Android 碎片从背面消失_Android_Android Fragments_Android Actionbar_Android Tabs

Android 碎片从背面消失

android android-fragments

Android 碎片从背面消失,android,android-fragments,android-actionbar,android-tabs,Android,Android Fragments,Android Actionbar,Android Tabs,为什么在以下情况下，FragmentTwo会从后台消失：我的应用程序在活动中有一个名为FragmentOne的片段 FragmentOne持有一个按钮。单击后，它将启动FragmentTwo，并将其添加到Fragmentbackstack中 FragmentTwo有一个按钮，单击该按钮时，会在操作栏中添加两个选项卡，链接到两个片段，FragmentThree和FragmentFour碎片三可见如果我现在单击后退按钮，我希望看到FragmentTwo。相反，我看到的是FragmentOne。

为什么在以下情况下，

FragmentTwo

会从后台消失：

我的应用程序在

活动中有一个名为FragmentOne
的片段


FragmentOne
持有一个按钮
。单击后，它将启动FragmentTwo
，并将其添加到Fragment
backstack中
FragmentTwo
有一个按钮
，单击该按钮时，会在操作栏
中添加两个选项卡，链接到两个片段
，FragmentThree
和FragmentFour
<代码>碎片三可见
如果我现在单击后退按钮，我希望看到FragmentTwo
。相反，我看到的是FragmentOne
。FragmentTwo
去了哪里


在我重写onKeyDown（）
并开始为片段实现我自己的backbackback之前，我想问一下是否有明显的遗漏？注意：测试时没有发生配置更改

详情：
FragmentOne的按钮单击处理程序包含：
    FragmentTransaction ft = getFragmentManager().beginTransaction();
    FragmentTwo fragment = new FragmentTwo();
    ft.addToBackStack(null);
    ft.replace(android.R.id.content, fragment).commit();

碎片两个按钮点击在活动中处理：
    getActionBar().setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
    FragmentFour fragmentThree = new FragmentThree();
    FragmentFive fragmentFive = new FragmentFive();

    ActionBar.Tab tab = getActionBar().newTab().setText("Frag 3").setTabListener(new CustomTabListener<FragmentThree>(fragmentThree));
    getActionBar().addTab(tab);
    tab = getActionBar().newTab().setText("Frag 4").setTabListener(new CustomTabListener<FragmentFour>(fragmentFour));
    getActionBar().addTab(tab);

getActionBar（）.setNavigationMode（ActionBar.NAVIGATION\u MODE\u选项卡）；
FragmentFour fragmentThree=新的fragmentThree（）；
FragmentFive FragmentFive=新的FragmentFive（）；
ActionBar.Tab Tab=getActionBar（）.newTab（）.setText（“Frag3”）.setTableListener（新的CustomTableListener（fragmentThree））；
getActionBar（）.addTab（选项卡）；
tab=getActionBar（）.newTab（）.setText（“碎片4”）.setTableListener（新的CustomTableListener（碎片四））；
getActionBar（）.addTab（选项卡）；

其中选项卡侦听器是：
public static class CustomTabListener<T extends Fragment> implements TabListener {
    Fragment fragment;

    public CustomTabListener(Fragment fragment) {
        this.fragment = fragment;
    }

    public void onTabSelected(Tab tab, FragmentTransaction ft) {
        ft.replace(android.R.id.content, fragment);
    }

    public void onTabUnselected(Tab tab, FragmentTransaction ft) {
        ft.remove(fragment);
    }

    public void onTabReselected(Tab tab, FragmentTransaction ft) {

    }
}

public静态类CustomTabListener实现了TabListener{
片段；
公共CustomTableListener（片段）{
this.fragment=片段；
}
已选择的公共事务（选项卡，碎片事务ft）{
ft.replace（android.R.id.content，fragment）；
}
已选择公共空页（选项卡，碎片事务ft）{
ft.去除（碎片）；
}
已重新选择公共无效页签（页签，碎片事务）{
}
}

如果在显示FragmentThree
之前向backstack添加更多FragmentThree
，则始终且仅FragmentThree
之前的片段
消失
当我按back键离开选项卡式用户视图并返回到FragmentOne
时，选项卡仍在显示。我知道我需要将ActionBar
重置为NAVIGATION\u MODE\u STANDARD
，但不清楚为什么显示FragmentOne
而不是FragmentTwo
，我认为问题在于是否构建了选项卡
public void onTabSelected(Tab tab, FragmentTransaction ft) {
    ft.replace(android.R.id.content, fragment);
}

调用，并且之前的片段未添加到backback
你试过打电话吗
ft.addToBackStack(null);

