author by afei
利用 android-support-v4 中的ViewPager可以轻松的实现跟手滑动。但是只支持 View 和 Fragment(也是利用view)。
之前也考虑过使用 ViewFliping 和 gallery ，但是都要将Activity转成View才可以。但是这样就会失去activity的特性。思来想后，还是改成Fragment靠谱点。
总体思路是这样：将本来放在TabActivity中的Activity们都改成 Fragment, 然后修改TabActivity，使其TabHost中content和width和height为0，然后把pager和tabHost关联起来。很trick。。。但是效果达到。
关键是如何修改activity至fragment,有没有这个可行性？
答案是必须应该可以的！万一有问题，也是可以商量的嘛。。。
1.将 extends Activity 改为 extends Fragment, 如果是 ListActivity 就改为 ListFragment。。。这明显就是为了修改方便啊。。。
2.一定会有XX出现，但是一定不多，fragment 的生命周期和 activity 很相似，包括onActivityResult() onStart() onPause() 等等。都有。
这里主要在onCreate()中，因为我们onCreate() 中会有 setContent(R.layout.layout_id) 恩，这里一定会报错，因为在fragment中单独抽出来了一个函数 onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState),把跟初始化view的相关代码都考到这个函数中就ok了，简单啊。将setContent 变为 inflater.inflate(R.layout.choose_accompany_layout, null) 然后return就ok。
3.最后一步，我们的代码中会有一些用到activity 和context 的地方，比如 getContentResolver() 和 其它的函数，这里只需要变为 getActivity() 就ok。因为fragment 中会和 外界的activity绑定起来。直接调用就可以。
修改完毕！！！
继承 FragmentTabsPager（代码在ChannelCommon中）, 在onCreate()中调用 addTab(), 需要几个tab页就加入几次，然后这可以完美实现跟手滑动的tabActivity效果了！！！哇哈哈。
FragmentTabsPager 代码 ：
/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.xiaomi.channel.common.pager_tabs;
import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TabHost;
import android.widget.TabWidget;
import java.util.ArrayList;
import com.xiaomi.channel.common.R;
/**
* 经过afei修改为抽象类，使用者只需要继承它，并在onCreate() 中调用addTab即可 addTab 时的tabSpec
* 可以使用布局，无需担心。可见UsageDemo
* Demonstrates combining a TabHost with a ViewPager to
* implement a tab UI that switches between tabs and also allows the user to
* perform horizontal flicks to move between the tabs.
*/
public abstract class FragmentTabsPager extends FragmentActivity {
TabHost mTabHost;
ViewPager mViewPager;
TabsAdapter mTabsAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_tabs_pager);
mTabHost = (TabHost) findViewById(android.R.id.tabhost);
mTabHost.setup();
mViewPager = (ViewPager) findViewById(R.id.pager);
mTabsAdapter = new TabsAdapter(this, mTabHost, mViewPager);
}
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
outState.putString("tab", mTabHost.getCurrentTabTag());
}
/**
* This is a helper class that implements the management of tabs and all
* details of connecting a ViewPager with associated TabHost. It relies on a
* trick. Normally a tab host has a simple API for supplying a View or
* Intent that each tab will show. This is not sufficient for switching
* between pages. So instead we make the content part of the tab host 0dp
* high (it is not shown) and the TabsAdapter supplies its own dummy view to
* show as the tab content. It listens to changes in tabs, and takes care of
* switch to the correct paged in the ViewPager whenever the selected tab
* changes.
*/
public static class TabsAdapter extends FragmentPagerAdapter
implements TabHost.OnTabChangeListener, ViewPager.OnPageChangeListener {
private final Context mContext;
private final TabHost mTabHost;
private final ViewPager mViewPager;
private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>();
static final class TabInfo {
private final String tag;
private final Class<?> clss;
private final Bundle args;
TabInfo(String _tag, Class<?> _class, Bundle _args) {
tag = _tag;
clss = _class;
args = _args;
}
}
static class DummyTabFactory implements TabHost.TabContentFactory {
private final Context mContext;
public DummyTabFactory(Context context) {
mContext = context;
}
@Override
public View createTabContent(String tag) {
View v = new View(mContext);
v.setMinimumWidth(0);
v.setMinimumHeight(0);
return v;
}
}
public TabsAdapter(FragmentActivity activity, TabHost tabHost, ViewPager pager) {
super(activity.getSupportFragmentManager());
mContext = activity;
mTabHost = tabHost;
mViewPager = pager;
mTabHost.setOnTabChangedListener(this);
mViewPager.setAdapter(this);
mViewPager.setOnPageChangeListener(this);
}
public void addTab(TabHost.TabSpec tabSpec, Class<?> clss, Bundle args) {
tabSpec.setContent(new DummyTabFactory(mContext));
String tag = tabSpec.getTag();
TabInfo info = new TabInfo(tag, clss, args);
mTabs.add(info);
mTabHost.addTab(tabSpec);
notifyDataSetChanged();
}
@Override
public int getCount() {
return mTabs.size();
}
@Override
public Fragment getItem(int position) {
TabInfo info = mTabs.get(position);
return Fragment.instantiate(mContext, info.clss.getName(), info.args);
}
@Override
public void onTabChanged(String tabId) {
int position = mTabHost.getCurrentTab();
mViewPager.setCurrentItem(position);
}
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
// Unfortunately when TabHost changes the current tab, it kindly
// also takes care of putting focus on it when not in touch mode.
// The jerk.
// This hack tries to prevent this from pulling focus out of our
// ViewPager.
TabWidget widget = mTabHost.getTabWidget();
int oldFocusability = widget.getDescendantFocusability();
widget.setDescendantFocusability(ViewGroup.FOCUS_BLOCK_DESCENDANTS);
mTabHost.setCurrentTab(position);
widget.setDescendantFocusability(oldFocusability);
}
@Override
public void onPageScrollStateChanged(int state) {
}
}
}
这是个通用的类，使用时继承就ok了，比如这样：
package com.xiaomi.channel.common.pager_tabs;
import android.os.Bundle;
public class UsageDemo extends FragmentTabsPager {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// 只需要将下面注释取消就可以，也就是说，只需要重写onCreate(),并加入tab就ok了。
// 每一行是一个TabSpec。记的要是Fragment,而不是activity
mTabsAdapter.addTab(mTabHost.newTabSpec("simple").setIndicator("Simple"),
ChooseAccompanyFragment.class, null);
mTabsAdapter.addTab(mTabHost.newTabSpec("contacts").setIndicator("Contacts"),
ChooseAccompanyFragment1.class, null);
mTabsAdapter.addTab(mTabHost.newTabSpec("custom").setIndicator("Custom"),
ChooseAccompanyFragment2.class, null);
mTabsAdapter.addTab(mTabHost.newTabSpec("throttle").setIndicator("Throttle"),
ChooseAccompanyFragment3.class, null);
}
}
纯原创，转载需保留出处噢亲。