我正在尝试修复方向更改时重新启动活动的问题。
我有一个带有下拉列表导航的ActionBar
,并且在每次旋转后,此列表的第一个元素都被激活。保留fragment
内容并不困难,但我不知道如何设置活动列表项。
以下是ActionBar
的定义:
getActionBar().setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);
ArrayAdapter<CharSequence> list = ArrayAdapter
.createFromResource(this, R.array.action_list, android.R.layout.simple_dropdown_item_1line);
list.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
getActionBar().setListNavigationCallbacks(list, this);
这是我的解决方法:
@Override
public boolean onNavigationItemSelected(int itemPosition, long itemId) {
if (!application.isRotated) {
application.activePosition = itemPosition;
application.activeId = itemId;
getFragmentManager().beginTransaction()
.replace(android.R.id.content, MyFragment.newInstance(itemPosition))
.commit();
} else {
application.isRotated = false;
this.onNavigationItemSelected(application.activePosition, application.activeId);
}
return true;
}
@Override
protected void onStop() {
super.onStop();
application.isRotated = true;
}
我不确定这是最好的解决方案。
答案 0 :(得分:83)
我刚刚找到了这个功能。它是setSelectedNavigationItem(int position)
。
在列表或选项卡式导航模式中设置所选导航项。
示例:
actionBar = getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_LIST);
actionBar.setListNavigationCallbacks(adapter, this);
actionBar.setSelectedNavigationItem(position);
答案 1 :(得分:1)
从支持库v7开始,您只需要保存/恢复ActionBar的状态:
private static final String STATE_SELECTED_NAVIGATION_ITEM = "selectedNavItem";
@Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
// Restore the previously serialized current dropdown position.
if (savedInstanceState.containsKey(STATE_SELECTED_NAVIGATION_ITEM)) {
getSupportActionBar().setSelectedNavigationItem(
savedInstanceState.getInt(STATE_SELECTED_NAVIGATION_ITEM));
}
}
@Override
public void onSaveInstanceState(Bundle outState) {
// Serialize the current dropdown position.
outState.putInt(STATE_SELECTED_NAVIGATION_ITEM, getSupportActionBar()
.getSelectedNavigationIndex());
}
答案 2 :(得分:0)
我也遇到了同样的问题。经过大量的研究,我在这里找到了解决方案:
http://mohitum.wordpress.com/tutorials/android/ - &gt;在提示5下。
实现OnPageChangeListener并在onPageSelected(int position)中调用此方法,如下所示:
@Override
public void onPageSelected(int position) {
mActionBar.setSelectedNavigationItem(position);
selectInSpinnerIfPresent(position, true);
}
private void selectInSpinnerIfPresent(int position, boolean animate) {
try {
ActionBar actionBarView = mActionBar;
Class<?> actionBarViewClass = actionBarView.getClass();
Field mTabScrollViewField = actionBarViewClass.getDeclaredField(“mTabScrollView”);
mTabScrollViewField.setAccessible(true);
Object mTabScrollView = mTabScrollViewField.get(actionBarView);
if (mTabScrollView == null) {
return;
}
Field mTabSpinnerField = mTabScrollView.getClass().getDeclaredField(“mTabSpinner”);
mTabSpinnerField.setAccessible(true);
Object mTabSpinner = mTabSpinnerField.get(mTabScrollView);
if (mTabSpinner == null) {
return;
}
Method setSelectionMethod = mTabSpinner.getClass().getSuperclass().getDeclaredMethod(“setSelection”, Integer.TYPE, Boolean.TYPE);
setSelectionMethod.invoke(mTabSpinner, position, animate);
Method requestLayoutMethod = mTabSpinner.getClass().getSuperclass().getDeclaredMethod(“requestLayout”);
requestLayoutMethod.invoke(mTabSpinner);
} catch (Exception e) {
e.printStackTrace();
}
}
我希望这也可以帮助其他人。
答案 3 :(得分:0)
@Override
public void onPageScrollStateChanged(int state) {
}
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
@Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
selectInSpinnerIfPresent(position, true);
}
/**
* Hack that takes advantage of interface parity between ActionBarSherlock and the native interface to reach inside
* the classes to manually select the appropriate tab spinner position if the overflow tab spinner is showing.
