高仿今日头条字体渐变指示器，滑动+点击切换，如丝顺滑

引言：今日头条的指示器很炫酷，随着你的滑动字体颜色可以逐渐的变化，实现方法主要是使用自定义控件结合ViewPager。

一、ViewPager onPageChangeListener研究

OnPageChangeListener分析：ViewPager在处理滑动事件的时候要用到OnPageChangeListener，OnPageChangeListener这个接口需要实现三个方法：（onPageScrollStateChanged、onPageScrolled
、onPageSelected）

实现代码如下，在每个函数中都加入了Log：

public class SelectOnPageChangeListener implements OnPageChangeListener {

private boolean  checkIfScroll = false;

public void onPageScrollStateChanged(int arg0) {
if (DEBUG) {
Log.d(TAG, "onPageScrollStateChanged:arg0=" + arg0);
}
if(arg0 == 1){
checkIfScroll = true;
} else if (arg0 == 0){
checkIfScroll = false;
}
}

@Override
public void onPageScrolled(int position, float positionOffset,
int positionOffsetPixels) {
if(checkIfScroll){
if (positionOffset > 0) {
ColorTrackView left = colorTrackViews.get(position);
ColorTrackView right = colorTrackViews.get(position + 1);

left.setDirection(1);
right.setDirection(0);
if (DEBUG) {
Log.d(TAG, "onPageScrolled:positionOffset="
+ positionOffset + "|" + "position=" + position);
}
left.setProgress(1 - positionOffset);
right.setProgress(positionOffset);
}
}
}

public void onPageSelected(int arg0) {
if (DEBUG) {
Log.d(TAG, "onPageSelected:arg0=" + arg0);
}
}

}

操作步骤为从第一个页面滑动到第二个页面，运行Demo得到如下Log信息：

04-26 05:36:55.448: D/LearnActivity(1180): fragments size=5
04-26 05:36:55.580: W/EGL_genymotion(1180): eglSurfaceAttrib not implemented
<strong>04-26 05:37:02.396: D/LearnActivity(1180): onPageScrollStateChanged:arg0=1</strong>
04-26 05:37:02.412: D/LearnActivity(1180): onPageScrolled:positionOffset=0.009722223|position=0
04-26 05:37:02.432: D/LearnActivity(1180): onPageScrolled:positionOffset=0.027777778|position=0
04-26 05:37:02.452: D/LearnActivity(1180): onPageScrolled:positionOffset=0.044444446|position=0
......(省略一部分Log)
04-26 05:37:05.364: D/LearnActivity(1180): onPageScrolled:positionOffset=0.73888886|position=0
<strong>04-26 05:37:05.364: D/LearnActivity(1180): onPageScrollStateChanged:arg0=2
04-26 05:37:05.364: D/LearnActivity(1180): onPageSelected:arg0=1</strong>
04-26 05:37:05.380: D/LearnActivity(1180): onPageScrolled:positionOffset=0.76666665|position=0
04-26 05:37:05.396: D/LearnActivity(1180): onPageScrolled:positionOffset=0.79583335|position=0
04-26 05:37:05.412: D/LearnActivity(1180): onPageScrolled:positionOffset=0.825|position=0
......(省略一部分Log)
04-26 05:37:05.728: D/LearnActivity(1180): onPageScrolled:positionOffset=0.99722224|position=0
04-26 05:37:05.748: D/LearnActivity(1180): onPageScrolled:positionOffset=0.9986111|position=0
<strong>04-26 05:37:06.012: D/LearnActivity(1180): onPageScrollStateChanged:arg0=0</strong>

1.onPageScrollStateChanged(int arg0)

此方法是在状态改变的时候调用，其中arg0这个参数有三种状态（0、1、2），由上面的Log可以知道当你滑动页面的时候，调用顺序为1，2，0。

0表示滑动完毕，1表示按下状态， 2表示手指抬起状态。当按下ViewPager的页面时onPageScrollStateChanged:arg0=1，这有助于我们区别你是滑动页面还是点击上部文字头标切换，从而修复ColorTrackView点击头标切换文字绘制变乱的bug。

2.onPageSelected(int arg0)

此方法当你抬起手指 onPageScrollStateChanged:arg0=2后马上触发onPageSelected:arg0=1，其中的参数arg0代表选中的页面。

3.onPageScrolled(int position, float positionOffset, int positionOffsetPixels)

