自定义控件之AndroidSegmentControlView，仿IOS平台UISegmentControlView，继承自View

控件简介

UISegmentControl在IOS平台的App中非常常见，其控件如下图所示：



这种控件的主要作用是动态的更改界面的显示内容，一般应用于内容较多的界面，且分屏显示不同种类的内容。

在Android开发过程中，有时需要实现类似UISegmentControl的效果，这里我将自己的代码开源在github上了，命名为SegmentControlView，下面是实现的效果：



动态图片可点击如下链接：

https://github.com/Carbs0126/AndroidSegmentControlView

控件说明

SegmentControlView extends View

这个SegmentControlView是继承自View的，而非组合控件，因此实现起来虽然有点繁琐，但是灵活性反而比组合控件要高很多，并且可以加上过度效果等，且比组合控件更加轻量化。

控件特点

我实现的这个SegmentControlView具有如下特点：

1.SegmentControlView可设置与ViewPager联动，在segment切换时具有颜色渐变效果，类似微信。
2.可以自定义SegmentControlView的四个corner的半径。
3.自定义背景颜色与字体颜色、字体大小等等。
4.在xml中设置SegmentControlView中的多个titles，自动按照titles生成多个segment。
5.设置按下颜色与normal颜色的色值对比度。
6.具有AT_MOST的适配功能,即具有wrap_content模式
7.可以设置回调响应事件

使用方法

属性文件说明

<?xml version="1.0" encoding="utf-8"?>
<resources>

<declare-styleable name="SegmentControlView">
<attr name="scv_BackgroundSelectedColor" format="reference|color" />//选中segment的背景颜色
<attr name="scv_BackgroundNormalColor" format="reference|color" />//未选中segment的背景颜色
<attr name="scv_TextSelectedColor" format="reference|color" />//选中segment的文字颜色
<attr name="scv_TextNormalColor" format="reference|color" />//未选中segment的文字颜色
<attr name="scv_FrameColor" format="reference|color" />//segment边框的颜色
<attr name="scv_FrameWidth" format="reference|dimension" />//segment边框的宽度
<attr name="scv_FrameCornerRadius" format="reference|dimension" />//segment四个圆角的半径大小
<attr name="scv_TextSize" format="reference|dimension" />//文字大小
<attr name="scv_TextArray" format="reference" />//string数组，每一个string都会填充到一个segment中
<attr name="scv_SelectedIndex" format="reference|integer" />//默认选中的segment
<attr name="scv_SegmentPaddingHorizontal" format="reference|dimension" />//每一个segment内部的水平padding
<attr name="scv_SegmentPaddingVertical" format="reference|dimension" />每一个Segment的竖直方向的padding
<attr name="scv_Gradient" format="reference|boolean" />//Segment改变时是否使用颜色渐变效果
</declare-styleable>

</resources>

布局文件创建SegmentControlView

<cn.carbs.android.segmentcontrolview.library.SegmentControlView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:paddingLeft="10dp"
android:paddingRight="10dp"
app:scv_FrameCornerRadius="6dp"
app:scv_FrameWidth="1dp"
app:scv_Gradient="true"
app:scv_SegmentPaddingVertical="5dp"
app:scv_TextArray="@array/segment_control_arrays_0"/>

使用方法

dependencies {
compile 'cn.carbs.android:SegmentControlView:1.0.0'
}

segmentcontrolview.setOnSegmentChangedListener(new SegmentControlView.OnSegmentChangedListener() {
@Override
public void onSegmentChanged(int newSelectedIndex) {
if(viewpager != null){
//change the second argument to true if you want the gradient effect when viewpager is changing
viewpager.setCurrentItem(newSelectedIndex, false);//viewpager changing without animation
}
}
});
//set viewpager to change segment according to the state of viewpager
segmentcontrolview.setViewPager(viewpager);
//set the selected index of segments initiatively
segmentcontrolview.setSelectedIndex();
//set gradient effect if you want
segmentcontrolview.setGradient(true);

项目地址：

https://github.com/Carbs0126/AndroidSegmentControlView

Git：

git clone https://github.com/Carbs0126/AndroidSegmentControlView.git

源码如下

package cn.carbs.android.segmentcontrolview.library;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Rect;
import android.graphics.RectF;
import android.support.v4.view.ViewPager;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

import java.lang.reflect.Field;