在片段中有两个按钮处理代码
但无论如何，您都需要实现onBackPressed（）
以摆脱选项卡。我想我应该使用选项卡创建新活动。
始终使用此代码块替换片段：
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(android.R.id.content, YOUR_FRAGMENT);
ft.addToBackStack(null);
ft.commit();

我认为您需要删除onTabUnselected（）
函数中的ft.remove
，因为replace已经这样做了。
根据上面显示的代码，您永远不会将Fragment2添加到后堆栈中
@gabe，@Pierre，您在侦听器中使用addToBackStack（）
获得非法状态异常的原因在API中有说明
在API级别11中添加
当选项卡进入选定状态时调用
“参数”选项卡选定的选项卡
ft一个FragmentTransaction，用于在选项卡切换期间对要执行的片段操作进行排队。上一个选项卡的取消选择和此选项卡的选择将在单个事务中执行
此FragmentTransaction不支持添加到后堆栈
解决这个问题的简单方法是使用FragmentManager在TabListener中获取您自己的FragmentTransaction，并将其添加到后堆栈中。像这样的
    public static class CustomTabListener<T extends Fragment> implements TabListener {
    Fragment fragment;

    public CustomTabListener(Fragment fragment) {
        this.fragment = fragment;
    }

    public void onTabSelected(Tab tab, FragmentTransaction ft) {
        FragmentManager fm = getFragmentManager();
        FragmentTransaction newFragTrans = fm.beginTransaction();
        newFragTrans.replace(android.R.id.content, fragment);
        newFragTrans.addToBackStack(null);
        newFragTrans.commit()
        
    }

    public void onTabUnselected(Tab tab, FragmentTransaction ft) {
        ft.remove(fragment);
    }

    public void onTabReselected(Tab tab, FragmentTransaction ft) {

    }
}

public静态类CustomTabListener实现了TabListener{
片段；
公共CustomTableListener（片段）{
this.fragment=片段；
}
已选择的公共事务（选项卡，碎片事务ft）{
FragmentManager fm=getFragmentManager（）；
FragmentTransaction newFragTrans=fm.beginTransaction（）；
newFragTrans.replace（android.R.id.content，fragment）；
newFragTrans.addToBackStack（空）；
newFragTrans.commit（）
}
已选择公共空页（选项卡，碎片事务ft）{
ft.去除（碎片）；
}
已重新选择公共无效页签（页签，碎片事务）{
}
}

我只是选了，但你明白了。另外，不要忘记提交此事务，因为侦听器只会自动提交提供的FragmentTransaction ft

最后一件事，确保在执行事务后调用addToBackStack（）
，因为这是要添加到堆栈中的内容，而不是实际的片段。在上面的代码中，这不是为Fragment1的按钮单击而做的
希望这有帮助。
@Pierre Rymiortz，我刚刚解决了这个问题。请参考下面的代码
public class StartActivity extends SherlockFragmentActivity implements
    TabListener, OnBackStackChangedListener {

private Context mContext = null;

private ActionBar mActionBar;

private Tab mTab;

private Fragment mSelectFragment;

private final static int ONE = 0;
private final static int TWO = 1;
private final static int THREE = 2;
private final static int PLAYERS = 3;

private MenuItem mPlayerItem = null;

private FragmentTransaction mFragmentTransaction = null;

/**
 * by default is false - TABS were taken in the starting true - when we are
 * changing back to TABS from STANDARD
 */
private boolean mTabsChanges = false;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    mContext = this;

    mActionBar = getSupportActionBar();

    // hiding the ActionBar icon
    mActionBar.setDisplayShowHomeEnabled(true);

    // for displaying the Arrow button
    mActionBar.setDisplayHomeAsUpEnabled(true);

    // hide Actionbar title
    mActionBar.setDisplayShowTitleEnabled(true);

    // Create Actionbar Tabs
    mActionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

    // Create first Tab
    mTab = mActionBar.newTab().setTabListener(this);
    mTab.setText("One");
    mActionBar.addTab(mTab);

    // Create Second Tab

    mTab = mActionBar.newTab().setTabListener(this);
    mTab.setText("Two");
    mActionBar.addTab(mTab);

    // Create Three Tab
    mTab = mActionBar.newTab().setTabListener(this);
    mTab.setText("Three");
    mActionBar.addTab(mTab);

    getSupportFragmentManager().addOnBackStackChangedListener(this);

