我已经创建了一个代表我的问题的小测试应用程序。我正在使用ActionBarSherlock来实现带有(神探夏洛克)片段的标签。
我的代码:TestActivity.java
public class TestActivity extends SherlockFragmentActivity {
private ActionBar actionBar;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setupTabs(savedInstanceState);
}
private void setupTabs(Bundle savedInstanceState) {
actionBar = getSupportActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
addTab1();
addTab2();
}
private void addTab1() {
Tab tab1 = actionBar.newTab();
tab1.setTag("1");
String tabText = "1";
tab1.setText(tabText);
tab1.setTabListener(new TabListener<MyFragment>(TestActivity.this, "1", MyFragment.class));
actionBar.addTab(tab1);
}
private void addTab2() {
Tab tab1 = actionBar.newTab();
tab1.setTag("2");
String tabText = "2";
tab1.setText(tabText);
tab1.setTabListener(new TabListener<MyFragment>(TestActivity.this, "2", MyFragment.class));
actionBar.addTab(tab1);
}
}
TabListener.java
public class TabListener<T extends SherlockFragment> implements com.actionbarsherlock.app.ActionBar.TabListener {
private final SherlockFragmentActivity mActivity;
private final String mTag;
private final Class<T> mClass;
public TabListener(SherlockFragmentActivity activity, String tag, Class<T> clz) {
mActivity = activity;
mTag = tag;
mClass = clz;
}
/* The following are each of the ActionBar.TabListener callbacks */
public void onTabSelected(Tab tab, FragmentTransaction ft) {
SherlockFragment preInitializedFragment = (SherlockFragment) mActivity.getSupportFragmentManager().findFragmentByTag(mTag);
// Check if the fragment is already initialized
if (preInitializedFragment == null) {
// If not, instantiate and add it to the activity
SherlockFragment mFragment = (SherlockFragment) SherlockFragment.instantiate(mActivity, mClass.getName());
ft.add(android.R.id.content, mFragment, mTag);
} else {
ft.attach(preInitializedFragment);
}
}
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
SherlockFragment preInitializedFragment = (SherlockFragment) mActivity.getSupportFragmentManager().findFragmentByTag(mTag);
if (preInitializedFragment != null) {
// Detach the fragment, because another one is being attached
ft.detach(preInitializedFragment);
}
}
public void onTabReselected(Tab tab, FragmentTransaction ft) {
// User selected the already selected tab. Usually do nothing.
}
}
MyFragment.java
public class MyFragment extends SherlockFragment {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
new AsyncTask<Void, Void, Void>() {
@Override
protected Void doInBackground(Void... params) {
try {
Thread.sleep(2000);
} catch (InterruptedException ex) {
}
return null;
}
@Override
protected void onPostExecute(Void result){
getResources().getString(R.string.app_name);
}
}.execute();
}
}
我已经添加了Thread.sleep
部件来模拟下载数据。onPostExecute
中的代码是为了模拟Fragment
的使用。
当我在横向和纵向之间非常快速地旋转屏幕时,我在onPostExecute
代码处得到一个异常:
java.lang.IllegalStateException:片段MyFragment{410f6060}未附加到Activity
我认为这是因为在此期间创建了一个新的MyFragment
,并且在AsyncTask
完成之前附加到了该活动。onPostExecute
中的代码调用未附加的MyFragment
。
但是我该如何解决这个问题呢?
https://stackoverflow.com/questions/10919240
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