/**
* an SegmentControlView inspired by the UISegmentControl on IOS platform.
* this view has many interesting such as :
*  1. set gradient effect when segment is changing by ViewPager if needed
*  2. set the corners' radius
*  3. set colors of texts and background
*  4. set titles in xml resource file
*  5. has pressed effect when finger touches this view, you can set the dark coefficient
*
* Author   Carbs.Wang
* Email    yeah0126#yeah.net
*/
public class SegmentControlView extends View {

/**
* onSegmentChanged function will be triggered if segment changed
*/
public interface OnSegmentChangedListener{
void onSegmentChanged(int newSelectedIndex);
}

private static final float TOUCHED_BACKGROUND_DARK_COEFFICIENT = 0.95F;

private static final int COLOR_PRIMARY_NORMAL = 0XFFFFFFFF;
private static final int COLOR_PRIMARY_SELECTED = 0XFF2CA99F;

private static final int DEFAULT_COLOR_BACKGROUND_SELECTED = COLOR_PRIMARY_SELECTED;
private static final int DEFAULT_COLOR_BACKGROUND_NORMAL = COLOR_PRIMARY_NORMAL;
private static final int DEFAULT_COLOR_TEXT_SELECTED = COLOR_PRIMARY_NORMAL;
private static final int DEFAULT_COLOR_TEXT_NORMAL = COLOR_PRIMARY_SELECTED;
private static final int DEFAULT_COLOR_FRAME = COLOR_PRIMARY_SELECTED;
private static final int DEFAULT_TEXT_SIZE_SP = 16;
private static final int DEFAULT_FRAME_WIDTH_PX = 2;
private static final int DEFAULT_FRAME_CORNER_RADIUS_PX = 0;
private static final int DEFAULT_SELECTED_INDEX = 0;
private static final int DEFAULT_SEGMENT_PADDING_HORIZONTAL = 16;
private static final int DEFAULT_SEGMENT_PADDING_VERTICAL = 12;
private static final boolean DEFAULT_IS_GRADIENT = false;

private String[] mTexts = null;

private int mColorBackgroundSelected = DEFAULT_COLOR_BACKGROUND_SELECTED;
private int mColorBackgroundNormal = DEFAULT_COLOR_BACKGROUND_NORMAL;
private int mColorTextSelected = DEFAULT_COLOR_TEXT_SELECTED;
private int mColorTextNormal = DEFAULT_COLOR_TEXT_NORMAL;
private int mColorFrame = DEFAULT_COLOR_FRAME;
private int mFrameWidth = DEFAULT_FRAME_WIDTH_PX;
private int mFrameCornerRadius = DEFAULT_FRAME_CORNER_RADIUS_PX;

private int mTextSize = 0;
private int mSelectedIndex = DEFAULT_SELECTED_INDEX;

//used in wrap_content mode
private int mSegmentPaddingHorizontal = DEFAULT_SEGMENT_PADDING_HORIZONTAL;
private int mSegmentPaddingVertical = DEFAULT_SEGMENT_PADDING_VERTICAL;

private boolean mIsGradient = DEFAULT_IS_GRADIENT;
private OnSegmentChangedListener mOnSegmentChangedListener;

private float unitWidth = 0;
private Paint paintText;        //painter of the text
private Paint paintBackground;  //painter of the background
private Paint paintFrame;       //painter of the frame
private RectF rectF;
private RectF rectFArc;
private Path pathFrame;

private float textCenterYOffset;

private int preTouchedIndex = -1;
private int curTouchedIndex = -1;

private ViewPager viewPager;

public SegmentControlView(Context context) {
super(context);
init();
}
public SegmentControlView(Context context, AttributeSet attrs) {
super(context, attrs);
initAttr(context, attrs);
init();
}
public SegmentControlView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
initAttr(context, attrs);
init();
}

private void initAttr(Context context, AttributeSet attrs) {
if (attrs == null) {
return;
}

