Android 滚动Tab

Android 滚动Tab

先看效果:

如果对效果感兴趣, 请耐心看完, 其实不复杂.

需要Android-support-v4.jar的支持.

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主布局文件activity_main.xml

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

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主Activity, 核心是给mViewPager设置一个Adapter--mFragmentAdapter

public class MainActivity extends FragmentActivity {
private FragmentAdapter mFragmentAdapter;
private ViewPager mViewPager;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mFragmentAdapter = new FragmentAdapter(MainActivity.this, getSupportFragmentManager());
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mFragmentAdapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
} 

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接下来看看FragmentAdapter如何实现的.

public class FragmentAdapter extends FragmentPagerAdapter {
private Context mContext;
public FragmentAdapter(Context context, FragmentManager fm) {
super(fm);
mContext = context;
}
@Override
public Fragment getItem(int position) {
Fragment fragment;
if (position == 2) {
fragment = new AboutMeFragment();
} else {
fragment = new TabFragment();
Bundle args = new Bundle();
args.putInt(TabFragment.TAB_POSITION, position + 1);
fragment.setArguments(args);
}
return fragment;
}
@Override
public int getCount() {
return 3;
}
@Override
public CharSequence getPageTitle(int position) {
if (position == 2) {
return mContext.getString(R.string.about_me_title);
} else {
Locale l = Locale.getDefault();
return mContext.getString(R.string.tab_fragment_title, position + 1).toUpperCase(l);
}
}
}

在getCount()里面设置了3个Tab页, 等position==2的时候也就是最后一个页, 我设置了一个不同于前两个页的about_me页面. 主要是表示: 可以根据需要设置不同类型的Fragment到Adapter里面. 这里两种Fragment分别是TabFragment()和AboutMeFragment()

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TabFragment的布局文件只有一个TextView, 就不贴了, 直接看java文件

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.TextView;
import com.lichen.remind.R;
public class TabFragment extends Fragment {
public static final String TAB_POSITION = "tab_position";
public TabFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_tab, container, false);
TextView tabLabel = (TextView) rootView.findViewById(R.id.tab_label);
tabLabel.setText(getString(R.string.tab_fragment_content, getArguments().getInt(TAB_POSITION)));
return rootView;
}
} 

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AboutMeFragment的布局文件fragment_tab.xml, 其实也一个TextView, 不过使用了android:drawableTop=""属性.

<?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"
android:gravity="center_horizontal|center_vertical"
android:orientation="vertical" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:drawableTop="@drawable/me"
android:text="@string/about_me_email"/>
</LinearLayout>

然后是AboutMeFragment.java

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import com.lichen.remind.R;
public class AboutMeFragment extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_about_me,container, false);
return rootView;
}
} 

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资源文件strings.xml中, 使用了传入参数的方式.

<?xml version="1.0" encoding="utf-8"?>
<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
<string name="app_name">Remind</string>
<string name="action_settings">Settings</string>
<string name="about_me_title">关于我</string>
<string name="about_me_email">chain_li7@163.com</string>
<string name="tab_fragment_title">第 <xliff:g id="tab_fragment_title_position">%1$d</xliff:g> 个Tab</string>
<string name="tab_fragment_content">这是第 <xliff:g id="tab_fragment_content_position">%1$d</xliff:g> 个Tab页面</string>
</resources> 

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这样就可以看到上图滚动Tab了.