[英]How to show selected fragment in action bar tab
I am facing one issue regarding tab swipe. 我正面临一个关于标签滑动的问题。 My project is built on Android 3.2. 我的项目是基于Android 3.2构建的。 I am implementing tab swipe using support library 4.0 (android-support-v4.jar). 我正在使用支持库4.0(android-support-v4.jar)实现选项卡滑动。 Everything implemented is working fine but when I deploy my app to an ICS device, then in portrait mode I am getting a spinner in action bar for tab selection. 所有实现的工作都运行正常,但是当我将我的应用程序部署到ICS设备时,然后在纵向模式下,我在操作栏中获得了一个用于选项卡选择的微调器。 In portrait mode, the tab selection is not changing when swipe is done although content is changing, and everything is working fine in landscape mode. 在纵向模式下,尽管内容正在更改,但在完成滑动时选项卡选择不会更改,并且在横向模式下一切正常。
final ActionBar actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
actionBar.setDisplayHomeAsUpEnabled(true);
// Set up the ViewPager with the sections adapter.
ViewPager mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
});
I have tried putting breakpoint actionBar.setSelectedNavigationItem(position);
我试过把断点actionBar.setSelectedNavigationItem(position);
on this line and even on portrait mode it's getting called but the selection is not changing. 在这条线上,甚至在肖像模式下它被调用,但选择没有改变。
Can anybody help with this? 任何人都可以帮忙吗?
EDITED: Found a similar problem but don't see exactly how it is solved and how to integrate it in my code. 编辑:发现了类似的问题,但没有看到它是如何解决的,以及如何将其集成到我的代码中。
Problem: Due to an insufficient real-state the platform uses collapsed navigation (ie Spinner). 问题:由于实际状态不足,平台使用折叠导航(即Spinner)。 The system auto-determines NAVIGATION_MODE_TABS for landscape & NAVIGATION_MODE_LIST for portrait, changing the orientation from landscape to portrait updates the UI but for some reason does not update the navigation mode property to NAVIGATION_MODE_LIST and hence mActionView.setDropdownSelectedPosition(position) is not called. 系统会自动确定横向的NAVIGATION_MODE_TABS和纵向的NAVIGATION_MODE_LIST,将方向从横向更改为纵向更新UI但由于某种原因不会将导航模式属性更新为NAVIGATION_MODE_LIST,因此不会调用mActionView.setDropdownSelectedPosition(位置)。 See the following code of ActionBarImpl : setSelectedNavigationItem 请参阅以下ActionBarImpl代码:setSelectedNavigationItem
public void setSelectedNavigationItem(int position) { switch (mActionView.getNavigationMode()) { case NAVIGATION_MODE_TABS: selectTab(mTabs.get(position)); break; case NAVIGATION_MODE_LIST: mActionView.setDropdownSelectedPosition(position); break; default: throw new IllegalStateException( "setSelectedNavigationIndex not valid for current navigation mode"); } }
Workaround solution: Through reflection we can get the tab spinner object and call setSelection method. 变通方法解决方案:通过反射,我们可以获取制表符微调器对象并调用setSelection方法。
private Spinner getTabSpinner()
{
try
{
int id = getResources().getIdentifier("action_bar", "id", "android");
View actionBarView = findViewById(id);
Class<?> actionBarViewClass = actionBarView.getClass();
Field mTabScrollViewField = actionBarViewClass.getDeclaredField("mTabScrollView");
mTabScrollViewField.setAccessible(true);
Object mTabScrollView = mTabScrollViewField.get(actionBarView);
if (mTabScrollView == null) {
return null;
}
Field mTabSpinnerField = mTabScrollView.getClass().getDeclaredField("mTabSpinner");
mTabSpinnerField.setAccessible(true);
Object mTabSpinner = mTabSpinnerField.get(mTabScrollView);
if (mTabSpinner != null)
{
return (Spinner)mTabSpinner;
}
}
catch (Exception e) {
return null;
}
return null;
}
Then call the above method in onPageSelected event. 然后在onPageSelected事件中调用上面的方法。
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
Spinner spinner = getTabSpinner();
if (spinner != null) {
spinner.setSelection(position);
}
}
Referred this post https://gist.github.com/2657485 推荐这篇文章https://gist.github.com/2657485
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