Android控件ViewPager与Fragment基础用法

    ViewPager与Fragment实现页面滑动效果:

    首先继承FragmentActivity,

    为ViewPager提供展示所需的Fragment和FragmentPagerAdapter:

Fragment来指定页面的布局以及功能

	// fragment
	private class MyFragment extends Fragment {

		private String text;
		private int color;

		public MyFragment(String text, int color) {
			this.text = text;
			this.color = color;
		}

		@Override
		public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
			TextView tv = new TextView(MainActivity.this);
			tv.setBackgroundColor(color);
			tv.setText(text);
			return tv;
		}
	}

 adapter指定该Viewpager有多少页面以及那个位置需要显示哪个页面:

// adapter
	private class MyAdapter extends FragmentPagerAdapter {
		public MyAdapter(FragmentManager fm) {
			super(fm);
		}

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

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

设置OnPageChangeListener,指定页面改变时需要做什么其他操作:

	@Override
	public void onPageScrollStateChanged(int arg0) {

	}

	@Override
	public void onPageScrolled(int arg0, float arg1, int arg2) {
		LinearLayout.LayoutParams lp = (android.widget.LinearLayout.LayoutParams) tabline.getLayoutParams();
		lp.leftMargin = (int) ((arg0 + arg1) * mTabLineWidth);
		tabline.setLayoutParams(lp);
	}

	@Override
	public void onPageSelected(int arg0) {
		// set titles
		for (int i = 0; i < titles.size(); i++) {
			if (arg0 == i) {
				titles.get(i).setSelected(true);
			} else {
				titles.get(i).setSelected(false);
			}
		}
	}

 完整的代码:

package com.hzy.myviewpager;

import java.util.ArrayList;

import android.graphics.Color;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.util.DisplayMetrics;
import android.view.Display;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.View.OnClickListener;
import android.view.ViewGroup.LayoutParams;
import android.widget.LinearLayout;
import android.widget.TextView;

import com.hzy.myviewpager.R.id;

public class MainActivity extends FragmentActivity implements OnPageChangeListener, OnClickListener {

	ViewPager pager = null;
	View tabline = null;
	private int mTabLineWidth;

	// titles
	TextView title1 = null;
	TextView title2 = null;
	TextView title3 = null;

	ArrayList<TextView> titles = null;
	ArrayList<Fragment> pages = null;

	@Override
	protected void onCreate(Bundle arg0) {
		super.onCreate(arg0);
		initView();
		initTabline();
	}

	private void initView() {
		setContentView(R.layout.activity_main);
		pages = new ArrayList<Fragment>();
		titles = new ArrayList<TextView>();

		pager = (ViewPager) findViewById(id.main_viewpager);
		title1 = (TextView) findViewById(id.main_tab1);
		title2 = (TextView) findViewById(id.main_tab2);
		title3 = (TextView) findViewById(id.main_tab3);

		title1.setOnClickListener(this);
		title2.setOnClickListener(this);
		title3.setOnClickListener(this);

		titles.add(title1);
		titles.add(title2);
		titles.add(title3);

		// create new fragments
		pages.add(new MyFragment("tab1", Color.BLUE));
		pages.add(new MyFragment("tab2", Color.RED));
		pages.add(new MyFragment("tab3", Color.CYAN));

		// set adapter
		pager.setAdapter(new MyAdapter(getSupportFragmentManager()));
		pager.setOnPageChangeListener(this);
		pager.setCurrentItem(0);
		titles.get(0).setSelected(true);
	}

	// tablines
	private void initTabline() {
		tabline = findViewById(id.main_tab_line);
		Display display = getWindow().getWindowManager().getDefaultDisplay();
		DisplayMetrics outMetrics = new DisplayMetrics();
		display.getMetrics(outMetrics);
		mTabLineWidth = outMetrics.widthPixels / 3;
		LayoutParams lp = tabline.getLayoutParams();
		lp.width = mTabLineWidth;
		tabline.setLayoutParams(lp);
	}

	@Override
	public void onClick(View v) {
		switch (v.getId()) {
		case id.main_tab1:
			pager.setCurrentItem(0, true);
			break;
		case id.main_tab2:
			pager.setCurrentItem(1, true);
			break;
		case id.main_tab3:
			pager.setCurrentItem(2, true);
			break;
		default:
			break;
		}
	}

	@Override
	public void onPageScrollStateChanged(int arg0) {

	}

	@Override
	public void onPageScrolled(int arg0, float arg1, int arg2) {
		LinearLayout.LayoutParams lp = (android.widget.LinearLayout.LayoutParams) tabline.getLayoutParams();
		lp.leftMargin = (int) ((arg0 + arg1) * mTabLineWidth);
		tabline.setLayoutParams(lp);
	}

	@Override
	public void onPageSelected(int arg0) {
		// set titles
		for (int i = 0; i < titles.size(); i++) {
			if (arg0 == i) {
				titles.get(i).setSelected(true);
			} else {
				titles.get(i).setSelected(false);
			}
		}
	}

	// fragment
	private class MyFragment extends Fragment {

		private String text;
		private int color;

		public MyFragment(String text, int color) {
			this.text = text;
			this.color = color;
		}

		@Override
		public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
			TextView tv = new TextView(MainActivity.this);
			tv.setBackgroundColor(color);
			tv.setText(text);
			return tv;
		}
	}

	// adapter
	private class MyAdapter extends FragmentPagerAdapter {
		public MyAdapter(FragmentManager fm) {
			super(fm);
		}

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

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

 代码中通过实现OnPageChangeListener接口手动设置了页面指示条的位置