ViewPager 结合Fragment实现一个Activity里包含多个可滑动的标签页,每个标签页可以有独立的布局及响应。
activity_main.xml
MainActivity.java
package com.example.viewpagernfragment;import java.util.ArrayList;import android.graphics.BitmapFactory;import android.graphics.Matrix;import android.os.Bundle;import android.support.v4.app.Fragment;import android.support.v4.app.FragmentActivity;import android.support.v4.view.ViewPager;import android.support.v4.view.ViewPager.OnPageChangeListener;import android.util.DisplayMetrics;import android.view.Menu;import android.view.View;import android.view.animation.Animation;import android.view.animation.TranslateAnimation;import android.widget.ImageView;import android.widget.TextView;import android.widget.Toast;public class MainActivity extends FragmentActivity { private ViewPager mPager; private ArrayListfragmentList; private ImageView image; private TextView view1, view2, view3, view4; private int currIndex;//当前页卡编号 private int bmpW;//横线图片宽度 private int offset;//图片移动的偏移量 @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); InitTextView(); InitImage(); InitViewPager(); } /* * 初始化标签名 */ public void InitTextView(){ view1 = (TextView)findViewById(R.id.tv_guid1); view2 = (TextView)findViewById(R.id.tv_guid2); view3 = (TextView)findViewById(R.id.tv_guid3); view4 = (TextView)findViewById(R.id.tv_guid4); view1.setOnClickListener(new txListener(0)); view2.setOnClickListener(new txListener(1)); view3.setOnClickListener(new txListener(2)); view4.setOnClickListener(new txListener(3)); } public class txListener implements View.OnClickListener{ private int index=0; public txListener(int i) { index =i; } @Override public void onClick(View v) { // TODO Auto-generated method stub mPager.setCurrentItem(index); } } /* * 初始化图片的位移像素 */ public void InitImage(){ image = (ImageView)findViewById(R.id.cursor); bmpW = BitmapFactory.decodeResource(getResources(), R.drawable.cursor).getWidth(); DisplayMetrics dm = new DisplayMetrics(); getWindowManager().getDefaultDisplay().getMetrics(dm); int screenW = dm.widthPixels; offset = (screenW/4 - bmpW)/2; //imgageview设置平移,使下划线平移到初始位置(平移一个offset) Matrix matrix = new Matrix(); matrix.postTranslate(offset, 0); image.setImageMatrix(matrix); } /* * 初始化ViewPager */ public void InitViewPager(){ mPager = (ViewPager)findViewById(R.id.viewpager); fragmentList = new ArrayList (); Fragment btFragment= new ButtonFragment(); Fragment secondFragment = TestFragment.newInstance("this is second fragment"); Fragment thirdFragment = TestFragment.newInstance("this is third fragment"); Fragment fourthFragment = TestFragment.newInstance("this is fourth fragment"); fragmentList.add(btFragment); fragmentList.add(secondFragment); fragmentList.add(thirdFragment); fragmentList.add(fourthFragment); //给ViewPager设置适配器 mPager.setAdapter(new MyFragmentPagerAdapter(getSupportFragmentManager(), fragmentList)); mPager.setCurrentItem(0);//设置当前显示标签页为第一页 mPager.setOnPageChangeListener(new MyOnPageChangeListener());//页面变化时的监听器 } public class MyOnPageChangeListener implements OnPageChangeListener{ private int one = offset *2 +bmpW;//两个相邻页面的偏移量 @Override public void onPageScrolled(int arg0, float arg1, int arg2) { // TODO Auto-generated method stub } @Override public void onPageScrollStateChanged(int arg0) { // TODO Auto-generated method stub } @Override public void onPageSelected(int arg0) { // TODO Auto-generated method stub Animation animation = new TranslateAnimation(currIndex*one,arg0*one,0,0);//平移动画 currIndex = arg0; animation.setFillAfter(true);//动画终止时停留在最后一帧,不然会回到没有执行前的状态 animation.setDuration(200);//动画持续时间0.2秒 image.startAnimation(animation);//是用ImageView来显示动画的 int i = currIndex + 1; Toast.makeText(MainActivity.this, "您选择了第"+i+"个页卡", Toast.LENGTH_SHORT).show(); } } @Override public boolean onCreateOptionsMenu(Menu menu) { // Inflate the menu; this adds items to the action bar if it is present. getMenuInflater().inflate(R.menu.main, menu); return true; }}
谷歌官方认为,ViewPager应该和Fragment一起使用时,此时ViewPager的适配器是FragmentPagerAdapter,当你实现一个FragmentPagerAdapter,你必须至少覆盖以下方法:
getCount()
getItem()
如果ViewPager没有和Fragment一起,ViewPager的适配器是PagerAdapter,它是基类提供适配器来填充页面ViewPager内部,当你实现一个PagerAdapter,你必须至少覆盖以下方法:
instantiateItem(ViewGroup, int) destroyItem(ViewGroup, int, Object) getCount() isViewFromObject(View, Object)
package com.example.viewpagernfragment;import java.util.ArrayList;import android.support.v4.app.Fragment;import android.support.v4.app.FragmentManager;import android.support.v4.app.FragmentPagerAdapter;public class MyFragmentPagerAdapter extends FragmentPagerAdapter{ ArrayListlist; public MyFragmentPagerAdapter(FragmentManager fm,ArrayList list) { super(fm); this.list = list; } @Override public int getCount() { return list.size(); } @Override public Fragment getItem(int arg0) { return list.get(arg0); } }
package com.example.viewpagernfragment;import android.os.Bundle;import android.support.v4.app.Fragment;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.Button;import android.widget.Toast;public class ButtonFragment extends Fragment{ Button myButton; @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.guide_1, container, false);//关联布局文件 myButton = (Button)rootView.findViewById(R.id.mybutton);//根据rootView找到button //设置按键监听事件 myButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { // TODO Auto-generated method stub Toast.makeText(ButtonFragment.this.getActivity(), "button is click!", Toast.LENGTH_SHORT).show(); } }); return rootView; }}
package com.example.viewpagernfragment;import android.os.Bundle;import android.support.v4.app.Fragment;import android.util.Log;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.TextView;public class TestFragment extends Fragment { private static final String TAG = "TestFragment"; private String hello;// = "hello android"; private String defaultHello = "default value"; static TestFragment newInstance(String s) { TestFragment newFragment = new TestFragment(); Bundle bundle = new Bundle(); bundle.putString("hello", s); newFragment.setArguments(bundle); //bundle还可以在每个标签里传送数据 return newFragment; } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) { Log.d(TAG, "TestFragment-----onCreateView"); Bundle args = getArguments(); hello = args != null ? args.getString("hello") : defaultHello; View view = inflater.inflate(R.layout.guide_2, container, false); TextView viewhello = (TextView) view.findViewById(R.id.tv); viewhello.setText(hello); return view; } }