转：ViewPager+Fragment基本使用方法(附源码)

2022-11-07 11:28:34

ViewPager+Fragment可以做出多页面滑动效果,让我们的应用程序界面操作起来更加灵活

对于ViewPager和Fragment组件还不熟悉的朋友,可以先看看相关的资料

首先在activity_main.xml布局文件中加入ViewPager组件

<android.support.v4.view.ViewPager
android:id="@+id/viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent">

既然要实现左右的页面滑动,肯定要往ViewPager中添加一些View视图或者Fragment,这里创建了3个Fragment的布局文件

这3个布局文件非常简单,跟Activity的布局用法一模一样,代码就不贴出来了,直接看Activity的java代码

package huahua.viewpager;
import java.util.ArrayList;
import java.util.List;
import android.os.Bundle;
import android.app.Activity;
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.app.FragmentStatePagerAdapter;
import android.support.v4.view.PagerTabStrip;
import android.support.v4.view.PagerTitleStrip;
import android.support.v4.view.ViewPager;
import android.util.Log;
import android.view.ViewGroup;
public class MainActivity extends FragmentActivity {
private ViewPager m_vp;
private fragment1 mfragment1;
private fragment2 mfragment2;
private fragment3 mfragment3;
//页面列表
private ArrayList<Fragment> fragmentList;
//标题列表
ArrayList<String> titleList = new ArrayList<String>();
//通过pagerTabStrip可以设置标题的属性
private PagerTabStrip pagerTabStrip;
private PagerTitleStrip pagerTitleStrip;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
m_vp = (ViewPager)findViewById(R.id.viewpager);
pagerTabStrip=(PagerTabStrip) findViewById(R.id.pagertab);
//设置下划线的颜色
pagerTabStrip.setTabIndicatorColor(getResources().getColor(android.R.color.holo_green_dark));
//设置背景的颜色
pagerTabStrip.setBackgroundColor(getResources().getColor(android.R.color.holo_blue_dark));
// pagerTitleStrip=(PagerTitleStrip) findViewById(R.id.pagertab);
// //设置背景的颜色
// pagerTitleStrip.setBackgroundColor(getResources().getColor(android.R.color.holo_blue_dark));
mfragment1 = new fragment1();
mfragment2 = new fragment2();
mfragment3 = new fragment3();
fragmentList = new ArrayList<Fragment>();
fragmentList.add(mfragment1);
fragmentList.add(mfragment2);
fragmentList.add(mfragment3);
titleList.add("第一页 ");
titleList.add("第二页");
titleList.add("第三页 ");
m_vp.setAdapter(new MyViewPagerAdapter(getSupportFragmentManager()));
}
public class MyViewPagerAdapter extends FragmentPagerAdapter{
public MyViewPagerAdapter(FragmentManager fm) {
super(fm);
// TODO Auto-generated constructor stub
}
@Override
public Fragment getItem(int arg0) {
return fragmentList.get(arg0);
}
@Override
public int getCount() {
return fragmentList.size();
}
@Override
public CharSequence getPageTitle(int position) {
// TODO Auto-generated method stub
return titleList.get(position);
}
}
}

看到Viewpager跟ListView一样,都需要设置一个Adapter,上面代码是继承了FragmentPagerAdapter,在里面重写了3个方法.往这个Viewpager中添加了要显示的3个页面fragment和对应的3个标题

接着看fragment1.java

package huahua.viewpager;
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.Button;
import android.widget.TextView;
public class fragment1 extends Fragment{
private View mMainView;
private TextView tv;
private Button btn;
@Override
public void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
Log.v("huahua", "fragment1-->onCreate()");
LayoutInflater inflater = getActivity().getLayoutInflater();
mMainView = inflater.inflate(R.layout.fragment1, (ViewGroup)getActivity().findViewById(R.id.viewpager), false);
tv = (TextView)mMainView.findViewById(R.id.tv1);
btn = (Button)mMainView.findViewById(R.id.btn1);
btn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
tv.setText("Hello Viewpager\"");
}
});
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
Log.v("huahua", "fragment1-->onCreateView()");
ViewGroup p = (ViewGroup) mMainView.getParent();
if (p != null) {
p.removeAllViewsInLayout();
Log.v("huahua", "fragment1-->移除已存在的View");
}
return mMainView;
}
@Override
public void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
Log.v("huahua", "fragment1-->onDestroy()");
}
@Override
public void onPause() {
// TODO Auto-generated method stub
super.onPause();
Log.v("huahua", "fragment1-->onPause()");
}
@Override
public void onResume() {
// TODO Auto-generated method stub
super.onResume();
Log.v("huahua", "fragment1-->onResume()");
}
@Override
public void onStart() {
// TODO Auto-generated method stub
super.onStart();
Log.v("huahua", "fragment1-->onStart()");
}
@Override
public void onStop() {
// TODO Auto-generated method stub
super.onStop();
Log.v("huahua", "fragment1-->onStop()");
}
}

可以看到Fragment中有个onCreateView方法,返回的是这个fragment的视图View,其他的生命周期方法都跟Activity一样,还要注意的是在回复View前一定要加入代码

ViewGroup p = (ViewGroup) mMainView.getParent();
if (p != null) {
p.removeAllViewsInLayout();
Log.v("huahua", "fragment1-->移除已存在的View");
}

不然在第二次加载onCreateView方法时会报异
常:java.lang.IllegalStateException: The specified child already has a
parent. You must call removeView() on the child's parent first.

其他的2个Fragment跟这个类似,代码不贴了,直接运行程序看看效果