android特效引导页面的实现

可能有些朋友需要实现比较炫酷的引导页面，接下来这个demo相信可以满足你！！！先看一下截图效果





这两站截图的意思呢就是引导圆点是根据你手指移动多少而左右滑动多少，感觉挺炫酷的有木有？o(∩_∩)o 哈哈

直接上代码吧！要是看不懂的朋友底部有源码的下载网址（需要积分哦！）

【一】首先在res目录下的values中新建attrs.xml文件内容为：(它是自定义控件属性的申明文件)

<resources>

<declare-styleable name="ViewFlow">
<attr name="sidebuffer" format="integer" />
</declare-styleable>
<declare-styleable name="CircleFlowIndicator">
<attr name="activeColor" format="color" />
<attr name="inactiveColor" format="color" />
<attr name="radius" format="dimension" />
<attr name="spacing" format="dimension" />
<attr name="centered" format="boolean" />
<attr name="fadeOut" format="integer" />
<attr name="inactiveType">
<flag name="stroke" value="0" />
<flag name="fill" value="1" />
</attr>
<attr name="activeType">
<flag name="stroke" value="0" />
<flag name="fill" value="1" />
</attr>
<attr name="circleSeparation" format="dimension" />
<attr name="activeRadius" format="dimension" />
</declare-styleable>

</resources>

【二】自定义控件类

1. 新建CircleFlowIndicator.java(这个是滑动圆点的自定义控件类)

package org.taptwo.android.widget;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.os.AsyncTask;
import android.util.AttributeSet;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.Animation.AnimationListener;
import android.view.animation.AnimationUtils;

import com.example.splashandfirstopen.R;

public class CircleFlowIndicator extends View implements FlowIndicator, AnimationListener {
private static final int STYLE_STROKE = 0;
private static final int STYLE_FILL = 1;

private float radius = 8;// 初始化圆的半径
private float circleSeparation = 3 * radius + radius;// 圆点的间距
private float activeRadius = 0.5f;
private int fadeOutTime = 0;
private final Paint mPaintInactive = new Paint(Paint.ANTI_ALIAS_FLAG);
private final Paint mPaintActive = new Paint(Paint.ANTI_ALIAS_FLAG);
private ViewFlow viewFlow;
private int currentScroll = 0;
private int flowWidth = 0;
private FadeTimer timer;
public AnimationListener animationListener = this;
private Animation animation;
private boolean mCentered = false;

/**
* Default constructor
*
* @param context
*/
public CircleFlowIndicator(Context context) {
super(context);
// 初始化圆点的颜色(第一个参数为移动圆的颜色)
initColors(0xFFFFFFFF, 0xFFFFFFFF, STYLE_FILL, STYLE_STROKE);
}

/**
* The contructor used with an inflater
*
* @param context
* @param attrs
*/
public CircleFlowIndicator(Context context, AttributeSet attrs) {
super(context, attrs);
// Retrieve styles attributs

TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CircleFlowIndicator);

// Gets the inactive circle type, defaulting to "fill"
int activeType = a.getInt(R.styleable.CircleFlowIndicator_activeType, STYLE_FILL);

int activeDefaultColor = 0xFFFFFFFF;

// Get a custom inactive color if there is one
int activeColor = a.getColor(R.styleable.CircleFlowIndicator_activeColor, activeDefaultColor);

// Gets the inactive circle type, defaulting to "stroke"
int inactiveType = a.getInt(R.styleable.CircleFlowIndicator_inactiveType, STYLE_STROKE);

int inactiveDefaultColor = 0x44FFFFFF; // Get a custom inactive color
// if there is one
int inactiveColor = a.getColor(R.styleable.CircleFlowIndicator_inactiveColor, inactiveDefaultColor);

// Retrieve the radius radius
a.getDimension(R.styleable.CircleFlowIndicator_radius, 4.0f);

circleSeparation = a.getDimension(R.styleable.CircleFlowIndicator_circleSeparation, 2 * radius + radius);
activeRadius = a.getDimension(R.styleable.CircleFlowIndicator_activeRadius, 0.5f);
// Retrieve the fade out time fadeOutTime =
a.getInt(R.styleable.CircleFlowIndicator_fadeOut, 0);

mCentered = a.getBoolean(R.styleable.CircleFlowIndicator_centered, false);

