android fragmenttabhost 不能将tabcontent定义在外面的解决办法

<FrameLayout
android:id="@+id/tabcontent"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1" />

<com.duandianer.ddr_android.Widget.FragmentTabHost
android:id="@android:id/tabhost"
android:layout_width="match_parent"
android:layout_height="150px"
android:layout_gravity="center">

<FrameLayout
android:id="@android:id/tabcontent"
android:layout_width="0dp"
android:layout_height="0dp" />

<TabWidget
android:id="@android:id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@color/colorTabBackGround" />
</com.duandianer.ddr_android.Widget.FragmentTabHost>

可能有很多人这样写的时候会报这个错误

private void ensureContent() {
if (mRealTabContent == null) {
if (mView == null)
mRealTabContent = (FrameLayout) findViewById(mContainerId);
else
mRealTabContent = (FrameLayout) mView.findViewById(mContainerId);
if (mRealTabContent == null) {
throw new IllegalStateException(
"No tab content FrameLayout found for id " + mContainerId);        }
}
}

"No tab content FrameLayout found for id " + mContainerId);

原因是什么呢？

看看fragmenttabhost的源码就知道了。

public void setup(Context context, FragmentManager manager, int containerId) {
ensureHierarchy(context);  // Ensure views required by super.setup()
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 ourselves.
if (getId() == View.NO_ID) {
setId(android.R.id.tabhost);
}
}

我们一般是调用这个方法来setup的

然后它又会调用这个

private void ensureContent() {
if (mRealTabContent == null) {
if (mView == null)
mRealTabContent = (FrameLayout) findViewById(mContainerId);
else
mRealTabContent = (FrameLayout) mView.findViewById(mContainerId);
if (mRealTabContent == null) {
throw new IllegalStateException(
"No tab content FrameLayout found for id " + mContainerId);
}
}
}

这里我们可以看到它是直接这样来找framlayout的：

mRealTabContent = (FrameLayout) findViewById(mContainerId);

也就是直接在fragmenttabhost的子view下面去找

然而呢 我们是把它定义在fragmenttabhost上面的，所以会报错！

那么解决办法很简单，我们加个view来保存我们自己的view不就行了

修改后的fragmenttabhost代码如下：

/*
* Copyright (C) 2012 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.duandianer.ddr_android.Widget;

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.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.LinearLayout;
import android.widget.TabHost;
import android.widget.TabWidget;

import com.duandianer.ddr_android.R;

import java.util.ArrayList;

/**
* 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.
* <p>
* <p>Here is a simple example of using a FragmentTabHost in an Activity:
* <p>
* {@sample frameworks/support/samples/Support4Demos/src/com/example/android/supportv4/app/FragmentTabs.java
* complete}
* <p&
4000
gt;
* <p>This can also be used inside of a fragment through fragment nesting:
* <p>
* {@sample frameworks/support/samples/Support4Demos/src/com/example/android/supportv4/app/FragmentTabsFragmentSupport.java
* complete}
*/

/* Changed by duandianer studio */
/* @author duandianer studio */
public class FragmentTabHost 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;
private View mView;

static final class TabInfo {
final String tag;
final Class<?> clss;
final Bundle args;
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);
}

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>() {
@Override
public SavedState createFromParcel(Parcel in) {
return new SavedState(in);
}

@Override
public SavedState[] newArray(int size) {
return new SavedState[size];
}
};
}

public FragmentTabHost(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 FragmentTabHost(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);
}

private void ensureHierarchy(Context context) {
// If owner hasn't made its own view hierarchy, then as a convenience
// we will construct a standard one here.
if (findViewById(android.R.id.tabs) == null) {
LinearLayout ll = new LinearLayout(context);
ll.setOrientation(LinearLayout.VERTICAL);
addView(ll, new FrameLayout.LayoutParams(
ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.MATCH_PARENT));

TabWidget tw = new TabWidget(context);
tw.setId(android.R.id.tabs);
tw.setOrientation(TabWidget.HORIZONTAL);
ll.addView(tw, new LinearLayout.LayoutParams(
ViewGroup.LayoutParams.MATCH_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.MATCH_PARENT, 0, 1));
}
}

/**
* @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) {
ensureHierarchy(context);  // Ensure views required by super.setup()
super.setup();
mContext = context;
mFragmentManager = manager;
ensureContent();
}

public void setup(Context context, FragmentManager manager, int containerId) {
ensureHierarchy(context);  // Ensure views required by super.setup()
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 ourselves.
if (getId() == View.NO_ID) {
setId(android.R.id.tabhost);
}
}

public void setup(Context context, FragmentManager manager, int containerId, int layoutId) {
ensureHierarchy(context);  // Ensure views required by super.setup()
super.setup();
mView = LayoutInflater.from(context).inflate(R.layout.main, null);
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 ourselves.
if (getId() == View.NO_ID) {
setId(android.R.id.tabhost);
}
}

private void ensureContent() {
if (mRealTabContent == null) {
if (mView == null)
mRealTabContent = (FrameLayout) findViewById(mContainerId);
else
mRealTabContent = (FrameLayout) mView.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.executePendingTrans
c30e
actions();
}
}

@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) {
if (!(state instanceof SavedState)) {
super.onRestoreInstanceState(state);
return;
}
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;
}
}

为了保留原始的方法，我们新写一个setup方法就行了，现在应该就不会报错了