}

@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
    mFragmentTransaction = ft;
    if (mTabsChanges) {
        // nothing to do here
        mTabsChanges = false;
    } else {
        switch (mActionBar.getSelectedNavigationIndex()) {
        case ONE:
            clearBackStack(mTabsChanges);
            mSelectFragment = new Fragment1();
            ft.replace(R.id.fragment_container, mSelectFragment, ONE + "");
            break;
        case TWO:
            clearBackStack(mTabsChanges);
            mSelectFragment = new Fragment2();
            ft.replace(R.id.fragment_container, mSelectFragment, TWO + "");
            break;
        case THREE:
            clearBackStack(mTabsChanges);
            mSelectFragment = new Fragment3();
            ft.replace(R.id.fragment_container, mSelectFragment, THREE + "");
            break;
        }
    }

}

@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
    Toast.makeText(
            mContext,
            "tab unselected." + mActionBar.getSelectedNavigationIndex()
                    + "", Toast.LENGTH_SHORT).show();
}

@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
    Toast.makeText(
            mContext,
            "tab reselected." + mActionBar.getSelectedNavigationIndex()
                    + "", Toast.LENGTH_SHORT).show();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // TODO Auto-generated method stub
    MenuInflater mInflate = getSupportMenuInflater();
    mInflate.inflate(R.menu.header_menu, menu);

    mPlayerItem = menu.findItem(R.id.men_set_players);

    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    if (item.getItemId() == R.id.men_set_players) {
        addFragmentToStack();
        return true;
    }
    return false;
}

private void addFragmentToStack() {

    // Add the fragment to the activity, pushing this transaction
    // on to the back stack.
    mActionBar.setTitle(getResources().getString(R.string.menu_players));
    mSelectFragment = new PlayersFragment();
    FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
    ft.replace(R.id.fragment_container, mSelectFragment, "Players");
    ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
    ft.addToBackStack("players");
    ft.commit();
}

@Override
public void onBackStackChanged() {
    FragmentManager fm = getSupportFragmentManager();
    if (fm.getBackStackEntryCount() > 0) {
        int TOP = fm.getBackStackEntryCount() - 1;
        Log.i("BACKSTACK", TOP + ".."
                + fm.getBackStackEntryAt(TOP).getName());
        if (fm.getBackStackEntryAt(TOP).getName()
                .equalsIgnoreCase("players")) {
            if (mActionBar.getNavigationMode() == ActionBar.NAVIGATION_MODE_TABS) {
                mTabsChanges = false;
                mActionBar
                        .setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
            }
        } else {
            if (mActionBar.getNavigationMode() == ActionBar.NAVIGATION_MODE_STANDARD) {
                mTabsChanges = true;
                mActionBar
                        .setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
            }
        }

    } else {
        if (mActionBar.getNavigationMode() == ActionBar.NAVIGATION_MODE_STANDARD) {
            mTabsChanges = true;
            mActionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
        } else if (mActionBar.getNavigationMode() == ActionBar.NAVIGATION_MODE_TABS) {
            mTabsChanges = false;
        }
    }

    Toast.makeText(mContext,
            "FM Back count." + fm.getBackStackEntryCount(),
            Toast.LENGTH_SHORT).show();
}

public void clearBackStack(boolean callFromSelection) {
    if (!callFromSelection) {
        FragmentManager fm = getSupportFragmentManager();
        for (int i = 0; i < fm.getBackStackEntryCount(); i++) {
            fm.popBackStackImmediate();
        }
    } else {
        Toast.makeText(mContext, "callfromreapprearence",
                Toast.LENGTH_SHORT).show();
    }
}

}

公共类StartActivity扩展SherlockFragmentActivity实现
TabListener，onbackbackchangedlistener{
私有上下文mContext=null；
私人行动吧；
私人标签mTab；
私有片段；
私有最终静态整数=0；
私有最终静态int 2=1；
私有最终静态int三=2；
私人决赛静态整数玩家=3；
private MenuItem mPlayerItem=null；
私有FragmentTransaction MFFragmentTransaction=null；
/**
*默认情况下为false-制表符在开始时为true-whe
public class StartActivity extends SherlockFragmentActivity implements
    TabListener, OnBackStackChangedListener {

private Context mContext = null;

private ActionBar mActionBar;

private Tab mTab;

private Fragment mSelectFragment;

private final static int ONE = 0;
private final static int TWO = 1;
private final static int THREE = 2;
private final static int PLAYERS = 3;

private MenuItem mPlayerItem = null;

private FragmentTransaction mFragmentTransaction = null;

/**
 * by default is false - TABS were taken in the starting true - when we are
 * changing back to TABS from STANDARD
 */
private boolean mTabsChanges = false;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    mContext = this;

    mActionBar = getSupportActionBar();

