Android FragmentTabHost - 还没有完全成熟? [英] Android FragmentTabHost - Not fully baked yet?
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问题描述
我想看看是否有人在使用新的 Android API 级别 17 附带的 FragmentTabHost 自定义选项卡方面取得了成功.
I wanted to see if anyone has had success with customization of tabs using FragmentTabHost that comes with the new Android API level 17.
我很高兴能够在我的 ViewPager SherlockFragments 中嵌套一个 tabHost，但是我在做一些简单的事情时遇到了麻烦，比如将标签移到底部或更改标签的布局.
I was excited to be able to nest a tabHost within my ViewPager SherlockFragments, but I'm having trouble doing simple things like moving the tabs to the bottom or changing the layout of the tabs.
有没有人见过使用这个功能的好例子?
Has anyone seen a good example of using this functionality?
这是我能在 Android 文档中找到的唯一示例，并且几乎没有描述它的用途.它似乎也忽略了 R.id.fragment1 布局中定义的任何内容.
This is the only example I could find in the Android docs, and theres just about nothing that describes its use. It also seems to ignore whatever is defined in the layout for R.id.fragment1.
我想我的问题是是否有人遇到过一个很好的教程 re:FragmentTabHost或者如果他们知道如何 a) 将嵌套选项卡放在底部或 b) 更改所述选项卡的布局.
My question I suppose would be if anyone has come across a good tutorial re:FragmentTabHost or if they have an idea about how to a) put the nested tabs at the bottom or b) change the layout of said tabs.
我已经尝试了所有常用方法，但由于 XML 布局文件似乎被覆盖了，我运气不佳.
I've tried all the usual methods, but since it appears the XML layout file is overridden, I haven't had much luck.
private FragmentTabHost mTabHost;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
setContentView(R.layout.fragment_tabs);
mTabHost = (FragmentTabHost)findViewById(android.R.id.tabhost);
mTabHost.setup(this, getSupportFragmentManager(), R.id.realtabcontent);
mTabHost.addTab(mTabHost.newTabSpec("simple").setIndicator("Simple"),
FragmentStackSupport.CountingFragment.class, null);
mTabHost.addTab(mTabHost.newTabSpec("contacts").setIndicator("Contacts"),
LoaderCursorSupport.CursorLoaderListFragment.class, null);
mTabHost.addTab(mTabHost.newTabSpec("custom").setIndicator("Custom"),
LoaderCustomSupport.AppListFragment.class, null);
mTabHost.addTab(mTabHost.newTabSpec("throttle").setIndicator("Throttle"),
LoaderThrottleSupport.ThrottledLoaderListFragment.class, null);
return mTabHost;
}
经过一些研究后，似乎在支持库中初始化 FragmentTabHost 时可能会出现故障.用户 Google 代码此处对此提出了建议:
After doing some research, it appears there may be a glitch with initializing the FragmentTabHost in the support library. The user here on Google code has provided a suggestion to this:
FragmentTabHost.java
FragmentTabHost.java
private void initFragmentTabHost(Context context, AttributeSet attrs) {
TypedArray a = context.obtainStyledAttributes(attrs,
new int[] { android.R.attr.inflatedId }, 0, 0);
mContainerId = a.getResourceId(0, 0);
a.recycle();
super.setOnTabChangedListener(this);
// If owner hasn't made its own view hierarchy, then as a convenience
// we will construct a standard one here.
/***** HERE COMMENT CODE BECAUSE findViewById(android.R.id.tabs) EVERY TIME IS NULL WE HAVE OWN LAYOUT ******//
// if (findViewById(android.R.id.tabs) == null) {
// LinearLayout ll = new LinearLayout(context);
// ll.setOrientation(LinearLayout.VERTICAL);
// addView(ll, new FrameLayout.LayoutParams(
// ViewGroup.LayoutParams.FILL_PARENT,
// ViewGroup.LayoutParams.FILL_PARENT));
//
// TabWidget tw = new TabWidget(context);
// tw.setId(android.R.id.tabs);
// tw.setOrientation(TabWidget.HORIZONTAL);
// ll.addView(tw, new LinearLayout.LayoutParams(
// ViewGroup.LayoutParams.FILL_PARENT,
// ViewGroup.LayoutParams.WRAP_CONTENT, 0));
//
// FrameLayout fl = new FrameLayout(context);
// fl.setId(android.R.id.tabcontent);
// ll.addView(fl, new LinearLayout.LayoutParams(0, 0, 0));
//
// mRealTabContent = fl = new FrameLayout(context);
// mRealTabContent.setId(mContainerId);
// ll.addView(fl, new LinearLayout.LayoutParams(
// LinearLayout.LayoutParams.FILL_PARENT, 0, 1));
// }
}
片段的 XML 布局:
XML Layout for fragment:
<android.support.v4.app.FragmentTabHost
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@android:id/tabhost"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<FrameLayout
android:id="@android:id/tabcontent"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_weight="0"/>
<FrameLayout
android:id="@+id/realtabcontent"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"/>
<TabWidget
android:id="@android:id/tabs"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_weight="0"/>
</LinearLayout>
</android.support.v4.app.FragmentTabHost>
推荐答案
我终于搞清楚了.FragmentTabHost.java 存在一个问题，它始终会为您创建一个 TabHost 元素，无论您在 XML 中定义什么并事先进行膨胀.
