我遇到了一些障碍.我的场景非常类似于
DialogFragment – retaining listener after screen rotation所描述的场景
建议的解决方案适用于作者,因为他的对话框是从活动中调用的.我的情况完全相同,但我的自定义对话框是从片段而不是活动调用的. (IE Activity-> Fragment-> Dialog)
我实现了相同的解决方案(从调用Fragment设置onResume中的监听器)但在这种情况下它不起作用.
似乎正在发生的事情是,当屏幕旋转时,Android会杀死对话框和片段.然后按顺序重新创建它们.因此,当在我的自定义对话框中调用onCreateDialog时,包含片段尚未重新创建,因此它为侦听器设置为正和负按钮时为null.
有没有人知道这方面的方法？
如果有人认为有必要,我可以发布代码,但它与链接线程上的代码几乎相同.
更新代码：
public class RecipeDetailEditFragment extends SherlockFragment implements DialogInterface.OnClickListener {
private EditStepFragmentDialog stepDialog;
private Recipe newRecipe; //main data object implements parcelable
...
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
...
stepDialog = EditStepFragmentDialog.newInstance(newRecipe);
//I've also tried passing 'this' into the newInstance constructor and
//setting the listener there,but that doesn't work either
}
public void onResume() {
stepDialog.setListener(this);
super.onResume();
}
...
}
public class EditStepFragmentDialog extends DialogFragment {
private DialogInterface.OnClickListener ocl;
private static final String ARG_RECIPE = "recipe";
private Recipe recipe;
public EditStepFragmentDialog() {}
public static EditStepFragmentDialog newInstance(Recipe rec) { //(Recipe rec,DialogInterface.OnClickListener oc) as mentioned doesn't work.
EditStepFragmentDialog dia = new EditStepFragmentDialog();
Bundle args = new Bundle();
args.putParcelable(ARG_RECIPE,rec);
//dia.setListener(oc);
return dia;
}
public Dialog onCreateDialog(Bundle savedInstanceState) {
AlertDialog.Builder adb = new AlertDialog.Builder(getActivity());
if (getArguments().containsKey(ARG_RECIPE)) {
recipe = (Recipe) getArguments().getParcelable(ARG_RECIPE);
}
...
adb.setPositiveButton("Done",ocl);
adb.setNegativeButton("Cancel",ocl);
...
return adb.create();
}
public void setListener(DialogInterface.OnClickListener cl) {
ocl = cl;
}
}
解决方法
我查看了所讨论链接的所有选项,但没有一个解决方案最终为我工作.在进一步使用go / setTargetFragment和FragmentManager.put / getFragment之后,我还尝试了许多其他选项.这些对我来说也不起作用.然后我再看看：
http://developer.android.com/training/basics/fragments/communicating.html
他们特别说“两片碎片不应该直接沟通”.我认为这是真正证明是真实的案例之一.
我最终实现了那里提供的建议回调机制,并最终得到了这个：
在DialogFragment中：
public interface OnEditStepDialogListener {
public void onEditStepDialogPositive(int pos,String description);
}
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
mCallback = (OnEditStepDialogListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString() + " must implement OnEditStepDialogListener");
}
}
在托管活动中：
public class MyActivity extends SherlockFragmentActivity implements EditStepFragmentDialog.OnEditStepDialogListener {
...
@Override
public void onEditStepDialogPositive(int pos,String desc) {
FragmentManager fm = getSupportFragmentManager();
RecipeDetailEditFragment ef = (RecipeDetailEditFragment)fm.findFragmentByTag(RecipeDetailEditFragment.TAG);
ef.applyStepEdit(pos,desc);
}
在片段中,它会触发FragmentDialog：
public static final String TAG = "tag1";
public void applyStepEdit(int pos,String description) {
...
}
这很好用,如果打开然后方向更改和编辑完成,它实际上会触发我需要在调用Fragment中运行的最终函数,而不是崩溃或不执行任何操作(null侦听器).