// 初始化圆点的颜色(第一个参数为移动圆的颜色)
initColors(activeColor, inactiveColor, activeType, inactiveType);
}

private void initColors(int activeColor, int inactiveColor, int activeType, int inactiveType) {
// Select the paint type given the type attr
switch (inactiveType) {
case STYLE_FILL:
mPaintInactive.setStyle(Style.FILL);
break;
default:
mPaintInactive.setStyle(Style.STROKE);
}
mPaintInactive.setColor(inactiveColor);

// Select the paint type given the type attr
switch (activeType) {
case STYLE_STROKE:
mPaintActive.setStyle(Style.STROKE);
break;
default:
mPaintActive.setStyle(Style.FILL);
}
mPaintActive.setColor(activeColor);
}

/*
* (non-Javadoc)
*
* @see android.view.View#onDraw(android.graphics.Canvas)
*/
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
int count = 3;
if (viewFlow != null) {
count = viewFlow.getViewsCount();
}

// this is the amount the first circle should be offset to make the
// entire thing centered
float centeringOffset = 0;

int leftPadding = getPaddingLeft();

// Draw stroked circles
for (int iLoop = 0; iLoop < count; iLoop++) {
canvas.drawCircle(leftPadding + radius + (iLoop * circleSeparation) + centeringOffset, getPaddingTop() + radius, radius, mPaintInactive);
}
float cx = 0;
if (flowWidth != 0) {
// Draw the filled circle according to the current scroll
cx = (currentScroll * circleSeparation) / flowWidth;
}
// The flow width has been upadated yet. Draw the default position
canvas.drawCircle(leftPadding + radius + cx + centeringOffset, getPaddingTop() + radius, radius + activeRadius, mPaintActive);
}

/*
* (non-Javadoc)
*
* @see
* org.taptwo.android.widget.ViewFlow.ViewSwitchListener#onSwitched(android
* .view.View, int)
*/
@Override
public void onSwitched(View view, int position) {
}

/*
* (non-Javadoc)
*
* @see
* org.taptwo.android.widget.FlowIndicator#setViewFlow(org.taptwo.android
* .widget.ViewFlow)
*/
@Override
public void setViewFlow(ViewFlow view) {
resetTimer();
viewFlow = view;
flowWidth = viewFlow.getWidth();
invalidate();
}

/*
* (non-Javadoc)
*
* @see org.taptwo.android.widget.FlowIndicator#onScrolled(int, int, int,
* int)
*/
@Override
public void onScrolled(int h, int v, int oldh, int oldv) {
setVisibility(View.VISIBLE);
resetTimer();
flowWidth = viewFlow.getWidth();
if (viewFlow.getViewsCount() * flowWidth != 0) {
currentScroll = h % (viewFlow.getViewsCount() * flowWidth);
} else {
currentScroll = h;
}
invalidate();
}

/*
* (non-Javadoc)
*
* @see android.view.View#onMeasure(int, int)
*/
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
setMeasuredDimension(measureWidth(widthMeasureSpec), measureHeight(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 measureWidth(int measureSpec) {
int result = 0;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);

// We were told how big to be
if (specMode == MeasureSpec.EXACTLY) {
result = specSize;
}
// Calculate the width according the views count
else {
int count = 3;
if (viewFlow != null) {
count = viewFlow.getViewsCount();
}
float temp = circleSeparation - 2 * radius;
result = (int) (getPaddingLeft() + getPaddingRight() + (count * 2 * radius) + (count - 1) * temp + 1);
// Respect AT_MOST value if that was what is called for by
// measureSpec
if (specMode == MeasureSpec.AT_MOST) {
result = 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 measureHeight(int measureSpec) {
int result = 0;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);

// We were told how big to be
if (specMode == MeasureSpec.EXACTLY) {
result = specSize;
}
// Measure the height
else {
result = (int) (2 * radius + getPaddingTop() + getPaddingBottom() + 1);
// Respect AT_MOST value if that was what is called for by
// measureSpec
if (specMode == MeasureSpec.AT_MOST) {
result = Math.min(result, specSize);
}
}
return result;
}

/**
* Sets the fill color
*
* @param color
*            ARGB value for the text
*/
public void setFillColor(int color) {
mPaintActive.setColor(color);
invalidate();
}

/**
* Sets the stroke color
*
* @param color
*            ARGB value for the text
*/
public void setStrokeColor(int color) {
mPaintInactive.setColor(color);
invalidate();
}

