventCompat.GetPointerId(ev, index);
break;
}
case MotionEventCompat.ActionPointerUp:
int pointerIndex = MotionEventCompat.GetActionIndex(ev);
int pointerId = MotionEventCompat.GetPointerId(ev, pointerIndex);
if (pointerId == mActivePointerId)
{
int newPointerIndex = pointerIndex == 0 ? 1 : 0;
mActivePointerId = MotionEventCompat.GetPointerId(ev, newPointerIndex);
}
mLastMotionX = MotionEventCompat.GetX(ev, MotionEventCompat.FindPointerIndex(ev, mActivePointerId));
break;
}
return true;
}
public void SetViewPager(ViewPager view)
{
if (view.Adapter == null)
{
throw new IllegalStateException("ViewPager does not have adapter instance.");
}
mViewPager = view;
mViewPager.SetOnPageChangeListener(this);
UpdatePageSize();
Invalidate();
}
private void UpdatePageSize()
{
if (mViewPager != null)
{
mPageSize = (mOrientation == HORIZONTAL) ? mViewPager.Width : mViewPager.Height;
}
}
public void SetViewPager(ViewPager view, int initialPosition)
{
SetViewPager(view);
SetCurrentItem(initialPosition);
}
public void SetCurrentItem(int item)
{
if (mViewPager == null)
{
throw new IllegalStateException("ViewPager has not been bound.");
}
mViewPager.CurrentItem = item;
mCurrentPage = item;
Invalidate();
}
public void NotifyDataSetChanged()
{
Invalidate();
}
public void OnPageScrollStateChanged(int state)
{
mScrollState = state;
if (mListener != null)
{
mListener.OnPageScrollStateChanged(state);
}
}
public void OnPageScrolled(int position, float positionOffset, int positionOffsetPixels)
{
mCurrentPage = position;
mCurrentOffset = positionOffsetPixels;
UpdatePageSize();
Invalidate();
if (mListener != null)
{
mListener.OnPageScrolled(position, positionOffset, positionOffsetPixels);
}
}
public void OnPageSelected(int position)
{
if (mSnap || mScrollState == ViewPager.ScrollStateIdle)
{
mCurrentPage = position;
mSnapPage = position;
Invalidate();
}
if (mListener != null)
{
mListener.OnPageSelected(position);
}
}
public void SetOnPageChangeListener(ViewPager.IOnPageChangeListener listener)
{
mListener = listener;
}
protected override void OnMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
if (mOrientation == HORIZONTAL)
{
SetMeasuredDimension(MeasureLong(widthMeasureSpec), MeasureShort(heightMeasureSpec));
}
else
{
SetMeasuredDimension(MeasureShort(widthMeasureSpec), MeasureLong(heightMeasureSpec));
}
}
/**
* Determines the width of this view
*
* @param measureSpec
* A measureSpec packed into an int
* @return The width of the view, honoring constraints from measureSpec
*/
private int MeasureLong(int measureSpec)
{
int result = 0;
var specMode = MeasureSpec.GetMode(measureSpec);
var specSize = MeasureSpec.GetSize(measureSpec);
if ((specMode == MeasureSpecMode.Exactly) || (mViewPager == null))
{
//We were told how big to be
result = specSize;
}
else
{
//Calculate the width according the views count
int count = mViewPager.Adapter.Count;
result = (int)(PaddingLeft + PaddingRight
+ (count * 2 * mRadius) + (count - 1) * mRadius + 1);
//Respect AT_MOST value if that was what is called for by measureSpec
if (specMode == MeasureSpecMode.AtMost)
{
result = Java.Lang.Math.Min(result, specSize);
}
}
return result;
}
/**
* Determines the height of this view
*
* @param measureSpec
* A measureSpec packed into an int
* @return The height of the view, honoring constraints from measureSpec
*/
private int MeasureShort(int measureSpec)
{
int 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
{
//Measure the height
result = (int)(2 * mRadius + PaddingTop + PaddingBottom + 1);
//Respect AT_MOST value if that was what is called for by measureSpec
if (specMode == MeasureSpecMode.AtMost)
{
result = Java.Lang.Math.Min(result, specSize);
}
}
return result;
}
protected override void OnRestoreInstanceState(IParcelable state)
{
try
{
SavedState savedState = (SavedState)state;
base.OnRestoreInstanceState(savedState.SuperState);
mCurrentPage = savedState.CurrentPage;
mSnapPage = savedState.CurrentPage;
}
catch
{
base.OnRestoreInstanceState(state);
// Ignore, this needs to support IParcelable...
}
RequestLayout();
}
protected override IParcelable OnSaveInstanceState()
{
var superState = base.OnSaveInstanceState();
var savedState = new SavedState(superState);
savedState.CurrentPage = mCurrentPage;
return savedState;
}
public class SavedState : BaseSavedState
{
public int CurrentPage { get; set; }
public SavedState(IParcelable superState) : base(superState)
{
}
private SavedState(Parcel parcel) : base(parcel)
{
CurrentPage = parcel.ReadInt();
}
public override void WriteToParcel(Parcel dest, ParcelableWriteFlags flags)
{
base.WriteToParcel(dest, flags);
dest.WriteInt(CurrentPage);
}
[ExportField("CREATOR")]
static SavedStateCreator InitializeCreator()
{
return new SavedStateCreator();
}
class SavedStateCreator : Java.Lang.Object, IParcelableCreator
{
public Java.Lang.Object CreateFromParcel(Parcel source)
{
return new SavedState(source);
}
public Java.Lang.Object[] NewArray(int size)
{
return new SavedState[size];
}
}
}
}
}
现在添加PageIndicator.cs文件到您的项目（不活动的文件）
using Android.Support.V4.View;
namespace MyApplication.Droid.Library
{
public interface PageIndicator : ViewPager.IOnPageChangeListener
{
/**
* Bind the indicator to a ViewPager.
