使用ViewPager和Fragment实现滑动导航

ViewPage是android-support-v4.jar包提供的用于页面滑动的库,android-support-v4.jar是google推荐使用的一个类库,在项目中使用之前,你必须其添加到项目中(项目点右键Build path->configure build path,然后找到jar进行添加)

1.在xml布局文件中添加android.support.v4.view.ViewPager容器及显示导航所用标签android.support.v4.view.PagerTitleStrip,如我添加的xml内容如下

<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/pager"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >

<!--
This title strip will display the currently visible page title, as well as the page
titles for adjacent pages.
-->

<android.support.v4.view.PagerTitleStrip
android:id="@+id/pager_title_strip"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="top"
android:background="#33b5e5"
android:paddingBottom="4dp"
android:paddingTop="4dp"
android:textColor="#fff" />

</android.support.v4.view.ViewPager>

2.在activity中导入以下包

import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;

3.声明变量

SectionsPagerAdapter mSectionsPagerAdapter;
ViewPager mViewPager;

4.在onCreate中对其进行初始化

mSectionsPagerAdapter = new SectionsPagerAdapter(
getSupportFragmentManager());

// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mSectionsPagerAdapter);

5.添加类SectionsPagerAdapter,我这里使用了3个标签

public class SectionsPagerAdapter extends FragmentPagerAdapter {

public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}

@Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a DummySectionFragment (defined as a static inner class
// below) with the page number as its lone argument.
Fragment fragment = new HjFragment();
Bundle args = new Bundle();
args.putInt("no", position + 1);
fragment.setArguments(args);

return fragment;
}

@Override
public int getCount() {
// Show 3 total pages.
return 3;
}

@Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return "标签1";
case 1:
return "标签2";
case 2:
return "标签3";
}
return null;
}
}

可以看到在getItem中返回了一个Fragment,这个就是当滑动到不同标签时显示在ViewPager中的内容,Fragment相当于一个Activity,在可以其中的onCreateView函数中构造需要显示的内容并返回

比如,以下代码将显示一个文本信息

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
TextView textView = new TextView(getActivity());
textView.setGravity(Gravity.CENTER);
textView.setText("你选择了标签:"+Integer.toString(getArguments().getInt(
"no")));
return textView;

}

最后,贴几个我做出来的界面做参考





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