/**
* Resets the fade out timer to 0. Creating a new one if needed
*/
private void resetTimer() {
// Only set the timer if we have a timeout of at least 1 millisecond
if (fadeOutTime > 0) {
// Check if we need to create a new timer
if (timer == null || timer._run == false) {
// Create and start a new timer
timer = new FadeTimer();
timer.execute();
} else {
// Reset the current tiemr to 0
timer.resetTimer();
}
}
}

/**
* Counts from 0 to the fade out time and animates the view away when
* reached
*/
private class FadeTimer extends AsyncTask<Void, Void, Void> {
// The current count
private int timer = 0;
// If we are inside the timing loop
private boolean _run = true;

public void resetTimer() {
timer = 0;
}

@Override
protected Void doInBackground(Void... arg0) {
while (_run) {
try {
// Wait for a millisecond
Thread.sleep(1);
// Increment the timer
timer++;

// Check if we've reached the fade out time
if (timer == fadeOutTime) {
// Stop running
_run = false;
}
} catch (InterruptedException e) {
e.printStackTrace();
}
}
return null;
}

@Override
protected void onPostExecute(Void result) {
animation = AnimationUtils.loadAnimation(getContext(), android.R.anim.fade_out);
animation.setAnimationListener(animationListener);
startAnimation(animation);
}
}

@Override
public void onAnimationEnd(Animation animation) {
setVisibility(View.GONE);
}

@Override
public void onAnimationRepeat(Animation animation) {
}

@Override
public void onAnimationStart(Animation animation) {
}
}

2.ViewFlow.java(展示滑动图片的自定义控件)

package org.taptwo.android.widget;

import java.util.ArrayList;
import java.util.LinkedList;
import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.Configuration;
import android.content.res.TypedArray;
import android.database.DataSetObserver;
import android.os.Handler;
import android.os.Message;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewGroup;
import android.view.ViewTreeObserver.OnGlobalLayoutListener;
import android.widget.AbsListView;
import android.widget.Adapter;
import android.widget.AdapterView;
import android.widget.Scroller;
import com.example.splashandfirstopen.R;

public class ViewFlow extends AdapterView<Adapter> {

private static final int SNAP_VELOCITY = 100;
private static final int INVALID_SCREEN = -1;
private final static int TOUCH_STATE_REST = 0;
private final static int TOUCH_STATE_SCROLLING = 1;

private LinkedList<View> mLoadedViews;
private int mCurrentBufferIndex;
private int mCurrentAdapterIndex;
private int mSideBuffer = 2;
private Scroller mScroller;
private VelocityTracker mVelocityTracker;
private int mTouchState = TOUCH_STATE_REST;
private float mLastMotionX;
private int mTouchSlop;
private int mMaximumVelocity;
private int mCurrentScreen;
private int mNextScreen = INVALID_SCREEN;
private boolean mFirstLayout = true;
private ViewSwitchListener mViewSwitchListener;
private Adapter mAdapter;
private int mLastScrollDirection;
private AdapterDataSetObserver mDataSetObserver;
private FlowIndicator mIndicator;
private int mLastOrientation = -1;
private long timeSpan = 3000;
private Handler handler;
private OnGlobalLayoutListener orientationChangeListener = new OnGlobalLayoutListener() {

@Override
public void onGlobalLayout() {
getViewTreeObserver().removeGlobalOnLayoutListener(
orientationChangeListener);
setSelection(mCurrentAdapterIndex);
}
};

/**
* Receives call backs when a new {@link View} has been scrolled to.
*/
public static interface ViewSwitchListener {

/**
* This method is called when a new View has been scrolled to.
*
* @param view
*            the {@link View} currently in focus.
* @param position
*            The position in the adapter of the {@link View} currently
*            in focus.
*/
void onSwitched(View view, int position);

}

public ViewFlow(Context context) {
super(context);
mSideBuffer = 3;
init();
}

public ViewFlow(Context context, int sideBuffer) {
super(context);
mSideBuffer = sideBuffer;
init();
}

