android 仿微信5版本实现滑动导航条

ViewPageAdapter.java

package com.rong;

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

import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.View;

public class ViewPagerAdapter extends PagerAdapter {

	private List<View> views;

	public ViewPagerAdapter(List<View> views) {
		this.views = views;
	}

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

	@Override
	public boolean isViewFromObject(View arg0, Object arg1) {
		return arg0 == arg1;
	}

	@Override
	public void destroyItem(View container, int position, Object object) {
		((ViewPager) container).removeView(views.get(position));
	}

	@Override
	public Object instantiateItem(View container, int position) {
		((ViewPager) container).addView(views.get(position));
		return views.get(position);
	}

	/**
	 * 插入一个View到viewpager中
	 * 
	 * @param view
	 * @return
	 */
	public boolean insert(View view) {
		if (this.views == null) {
			this.views = new ArrayList<View>();
		}

		return this.views.add(view);
	}
}

HomeAcitivity.java

package com.rong;

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

import android.app.Activity;
import android.os.Bundle;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.util.DisplayMetrics;
import android.util.Log;
import android.view.Display;
import android.view.View;
import android.view.ViewGroup.LayoutParams;
import android.widget.LinearLayout;

import com.rong.wechat5.R;

public class HomeActivity extends Activity {
	private View home_line;
	private int screenWidth1_3;
	private ViewPager home_vp;
	private ViewPagerAdapter viewPagerAdapter;
	private List<View> views = new ArrayList<View>();

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

	private void initView() {
		Display display = getWindow().getWindowManager().getDefaultDisplay();
		DisplayMetrics dm = new DisplayMetrics();
		display.getMetrics(dm);

		home_line = (View) findViewById(R.id.home_line);
		home_vp = (ViewPager) findViewById(R.id.home_vp);

		LayoutParams lp = home_line.getLayoutParams();
		screenWidth1_3 = dm.widthPixels / 3;
		lp.width = screenWidth1_3;
		lp.height = 5;
		home_line.setLayoutParams(lp);

		View layout1 = View.inflate(this, R.layout.layout_view1, null);
		View layout2 = View.inflate(this, R.layout.layout_view2, null);
		View layout3 = View.inflate(this, R.layout.layout_view3, null);
		views.add(layout1);
		views.add(layout2);
		views.add(layout3);
		viewPagerAdapter = new ViewPagerAdapter(views);
		home_vp.setAdapter(viewPagerAdapter);

		home_vp.setOnPageChangeListener(new OnPageChangeListener() {

			@Override
			public void onPageSelected(int arg0) {

			}

			@Override
			public void onPageScrolled(int position, float positionOffset,int positionOffsetPixels) {
				Log.i("TAG", position+"=="+positionOffset+"=="+positionOffsetPixels);
				LinearLayout.LayoutParams lp = (android.widget.LinearLayout.LayoutParams) home_line.getLayoutParams();
				lp.leftMargin = (int) (screenWidth1_3 * position + screenWidth1_3* positionOffset);
				home_line.setLayoutParams(lp);
			}

			@Override
			public void onPageScrollStateChanged(int arg0) {

			}
		});
	}

}

layout_home.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="#ffffff"
    android:orientation="vertical" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="60dp"
        android:orientation="horizontal" >

        <RelativeLayout
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1" >

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="消息"
                android:textColor="#000000"
                android:textSize="24sp" />
        </RelativeLayout>

        <RelativeLayout
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1" >

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="朋友圈"
                android:textColor="#000000"
                android:textSize="24sp" />
        </RelativeLayout>

        <RelativeLayout
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1" >

            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_centerInParent="true"
                android:text="我"
                android:textColor="#000000"
                android:textSize="24sp" />
        </RelativeLayout>
    </LinearLayout>

    <View
        android:id="@+id/home_line"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:background="#ff0000" />

    <android.support.v4.view.ViewPager
        android:id="@+id/home_vp"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1" />

</LinearLayout>