当页面被按下这个方法就开始执行，直到页面滑动结束onPageScrollStateChanged:arg0=0，期间都会调用。

其中三个参数的含义分别为：

position：当前可见页面的第一个页面，也可以理解为当前滑动页面的前一个页面position。我们从第一个页面滑动到第二个页面，这也是我们上面Log打印出来的信息为什么position=0的缘故，而不是我们想当然的觉得position为1。

positionOffset：页面偏移的百分比（取值0到1之间）

positionOffsetPixels：页面偏移的像素位置

二、使用ColorTrackView打造文字渐变指示器

首先感谢张鸿洋，这个自定义控件是他写的，具体地址在这里：/article/1580266.html，我把他的这个控件代码稍微优化了一下，去除了一些没用的代码，并添加了一些注释，这个控件主要是使用了自定义View中的两步，测量和绘制也就是onMeasure和onDraw。
我们来看一下文字的绘制起点，这里用高度表示，宽度道理是一样的。这两行代码计算后正好是我们的文字绘制起点，图中的大红点。代码如下：
mTextStartX = mRealWidth / 2 - mTextWidth / 2;
canvas.drawText((String) mText, mTextStartX, getMeasuredHeight() / 2 + mTextBound.height() / 2, mPaint);





下面是各部分代码。完整的DEMO可下载。附上效果图：

点此下载

1.values下面的文件

attrs.xml

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

<declare-styleable name="ColorTrackView">
<attr name="text" format="string" />
<attr name="textSize" format="dimension" />
<attr name="textOriginColor" format="color|reference" />
<attr name="textChangeColor" format="color|reference" />
<attr name="progress" format="float" />
<attr name="direction">
<enum name="left" value="0" />
<enum name="right" value="1" />
</attr>
</declare-styleable>

</resources>

colors.xml

<?xml version="1.0" encoding="utf-8"?>
<resources>
<color name="MyWhite">#FFFFF0F5</color>
<color name="MyDarkRed">#FF961F21</color>
<color name="MyActiveColor">#F26C4F</color>
<color name="MyGray">#50696969</color>
<!-- 纳瓦白/土著白 -->
<color name="navajo_white">#FFDEAD</color>
<color name="black">#000000</color>
<color name="gray">#696969</color>
</resources>

dimens.xml

<resources>

<dimen name="activity_horizontal_margin">6dp</dimen>
<dimen name="activity_vertical_margin">6dp</dimen>
<dimen name="font_size_title">20sp</dimen>
<dimen name="font_size_normal">18sp</dimen>
<dimen name="font_size_big">40sp</dimen>
<dimen name="font_size_biger">60sp</dimen>
<dimen name="font_size_center">16sp</dimen>
<dimen name="font_size_small">13sp</dimen>
<dimen name="font_size_cursor">12sp</dimen>
</resources>

strings.xml

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

<string name="app_name">CompleteTrackColorViewDemo</string>
<string name="hello_world">Hello world!</string>
<string name="action_settings">Settings</string>

</resources>

2.AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.completetrackcolorviewdemo"
android:versionCode="1"
android:versionName="1.0" >

<uses-sdk
android:minSdkVersion="14"
android:targetSdkVersion="21" />

<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@android:style/Theme.NoTitleBar" >
<activity
android:name=".LearnActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>

</manifest>

3.layout下的文件

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:lhw="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="@color/MyWhite" >

<include layout="@layout/top_bar" />

<LinearLayout
android:layout_width="match_parent"
android:layout_height="30dp"
android:background="@color/MyGray"
android:gravity="center_vertical"
android:orientation="horizontal"
android:weightSum="5.0" >

<com.example.completetrackcolorviewdemo.ColorTrackView
android:id="@+id/ctv_1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1.0"
lhw:text="DEMO"
lhw:textSize="@dimen/font_size_center"
lhw:textChangeColor="@color/MyDarkRed"
lhw:textOriginColor="@color/black"
lhw:progress="1.0" />

<com.example.completetrackcolorviewdemo.ColorTrackView
android:id="@+id/ctv_2"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1.0"
lhw:text="DEMO"
lhw:textSize="@dimen/font_size_center"
lhw:textChangeColor="@color/MyDarkRed"
lhw:textOriginColor="@color/black" />

<com.example.completetrackcolorviewdemo.ColorTrackView
android:id="@+id/ctv_3"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1.0"
lhw:text="DEMO"
lhw:textSize="@dimen/font_size_center"
lhw:textChangeColor="@color/MyDarkRed"
lhw:textOriginColor="@color/black" />

<com.example.completetrackcolorviewdemo.ColorTrackView
android:id="@+id/ctv_4"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1.0"
lhw:text="DEMO"
lhw:textSize="@dimen/font_size_center"
lhw:textChangeColor="@color/MyDarkRed"
lhw:textOriginColor="@color/black" />

