在我的 android 应用程序中，我在选项卡中使用活动组，我也在维护先前屏幕的列表。问题是，如果我们在屏幕加载后立即按下，则不会调用 Backpress 方法并且应用程序会退出，而如果我在屏幕上延迟说 30 秒后做同样的事情，它会按预期工作。根本无法解决问题。已经调试了代码并注意到新屏幕已添加到堆栈列表中，但 backpress 方法本身不是调用。尝试在活动和选项卡组类中实现回压，但没有用。请让我知道我哪里出错了。我用来添加活动的代码是
Intent intent = new Intent(context, TrialActivity.class);
intent.putExtra("feedId", moreitems.get(arg2).getItem_id());
intent.putExtra("heading", moreitems.get(arg2).getItem_name());
TabGroupActivity parentActivity = (TabGroupActivity) ((Activity) context)
.getParent();
parentActivity.startChildActivity(moreitems.get(arg2).getItem_name()
+ Calendar.getInstance().getTimeInMillis(), intent);
MyTabgroup 类是
@SuppressWarnings("deprecation")
public class TabGroupActivity extends ActivityGroup {
private ArrayList<String> mIdList;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (mIdList == null)
mIdList = new ArrayList<String>();
}
@Override
protected void onPause()
{
super.onPause();
}
@Override
protected void onResume() {
// to start the first activity every time on reload( on focus of tab).
// remove the search activity if it is in the stack
if (mIdList != null && mIdList.size() > 0) {
int index = -1;
for (int i = 0; i < mIdList.size(); i++) {
String firstId = mIdList.get(i);
if (firstId != null
&& "search".equalsIgnoreCase(firstId.substring(0,
firstId.length() - 1))) {
index = i;
}
}
if (index != -1) {
LocalActivityManager manager = getLocalActivityManager();
manager.destroyActivity(mIdList.get(index), true);
mIdList.remove(index);
index--;
String lastId = mIdList.get(index);
Intent lastIntent = manager.getActivity(lastId).getIntent();
Window newWindow = manager.startActivity(lastId, lastIntent);
setContentView(newWindow.getDecorView());
}
}
super.onResume();
}
/**
* This is called when a child activity of this one calls its finish method.
* This implementation calls {@link LocalActivityManager#destroyActivity} on
* the child activity and starts the previous activity. If the last child
* activity just called finish(),this activity (the parent), calls finish to
* finish the entire group.
*/
@Override
public void finishFromChild(Activity child) {
LocalActivityManager manager = getLocalActivityManager();
int index = mIdList.size() - 1;
if (index < 1) {
Alerts.exit("Confirm",
"Do you really wish to exit from iDream Media?", this);
return;
}
manager.destroyActivity(mIdList.get(index), true);
mIdList.remove(index);
index--;
String lastId = mIdList.get(index);
Intent lastIntent = manager.getActivity(lastId).getIntent();
Window newWindow = manager.startActivity(lastId, lastIntent);
setContentView(newWindow.getDecorView());
}
/**
* Starts an Activity as a child Activity to this.
*
* @param Id
* Unique identifier of the activity to be started.
* @param intent
* The Intent describing the activity to be started.
* @throws android.content.ActivityNotFoundException.
*/
public void startChildActivity(String Id, Intent intent) {
Window window = getLocalActivityManager().startActivity(Id,
intent.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP));
if (window != null) {
mIdList.add(Id);
setContentView(window.getDecorView());
}
}
/**
* The primary purpose is to prevent systems before
* android.os.Build.VERSION_CODES.ECLAIR from calling their default
* KeyEvent.KEYCODE_BACK during onKeyDown.
*/
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
// onBackPressed();
// preventing default implementation previous to
// android.os.Build.VERSION_CODES.ECLAIR
return true;
}
return super.onKeyDown(keyCode, event);
}
/**
* Overrides the default implementation for KeyEvent.KEYCODE_BACK so that
* all systems call onBackPressed().
*/
@Override
public boolean onKeyUp(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
onBackPressed();
return true;
}
return super.onKeyUp(keyCode, event);
}
/**
* If a Child Activity handles KeyEvent.KEYCODE_BACK. Simply override and
* add this method.
*/
@Override
public void onBackPressed() {
int length = mIdList.size();
if (length > 1) {
Activity current = getLocalActivityManager().getActivity(
mIdList.get(length - 1));
current.finishFromChild(current);
}
}
}
请让我知道我哪里出错了。