@SuppressLint("Recycle")
public ViewFlow(Context context, AttributeSet attrs) {
super(context, attrs);
TypedArray styledAttrs = context.obtainStyledAttributes(attrs,
R.styleable.ViewFlow);
mSideBuffer = styledAttrs.getInt(0, 3);
init();
}

private void init() {
mLoadedViews = new LinkedList<View>();
mScroller = new Scroller(getContext());
final ViewConfiguration configuration = ViewConfiguration
.get(getContext());
mTouchSlop = configuration.getScaledTouchSlop();
mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
}

public void startAutoFlowTimer() {
handler = new Handler() {
@Override
public void handleMessage(Message msg) {

snapToScreen((mCurrentScreen + 1) % getChildCount());
Message message = handler.obtainMessage(0);
sendMessageDelayed(message, timeSpan);
}
};

Message message = handler.obtainMessage(0);
handler.sendMessageDelayed(message, timeSpan);
}

public void stopAutoFlowTimer() {
if (handler != null)
handler.removeMessages(0);
handler = null;
}

public void onConfigurationChanged(Configuration newConfig) {
if (newConfig.orientation != mLastOrientation) {
mLastOrientation = newConfig.orientation;
getViewTreeObserver().addOnGlobalLayoutListener(
orientationChangeListener);
}
}

public int getViewsCount() {
return mSideBuffer;
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);

final int width = MeasureSpec.getSize(widthMeasureSpec);
final int widthMode = MeasureSpec.getMode(widthMeasureSpec);
if (widthMode != MeasureSpec.EXACTLY && !isInEditMode()) {
throw new IllegalStateException(
"ViewFlow can only be used in EXACTLY mode.");
}

final int heightMode = MeasureSpec.getMode(heightMeasureSpec);
if (heightMode != MeasureSpec.EXACTLY && !isInEditMode()) {
throw new IllegalStateException(
"ViewFlow can only be used in EXACTLY mode.");
}

// The children are given the same width and height as the workspace
final int count = getChildCount();
for (int i = 0; i < count; i++) {
getChildAt(i).measure(widthMeasureSpec, heightMeasureSpec);
}

if (mFirstLayout) {
mScroller.startScroll(0, 0, mCurrentScreen * width, 0, 0);
mFirstLayout = false;
}
}

@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
int childLeft = 0;

final int count = getChildCount();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.getVisibility() != View.GONE) {
final int childWidth = child.getMeasuredWidth();
child.layout(childLeft, 0, childLeft + childWidth,
child.getMeasuredHeight());
childLeft += childWidth;
}
}
}

@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
if (getChildCount() == 0)
return false;

if (mVelocityTracker == null) {
mVelocityTracker = VelocityTracker.obtain();
}
mVelocityTracker.addMovement(ev);

final int action = ev.getAction();
final float x = ev.getX();

switch (action) {
case MotionEvent.ACTION_DOWN:
/*
* If being flinged and user touches, stop the fling. isFinished
* will be false if being flinged.
*/
if (!mScroller.isFinished()) {
mScroller.abortAnimation();
}

// Remember where the motion event started
mLastMotionX = x;

mTouchState = mScroller.isFinished() ? TOUCH_STATE_REST
: TOUCH_STATE_SCROLLING;
if (handler != null)
handler.removeMessages(0);
break;

case MotionEvent.ACTION_MOVE:
final int xDiff = (int) Math.abs(x - mLastMotionX);

boolean xMoved = xDiff > mTouchSlop;

if (xMoved) {
// Scroll if the user moved far enough along the X axis
mTouchState = TOUCH_STATE_SCROLLING;
}

if (mTouchState == TOUCH_STATE_SCROLLING) {
// Scroll to follow the motion event
final int deltaX = (int) (mLastMotionX - x);
mLastMotionX = x;

final int scrollX = getScrollX();
if (deltaX < 0) {
if (scrollX > 0) {
scrollBy(Math.max(-scrollX, deltaX), 0);
}
} else if (deltaX > 0) {
final int availableToScroll = getChildAt(
getChildCount() - 1).getRight()
- scrollX - getWidth();
if (availableToScroll > 0) {
scrollBy(Math.min(availableToScroll, deltaX), 0);
}
}
return true;
}
break;

case MotionEvent.ACTION_UP:
if (mTouchState == TOUCH_STATE_SCROLLING) {
// final VelocityTracker velocityTracker = mVelocityTracker;
// velocityTracker.computeCurrentVelocity(SNAP_VELOCITY,
// mMaximumVelocity);
// int velocityX = (int) velocityTracker.getXVelocity();

