android实现ViewPager的Indicator的实例代码

publicclassViewPagerIndicatorextendsLinearLayout{

  //画笔

  privatePaint mPaint;

   //用来画一条线

  privatePath mPath;

  //绘制线的宽度

  privateintmLineWidth;

  //线的初始位置

  privateintmInitTranslationX;

  //移动位置

  privateintmTranslationX;

  //子控件

  privateView mChildView;

  publicViewPagerIndicator(Context context) {

    super(context,null);

  }

  publicViewPagerIndicator(Context context, AttributeSet attrs) {

    super(context, attrs);

    mPaint =newPaint();

    mPaint.setAntiAlias(true);

    mPaint.setColor(Color.parseColor("#ffba00"));

    mPaint.setStrokeWidth(3);

    mPaint.setStyle(Paint.Style.STROKE);

  }

  //完成布局后获取子控件

  @Override

  protectedvoidonFinishInflate() {

    super.onFinishInflate();

    mChildView = getChildAt(0);

  }

//在onSizeChanged中获取宽和初始位置，并根据位置初始化线

  @Override

  protectedvoidonSizeChanged(intw,inth,intoldw,intoldh) {

    super.onSizeChanged(w, h, oldw, oldh);

    mTranslationX =0;

    mLineWidth = mChildView.getMeasuredWidth();

    mInitTranslationX = (w/getChildCount()-mLineWidth)/2;

    initLine();

  }

//初始化线

  privatevoidinitLine(){

    mPath =newPath();

    mPath.moveTo(0,0);

    mPath.lineTo(mLineWidth,0);

  }

//绘制线

  @Override

  protectedvoiddispatchDraw(Canvas canvas) {

    canvas.save();

    //移动到该坐标后开始绘制

    canvas.translate(mInitTranslationX + mTranslationX,getHeight());

    canvas.drawPath(mPath,mPaint);

    canvas.restore();

    super.dispatchDraw(canvas);

  }

  ////在viewpager的onPageScrolled监听方法中调用此方法。viewPager滑动时mTranslationX的距离跟着变化，实现线的滑动，position，offset由onPageScrolled传值

  publicvoidscroll(intposition ,floatoffset){

    inttabWidth = getWidth()/getChildCount();

    mTranslationX =(int) (tabWidth * offset +tabWidth * position);

    //请求重绘，调用dispatchDraw方法

    invalidate();

  }

}

layout\orderpicking

  android:id="@+id/indicator"

  android:layout_width="match_parent"

  android:layout_height="@dimen/xhdpi_40"

  android:gravity="center"

  android:background="@color/white"

  android:orientation="horizontal">

  android:id="@+id/for_picking"

  android:layout_width="@dimen/xhdpi_60"

  android:layout_height="match_parent"

  android:layout_marginRight="@dimen/xhdpi_60"

  android:clickable="true"

  android:gravity="center"

  android:onClick="onClick"

  android:text="待拣货"

  android:textColor="@color/light_black"

  android:textSize="@dimen/xhdpi_14"/>

  android:id="@+id/has_been_picking"

  android:layout_width="@dimen/xhdpi_60"

  android:layout_height="match_parent"

  android:layout_marginRight="@dimen/xhdpi_60"

  android:clickable="true"

  android:gravity="center"

  android:onClick="onClick"

  android:text="已拣货"

  android:textColor="@color/light_black"

  android:textSize="@dimen/xhdpi_14"

  />

  android:id="@+id/all"

  android:layout_width="@dimen/xhdpi_60"

  android:layout_height="match_parent"

  android:clickable="true"

  android:gravity="center"

  android:onClick="onClick"

  android:text="全部"

  android:textColor="@color/light_black"

  android:textSize="@dimen/xhdpi_14"/>

    android:id="@+id/orderpicking_date"

    android:layout_width="match_parent"

    android:layout_height="0dp"

    android:layout_weight="1"

    android:background="@color/white">

在activity中完成ViewPagerIndicator与Viewpager的关联

publicclassOrderPickingActivityextendsFragmentActivityimplementsView.OnClickListener {

