ViewPager和Fragment結(jié)合看到很多地方在講解遍略，我今天也寫了一個(gè)小例子幅恋，和大家分享一下锐锣，也幫助我深度理解他們的用法未蝌。
這個(gè)小案例要用到Fragment所以適配器要繼承FragmentPagerAdapter。它里面要是實(shí)現(xiàn)二個(gè)方法：
- public Fragment getItem(position){ }
這個(gè)是根據(jù)position返回一個(gè)Fragment - public int Count(){ }
這個(gè)是返回一共有幾個(gè)Fragment
先看一下效果圖：
1526393863618.gif
Tep1：建一個(gè)viewpager.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"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical">
<android.support.v4.view.ViewPager
android:id="@+id/viewpager"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="7">
</android.support.v4.view.ViewPager>
<android.support.design.widget.BottomNavigationView
android:id="@+id/bottom"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
app:menu="@layout/item" />
</LinearLayout>
這里我在最底部加了一個(gè)導(dǎo)航欄易茬，不要忘了加載庫文件俺晏！！
Tep2：接著建一個(gè)item.xml文件
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<item
android:id="@+id/one"
android:title="第一"/>
<item
android:id="@+id/two"
android:title="第二"/>
<item
android:id="@+id/three"
android:title="第三"/>
</menu>
Tep3：建立一個(gè)content.xml（content2.xml抽莱，content3.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">
<TextView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/content"
android:textSize="50sp"
android:gravity="center"
android:background="@color/colorAccent"
android:text="第一個(gè)fragment"/>
</LinearLayout>
其他的兩個(gè)依葫蘆畫瓢就行了范抓，相信大家都會的。
Tap4：建立三個(gè)Fragment類（這是三個(gè)界面）
package com.example.jiangyou.pic_watch;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class Fragment1 extends Fragment {
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = LayoutInflater.from(getContext()).inflate(R.layout.content,container,false);
return view;
}
}
其他的兩個(gè)也是按照這個(gè)畫一個(gè)食铐。
Tap5：下面就要寫適配器匕垫，新建一個(gè)FragmentAdapter
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import java.util.List;
public class FragmentAdapter extends FragmentPagerAdapter{
//private List<Fragment> mFragment;
private Fragment1 fragment1;
private Fragment2 fragment2;
private Fragment3 fragment3;
public FragmentAdapter(FragmentManager fm) {//這是一個(gè)內(nèi)部類
super(fm);
fragment1 = new Fragment1();
fragment2 = new Fragment2();
fragment3 = new Fragment3();
}
@Override
public Fragment getItem(int position) {
Fragment fragment= null;
switch (position){
case 0:
fragment = fragment1;
break;
case 1:
fragment = fragment2;
break;
case 2:
fragment = fragment3;
break;
}
return fragment;
}
@Override
public int getCount() {
return 3;
}
}
Tab6:在主activity寫邏輯
import android.os.Bundle;
import android.os.PersistableBundle;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.design.widget.BottomNavigationView;
import android.support.design.widget.TabLayout;
import android.support.v4.app.Fragment;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.view.MenuItem;
import java.util.ArrayList;
import java.util.List;
public class MainViewPager extends AppCompatActivity {
private ViewPager vp;
@Override
public void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.viewpager);
FragmentAdapter fragmentAdapter= new FragmentAdapter(getSupportFragmentManager());//實(shí)例化adapter，得到fragment
vp=(ViewPager)findViewById(R.id.viewpager);
vp.setAdapter(fragmentAdapter);//建立連接
final BottomNavigationView bottom = (BottomNavigationView)findViewById(R.id.bottom);
bottom.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {//底部導(dǎo)航欄點(diǎn)擊事件
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
switch (item.getItemId()){
case R.id.one:
vp.setCurrentItem(0);
break;
case R.id.two:
vp.setCurrentItem(1);
break;
case R.id.three:
vp.setCurrentItem(2);
break;
}
return true;
}
});
//viewpager監(jiān)聽事件虐呻，當(dāng)viewpager滑動(dòng)時(shí)得到對應(yīng)的fragment碎片
vp.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
bottom.getMenu().getItem(position).setChecked(true);
}
@Override
public void onPageScrollStateChanged(int state) {
}
});
}
}