*
* Related issues: https://github.com/JakeWharton/ActionBarSherlock/issues/240 and
* https://android-review.googlesource.com/#/c/32492/
*
* @author toulouse@crunchyroll.com
*/
private void selectInSpinnerIfPresent(int position, boolean animate) {
try {
View actionBarView = findViewById(R.id.abs__action_bar);
if (actionBarView == null) {
int id = getResources().getIdentifier("action_bar", "id", "android");
actionBarView = findViewById(id);
}
Class<?> actionBarViewClass = actionBarView.getClass();
Field mTabScrollViewField = actionBarViewClass.getDeclaredField("mTabScrollView");
mTabScrollViewField.setAccessible(true);
Object mTabScrollView = mTabScrollViewField.get(actionBarView);
if (mTabScrollView == null) {
return;
}
Field mTabSpinnerField = mTabScrollView.getClass().getDeclaredField("mTabSpinner");
mTabSpinnerField.setAccessible(true);
Object mTabSpinner = mTabSpinnerField.get(mTabScrollView);
if (mTabSpinner == null) {
return;
}
Method setSelectionMethod = mTabSpinner.getClass().getSuperclass().getDeclaredMethod("setSelection", Integer.TYPE, Boolean.TYPE);
setSelectionMethod.invoke(mTabSpinner, position, animate);
Method requestLayoutMethod = mTabSpinner.getClass().getSuperclass().getDeclaredMethod("requestLayout");
requestLayoutMethod.invoke(mTabSpinner);
} catch (IllegalArgumentException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
} catch (NoSuchFieldException e) {
e.printStackTrace();
} catch (NoSuchMethodException e) {
e.printStackTrace();
} catch (InvocationTargetException e) {
e.printStackTrace();
}
}
围绕官方Android Bug这个黑客为我做了,上面的代码片段没有:/
答案 4 :(得分:0)
此实现适用于我(@ mohitum007的响应的修改版本):
public static void selectInSpinnerIfPresent(Object inActionBar,
int position, boolean animate) {
// get the ActionBar class
Class<?> actionBarClass = inActionBar.getClass();
// if it is a Jelly Bean implementation (ActionBarImplJB), get the super
// class (ActionBarImplICS)
if ("android.support.v7.app.ActionBarImplJB".equals(actionBarClass
.getName())) {
actionBarClass = actionBarClass.getSuperclass();
}
try {
// try to get the mActionBar field, because the current ActionBar is
// probably just a wrapper Class
// if this fails, no worries, this will be an instance of the native
// ActionBar class or from the ActionBarImplBase class
final Field actionBarField = actionBarClass
.getDeclaredField("mActionBar");
actionBarField.setAccessible(true);
inActionBar = actionBarField.get(inActionBar);
actionBarClass = inActionBar.getClass();
} catch (IllegalAccessException e) {
} catch (IllegalArgumentException e) {
} catch (NoSuchFieldException e) {
}
try {
Field mTabScrollViewField = actionBarClass
.getDeclaredField("mTabScrollView");
mTabScrollViewField.setAccessible(true);
Object mTabScrollView = mTabScrollViewField.get(inActionBar);
if (mTabScrollView == null) {
return;
}
Field mTabSpinnerField = mTabScrollView.getClass()
.getDeclaredField("mTabSpinner");
mTabSpinnerField.setAccessible(true);
Object mTabSpinner = mTabSpinnerField.get(mTabScrollView);
if (mTabSpinner == null) {
return;
}
Method setSelectionMethod = mTabSpinner
.getClass()
.getSuperclass()
.getDeclaredMethod("setSelection", Integer.TYPE,
Boolean.TYPE);
setSelectionMethod.invoke(mTabSpinner, position, animate);
Method requestLayoutMethod = mTabSpinner.getClass().getSuperclass()
.getDeclaredMethod("requestLayout");
requestLayoutMethod.invoke(mTabSpinner);
} catch (NoSuchMethodException | InvocationTargetException
| IllegalAccessException | IllegalArgumentException | NoSuchFieldException e) {
}
}