// if (velocityX > SNAP_VELOCITY && mCurrentScreen > 0) {
// // Fling hard enough to move left
// snapToScreen(mCurrentScreen - 1);
// } else if (velocityX < -SNAP_VELOCITY && mCurrentScreen <
// getChildCount() - 1) {
// // Fling hard enough to move right
// snapToScreen(mCurrentScreen + 1);
// } else {
// snapToDestination();
// }
final int deltaX = (int) (mLastMotionX - x);
if (deltaX > 30) {
snapToScreen(mCurrentScreen + 1);
} else if (deltaX < 30) {
snapToScreen(mCurrentScreen - 1);
}
// if (mVelocityTracker != null) {
// mVelocityTracker.recycle();
// mVelocityTracker = null;
// }
}

mTouchState = TOUCH_STATE_REST;
if (handler != null) {
Message message = handler.obtainMessage(0);
handler.sendMessageDelayed(message, timeSpan);
}
break;
case MotionEvent.ACTION_CANCEL:
mTouchState = TOUCH_STATE_REST;
}
return false;
}

@Override
public boolean onTouchEvent(MotionEvent ev) {
if (getChildCount() == 0)
return false;

if (mVelocityTracker == null) {
mVelocityTracker = VelocityTracker.obtain();
}
mVelocityTracker.addMovement(ev);

final int action = ev.getAction();
final float x = ev.getX();

switch (action) {
case MotionEvent.ACTION_DOWN:
/*
* If being flinged and user touches, stop the fling. isFinished
* will be false if being flinged.
*/
if (!mScroller.isFinished()) {
mScroller.abortAnimation();
}

// Remember where the motion event started
mLastMotionX = x;

mTouchState = mScroller.isFinished() ? TOUCH_STATE_REST
: TOUCH_STATE_SCROLLING;
if (handler != null)
handler.removeMessages(0);
break;

case MotionEvent.ACTION_MOVE:
final int xDiff = (int) Math.abs(x - mLastMotionX);

boolean xMoved = xDiff > mTouchSlop;

if (xMoved) {
// Scroll if the user moved far enough along the X axis
mTouchState = TOUCH_STATE_SCROLLING;
}

if (mTouchState == TOUCH_STATE_SCROLLING) {
// Scroll to follow the motion event
final int deltaX = (int) (mLastMotionX - x);
mLastMotionX = x;

final int scrollX = getScrollX();
if (deltaX < 0) {
if (scrollX > 0) {
scrollBy(Math.max(-scrollX, deltaX), 0);
}
} else if (deltaX > 0) {
final int availableToScroll = getChildAt(
getChildCount() - 1).getRight()
- scrollX - getWidth();
if (availableToScroll > 0) {
scrollBy(Math.min(availableToScroll, deltaX), 0);
}
}
return true;
}
break;
case MotionEvent.ACTION_UP:
if (mTouchState == TOUCH_STATE_SCROLLING) {
final VelocityTracker velocityTracker = mVelocityTracker;
velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
int velocityX = (int) velocityTracker.getXVelocity();

if (velocityX > SNAP_VELOCITY && mCurrentScreen > 0) {
// Fling hard enough to move left
snapToScreen(mCurrentScreen - 1);
} else if (velocityX < -SNAP_VELOCITY
&& mCurrentScreen < getChildCount() - 1) {
// Fling hard enough to move right
snapToScreen(mCurrentScreen + 1);
}
// else if (velocityX < -SNAP_VELOCITY
// && mCurrentScreen == getChildCount() - 1) {
// snapToScreen(0);
// }
// else if (velocityX > SNAP_VELOCITY
// && mCurrentScreen == 0) {
// snapToScreen(getChildCount() - 1);
// }
else {
snapToDestination();
}

if (mVelocityTracker != null) {
mVelocityTracker.recycle();
mVelocityTracker = null;
}
}

mTouchState = TOUCH_STATE_REST;

if (handler != null) {
Message message = handler.obtainMessage(0);
handler.sendMessageDelayed(message, timeSpan);
}
break;
case MotionEvent.ACTION_CANCEL:
snapToDestination();
mTouchState = TOUCH_STATE_REST;
}
return true;
}