  TextView forPicking;

  TextView hasBeenPicking;

  TextView hasBeenPicking;

  ViewPagerIndicator mIndicator;

  ViewPager orderPickingDate;

  privateListmFragmentList;

  privateFragmentPagerAdapter orderPickingAdapter;

  privateViewPager.OnPageChangeListener onPageChangeListener;

  //当前选中的indicator

  privateTextView currentItem;

   protectedvoidonCreate(Bundle savedInstanceState) {

       super.onCreate(savedInstanceState);

       requestWindowFeature(Window.FEATURE_NO_TITLE);

       setContentView(R.layout.orderpicking);

     init();

     orderPickingDate.setAdapter(orderPickingAdapter);

     orderPickingDate.addOnPageChangeListener();

     orderPickingDate.setCurrentItem(0);

       currentItem = forPicking;

         currentItem.setTextColor(Color.parseColor("#ffba00"));

  }

  privatevoidinit(){

    forPicking = (TextView) findViewById(R.id.for_picking);

    hasBeenPicking = (TextView) findViewById(R.id.has_been_picking);

    all = (TextView) findViewById(R.id.all);

    mIndicator=(ViewPagerIndicator)findViewById(R.id.indicator);

    orderPickingDate = (ViewPager)findViewById(R.id.orderpicking_date);

    //初始化viewpager的item，并添加到list中

      mFragmentList =newArrayList<>();

      OrderPickingFragmentForPicking orderPickingFragmentForPicking =

      newOrderPickingFragmentForPicking();

      OrderPickingFragmentHasBeenPicking orderPickingFragmentHasBeenPicking =

        newOrderPickingFragmentHasBeenPicking();

      OrderPickingFragmentAll orderPickingFragmentAll =

        newOrderPickingFragmentAll();

      mFragmentList.add(orderPickingFragmentForPicking);

      mFragmentList.add(orderPickingFragmentHasBeenPicking);

      mFragmentList.add(orderPickingFragmentAll);

      //设置viewpager的适配器；

      orderPickingAdapter =newFragmentPagerAdapter(getSupportFragmentManager()) {

        @Override

        publicintgetCount() {

          returnmFragmentList.size();

        }

        @Override

        publicFragment getItem(inti) {

          returnmFragmentList.get(i);

        }

      };

      //设置ViewPager监听事件

      onPageChangeListener =newViewPager.OnPageChangeListener(){

        //滑动时，indicator下面的横线跟着滑动

        @Override

        publicvoidonPageScrolled(inti,floatv,inti1) {

          mIndicator.scroll(i, v);

        }

        //选中监听，改变indicator文字颜色

        @Override

        publicvoidonPageSelected(inti) {

          switch(i) {

            case0:

              if(currentItem == forPicking)

                return;

              forPicking.setTextColor(Color.parseColor("#ffba00"));

              currentItem.setTextColor(Color.parseColor("#646464"));

              currentItem = forPicking;

              break;

            case1:

              if(currentItem == hasBeenPicking)

                return;

              hasBeenPicking.setTextColor(Color.parseColor("#ffba00"));

              currentItem.setTextColor(Color.parseColor("#646464"));

              currentItem = hasBeenPicking;

              break;

            case2:

              if(currentItem == all)

                return;

              all.setTextColor(Color.parseColor("#ffba00"));

              currentItem.setTextColor(Color.parseColor("#646464"));

              currentItem = all;

          }

        }

        @Override

        publicvoidonPageScrollStateChanged(inti) {}

      });

  }

  @Override

  publicvoidonClick(View v) {

        switch(v.getId()) {

        caseR.id.for_picking:

          orderPickingDate.setCurrentItem(0);

          break;

        caseR.id.has_been_picking:

          orderPickingDate.setCurrentItem(1);

          break;

        caseR.id.all:

          orderPickingDate.setCurrentItem(2);

          break;

        default:

          break;

  }

}