我正在使用 ActionBarSherlock 4.1,我的目标是在一个屏幕中有两个片段:一个 ListView 和一个详细信息片段。在此处的帮助下,我扩展了在 ABS 网站上找到的 FragmentTabsPager 示例。
该异常似乎与使用 ViewPager 有关。如果我想要滑动到想要隐藏布局的屏幕,应用程序会崩溃。如果我使用选项卡切换到同一屏幕,它可以工作。
我使用以下布局:
肖像布局:
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/pager"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
景观布局:
<FrameLayout
android:id="@+id/main_container"
android:layout_width="0px"
android:layout_height="match_parent"
android:layout_weight="1" >
<android.support.v4.view.ViewPager
android:id="@+id/pager"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
</FrameLayout>
<FrameLayout
android:id="@+id/details_container"
android:layout_width="0px"
android:layout_height="match_parent"
android:layout_weight="1" />
魔法:
@Override
public void onTabSelected(Tab tab, FragmentTransaction ft) {
if (mContext.getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {
if (tab.getText().equals("Simple")) {
countingFragment = new FragmentStackSupport.CountingFragment();
detailsFragment = new FragmentStackSupport.DetailsFragment();
ft.add(R.id.main_container, countingFragment, "frag1");
ft.add(R.id.details_container, detailsFragment, "frag2");
} else {
// if it's not the first tab
mViewPager.setCurrentItem(mContext.getSupportActionBar()
.getSelectedNavigationIndex());
if (countingFragment != null) {
ft.detach(countingFragment);
}
if (detailsFragment != null) {
ft.detach(detailsFragment);
}
FrameLayout detailsFragmentLayout = (FrameLayout) mContext.findViewById(R.id.details_container);
detailsFragmentLayout.setVisibility(View.GONE);
}
} else {
//Portrait mode is being used
mViewPager.setCurrentItem(mContext.getSupportActionBar().getSelectedNavigationIndex());
}
这个想法是为景观布局提供两个容器,并将片段附加到它们上,效果很好。
两个容器(内容和细节)都占屏幕的一半(它们的权重相等)。当我退出使用详细信息片段的屏幕时,我想确保内容容器使用所有宽度,并且我需要以某种方式隐藏详细信息容器。
不幸的是,上面的代码(detailsFragmentLayout.setVisibility(View.GONE))产生了一个异常:
FATAL EXCEPTION: main
java.lang.NullPointerException
at android.widget.FrameLayout.onMeasure(FrameLayout.java:244)
at android.view.View.measure(View.java:8171)
at android.widget.LinearLayout.measureHorizontal(LinearLayout.java:678)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:306)
at android.view.View.measure(View.java:8171)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3132)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
at android.view.View.measure(View.java:8171)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:526)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:304)
at android.view.View.measure(View.java:8171)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3132)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
at android.view.View.measure(View.java:8171)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3132)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:245)
at android.view.View.measure(View.java:8171)
at android.view.ViewRoot.performTraversals(ViewRoot.java:801)
at android.view.ViewRoot.handleMessage(ViewRoot.java:1727)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:123)
at android.app.ActivityThread.main(ActivityThread.java:4627)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:521)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:878)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:636)
at dalvik.system.NativeStart.main(Native Method)
有什么关于隐藏 LinearLayout 的建议或其他关于到达我想要的地方的提示吗?