Android自定义ViewPagerIndicator实现炫酷导航栏指示器（ViewPager+Fragment）

public viewpagerindicator(context context, attributeset attrs) { 
 super(context, attrs); 
 mpaint = new paint();//实例化画笔 
 mpaint.setantialias(true);//设置抗锯齿 
 mpaint.setcolor(color.parsecolor("#c9b2ab"));//设置画笔的颜色,也就是三角形的颜色 
 mpaint.setstyle(paint.style.fill);//设置style 
 mpaint.setpatheffect(new cornerpatheffect(3));//设置三角形圆角 
 
 } 

/** 
 * 当控件的宽高发生变化时都会回调这个方法 
 * @param w 控件的长度 
 * @param h 高度 
 * @param oldw 以前的长度 
 * @param oldh 以前的高度 
 */ 
 @override 
 protected void onsizechanged(int w, int h, int oldw, int oldh) { 
 super.onsizechanged(w, h, oldw, oldh); 
 
 /* 
 控件的长度（3个tab的总长度）/3就得到每个tab的长度 
 而三角形的宽度又是每个tab的长度的六分之一 
 */ 
 mtrianglewidth = (int) (w / 3 * radio_triangle_width); 
 /* 
 三角形初始的偏移量，也就是三角形初始的位置 
 w / 3 / 2：每个tab长度的一半就是tab的正中间 
 再减去三角形宽度的一半，这个偏移量刚好三角形就显示在tab的正中间 
 */ 
 minittranslationx = w / 3 / 2 - mtrianglewidth / 2; 
 inittriangle(); 
 
 
 } 
 
 /** 
 * 初始化三角形 
 */ 
 private void inittriangle() { 
 mtriangleheight = mtrianglewidth / 2;//三角形的高度设置为宽度的一半 
 //实例化三角形 
 mpath = new path(); 
 mpath.moveto(0, 0);//三角形的起点 
 mpath.lineto(mtrianglewidth, 0);//首先绘制一条宽度为三角形宽度的一条直线 
 //然后绘制三角形右边的那条线x坐标为宽度的一半，y坐标为宽度的一半 
 mpath.lineto(mtrianglewidth / 2, -mtriangleheight); 
 mpath.close();//完成闭合，绘制了一个完整的三角形 
 } 

/** 
 * 绘制 
 * @param canvas 
 */ 
 @override 
 protected void dispatchdraw(canvas canvas) { 
 /* 
 canvas.save();和canvas.restore();是两个相互匹配出现的，作用是用来保存画布的状态和取出保存的状态的。 
 save：用来保存canvas的状态。save之后，可以调用canvas的平移、放缩、旋转、错切、裁剪等操作 
 */ 
 canvas.save(); 
 canvas.translate(minittranslationx + mtranslationx, getheight()+2);//绘制之前先平移到指定的位置 
 canvas.drawpath(mpath,mpaint);//平移到指定的位置后开始绘制， 
 /* 
 restore：用来恢复canvas之前保存的状态。防止save后对canvas执行的操作对后续的绘制有影响。 
 */ 
 canvas.restore(); 
 super.dispatchdraw(canvas); 
 } 

/** 
 * 指示器根据手指滚动而滚动 
 * @param position 
 */ 
 public void scroll(int position, float offset) { 
 int tabwidth = getwidth() / 3; 
 mtranslationx = (int)(tabwidth * offset + position * tabwidth);//三角形的偏移量 
 invalidate(); 
 } 

<?xml version="1.0" encoding="utf-8"?> 
<linearlayout xmlns:android="http://schemas.android.com/apk/res/android" 
 xmlns:duanlian="http://schemas.android.com/apk/res-auto" 
 android:layout_width="match_parent" 
 android:layout_height="match_parent" 
 android:orientation="vertical"> 
 
 <com.duanlian.tabviewpagerindicator.view.viewpagerindicator 
 android:id="@+id/id_indicator" 
 android:layout_width="match_parent" 
 android:layout_height="45dp" 
 android:background="#000000" 
 android:orientation="horizontal" 
 duanlian:visible_tab_count="4"> 
 
 <textview 
 android:id="@+id/main_yiyan" 
 android:layout_width="0dp" 
 android:layout_height="match_parent" 
 android:layout_weight="1" 
 android:gravity="center" 
 android:onclick="meizi" 
 android:text="江一燕" 
 android:textcolor="#ffffff" 
 android:textsize="16sp" /> 
 
 <textview 
 android:id="@+id/main_liya" 
 android:layout_width="0dp" 
 android:layout_height="match_parent" 
 android:layout_weight="1" 
 android:gravity="center" 
 android:onclick="meizi" 
 android:text="佟丽娅" 
 android:textcolor="#ffffff" 
 android:textsize="16sp" /> 
 