@Override
protected void onScrollChanged(int h, int v, int oldh, int oldv) {
super.onScrollChanged(h, v, oldh, oldv);
if (mIndicator != null) {
/*
* The actual horizontal scroll origin does typically not match the
* perceived one. Therefore, we need to calculate the perceived
* horizontal scroll origin here, since we use a view buffer.
*/
int hPerceived = h + (mCurrentAdapterIndex - mCurrentBufferIndex)
* getWidth();
mIndicator.onScrolled(hPerceived, v, oldh, oldv);
}
}

private void snapToDestination() {
final int screenWidth = getWidth();
final int whichScreen = (getScrollX() + (screenWidth / 2))
/ screenWidth;

snapToScreen(whichScreen);
}

private void snapToScreen(int whichScreen) {
mLastScrollDirection = whichScreen - mCurrentScreen;
if (!mScroller.isFinished())
return;

whichScreen = Math.max(0, Math.min(whichScreen, getChildCount() - 1));

mNextScreen = whichScreen;

final int newX = whichScreen * getWidth();
final int delta = newX - getScrollX();
mScroller.startScroll(getScrollX(), 0, delta, 0, Math.abs(delta) * 2);
invalidate();
}

@Override
public void computeScroll() {
if (mScroller.computeScrollOffset()) {
scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
postInvalidate();
} else if (mNextScreen != INVALID_SCREEN) {
mCurrentScreen = Math.max(0,
Math.min(mNextScreen, getChildCount() - 1));
mNextScreen = INVALID_SCREEN;
postViewSwitched(mLastScrollDirection);
}
}

/**
* Scroll to the {@link View} in the view buffer specified by the index.
*
* @param indexInBuffer
*            Index of the view in the view buffer.
*/
private void setVisibleView(int indexInBuffer, boolean uiThread) {
mCurrentScreen = Math.max(0,
Math.min(indexInBuffer, getChildCount() - 1));
int dx = (mCurrentScreen * getWidth()) - mScroller.getCurrX();
mScroller.startScroll(mScroller.getCurrX(), mScroller.getCurrY(), dx,
0, 0);
if (dx == 0)
onScrollChanged(mScroller.getCurrX() + dx, mScroller.getCurrY(),
mScroller.getCurrX() + dx, mScroller.getCurrY());
if (uiThread)
invalidate();
else
postInvalidate();
}

/**
* Set the listener that will receive notifications every time the {code
* ViewFlow} scrolls.
*
* @param l
*            the scroll listener
*/
public void setOnViewSwitchListener(ViewSwitchListener l) {
mViewSwitchListener = l;
}

@Override
public Adapter getAdapter() {
return mAdapter;
}

@Override
public void setAdapter(Adapter adapter) {
setAdapter(adapter, 0);
}

public void setAdapter(Adapter adapter, int initialPosition) {
if (mAdapter != null) {
mAdapter.unregisterDataSetObserver(mDataSetObserver);
}

mAdapter = adapter;

if (mAdapter != null) {
mDataSetObserver = new AdapterDataSetObserver();
mAdapter.registerDataSetObserver(mDataSetObserver);

}
if (mAdapter == null || mAdapter.getCount() == 0)
return;

setSelection(initialPosition);
}

@Override
public View getSelectedView() {
return (mCurrentBufferIndex < mLoadedViews.size() ? mLoadedViews
.get(mCurrentBufferIndex) : null);
}

@Override
public int getSelectedItemPosition() {
return mCurrentAdapterIndex;
}

/**
* Set the FlowIndicator
*
* @param flowIndicator
*/
public void setFlowIndicator(FlowIndicator flowIndicator) {
mIndicator = flowIndicator;
mIndicator.setViewFlow(this);
}

@Override
public void setSelection(int position) {
mNextScreen = INVALID_SCREEN;
mScroller.forceFinished(true);
if (mAdapter == null)
return;

position = Math.max(position, 0);
position = Math.min(position, mAdapter.getCount() - 1);

ArrayList<View> recycleViews = new ArrayList<View>();
View recycleView;
while (!mLoadedViews.isEmpty()) {
recycleViews.add(recycleView = mLoadedViews.remove());
detachViewFromParent(recycleView);
}