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

int n = a.getIndexCount();
for (int i = 0; i < n; i++) {
int attr = a.getIndex(i);
if(attr == R.styleable.SegmentControlView_scv_BackgroundSelectedColor){
mColorBackgroundSelected = a.getColor(attr, DEFAULT_COLOR_BACKGROUND_SELECTED);
}else if(attr == R.styleable.SegmentControlView_scv_BackgroundNormalColor){
mColorBackgroundNormal = a.getColor(attr, DEFAULT_COLOR_BACKGROUND_NORMAL);
}else if(attr == R.styleable.SegmentControlView_scv_TextSelectedColor){
mColorTextSelected = a.getColor(attr, DEFAULT_COLOR_TEXT_SELECTED);
}else if(attr == R.styleable.SegmentControlView_scv_TextNormalColor){
mColorTextNormal = a.getColor(attr, DEFAULT_COLOR_TEXT_NORMAL);
}else if(attr == R.styleable.SegmentControlView_scv_FrameColor){
mColorFrame = a.getColor(attr, DEFAULT_COLOR_FRAME);
}else if(attr == R.styleable.SegmentControlView_scv_TextSize){
mTextSize = a.getDimensionPixelSize(attr, sp2px(getContext(), DEFAULT_TEXT_SIZE_SP));
}else if(attr == R.styleable.SegmentControlView_scv_TextArray){
mTexts = convertCharSequenceToString(a.getTextArray(attr));
}else if(attr == R.styleable.SegmentControlView_scv_FrameWidth){
mFrameWidth = a.getDimensionPixelSize(attr, DEFAULT_FRAME_WIDTH_PX);
}else if(attr == R.styleable.SegmentControlView_scv_FrameCornerRadius){
mFrameCornerRadius = a.getDimensionPixelSize(attr, DEFAULT_FRAME_CORNER_RADIUS_PX);
}else if(attr == R.styleable.SegmentControlView_scv_SelectedIndex){
mSelectedIndex = a.getInteger(attr, DEFAULT_SELECTED_INDEX);
}else if(attr == R.styleable.SegmentControlView_scv_SegmentPaddingHorizontal){
mSegmentPaddingHorizontal = a.getDimensionPixelSize(attr, DEFAULT_SEGMENT_PADDING_HORIZONTAL);
}else if(attr == R.styleable.SegmentControlView_scv_SegmentPaddingVertical){
mSegmentPaddingVertical = a.getDimensionPixelSize(attr, DEFAULT_SEGMENT_PADDING_VERTICAL);
}else if(attr == R.styleable.SegmentControlView_scv_Gradient){
mIsGradient = a.getBoolean(attr, DEFAULT_IS_GRADIENT);
}
}
a.recycle();
}

private void init(){
rectF = new RectF();
rectFArc = new RectF();
pathFrame = new Path();

if(mTextSize == 0)
mTextSize = sp2px(getContext(), DEFAULT_TEXT_SIZE_SP);

paintText = new Paint();
paintText.setAntiAlias(true);
paintText.setTextAlign(Paint.Align.CENTER);
paintText.setTextSize(mTextSize);

paintBackground = new Paint();
paintBackground.setAntiAlias(true);
paintBackground.setStyle(Paint.Style.FILL);

paintFrame = new Paint();
paintFrame.setAntiAlias(true);
paintFrame.setStyle(Paint.Style.STROKE);
paintFrame.setStrokeWidth(mFrameWidth);
paintFrame.setColor(mColorFrame);

textCenterYOffset = getTextCenterYOffset(paintText.getFontMetrics());
this.setClickable(true);
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
setMeasuredDimension(measureWidth(widthMeasureSpec, paintText),
measureHeight(heightMeasureSpec, paintText));
}

@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);

rectF.left = getPaddingLeft();
rectF.top = getPaddingTop();
rectF.right = w - getPaddingRight();
rectF.bottom = h - getPaddingBottom();
float inset = (float)Math.ceil(mFrameWidth / 2);
rectF.inset(inset, inset);

if(mTexts!= null && mTexts.length > 0){
unitWidth = rectF.width() / mTexts.length;
}

rectFArc.left = 0;
rectFArc.top = 0;
rectFArc.right = 2 * mFrameCornerRadius;
rectFArc.bottom = 2 * mFrameCornerRadius;
}

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if(!isStringArrayEmpty(mTexts)){
drawBackgroundAndFrameAndText(canvas);
}
}

@Override
public boolean onTouchEvent(MotionEvent event) {
preTouchedIndex = curTouchedIndex;
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
curTouchedIndex = getTouchedIndex(event.getX(), event.getY());
if(preTouchedIndex != curTouchedIndex){
invalidate();
}
break;
case MotionEvent.ACTION_MOVE:
curTouchedIndex = getTouchedIndex(event.getX(), event.getY());
if(preTouchedIndex != curTouchedIndex){
invalidate();
}
break;
case MotionEvent.ACTION_UP:
curTouchedIndex = getTouchedIndex(event.getX(), event.getY());
if(curTouchedIndex != -1){
if(mOnSegmentChangedListener != null && mSelectedIndex != curTouchedIndex){
mOnSegmentChangedListener.onSegmentChanged(curTouchedIndex);
}
mSelectedIndex = curTouchedIndex;
}
curTouchedIndex = -1;
if(mIsGradient && checkViewPagerOnPageChangeListener(this.viewPager)){