I finally got to the bottom of this. There is an issue with FragmentTabHost.java which will always create a TabHost element for you, no matter what you define in XML and inflate beforehand.
因此，我在编写自己的 FragmentTabHost.java 版本时注释掉了那部分代码.
As such, I commented out that part of code when writing my own version of FragmentTabHost.java.
确保在您的 XML 布局中使用您的新版本，<com.example.app.MyFragmentTabHost
Make sure to use your new version of this in your XML layout, <com.example.app.MyFragmentTabHost
当然还有充气:
Fragment1.java:
Fragment1.java:
mTabHost = (MyFragmentTabHost) view.findViewById(android.R.id.tabhost);
mTabHost.setup(getActivity(), getChildFragmentManager(), android.R.id.tabcontent);
MyFragmentTabHost.java:
MyFragmentTabHost.java:
package com.example.app;
import java.util.ArrayList;
import android.content.Context;
import android.content.res.TypedArray;
import android.os.Bundle;
import android.os.Parcel;
import android.os.Parcelable;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentTransaction;
import android.util.AttributeSet;
import android.view.View;
import android.widget.FrameLayout;
import android.widget.TabHost;
/**
* Special TabHost that allows the use of {@link Fragment} objects for
* its tab content. When placing this in a view hierarchy, after inflating
* the hierarchy you must call {@link #setup(Context, FragmentManager, int)}
* to complete the initialization of the tab host.
*
*/
public class MyFragmentTabHost extends TabHost
implements TabHost.OnTabChangeListener {
private final ArrayList<TabInfo> mTabs = new ArrayList<TabInfo>();
private FrameLayout mRealTabContent;
private Context mContext;
private FragmentManager mFragmentManager;
private int mContainerId;
private TabHost.OnTabChangeListener mOnTabChangeListener;
private TabInfo mLastTab;
private boolean mAttached;
static final class TabInfo {
private final String tag;
private final Class<?> clss;
private final Bundle args;
private Fragment fragment;
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;
}
}
static class SavedState extends BaseSavedState {
String curTab;
SavedState(Parcelable superState) {
super(superState);
}
private SavedState(Parcel in) {
super(in);
curTab = in.readString();
}
@Override
public void writeToParcel(Parcel out, int flags) {
super.writeToParcel(out, flags);
out.writeString(curTab);
}
@Override
public String toString() {
return "FragmentTabHost.SavedState{"
+ Integer.toHexString(System.identityHashCode(this))
+ " curTab=" + curTab + "}";
}
public static final Parcelable.Creator<SavedState> CREATOR
= new Parcelable.Creator<SavedState>() {
public SavedState createFromParcel(Parcel in) {
return new SavedState(in);
}
public SavedState[] newArray(int size) {
return new SavedState[size];
}
};
}
public MyFragmentTabHost(Context context) {
// Note that we call through to the version that takes an AttributeSet,
// because the simple Context construct can result in a broken object!
super(context, null);
initFragmentTabHost(context, null);
}
public MyFragmentTabHost(Context context, AttributeSet attrs) {
super(context, attrs);
initFragmentTabHost(context, attrs);
}
private void initFragmentTabHost(Context context, AttributeSet attrs) {
TypedArray a = context.obtainStyledAttributes(attrs,
new int[] { android.R.attr.inflatedId }, 0, 0);
mContainerId = a.getResourceId(0, 0);
a.recycle();
super.setOnTabChangedListener(this);
/*** REMOVE THE REST OF THIS FUNCTION ***/
/*** findViewById(android.R.id.tabs) IS NULL EVERY TIME ***/
}
/**
* @deprecated Don't call the original TabHost setup, you must instead
* call {@link #setup(Context, FragmentManager)} or
* {@link #setup(Context, FragmentManager, int)}.