View currentView = makeAndAddView(position, true,
(recycleViews.isEmpty() ? null : recycleViews.remove(0)));
mLoadedViews.addLast(currentView);

for (int offset = 1; mSideBuffer - offset >= 0; offset++) {
int leftIndex = position - offset;
int rightIndex = position + offset;
if (leftIndex >= 0)
mLoadedViews
.addFirst(makeAndAddView(
leftIndex,
false,
(recycleViews.isEmpty() ? null : recycleViews
.remove(0))));
if (rightIndex < mAdapter.getCount())
mLoadedViews
.addLast(makeAndAddView(rightIndex, true, (recycleViews
.isEmpty() ? null : recycleViews.remove(0))));
}

mCurrentBufferIndex = mLoadedViews.indexOf(currentView);
mCurrentAdapterIndex = position;

for (View view : recycleViews) {
removeDetachedView(view, false);
}
requestLayout();
setVisibleView(mCurrentBufferIndex, false);
if (mIndicator != null) {
mIndicator.onSwitched(mLoadedViews.get(mCurrentBufferIndex),
mCurrentAdapterIndex);
}
if (mViewSwitchListener != null) {
mViewSwitchListener
.onSwitched(mLoadedViews.get(mCurrentBufferIndex),
mCurrentAdapterIndex);
}
}

private void resetFocus() {
mLoadedViews.clear();
removeAllViewsInLayout();

for (int i = Math.max(0, mCurrentAdapterIndex - mSideBuffer); i < Math
.min(mAdapter.getCount(), mCurrentAdapterIndex + mSideBuffer
+ 1); i++) {
mLoadedViews.addLast(makeAndAddView(i, true, null));
if (i == mCurrentAdapterIndex)
mCurrentBufferIndex = mLoadedViews.size() - 1;
}
requestLayout();
}

private void postViewSwitched(int direction) {
if (direction == 0)
return;

if (direction > 0) { // to the right
mCurrentAdapterIndex++;
mCurrentBufferIndex++;

// if(direction > 1) {
// mCurrentAdapterIndex += mAdapter.getCount() - 2;
// mCurrentBufferIndex += mAdapter.getCount() - 2;
// }

View recycleView = null;

// Remove view outside buffer range
if (mCurrentAdapterIndex > mSideBuffer) {
recycleView = mLoadedViews.removeFirst();
detachViewFromParent(recycleView);
// removeView(recycleView);
mCurrentBufferIndex--;
}

// Add new view to buffer
int newBufferIndex = mCurrentAdapterIndex + mSideBuffer;
if (newBufferIndex < mAdapter.getCount())
mLoadedViews.addLast(makeAndAddView(newBufferIndex, true,
recycleView));

} else { // to the left
mCurrentAdapterIndex--;
mCurrentBufferIndex--;

// if(direction < -1) {
// mCurrentAdapterIndex -= mAdapter.getCount() - 2;
// mCurrentBufferIndex -= mAdapter.getCount() - 2;
// }

View recycleView = null;

// Remove view outside buffer range
if (mAdapter.getCount() - 1 - mCurrentAdapterIndex > mSideBuffer) {
recycleView = mLoadedViews.removeLast();
detachViewFromParent(recycleView);
}

// Add new view to buffer
int newBufferIndex = mCurrentAdapterIndex - mSideBuffer;
if (newBufferIndex > -1) {
mLoadedViews.addFirst(makeAndAddView(newBufferIndex, false,
recycleView));
mCurrentBufferIndex++;
}

}

requestLayout();
setVisibleView(mCurrentBufferIndex, true);
if (mIndicator != null) {
mIndicator.onSwitched(mLoadedViews.get(mCurrentBufferIndex),
mCurrentAdapterIndex);
}
if (mViewSwitchListener != null) {
mViewSwitchListener
.onSwitched(mLoadedViews.get(mCurrentBufferIndex),
mCurrentAdapterIndex);
}
}

private View setupChild(View child, boolean addToEnd, boolean recycle) {
ViewGroup.LayoutParams p = (ViewGroup.LayoutParams) child
.getLayoutParams();
if (p == null) {
p = new AbsListView.LayoutParams(
ViewGroup.LayoutParams.FILL_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT, 0);
}
if (recycle)
attachViewToParent(child, (addToEnd ? -1 : 0), p);
else
addViewInLayout(child, (addToEnd ? -1 : 0), p, true);
return child;
}

private View makeAndAddView(int position, boolean addToEnd, View convertView) {
View view = mAdapter.getView(position, convertView, this);
return setupChild(view, addToEnd, convertView != null);
}

class AdapterDataSetObserver extends DataSetObserver {

@Override
public void onChanged() {
View v = getChildAt(mCurrentBufferIndex);
if (v != null) {
for (int index = 0; index < mAdapter.getCount(); index++) {
if (v.equals(mAdapter.getItem(index))) {
mCurrentAdapterIndex = index;
break;
}
}
}
resetFocus();
}