}else{
invalidate();
}
break;
case MotionEvent.ACTION_CANCEL:
curTouchedIndex = -1;
invalidate();
break;
}
return super.onTouchEvent(event);
}

public void setTextSize(int textSize){
if(this.mTextSize != textSize){
this.mTextSize = textSize;
paintText.setTextSize(textSize);
textCenterYOffset = getTextCenterYOffset(paintText.getFontMetrics());
requestLayout();
invalidate();
}
}

public int getSelectedIndex(){
return mSelectedIndex;
}

public void setSelectedIndex(int selectedIndex){
if(mSelectedIndex != selectedIndex){
mSelectedIndex = selectedIndex;
if(mOnSegmentChangedListener != null){
mOnSegmentChangedListener.onSegmentChanged(mSelectedIndex);
}
//          invalidate();
if(mIsGradient && checkViewPagerOnPageChangeListener(this.viewPager)){
}else{
invalidate();
}
}
}

public void setTextColor(int textColorNormal, int textColorSelected){
this.mColorTextNormal = textColorNormal;
this.mColorTextSelected = textColorSelected;
invalidate();
}

public void setBackgroundColor(int backgroundColorNormal, int backgroundColorSelected){
this.mColorBackgroundNormal = backgroundColorNormal;
this.mColorBackgroundSelected = backgroundColorSelected;
invalidate();
}

public void setFrameColor(int frameColor){
this.mColorFrame = frameColor;
invalidate();
}

public void setFrameWidth(int frameWidth){
this.mFrameWidth = frameWidth;
requestLayout();
invalidate();
}

public void setTexts(String[] texts){
assertTextsValid(texts);
if(texts == null || texts.length < 2){
throw new IllegalArgumentException("SegmentControlView's content text array'length should larger than 1");
}
if(checkIfEqual(this.mTexts, texts)){
return;
}
this.mTexts = texts;
unitWidth = rectF.width() / texts.length;
requestLayout();
invalidate();
}

public int getCount(){
if(mTexts == null) return 0;
return mTexts.length;
}

/**
* setViewPager(viewpager) to response to the change of ViewPager
* @param viewPager the viewPager you want segmentcontrolview to respond with
*/
public void setViewPager(ViewPager viewPager) {
this.viewPager = viewPager;
if (viewPager != null) {
viewPager.setOnPageChangeListener(new InternalViewPagerListener());
}
}

/**
* set if this view has the Gradient effect when segment changed
* @param gradient set if you want gradient effect
*/
public void setGradient(boolean gradient){
if(mIsGradient != gradient){
mIsGradient = gradient;
}
}

public boolean getGradient(){
return mIsGradient;
}

/**
* when segment changed,
* mOnSegmentChangedListener.onSegmentChanged(newSelectedIndex) will be triggered
* @param listener OnSegmentChangedListener
*/
public void setOnSegmentChangedListener(OnSegmentChangedListener listener){
mOnSegmentChangedListener = listener;
}

public void update(){
invalidate();
}

private float getTextCenterYOffset(Paint.FontMetrics fontMetrics){
if(fontMetrics == null) return 0;
return Math.abs(fontMetrics.top + fontMetrics.bottom)/2;
}

private String[] convertCharSequenceToString(CharSequence[] csArray){
if(csArray == null) return null;
String[] sArray = new String[csArray.length];
for(int i = 0; i < csArray.length; i++){
sArray[i] = csArray[i].toString();
}
return sArray;
}

private void assertTextsValid(String[] texts){
if(texts == null || texts.length < 2){
throw new IllegalArgumentException("SegmentControlView's content text array'length should larger than 1");
}
}

private boolean checkViewPagerOnPageChangeListener(ViewPager viewPager){
if(viewPager == null) return false;
Field field = null;
try {
field = ViewPager.class.getDeclaredField("mOnPageChangeListener");
if(field == null) return false;
field.setAccessible(true);
Object o = field.get(viewPager);
if(o != null && o instanceof InternalViewPagerListener){
return true;
}
} catch (Exception e) {
return false;
}
return false;
}

private int getTouchedIndex(float x, float y){

if(!rectF.contains(x, y)){
return -1;
}
for(int i = 0; i < mTexts.length; i++){
if(rectF.left + i * unitWidth <= x && x < rectF.left + (i + 1) * unitWidth){
return i;
}
}
return -1;
}