 <textview 
 android:id="@+id/yuanyuan" 
 android:layout_width="0dp" 
 android:layout_height="match_parent" 
 android:layout_weight="1" 
 android:gravity="center" 
 android:onclick="meizi" 
 android:text="高圆圆" 
 android:textcolor="#ffffff" 
 android:textsize="16sp" /> 
 </com.duanlian.tabviewpagerindicator.view.viewpagerindicator> 
 
 <android.support.v4.view.viewpager 
 android:id="@+id/id_viewpager" 
 android:layout_width="fill_parent" 
 android:layout_height="0dp" 
 android:layout_weight="1" /> 
</linearlayout> 

package com.duanlian.tabviewpagerindicator.fragment; 
 
import android.os.bundle; 
import android.support.annotation.nullable; 
import android.support.v4.app.fragment; 
import android.view.layoutinflater; 
import android.view.view; 
import android.view.viewgroup; 
 
import com.duanlian.tabviewpagerindicator.r; 
 
public class fragmenta extends fragment { 
 @override 
 public void oncreate( bundle savedinstancestate) { 
 super.oncreate(savedinstancestate); 
 } 
 
 @nullable 
 @override 
 public view oncreateview(layoutinflater inflater, viewgroup container, bundle savedinstancestate) { 
 view view = inflater.inflate(r.layout.a_fragment, null); 
 return view; 
 } 
 
 
 @override 
 public void onactivitycreated( bundle savedinstancestate) { 
 super.onactivitycreated(savedinstancestate); 
 } 
} 

<?xml version="1.0" encoding="utf-8"?> 
<framelayout xmlns:android="http://schemas.android.com/apk/res/android" 
 android:layout_width="match_parent" 
 android:layout_height="match_parent" 
 android:orientation="vertical"> 
 
 <imageview 
 android:layout_width="match_parent" 
 android:layout_height="match_parent" 
 android:background="@mipmap/jiangyiyan" 
 android:scaletype="fitxy" /> 
 
 <textview 
 android:layout_width="match_parent" 
 android:layout_height="wrap_content" 
 android:layout_gravity="bottom" 
 android:gravity="center_horizontal" 
 android:text="fregmenta" 
 android:textcolor="#e44316" 
 android:textsize="36dp" /> 
</framelayout> 

//定义两个颜色和大小 
 private int colora = color.parsecolor("#ff00ff");//选中的颜色 
 private int colorb = color.white;//默认的颜色 
 private float sizea = 19f;//选中大小 
 private float sizeb = 16f;//默认大小 

/** 
 * 设置监听的方法 
 */ 
 private void setlistener() { 
 //viewpager的监听事件 
 mviewpager.addonpagechangelistener(new viewpager.onpagechangelistener() { 
 @override 
 public void onpagescrolled(int position, float positionoffset, int positionoffsetpixels) { 
 //让indicator和viewpager联动 
 mindicator.scroll(position, positionoffset); 
 } 
 
 @override 
 public void onpageselected(int position) { 
 switch (position) { 
  case 0: 
  settextattribute(colora,colorb,colorb,sizea,sizeb,sizeb); 
  break; 
  case 1: 
  settextattribute(colorb,colora,colorb,sizeb,sizea,sizeb); 
  break; 
  case 2: 
  settextattribute(colorb,colorb,colora,sizeb,sizeb,sizea); 
  break; 
 } 
 } 
 @override 
 public void onpagescrollstatechanged(int state) { 
 } 
 }); 
 
 } 
 /** 
 * 自己定义一个给textview设置属性的方法 
 */ 
 private void settextattribute(int color1, int color2, int color3, float size1, float size2, float size3){ 
 yiyan.settextcolor(color1); 
 liya.settextcolor(color2); 
 yuanyuan.settextcolor(color3); 
 yiyan.settextsize(size1); 
 liya.settextsize(size2); 
 yuanyuan.settextsize(size3); 
 
 } 

/** 
 * 导航栏点击事件 
 * @param view 
 */ 
 public void meizi(view view){ 
 switch (view.getid()) { 
 case r.id.main_yiyan: 
 mviewpager.setcurrentitem(0); 
 break; 
 case r.id.main_liya: 
 mviewpager.setcurrentitem(1); 
 break; 
 case r.id.yuanyuan: 
 mviewpager.setcurrentitem(2); 
 break; 
 } 
 
