由于TabActivity已弃用，我尝试将其替换为已在开发者android网站中提及的Fragments。但是你们已经知道有一个关于用片段替换制表符的问题，因为只有一个活动，即Fragment Activity，每个片段都没有后台堆栈，你可以在其他SO问题中看到开发人员说你需要管理自己的自定义后台堆栈作为解决方案。
我已经创建并实现了我自己的自定义后台堆栈，如下所示，它工作正常我可以跟踪每个选项卡中的每个片段。
TAB1
Fragment1 > Fragment2 > Fragment3
TAB2
Fragment5 > Fragment6
根据上面的导航，如果我从Fragment1导航到片段3，之后如果我将选项卡更改为Tab2并返回到Tab1，我仍然可以看到Fragment3，我甚至可以使用我的自定义导航回Fragment1后筹码。
但问题是，当我回到Tab1并看到Fragment3时，Fragment3被重新创建，在我将标签更改为Tab2之前，我无法看到更改。
这是我的自定义后台堆栈;
public static HashMap<String, Stack<Fragment>> customBackStack;
public static Stack<Fragment> simpleStack;
public static Stack<Fragment> contactStack;
public static Stack<Fragment> customStack;
public static Stack<Fragment> throttleStack;
public static Stack<Fragment> homeStack;
customBackStack = new HashMap<String, Stack<Fragment>>();
homeStack = new Stack<Fragment>();
simpleStack = new Stack<Fragment>();
contactStack = new Stack<Fragment>();
customStack = new Stack<Fragment>();
throttleStack = new Stack<Fragment>();
customBackStack.put("home", homeStack);
customBackStack.put("simple", simpleStack);
customBackStack.put("contacts", contactStack);
customBackStack.put("custom", customStack);
customBackStack.put("throttle", throttleStack);
这是onTabChanged方法;
public void onTabChanged(String tabId) {
TabInfo newTab = mTabs.get(tabId);
if (mLastTab != newTab) {
FragmentTransaction ft = mActivity.getSupportFragmentManager().beginTransaction();
if (mLastTab != null) {
if (mLastTab.fragment != null) {
ft.detach(mLastTab.fragment);
}
}
if (newTab != null) {
if (newTab.fragment == null) {
if (!customBackStack.get(tabId).isEmpty()) {
Fragment fragment = customBackStack.get(tabId).pop();
customBackStack.get(tabId).push(fragment);
ft.replace(mContainerId, fragment);
}
} else {
if (!customBackStack.get(tabId).isEmpty()) {
Fragment fragment = customBackStack.get(tabId).pop();
customBackStack.get(tabId).push(fragment);
ft.replace(mContainerId, fragment);
}
}
}
mLastTab = newTab;
ft.commit();
mActivity.getSupportFragmentManager().executePendingTransactions();
}
}
这是onBackPressed;
public void onBackPressed() {
Stack<Fragment> stack = customBackStack.get(mTabHost.getCurrentTabTag());
if (stack.isEmpty()) {
super.onBackPressed();
} else {
Fragment fragment = stack.pop();
if (fragment.isVisible()) {
if (stack.isEmpty()) {
super.onBackPressed();
} else {
Fragment frg = stack.pop();
customBackStack.get(mTabHost.getCurrentTabTag()).push(frg);
transaction = getSupportFragmentManager().beginTransaction();
transaction.setCustomAnimations(R.anim.slide_in_left, R.anim.slide_out_right,
R.anim.slide_in_right, R.anim.slide_out_left);
transaction.replace(R.id.realtabcontent, frg).commit();
}
} else {
getSupportFragmentManager().beginTransaction().replace(R.id.realtabcontent, fragment).commit();
}
}
}
因此，除了最后一个片段之外，自定义后端堆栈工作正常，然后在返回选项卡后重新创建选项卡，它不会像在tab选项卡中一样恢复。
知道怎么解决吗？
修改
您可以在此处找到我的示例应用程序作为解决此问题的解决方案。
答案 0 :(得分：2)
我将googles sample tablistener修改为以下内容：
public static class TabListener<T extends SherlockFragment> implements ActionBar.TabListener {
private final SherlockFragmentActivity mActivity;
private final String mTag;
private final Class<T> mClass;
private final Bundle mArgs;
public SherlockFragment mFragment;
private final Stack<SherlockFragment> mStack;
public TabListener(SherlockFragmentActivity activity, String tag, Class<T> clz) {
this(activity, tag, clz, null, null);
}
public TabListener(SherlockFragmentActivity activity, String tag, Class<T> clz, Bundle args, Stack<SherlockFragment> stack) {
mActivity = activity;
mTag = tag;
mClass = clz;
mArgs = args;
mStack = stack;
// Check to see if we already have a fragment for this tab, probably
// from a previously saved state. If so, deactivate it, because our
// initial state is that a tab isn't shown.
mFragment = (SherlockFragment) mActivity.getSupportFragmentManager().findFragmentByTag(mTag);
if (mFragment != null && !mFragment.isDetached()) {
FragmentTransaction ft = mActivity.getSupportFragmentManager().beginTransaction();
ft.detach(mFragment);
ft.commit();
}
}
public void onTabSelected(Tab tab, FragmentTransaction ft) {
// we need to reattach ALL fragments thats in the custom stack, if we don't we'll have problems with setCustomAnimation for fragments.
if (mFragment == null) {
mFragment = (SherlockFragment) SherlockFragment.instantiate(mActivity, mClass.getName(), mArgs);
ft.replace(android.R.id.content, mFragment, mTag);
} else {
ft.attach(mFragment);
}
if(mStack != null) {
for(SherlockFragment fragment: mStack) {
ft.attach(fragment);
}
}
}
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
if (mFragment != null) {
ft.detach(mFragment);
}
if(mStack != null) {
for(SherlockFragment fragment: mStack) {
if(fragment!= null && !fragment.isDetached()) {
ft.detach(fragment);
}
}
}
}
public void onTabReselected(Tab tab, FragmentTransaction ft) {
}
}
活动onKeyDown方法我改写为以下：
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
int index = getSupportActionBar().getSelectedNavigationIndex();
Stack<SherlockFragment> stack = null;
SherlockFragment fragment = null;
String rootTag = null;
switch(index) {
case 0:
stack = mWatersTabListener.mStack;
fragment = mWatersTabListener.mFragment;
rootTag = mWatersTabListener.mTag;
break;
case 1:
stack = mHarborTabListener.mStack;
fragment = mHarborTabListener.mFragment;
rootTag = mHarborTabListener.mTag;
break;
}
if(stack.isEmpty()) {
return super.onKeyDown(keyCode, event);
} else {
SherlockFragment topFragment = stack.pop();
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction ft = fragmentManager.beginTransaction();
ft.setCustomAnimations(R.anim.fragment_slide_right_enter,
R.anim.fragment_slide_right_exit);
if(topFragment != null && !topFragment.isDetached()) {
ft.detach(topFragment);
}
if(stack.isEmpty()) {
ft.replace(android.R.id.content, fragment, rootTag);
ft.commit();
return true;
} else {
SherlockFragment nextFragment = stack.peek();
ft.replace(android.R.id.content, nextFragment);
ft.commit();
return true;
}
}
}
return super.onKeyDown(keyCode, event);
}
需要注意的重要事项是，在选择时必须将所有片段附加到自定义堆栈中，并且在取消选择时必须分离所有片段。如果在理解代码片段时遇到问题，请询问。