private boolean checkIfEqual(String[] a, String[] b){
if(a == null && b == null){
return true;
}
if(a != null){
if(b == null){
return false;
}
if(a.length != b.length){
return false;
}
for(int i = 0; i < a.length; i++){
if(a[i] == null && b[i] == null){
continue;
}
if(a[i] != null && a[i].equals(b[i])){
continue;
}else{
return false;
}
}
return true;
}
return false;
}

private int measureWidth(int measureSpec, Paint paint) {
int result = 0;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);

if (specMode == MeasureSpec.EXACTLY) {
result = specSize;
} else {
int maxWidth = 0;
int maxWidthItem = getMaxWidthOfTextArray(mTexts, paint);
maxWidth = (maxWidthItem + 2 * mSegmentPaddingHorizontal + 2 * mFrameWidth) * mTexts.length;

if(maxWidth < 2 * mFrameCornerRadius){
maxWidth = 2 * mFrameCornerRadius;
}

result = this.getPaddingLeft() + this.getPaddingRight() + maxWidth;//MeasureSpec.UNSPECIFIED
if (specMode == MeasureSpec.AT_MOST) {
result = Math.min(result, specSize);
}
}
return result;
}

private int measureHeight(int measureSpec, Paint paint) {
int result = 0;
int specMode = MeasureSpec.getMode(measureSpec);
int specSize = MeasureSpec.getSize(measureSpec);

if (specMode == MeasureSpec.EXACTLY) {
result = specSize;
} else {
int maxHeight = 0;
int maxHeightItem = getMaxHeightOfTextArray(mTexts, paint);

maxHeight = maxHeightItem + 2 * mSegmentPaddingVertical + 2 * mFrameWidth;

if(maxHeight < 2 * mFrameCornerRadius){
maxHeight = 2 * mFrameCornerRadius;
}

result = this.getPaddingTop() + this.getPaddingBottom() + maxHeight;//MeasureSpec.UNSPECIFIED
if (specMode == MeasureSpec.AT_MOST) {
result = Math.min(result, specSize);
}
}
return result;
}

private int getMaxWidthOfTextArray(String[] array, Paint paint){
if(array == null){
return 0;
}
int maxWidth = 0;
for(String item : array){
if(item != null){
int itemWidth = getTextWidth(item, paint);
maxWidth = Math.max(itemWidth, maxWidth);
}
}
return maxWidth;
}

private int getMaxHeightOfTextArray(String[] array, Paint paint){
if(array == null){
return 0;
}
int maxHeight = 0;
for(String item : array){
if(item != null){
int itemHeight = getTextHeight(item, paint);
maxHeight = Math.max(itemHeight, maxHeight);
}
}
return maxHeight;
}

private void drawBackgroundAndFrameAndText(Canvas canvas){
int curBackgroundColor = 0;
int curTextColor = 0;
for(int i = 0; i < mTexts.length; i++){
float left = rectF.left + unitWidth * i;
pathFrame.reset();
if(i == 0){
pathFrame.moveTo(rectF.left, rectF.top + mFrameCornerRadius);
rectFArc.offsetTo(rectF.left, rectF.top);
pathFrame.arcTo(rectFArc, 180, 90);
pathFrame.lineTo(rectF.left + unitWidth, rectF.top);
pathFrame.lineTo(rectF.left + unitWidth, rectF.bottom);
pathFrame.lineTo(rectF.left + mFrameCornerRadius, rectF.bottom);
rectFArc.offsetTo(rectF.left, rectF.bottom - 2 * mFrameCornerRadius);
pathFrame.arcTo(rectFArc, 90, 90);
}else if(i == (mTexts.length - 1)){
pathFrame.moveTo(rectF.left + i * unitWidth, rectF.top);
pathFrame.lineTo(rectF.right - mFrameCornerRadius, rectF.top);
rectFArc.offsetTo(rectF.right - 2 * mFrameCornerRadius, rectF.top);
pathFrame.arcTo(rectFArc, 270, 90);
pathFrame.lineTo(rectF.right, rectF.bottom - mFrameCornerRadius);
rectFArc.offsetTo(rectF.right - 2 * mFrameCornerRadius, rectF.bottom - 2 * mFrameCornerRadius);
pathFrame.arcTo(rectFArc, 0, 90);
pathFrame.lineTo(rectF.left + i * unitWidth, rectF.bottom);
}else{
pathFrame.moveTo(left, rectF.top);
pathFrame.lineTo(left + unitWidth, rectF.top);
pathFrame.lineTo(left + unitWidth, rectF.bottom);
pathFrame.lineTo(left, rectF.bottom);
}
pathFrame.close();