@Override
public void onInvalidated() {
// Not yet implemented!
}

}

public void setTimeSpan(long timeSpan) {
this.timeSpan = timeSpan;
}

public void setmSideBuffer(int mSideBuffer) {
this.mSideBuffer = mSideBuffer;
}
}

3.FlowIndicator.java(连接这两个控件的桥梁)

package org.taptwo.android.widget;

import org.taptwo.android.widget.ViewFlow.ViewSwitchListener;

public interface FlowIndicator extends ViewSwitchListener {

/**
* Set the current ViewFlow. This method is called by the ViewFlow when the
* FlowIndicator is attached to it.
*
* @param view
*/
public void setViewFlow(ViewFlow view);

/**
* The scroll position has been changed. A FlowIndicator may implement this
* method to reflect the current position
*
* @param h
* @param v
* @param oldh
* @param oldv
*/
public void onScrolled(int h, int v, int oldh, int oldv);
}

【三】怎么调用
只会第一次使用本应用时才会进入的Activity

FirstTimeInActivity.java

package com.example.splashandfirstopen;

import org.taptwo.android.widget.CircleFlowIndicator;
import org.taptwo.android.widget.ViewFlow;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.view.Window;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.ImageView;

public class FirstTimeInActivity extends Activity {
/** Called when the activity is first created. */
private ViewFlow viewFlow;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_first_time_in);
viewFlow = (ViewFlow) findViewById(R.id.viewflow);
viewFlow.setAdapter(new ImageAdapter());
viewFlow.setmSideBuffer(ids.length); // 实际图片张数

CircleFlowIndicator indic = (CircleFlowIndicator) findViewById(R.id.viewflowindic);
viewFlow.setFlowIndicator(indic);
viewFlow.setSelection(0); // 设置初始位置
}

public int[] ids = { R.drawable.first_time_post_1, R.drawable.first_time_post_2, R.drawable.first_time_post_3, R.drawable.first_time_post_4 };

class ImageAdapter extends BaseAdapter {
private LayoutInflater mInflater;

public ImageAdapter() {
mInflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}

@Override
public int getCount() {
return ids.length;
}

@Override
public Object getItem(int position) {
return position;
}

@Override
public long getItemId(int position) {
return position;
}

@Override
public View getView(final int position, View convertView, ViewGroup parent) {
if (convertView == null) {
convertView = mInflater.inflate(R.layout.image_item, null);
}
((ImageView) convertView.findViewById(R.id.imgView)).setImageResource(ids[position % ids.length]);
if (position == (ids.length-1)) {
Button button = (Button) convertView.findViewById(R.id.startLogin);
button.setVisibility(View.VISIBLE);
button.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
finish();
}
});
}
return convertView;
}
}
}

【四、xml文件】

activity_first_time_in.xml文件

<pre name="code" class="html"><?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res/com.example.splashandfirstopen"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#ffffff" >

<org.taptwo.android.widget.ViewFlow
android:id="@+id/viewflow"
android:layout_width="fill_parent"
android:layout_height="fill_parent" >
</org.taptwo.android.widget.ViewFlow>

<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:background="#00252525"
android:gravity="center"
android:padding="3dip" >

<org.taptwo.android.widget.CircleFlowIndicator
android:id="@+id/viewflowindic"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal|bottom"
android:layout_marginBottom="25dp"
android:padding="2dp"
app:activeColor="#ffffff"
app:activeType="fill"
app:circleSeparation="30dp"
app:inactiveColor="#88ffffff"
app:inactiveType="fill"
app:radius="4dip" />
</LinearLayout>

</FrameLayout>

image_item.xml文件

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="match_parent" >

<ImageView
android:id="@+id/imgView"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:layout_gravity="center_vertical|center_horizontal"
android:scaleType="centerCrop"
android:src="#00000000" >
</ImageView>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="14" />

<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="3"
android:orientation="vertical" >

<Button
android:id="@+id/startLogin"
android:layout_width="match_parent"
android:layout_height="40dp"
android:layout_marginLeft="70dp"
android:layout_marginRight="70dp"
android:text="马上体验"
android:layout_gravity="center_horizontal"
android:visibility="gone" />
</LinearLayout>
</LinearLayout>

</RelativeLayout>

到此代码结束，小编小手已废。。。。

废话少说直接上源码：http://download.csdn.net/detail/sinat_21283073/9176777