 } 

package com.duanlian.tabviewpagerindicator; 
 
import android.graphics.color; 
import android.os.bundle; 
import android.support.v4.app.fragment; 
import android.support.v4.app.fragmentactivity; 
import android.support.v4.view.viewpager; 
import android.view.view; 
import android.view.window; 
import android.widget.textview; 
 
import com.duanlian.tabviewpagerindicator.adapter.myfragmentpageradapter; 
import com.duanlian.tabviewpagerindicator.fragment.fragmenta; 
import com.duanlian.tabviewpagerindicator.fragment.fragmentb; 
import com.duanlian.tabviewpagerindicator.fragment.fragmentc; 
import com.duanlian.tabviewpagerindicator.view.viewpagerindicator; 
 
import java.util.arraylist; 
import java.util.list; 
 
public class mainactivity extends fragmentactivity { 
 private viewpager mviewpager; 
 private viewpagerindicator mindicator;//导航栏指示器 
 private list<fragment> mcontents;//装载fragment的集合 
 private myfragmentpageradapter madapter; 
 private textview yiyan; 
 private textview liya; 
 private textview yuanyuan; 
 //定义两个颜色和大小 
 private int colora = color.parsecolor("#ff00ff");//选中的颜色 
 private int colorb = color.white;//默认的颜色 
 private float sizea = 19f;//选中大小 
 private float sizeb = 16f;//默认大小 
 
 
 @override 
 protected void oncreate(bundle savedinstancestate) { 
 super.oncreate(savedinstancestate); 
 requestwindowfeature(window.feature_no_title); 
 setcontentview(r.layout.activity_main); 
 initviews(); 
 setlistener(); 
 } 
 
 /** 
 * 初始化view 
 */ 
 private void initviews() { 
 mindicator = (viewpagerindicator) findviewbyid(r.id.id_indicator); 
 mviewpager = (viewpager) findviewbyid(r.id.id_viewpager); 
 //3个标题 
 yiyan = (textview) findviewbyid(r.id.main_yiyan); 
 liya = (textview) findviewbyid(r.id.main_liya); 
 yuanyuan = (textview) findviewbyid(r.id.yuanyuan); 
 fragmenta fragmenta = new fragmenta(); 
 fragmentb fragmentb = new fragmentb(); 
 fragmentc fragmentc = new fragmentc(); 
 mcontents = new arraylist<>(); 
 mcontents.add(fragmenta); 
 mcontents.add(fragmentb); 
 mcontents.add(fragmentc); 
 madapter = new myfragmentpageradapter(getsupportfragmentmanager(), mcontents); 
 mviewpager.setadapter(madapter); 
 //设置默认页面和颜色 
 mviewpager.setcurrentitem(0); 
 settextattribute(colora,colorb,colorb,sizea,sizeb,sizeb); 
 } 
 /** 
 * 导航栏点击事件 
 * @param view 
 */ 
 public void meizi(view view){ 
 switch (view.getid()) { 
 case r.id.main_yiyan: 
 mviewpager.setcurrentitem(0); 
 break; 
 case r.id.main_liya: 
 mviewpager.setcurrentitem(1); 
 break; 
 case r.id.yuanyuan: 
 mviewpager.setcurrentitem(2); 
 break; 
 } 
 
 } 
 
 /** 
 * 设置监听的方法 
 */ 
 private void setlistener() { 
 //viewpager的监听事件 
 mviewpager.addonpagechangelistener(new viewpager.onpagechangelistener() { 
 @override 
 public void onpagescrolled(int position, float positionoffset, int positionoffsetpixels) { 
 //让indicator和viewpager联动 
 mindicator.scroll(position, positionoffset); 
 } 
 
 @override 
 public void onpageselected(int position) { 
 switch (position) { 
  case 0: 
  settextattribute(colora,colorb,colorb,sizea,sizeb,sizeb); 
  break; 
  case 1: 
  settextattribute(colorb,colora,colorb,sizeb,sizea,sizeb); 
  break; 
  case 2: 
  settextattribute(colorb,colorb,colora,sizeb,sizeb,sizea); 
  break; 
 } 
 } 
 @override 
 public void onpagescrollstatechanged(int state) { 
 } 
 }); 
 
 } 
 /** 
 * 自己定义一个给textview设置属性的方法 
 */ 
 private void settextattribute(int color1, int color2, int color3, float size1, float size2, float size3){ 
 yiyan.settextcolor(color1); 
 liya.settextcolor(color2); 
 yuanyuan.settextcolor(color3); 
 yiyan.settextsize(size1); 
 liya.settextsize(size2); 
 yuanyuan.settextsize(size3); 
 
 } 
} 

package com.duanlian.tabviewpagerindicator.adapter; 
 
import android.support.v4.app.fragment; 
import android.support.v4.app.fragmentmanager; 
import android.support.v4.app.fragmentpageradapter; 
 
import java.util.list; 
 
public class myfragmentpageradapter extends fragmentpageradapter { 
 private list<fragment> list; 
 public myfragmentpageradapter(fragmentmanager fm,list<fragment> mcontents) { 
 super(fm); 
 this.list = mcontents; 
 } 
 
 @override 
 public fragment getitem(int position) { 
 return list.get(position); 
 } 
 
 @override 
 public int getcount() { 
 return list.size(); 
 } 
}