*/
@Override @Deprecated
public void setup() {
throw new IllegalStateException(
"Must call setup() that takes a Context and FragmentManager");
}
public void setup(Context context, FragmentManager manager) {
super.setup();
mContext = context;
mFragmentManager = manager;
ensureContent();
}
public void setup(Context context, FragmentManager manager, int containerId) {
super.setup();
mContext = context;
mFragmentManager = manager;
mContainerId = containerId;
ensureContent();
mRealTabContent.setId(containerId);
// We must have an ID to be able to save/restore our state. If
// the owner hasn't set one at this point, we will set it ourself.
if (getId() == View.NO_ID) {
setId(android.R.id.tabhost);
}
}
private void ensureContent() {
if (mRealTabContent == null) {
mRealTabContent = (FrameLayout)findViewById(mContainerId);
if (mRealTabContent == null) {
throw new IllegalStateException(
"No tab content FrameLayout found for id " + mContainerId);
}
}
}
@Override
public void setOnTabChangedListener(OnTabChangeListener l) {
mOnTabChangeListener = l;
}
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);
if (mAttached) {
// If we are already attached to the window, then check to make
// sure this tab's fragment is inactive if it exists. This shouldn't
// normally happen.
info.fragment = mFragmentManager.findFragmentByTag(tag);
if (info.fragment != null && !info.fragment.isDetached()) {
FragmentTransaction ft = mFragmentManager.beginTransaction();
ft.detach(info.fragment);
ft.commit();
}
}
mTabs.add(info);
addTab(tabSpec);
}
@Override
protected void onAttachedToWindow() {
super.onAttachedToWindow();
String currentTab = getCurrentTabTag();
// Go through all tabs and make sure their fragments match
// the correct state.
FragmentTransaction ft = null;
for (int i=0; i<mTabs.size(); i++) {
TabInfo tab = mTabs.get(i);
tab.fragment = mFragmentManager.findFragmentByTag(tab.tag);
if (tab.fragment != null && !tab.fragment.isDetached()) {
if (tab.tag.equals(currentTab)) {
// The fragment for this tab is already there and
// active, and it is what we really want to have
// as the current tab. Nothing to do.
mLastTab = tab;
} else {
// This fragment was restored in the active state,
// but is not the current tab. Deactivate it.
if (ft == null) {
ft = mFragmentManager.beginTransaction();
}
ft.detach(tab.fragment);
}
}
}
// We are now ready to go. Make sure we are switched to the
// correct tab.
mAttached = true;
ft = doTabChanged(currentTab, ft);
if (ft != null) {
ft.commit();
mFragmentManager.executePendingTransactions();
}
}
@Override
protected void onDetachedFromWindow() {
super.onDetachedFromWindow();
mAttached = false;
}
@Override
protected Parcelable onSaveInstanceState() {
Parcelable superState = super.onSaveInstanceState();
SavedState ss = new SavedState(superState);
ss.curTab = getCurrentTabTag();
return ss;
}
@Override
protected void onRestoreInstanceState(Parcelable state) {
SavedState ss = (SavedState)state;
super.onRestoreInstanceState(ss.getSuperState());
setCurrentTabByTag(ss.curTab);
}
@Override
public void onTabChanged(String tabId) {
if (mAttached) {
FragmentTransaction ft = doTabChanged(tabId, null);
if (ft != null) {
ft.commit();
}
}
if (mOnTabChangeListener != null) {
mOnTabChangeListener.onTabChanged(tabId);
}
}
private FragmentTransaction doTabChanged(String tabId, FragmentTransaction ft) {
TabInfo newTab = null;
for (int i=0; i<mTabs.size(); i++) {
TabInfo tab = mTabs.get(i);
if (tab.tag.equals(tabId)) {
newTab = tab;
}
}
if (newTab == null) {
throw new IllegalStateException("No tab known for tag " + tabId);
}
if (mLastTab != newTab) {
if (ft == null) {
ft = mFragmentManager.beginTransaction();
}
if (mLastTab != null) {
if (mLastTab.fragment != null) {
ft.detach(mLastTab.fragment);
}
}
if (newTab != null) {
if (newTab.fragment == null) {
newTab.fragment = Fragment.instantiate(mContext,
newTab.clss.getName(), newTab.args);
ft.add(mContainerId, newTab.fragment, newTab.tag);
} else {
ft.attach(newTab.fragment);
}
}
mLastTab = newTab;
}
return ft;
}
}
这篇关于Android FragmentTabHost - 还没有完全成熟?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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