<com.example.completetrackcolorviewdemo.ColorTrackView
android:id="@+id/ctv_5"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1.0"
lhw:text="DEMO"
lhw:textSize="@dimen/font_size_center"
lhw:textChangeColor="@color/MyDarkRed"
lhw:textOriginColor="@color/black" />

</LinearLayout>

<android.support.v4.view.ViewPager
android:id="@+id/vp_activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center"
android:flipInterval="30"
android:persistentDrawingCache="animation" />

</LinearLayout>

fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/gray"
android:gravity="center"
android:orientation="vertical" >

<TextView
android:id="@+id/tv_fragment"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="@color/MyActiveColor"
android:textSize="@dimen/font_size_center" />

</LinearLayout>

top_bar.xml

<?xml version="1.0" encoding="utf-8"?>
<merge xmlns:android="http://schemas.android.com/apk/res/android" >

<RelativeLayout
android:layout_width="match_parent"
android:layout_height="48dp"
android:background="@color/MyDarkRed" >

<TextView
android:id="@+id/tv_title_back"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:clickable="true"
android:gravity="center"
android:text="loading"
android:layout_marginLeft="@dimen/activity_horizontal_margin"
android:textColor="@color/black"
android:textSize="@dimen/font_size_title" />
</RelativeLayout>

</merge>

4.src下的代码片段

ColorTrackView.java

package com.example.completetrackcolorviewdemo;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.View;

public class ColorTrackView extends View {

private static final int DIRECTION_LEFT = 0;
private static final int DIRECTION_RIGHT = 1;
//以下定义一些默认的变量
private int mDirection = DIRECTION_LEFT;

private int mTextStartX;

private Paint mPaint;

private int mTextOriginColor = 0xffffff;//字体改变前的颜色
private int mTextChangeColor = 0xff0000;//字体改变中的颜色

private String mText = "xx";
private int mTextSize = DisplayUtil.dip2px(getContext(), 30); //字体大小
private int mTextWidth;

private int mRealWidth;

private float mProgress; // 进度，从0到1之间取值

private Rect mTextBound = new Rect();

public ColorTrackView(Context context) {
super(context, null);
}

public ColorTrackView(Context context, AttributeSet attrs) {
super(context, attrs);

mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);

TypedArray ta = context.obtainStyledAttributes(attrs,
R.styleable.ColorTrackView);
mText = ta.getString(R.styleable.ColorTrackView_text);
mTextSize = ta.getDimensionPixelSize(
R.styleable.ColorTrackView_textSize, mTextSize);
mTextOriginColor = ta.getColor(
R.styleable.ColorTrackView_textOriginColor,
mTextOriginColor);
mTextChangeColor = ta.getColor(
R.styleable.ColorTrackView_textChangeColor,
mTextChangeColor);
mProgress = ta.getFloat(R.styleable.ColorTrackView_progress, 0);
mDirection = ta.getInt(R.styleable.ColorTrackView_direction,
mDirection);

ta.recycle();
mPaint.setTextSize(mTextSize);

}

private void measureText() {
mTextWidth = (int) mPaint.measureText(mText);
//这个函数可以获取最小的包裹文字矩形，赋值到mTextBound
mPaint.getTextBounds(mText, 0,mText.length(), mTextBound);
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int width = measureWidth(widthMeasureSpec);
int height = measureHeight(heightMeasureSpec);
setMeasuredDimension(width, height);
measureText();
mRealWidth = getMeasuredWidth() - getPaddingLeft() - getPaddingRight();
mTextStartX = mRealWidth / 2 - mTextWidth / 2;

}

private int measureHeight(int measureSpec) {
int mode = MeasureSpec.getMode(measureSpec);
int val = MeasureSpec.getSize(measureSpec);
int result = 0;
switch (mode) {
case MeasureSpec.EXACTLY:
result = val;
break;
case MeasureSpec.AT_MOST:
case MeasureSpec.UNSPECIFIED:
result = mTextBound.height();
break;
}
result = mode == MeasureSpec.AT_MOST ? Math.min(result, val) : result;
return result + getPaddingTop() + getPaddingBottom();
}

private int measureWidth(int measureSpec) {
int mode = MeasureSpec.getMode(measureSpec);
int val = MeasureSpec.getSize(measureSpec);
int result = 0;
switch (mode) {
case MeasureSpec.EXACTLY:
result = val;
break;
case MeasureSpec.AT_MOST:
case MeasureSpec.UNSPECIFIED:
result = mTextBound.width();
break;
}
result = mode == MeasureSpec.AT_MOST ? Math.min(result, val) : result;
return result + getPaddingLeft() + getPaddingRight();
}