    // hiding the ActionBar icon
    mActionBar.setDisplayShowHomeEnabled(true);

    // for displaying the Arrow button
    mActionBar.setDisplayHomeAsUpEnabled(true);

    // hide Actionbar title
    mActionBar.setDisplayShowTitleEnabled(true);

    // Create Actionbar Tabs
    mActionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);

    // Create first Tab
    mTab = mActionBar.newTab().setTabListener(this);
    mTab.setText("One");
    mActionBar.addTab(mTab);

    // Create Second Tab

    mTab = mActionBar.newTab().setTabListener(this);
    mTab.setText("Two");
    mActionBar.addTab(mTab);

    // Create Three Tab
    mTab = mActionBar.newTab().setTabListener(this);
    mTab.setText("Three");
    mActionBar.addTab(mTab);

    getSupportFragmentManager().addOnBackStackChangedListener(this);

}

@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
    mFragmentTransaction = ft;
    if (mTabsChanges) {
        // nothing to do here
        mTabsChanges = false;
    } else {
        switch (mActionBar.getSelectedNavigationIndex()) {
        case ONE:
            clearBackStack(mTabsChanges);
            mSelectFragment = new Fragment1();
            ft.replace(R.id.fragment_container, mSelectFragment, ONE + "");
            break;
        case TWO:
            clearBackStack(mTabsChanges);
            mSelectFragment = new Fragment2();
            ft.replace(R.id.fragment_container, mSelectFragment, TWO + "");
            break;
        case THREE:
            clearBackStack(mTabsChanges);
            mSelectFragment = new Fragment3();
            ft.replace(R.id.fragment_container, mSelectFragment, THREE + "");
            break;
        }
    }

}

@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
    Toast.makeText(
            mContext,
            "tab unselected." + mActionBar.getSelectedNavigationIndex()
                    + "", Toast.LENGTH_SHORT).show();
}

@Override
public void onTabReselected(Tab tab, FragmentTransaction ft) {
    Toast.makeText(
            mContext,
            "tab reselected." + mActionBar.getSelectedNavigationIndex()
                    + "", Toast.LENGTH_SHORT).show();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // TODO Auto-generated method stub
    MenuInflater mInflate = getSupportMenuInflater();
    mInflate.inflate(R.menu.header_menu, menu);

    mPlayerItem = menu.findItem(R.id.men_set_players);

    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    if (item.getItemId() == R.id.men_set_players) {
        addFragmentToStack();
        return true;
    }
    return false;
}

private void addFragmentToStack() {

    // Add the fragment to the activity, pushing this transaction
    // on to the back stack.
    mActionBar.setTitle(getResources().getString(R.string.menu_players));
    mSelectFragment = new PlayersFragment();
    FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
    ft.replace(R.id.fragment_container, mSelectFragment, "Players");
    ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
    ft.addToBackStack("players");
    ft.commit();
}

@Override
public void onBackStackChanged() {
    FragmentManager fm = getSupportFragmentManager();
    if (fm.getBackStackEntryCount() > 0) {
        int TOP = fm.getBackStackEntryCount() - 1;
        Log.i("BACKSTACK", TOP + ".."
                + fm.getBackStackEntryAt(TOP).getName());
        if (fm.getBackStackEntryAt(TOP).getName()
                .equalsIgnoreCase("players")) {
            if (mActionBar.getNavigationMode() == ActionBar.NAVIGATION_MODE_TABS) {
                mTabsChanges = false;
                mActionBar
                        .setNavigationMode(ActionBar.NAVIGATION_MODE_STANDARD);
            }
        } else {
            if (mActionBar.getNavigationMode() == ActionBar.NAVIGATION_MODE_STANDARD) {
                mTabsChanges = true;
                mActionBar
                        .setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
            }
        }

    } else {
        if (mActionBar.getNavigationMode() == ActionBar.NAVIGATION_MODE_STANDARD) {
            mTabsChanges = true;
            mActionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
        } else if (mActionBar.getNavigationMode() == ActionBar.NAVIGATION_MODE_TABS) {
            mTabsChanges = false;
        }
    }

    Toast.makeText(mContext,
            "FM Back count." + fm.getBackStackEntryCount(),
            Toast.LENGTH_SHORT).show();
}

public void clearBackStack(boolean callFromSelection) {
    if (!callFromSelection) {
        FragmentManager fm = getSupportFragmentManager();
        for (int i = 0; i < fm.getBackStackEntryCount(); i++) {
            fm.popBackStackImmediate();
        }
    } else {
        Toast.makeText(mContext, "callfromreapprearence",
                Toast.LENGTH_SHORT).show();
    }
}

}