*
* @param view
*/
void SetViewPager(ViewPager view);
/**
* Bind the indicator to a ViewPager.
*
* @param view
* @param initialPosition
*/
void SetViewPager(ViewPager view, int initialPosition);
/**
* <p>Set the current page of both the ViewPager and indicator.</p>
*
* <p>This <strong>must</strong> be used if you need to set the page before
* the views are drawn on screen (e.g., default start page).</p>
*
* @param item
*/
void SetCurrentItem(int item);
/**
* Set a page change listener which will receive forwarded events.
*
* @param listener
*/
void SetOnPageChangeListener(ViewPager.IOnPageChangeListener listener);
/**
* Notify the indicator that the fragment list has changed.
*/
void NotifyDataSetChanged();
}
}
现在下面的文件添加到您的值文件： vpi__styles.xml
<?xml version="1.0" encoding="utf-8" ?>
<resources>
<style name="Widget"></style>
<style name="Widget.CirclePageIndicator" parent="Widget">
<item name="centered">@bool/default_circle_indicator_centered</item>
<item name="fillColor">@color/default_circle_indicator_fill_color</item>
<item name="pageColor">@color/default_circle_indicator_page_color</item>
<item name="orientation">@integer/default_circle_indicator_orientation</item>
<item name="radius">@dimen/default_circle_indicator_radius</item>
<item name="snap">@bool/default_circle_indicator_snap</item>
<item name="strokeColor">@color/default_circle_indicator_stroke_color</item>
<item name="strokeWidth">@dimen/default_circle_indicator_stroke_width</item>
</style>
</resources>
vpi__defaults .xml
<?xml version="1.0" encoding="utf-8" ?>
<resources>
<bool name="default_circle_indicator_centered">true</bool>
<color name="default_circle_indicator_fill_color">#FFFFFFFF</color>
<color name="default_circle_indicator_page_color">#00000000</color>
<integer name="default_circle_indicator_orientation">0</integer>
<dimen name="default_circle_indicator_radius">3dp</dimen>
<bool name="default_circle_indicator_snap">false</bool>
<color name="default_circle_indicator_stroke_color">#FFDDDDDD</color>
<dimen name="default_circle_indicator_stroke_width">1dp</dimen>
</resources>
vpi__colors.xml
<?xml version="1.0" encoding="utf-8" ?>
<resources>
<color name="vpi__background_holo_dark">#ff000000</color>
<color name="vpi__background_holo_light">#fff3f3f3</color>
<color name="vpi__bright_foreground_disabled_holo_dark">#ff4c4c4c</color>
<color name="vpi__bright_foreground_disabled_holo_light">#ffb2b2b2</color>
</resources>
vpi__attrs.xml
<?xml version="1.0" encoding="utf-8" ?>
<resources>
<declare-styleable name="ViewPagerIndicator">
<!-- Style of the circle indicator. -->
<attr name="vpiCirclePageIndicatorStyle" format="reference"/>
</declare-styleable>
<declare-styleable name="CirclePageIndicator">
<!-- Whether or not the indicators should be centered. -->
<attr name="centered" format="boolean" />
<!-- Color of the filled circle that represents the current page. -->
<attr name="fillColor" format="color" />
<!-- Color of the filled circles that represents pages. -->
<attr name="pageColor" format="color" />
<!-- Orientation of the indicator. -->
<attr name="orientation">
<enum name="horizontal" value="0" />
<enum name="vertical" value="1" />
</attr>
<!-- Radius of the circles. This is also the spacing between circles. -->
<attr name="radius" format="dimension" />
<!-- Whether or not the selected indicator snaps to the circles. -->
<attr name="snap" format="boolean" />
<!-- Color of the open circles. -->
<attr name="strokeColor" format="color" />
<!-- Width of the stroke used to draw the circles. -->
<attr name="strokeWidth" format="dimension" />
</declare-styleable>
</resources>
现在添加以下代码，设计文件。 在这里，你必须注意到MyApplication.Droid.Library是我的名字空间和CirclePageIndicator是我的网页指示文件名，以便与您的
<MyApplication.Droid.Library.CirclePageIndicator
android:id="@+id/indicator"
android:padding="10dip"
android:layout_height="wrap_content"
android:layout_width="fill_parent"
/>
现在取代它添加在活动文件中的以下。
using Android.Support.V4.App;
using MyApplication.Droid.Library;
//global
public ViewPager mPager;
public PageIndicator mIndicator;
//in on create
var indicator = FindViewById<CirclePageIndicator>(Resource.Id.indicator);
mIndicator = indicator;
indicator.SetViewPager(mPager);
indicator.SetSnap(true);
我已经从GitHub的
我一直在使用这种尝试解决这一点，但在安装块包（希望这是你所谈论的库）可以请你帮我块包有一个问题，金块包安装等。 –
我已更新源代码链接。在这里看一下实现示例。您需要在解决方案中包含“Library not LibraryV4”，并通过包含“使用DK.Ostebaronen.Droid.ViewPagerIndicator;”的命名空间进行访问 –
您可以使用下面的代码直接实现点指示器到您的应用程序 –