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);

if (mDirection == DIRECTION_LEFT) {
drawChangeLeft(canvas);
drawOriginLeft(canvas);
} else if (mDirection == DIRECTION_RIGHT) {
drawOriginRight(canvas);
drawChangeRight(canvas);
} else {
System.out.println("ColorTrackView direction error");
}

}

private void drawChangeRight(Canvas canvas) {
drawText(canvas, mTextChangeColor, (int) (mTextStartX + (1 - mProgress)
* mTextWidth), mTextStartX + mTextWidth);
}

private void drawOriginRight(Canvas canvas) {
drawText(canvas, mTextOriginColor, mTextStartX,
(int) (mTextStartX + (1 - mProgress) * mTextWidth));
}

private void drawChangeLeft(Canvas canvas) {
drawText(canvas, mTextChangeColor, mTextStartX,
(int) (mTextStartX + mProgress * mTextWidth));
}

private void drawOriginLeft(Canvas canvas) {
drawText(canvas, mTextOriginColor, (int) (mTextStartX + mProgress
* mTextWidth), mTextStartX + mTextWidth);
}

private void drawText(Canvas canvas, int color, int startX, int endX) {
mPaint.setColor(color);
canvas.save(Canvas.CLIP_SAVE_FLAG);
canvas.clipRect(startX, 0, endX, getMeasuredHeight());
canvas.drawText((String) mText, mTextStartX, getMeasuredHeight()
/ 2 + mTextBound.height() / 2, mPaint);
canvas.restore();
}

public int getDirection() {
return mDirection;
}

public void setDirection(int mDirection) {
this.mDirection = mDirection;
invalidate(); //重新改变方向，需要重绘
}

public int getTextOriginColor() {
return mTextOriginColor;
}

public void setTextOriginColor(int mTextOriginColor) {
this.mTextOriginColor = mTextOriginColor;
invalidate(); //改变原始颜色，需要重绘
}

public int getTextChangeColor() {
return mTextChangeColor;
}

public void setTextChangeColor(int mTextChangeColor) {
this.mTextChangeColor = mTextChangeColor;
invalidate();//改变变化中的颜色，需要重绘
}

public String getText() {
return mText;
}

public void setText(String mText) {
this.mText = mText;
}

public int getTextSize() {
return mTextSize;
}

public void setTextSize(int mTextSize) {
this.mTextSize = mTextSize;
requestLayout();//改变字体大小，重新布局
invalidate();//改变字体大小，需要重绘
}

public float getProgress() {
return mProgress;
}

public void setProgress(float mProgress) {
this.mProgress = mProgress;
invalidate();//改变进度，需要重绘，实现字体渐变的效果
}

}

工具类DisplayUtil.java

package com.example.completetrackcolorviewdemo;

import android.content.Context;

public class DisplayUtil {
/**
* 根据手机的分辨率从 dp 的单位 转成为 px(像素)
*/
public static int dip2px(Context context, float dpValue) {
final float scale = context.getResources().getDisplayMetrics().density;
return (int) (dpValue * scale + 0.5f);
}

/**
* 根据手机的分辨率从 px(像素) 的单位 转成为 dp
*/
public static int px2dip(Context context, float pxValue) {
final float scale = context.getResources().getDisplayMetrics().density;
return (int) (pxValue / scale + 0.5f);
}
}

LearnActivity.java

package com.example.completetrackcolorviewdemo;

import java.util.ArrayList;
import java.util.List;

//import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.TextView;

public class LearnActivity extends FragmentActivity {
private String TAG = "LearnActivity";
private boolean DEBUG = true;
private TextView tv_back_learn_activity;
private ColorTrackView ctv_1, ctv_3, ctv_2,
ctv_4, ctv_5;
private ViewPager vp_learn_activity;
private List<Fragment> fragments;// Tab页面列表
private List<ColorTrackView> colorTrackViews; // Tab页面头标列表

// private Context context;// 上下文

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// context = LearnActivity.this;
initView();
setListener();
}

private void initView() {
tv_back_learn_activity = (TextView) findViewById(R.id.tv_title_back);
ctv_1 = (ColorTrackView) findViewById(R.id.ctv_1);
ctv_2 = (ColorTrackView) findViewById(R.id.ctv_2);
ctv_3 = (ColorTrackView) findViewById(R.id.ctv_3);
ctv_4 = (ColorTrackView) findViewById(R.id.ctv_4);
ctv_5 = (ColorTrackView) findViewById(R.id.ctv_5);

tv_back_learn_activity.setText("学习DEMO");

colorTrackViews = new ArrayList<ColorTrackView>();
colorTrackViews.add(ctv_1);
colorTrackViews.add(ctv_2);
colorTrackViews.add(ctv_3);
colorTrackViews.add(ctv_4);
colorTrackViews.add(ctv_5);

