horizaontal_scroll使用

布局：

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


    <com.example.a18_horizaontal_scroll.MyIndicator
        android:layout_width="wrap_content"
        android:layout_height="40dp"
        android:background="@android:color/holo_blue_bright"
        android:id="@+id/indicador">


    </com.example.a18_horizaontal_scroll.MyIndicator>


    <android.support.v4.view.ViewPager
        android:layout_below="@+id/indicador"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/pager"/>
</RelativeLayout>

代码：MainActivity:

package com.example.a18_horizaontal_scroll;


import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;


public class MainActivity extends AppCompatActivity {


    private MyIndicator indicator;
    private ViewPager viewPager;
    private String[] titles;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);


        indicator = (MyIndicator) findViewById(R.id.indicador);
        viewPager = (ViewPager) findViewById(R.id.pager);


        //1.设置标题
        titles = new String[]{"推荐","北京","头条","军事","娱乐","八卦","图片","视频","小说","体育"};
        indicator.setTitles(titles);


        //2.viewpager设置适配器
        viewPager.setAdapter(new FragmentPagerAdapter(getSupportFragmentManager()) {
            @Override
            public Fragment getItem(int position) {


                NewsFragment newsFragment = new NewsFragment();




                Bundle bundle = new Bundle();


                bundle.putString("name",titles[position]);
                newsFragment.setArguments(bundle);


                return newsFragment;
            }


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


        //3.指示器与viewpager关联
        indicator.setViewPager(viewPager);
    }
}

NewsFragment:

package com.example.a18_horizaontal_scroll;


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 android.widget.TextView;


/**
 * @author Dash
 * @date 2017/9/19
 * @description:
 */
public class NewsFragment extends Fragment {


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


        Bundle arguments = getArguments();
        TextView textView = new TextView(getActivity());


        textView.setText(arguments.getString("name","推荐"));




        return textView;
    }


    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);


    }
}

MyIndicator

package com.example.a18_horizaontal_scroll;


import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.View;
import android.widget.HorizontalScrollView;
import android.widget.LinearLayout;
import android.widget.TextView;


/**
 * @author Dash
 * @date 2017/9/19
 * @description:
 */
public class MyIndicator extends HorizontalScrollView implements ViewPager.OnPageChangeListener{


    private static final int COLOR_TEXT_NORMAL = 0xFF000000;
    private static final int COLOR_INDICATOR_COLOR = Color.BLACK;


    private Context context;
    private  int tabWidth;
    private String[] titles;
    private int count;
    private Paint mPaint;
    private float mTranslationX;
    private ViewPager viewPager;
    private int SCREEN_WIDTH;
    private float lineheight = 2.0f;


    public MyIndicator(Context context) {
        this(context, null);
    }


    public MyIndicator(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(context);
    }


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


    private void init(Context context){
        this.context = context;
        mPaint = new Paint();
        mPaint.setColor(COLOR_INDICATOR_COLOR);
        mPaint.setStrokeWidth(lineheight);//底部指示线的宽度
        setHorizontalScrollBarEnabled(false);
        SCREEN_WIDTH = context.getResources().getDisplayMetrics().widthPixels;
    }


    public void setLineheight(float height){
        this.lineheight = height;
        mPaint.setStrokeWidth(lineheight);//底部指示线的宽度
    }


    public void setViewPager(ViewPager viewPager){
        this.viewPager = viewPager;
        viewPager.addOnPageChangeListener(this);
    }


    public void setTitles(String[] titles){
        this.titles = titles;
        count = titles.length;
        tabWidth = SCREEN_WIDTH/4;
        generateTitleView();
    }


    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        tabWidth = SCREEN_WIDTH/4;
    }


    @Override
    protected void dispatchDraw(Canvas canvas)
    {
        super.dispatchDraw(canvas);
        canvas.save();
        canvas.translate(mTranslationX, getHeight() - lineheight);
        canvas.drawLine(0, 0, tabWidth, 0, mPaint);//（startX, startY, stopX, stopY, paint）
        canvas.restore();
    }


    public void scroll(int position, float offset)
    {
        mTranslationX = tabWidth * (position + offset);
        scrollTo((int)mTranslationX-(SCREEN_WIDTH-tabWidth)/2, 0);
        invalidate();
    }


    private void generateTitleView()
    {
        if (getChildCount() > 0)
            this.removeAllViews();
        count = titles.length;


        LinearLayout linearLayout = new LinearLayout(context);
        linearLayout.setOrientation(LinearLayout.HORIZONTAL);
        linearLayout.setLayoutParams(new LinearLayout.LayoutParams(count*tabWidth, LinearLayout.LayoutParams.MATCH_PARENT));
        for (int i = 0; i < count; i++)
        {
            TextView tv = new TextView(getContext());
            LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(tabWidth,
                    LinearLayout.LayoutParams.MATCH_PARENT);
            tv.setGravity(Gravity.CENTER);
            tv.setTextColor(COLOR_TEXT_NORMAL);
            tv.setText(titles[i]);
            tv.setTextSize(TypedValue.COMPLEX_UNIT_SP, 16);//字体大小
            tv.setLayoutParams(lp);
            final int finalI = i;
            tv.setOnClickListener(new OnClickListener()
            {
                @Override
                public void onClick(View v)
                {
                    if(viewPager!=null){
                        viewPager.setCurrentItem(finalI,false);
                    }
                }
            });
            linearLayout.addView(tv);
        }
        addView(linearLayout);
    }


    @Override
    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
        scroll(position, positionOffset);
    }


    @Override
    public void onPageSelected(int position) {


    }


    @Override
    public void onPageScrollStateChanged(int state) {


    }
}