if(!mIsGradient){
if(i == mSelectedIndex){
curBackgroundColor = mColorBackgroundSelected;
curTextColor = mColorTextSelected;
}else{
curBackgroundColor = mColorBackgroundNormal;
curTextColor = mColorTextNormal;
}
}
if(mIsGradient){
if(viewPagerPositionOffset != 0f){
if(i == viewPagerPosition){
curBackgroundColor = getEvaluateColor(viewPagerPositionOffset, mColorBackgroundSelected, mColorBackgroundNormal);
curTextColor = getEvaluateColor(viewPagerPositionOffset, mColorTextSelected, mColorTextNormal);
}else if(i == viewPagerPosition + 1){
curBackgroundColor = getEvaluateColor(viewPagerPositionOffset, mColorBackgroundNormal, mColorBackgroundSelected);
curTextColor = getEvaluateColor(viewPagerPositionOffset, mColorTextNormal, mColorTextSelected);
}else{
curBackgroundColor = mColorBackgroundNormal;
curTextColor = mColorTextNormal;
}
}else{
if(i == mSelectedIndex){
curBackgroundColor = mColorBackgroundSelected;
curTextColor = mColorTextSelected;
}else{
curBackgroundColor = mColorBackgroundNormal;
curTextColor = mColorTextNormal;
}
}
}
paintBackground.setColor(curBackgroundColor);

if(curTouchedIndex == i){
paintBackground.setColor(getDarkColor(curBackgroundColor, TOUCHED_BACKGROUND_DARK_COEFFICIENT));
}
canvas.drawPath(pathFrame, paintBackground);
canvas.drawPath(pathFrame, paintFrame);

paintText.setColor(curTextColor);
canvas.drawText(mTexts[i], left + unitWidth / 2,rectF.centerY() + textCenterYOffset, paintText);
}
}

private int viewPagerPosition = -1;
private float viewPagerPositionOffset = 0f;
private class InternalViewPagerListener implements ViewPager.OnPageChangeListener {

@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
if(mIsGradient){
mSelectedIndex = position;
viewPagerPosition = position;
viewPagerPositionOffset = positionOffset;
invalidate();
}
}

@Override
public void onPageScrollStateChanged(int state) {
}

@Override
public void onPageSelected(int position) {
if(mIsGradient){
}else{
SegmentControlView.this.setSelectedIndex(position);
}
}
}

private int getDarkColor(int color, float darkCoefficient){

int a = (color & 0xff000000) >>> 24;
int r = (color & 0x00ff0000) >>> 16;
int g = (color & 0x0000ff00) >>> 8;
int b = (color & 0x000000ff) >>> 0;

r = (int)(r * darkCoefficient);
g = (int)(g * darkCoefficient);
b = (int)(b * darkCoefficient);

return a << 24 | r << 16 | g << 8 | b;
}

private int getEvaluateColor(float fraction, int startColor, int endColor){

int a, r, g, b;

int sA = (startColor & 0xff000000) >>> 24;
int sR = (startColor & 0x00ff0000) >>> 16;
int sG = (startColor & 0x0000ff00) >>> 8;
int sB = (startColor & 0x000000ff) >>> 0;

int eA = (endColor & 0xff000000) >>> 24;
int eR = (endColor & 0x00ff0000) >>> 16;
int eG = (endColor & 0x0000ff00) >>> 8;
int eB = (endColor & 0x000000ff) >>> 0;

a = (int)(sA + (eA - sA) * fraction);
r = (int)(sR + (eR - sR) * fraction);
g = (int)(sG + (eG - sG) * fraction);
b = (int)(sB + (eB - sB) * fraction);

return a << 24 | r << 16 | g << 8 | b;
}

private boolean isStringArrayEmpty(String[] array){
return (array == null || array.length == 0);
}

private static int sp2px(Context context, float spValue) {
final float fontScale = context.getResources().getDisplayMetrics().scaledDensity;
return (int) (spValue * fontScale + 0.5f);
}

private int getTextWidth(String text, Paint paint){
if(!TextUtils.isEmpty(text)){
return (int)(paint.measureText(text) + 0.5f);
}
return -1;
}

private int getTextHeight(String text, Paint paint){
if(!TextUtils.isEmpty(text)){
Rect textBounds = new Rect();
paint.getTextBounds(text, 0, text.length(), textBounds);
return textBounds.height();
}
return -1;
}
}