InitViewPager();
}

private void InitViewPager() {
vp_learn_activity = (ViewPager) findViewById(R.id.vp_activity_main);
fragments = new ArrayList<Fragment>();
// 后面用对应的数据去填充MyFragement，这里仅仅作为一个测试循环添加
for (int i = 0; i < 5; i++) {
MyFragment fragment = new MyFragment(i);
fragments.add(fragment);
}
if (DEBUG) {
Log.d(TAG, "fragments size=" + fragments.size());
}
vp_learn_activity.setAdapter(new SelectFragmentPagerAdapter(
getSupportFragmentManager(), fragments));
vp_learn_activity.setCurrentItem(0);
vp_learn_activity
.setOnPageChangeListener(new SelectOnPageChangeListener());
}

/**
* 头标点击监听
*/
private class SelectOnClickListener implements OnClickListener {
private int index = 0;

public SelectOnClickListener(int i) {
index = i;
}

public void onClick(View v) {
vp_learn_activity.setCurrentItem(index);
changeColorTrackViewColor(index);
}

}

private void setListener() {
tv_back_learn_activity.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
LearnActivity.this.finish();
}
});

ctv_1.setOnClickListener(new SelectOnClickListener(0));
ctv_2.setOnClickListener(new SelectOnClickListener(1));
ctv_3.setOnClickListener(new SelectOnClickListener(2));
ctv_4.setOnClickListener(new SelectOnClickListener(3));
ctv_5.setOnClickListener(new SelectOnClickListener(4));
}

/**
* 改变选中ColorTrackView的文字颜色
*
* @param index
*            表示选中的是那个标签（0、1、2、3）
*/
private void changeColorTrackViewColor(int index) {
ctv_1.setDirection(0);
ctv_1.setProgress(((index == 0) ? 1.0f : 0));
ctv_2.setDirection(0);
ctv_2.setProgress(((index == 1) ? 1.0f : 0));
ctv_3.setDirection(0);
ctv_3.setProgress(((index == 2) ? 1.0f : 0));
ctv_4.setDirection(0);
ctv_4.setProgress(((index == 3) ? 1.0f : 0));
ctv_5.setDirection(0);
ctv_5.setProgress(((index == 4) ? 1.0f : 0));
}

@Override
protected void onPause() {
super.onPause();
}

@Override
protected void onDestroy() {
super.onDestroy();
}

public class SelectOnPageChangeListener implements OnPageChangeListener {

private boolean  checkIfScroll = false;

public void onPageScrollStateChanged(int arg0) {
if (DEBUG) {
Log.d(TAG, "onPageScrollStateChanged:arg0=" + arg0);
}
if(arg0 == 1){
checkIfScroll = true;
} else if (arg0 == 0){
checkIfScroll = false;
}
}

@Override
public void onPageScrolled(int position, float positionOffset,
int positionOffsetPixels) {
if(checkIfScroll){
if (positionOffset > 0) {
ColorTrackView left = colorTrackViews.get(position);
ColorTrackView right = colorTrackViews.get(position + 1);

left.setDirection(1);
right.setDirection(0);
if (DEBUG) {
Log.d(TAG, "onPageScrolled:positionOffset="
+ positionOffset + "|" + "position=" + position);
}
left.setProgress(1 - positionOffset);
right.setProgress(positionOffset);
}
}
}

public void onPageSelected(int arg0) {
if (DEBUG) {
Log.d(TAG, "onPageSelected:arg0=" + arg0);
}
}

}

}

MyFragment.java

package com.example.completetrackcolorviewdemo;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.support.v4.app.Fragment;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

public class MyFragment extends Fragment {

private View layout;
private TextView tv;
int i;

public MyFragment(int i) {
super();
this.i = i;
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {

layout = inflater.inflate(R.layout.fragment,
container, false);
tv = (TextView)layout.findViewById(R.id.tv_fragment);
tv.setText("第"+i+"页");
return layout;
}

}

SelectFragmentPagerAdapter.java

package com.example.completetrackcolorviewdemo;

import java.util.List;

import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;

public class SelectFragmentPagerAdapter extends FragmentPagerAdapter {

private List<Fragment> list;

public SelectFragmentPagerAdapter(FragmentManager fm, List<Fragment> list) {
super(fm);
this.list = list;

}

@Override
public int getCount() {
return list.size();
}

@Override
public Fragment getItem(int arg0) {
return list.get(arg0);
}

}

完结！