将变量从Dialog传递到Listview片段

Question

我正在制作一个由IP地址组成的Listview片段，用户将被提示通过对话框输入，该对话框将在按下+按钮时弹出。

我想提取用户在对话框中引入的edittext的值，并使用它来填充"main"片段的Listview。

问题是，我要么有范围问题，要么有Logcat错误，比如：

java.lang.NullPointerException：尝试调用虚拟方法'android.view.Viewandroid.vview.view.findViewById(int(在null上目标参考

我有两个类：

UserSettings.java

包含一个带有硬编码测试字符串的列表视图，两个按钮(其中一个调用方法openDialog(

public class UserSettings extends Fragment implements SettingsIPDialog.IPDialogListener {
private static final String TAG = "UserSettings";
Context context;

UserSettings(Context ctx) {
context = ctx;
}
private ImageButton addIP_button;
private ImageButton notification_button;
SwipeMenuListView listView;
ArrayList<String> list;
@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.fragment_settings, container, false);
listView = v.findViewById(R.id.listView);
addIP_button = v.findViewById(R.id.imageButton_AddIP);
notification_button = v.findViewById(R.id.imageButton_modifySettings);
String IPnumber ="AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA";
if(settingsIPDialog != null) {
IPnumber = ((EditText) settingsIPDialog.getView().findViewById(R.id.edit_ip_address)).getText().toString();
}
System.out.println(IPnumber);
list = new ArrayList<>();
list.add("IP1");
list.add("IP2");
list.add("IP3");
list.add("IP4");
list.add("IP6");
list.add("IP7");
list.add("IP8");

final ArrayAdapter adapter = new ArrayAdapter(context, android.R.layout.simple_list_item_1, list);
listView.setAdapter(adapter);
SwipeMenuCreator creator = new SwipeMenuCreator() {
@Override
public void create(SwipeMenu menu) {
//Open :
SwipeMenuItem openItem = new SwipeMenuItem(context);
//Set item background
openItem.setBackground(new ColorDrawable(Color.GRAY));
//Set item width
openItem.setWidth(200);
//Set item title
openItem.setTitle("Modifier");
//Set item titlesize
openItem.setTitleSize(18);
//Set item titlecolour
openItem.setTitleColor(Color.BLACK);
//Add to menu :
menu.addMenuItem(openItem);
//Create "delete" item
SwipeMenuItem deleteItem = new SwipeMenuItem(context);
//set item background
deleteItem.setBackground(new ColorDrawable(Color.rgb(0xF9, 0x3F, 0x25)));
//set item width
deleteItem.setWidth(200);
deleteItem.setIcon(R.drawable.ic_delete);
//Add to menu :
menu.addMenuItem(deleteItem);
}
};
listView.setMenuCreator(creator);
listView.setOnMenuItemClickListener(new SwipeMenuListView.OnMenuItemClickListener() {
@Override
public boolean onMenuItemClick(int position, SwipeMenu menu, int index) {
switch (index) {
case 0:
Log.d(TAG, "onMenuItemClick: clicked item " + index);
break;
case 1:
Log.d(TAG, "onMenuItemClick: clicked item " + index);
break;
}
// false : close the menu; true : not close the menu
return false;
}
});
addIP_button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
openDialog();
}
});
notification_button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
openDialog2();
}
});

return v;

}
SettingsIPDialog settingsIPDialog;
public void openDialog() {
settingsIPDialog = new SettingsIPDialog();
settingsIPDialog.show(getFragmentManager(), "Ajouter un serveur");
String IPnumber ="bbbbbbbbbbbbbbbbbbbbb";
if(settingsIPDialog != null) {
System.out.println(IPnumber);
IPnumber = ((EditText) settingsIPDialog.getView().findViewById(R.id.edit_ip_address)).getText().toString(); //ERROR ORIGINATING FRO
settingsIPDialog.getDialog().findViewById(R.id.edit_ip_address);
}
ArrayAdapter adapter = new ArrayAdapter(context, android.R.layout.simple_list_item_1, list);
listView.setAdapter(adapter);
}
public void openDialog2() {
SettingsIPDialog2 settingsIPDialog2 = new SettingsIPDialog2();
settingsIPDialog2.show(getFragmentManager(), "Paramètres");
}

@Override
public void applyIP(String IPnumber, String IPname) {
}}

另一个包含对话框本身的：

设置PDialog.java

public class SettingsIPDialog extends AppCompatDialogFragment {
private EditText editTextIPNum;
private EditText editTextIPname;
private SettingsIPDialog listener;

@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
android.support.v7.app.AlertDialog.Builder builder = new android.support.v7.app.AlertDialog.Builder(getActivity());
LayoutInflater inflater = getActivity().getLayoutInflater();
View view = inflater.inflate(R.layout.layout_dialog_ip, null);
builder.setView(view).setTitle("Ajouter une adresse IP").setNegativeButton("Annuler", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
}
})
.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int which) {
String IPnumber = editTextIPNum.getText().toString();
String IPname = editTextIPname.getText().toString();

}
});
editTextIPNum = view.findViewById(R.id.edit_ip_address);
editTextIPname = view.findViewById(R.id.edit_ip_name);
return builder.create();
}
@Override
public void onAttach(Context context) {
super.onAttach(context);
try {
//listener = (IPDialogListener)context;
} catch (ClassCastException e) {
throw new ClassCastException(context.toString() + "Il faut implémenter IPDialogListener");
}
}

public interface IPDialogListener {
void applyIP(String IPnumber, String IPname);
}
}

正如你所知，我是一个完全的Java初学者，这是我通过拼凑我在互联网上发现的3个不同的例子来完成的。

非常感谢你的阅读和你愿意给我的任何帮助。

编辑：

layout_dialog_ip

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="match_parent"
android:padding="16dp">
<EditText
android:id="@+id/edit_ip_address"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Adresse IP" />
<EditText
android:id="@+id/edit_ip_name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentStart="true"
android:layout_below="@+id/edit_ip_address"
android:hint="Nom du serveur"
android:inputType="text" />
</RelativeLayout>

layout_fragment_settings

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/frameLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".UserSettings">

<ImageButton
android:id="@+id/imageButton_modifySettings"
android:layout_width="46dp"
android:layout_height="49dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:src="@drawable/ic_settings_ip"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toStartOf="@+id/imageButton_AddIP"
app:layout_constraintHorizontal_bias="0.03"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="1.0" />
<ImageButton
android:id="@+id/imageButton_AddIP"
android:layout_width="46dp"
android:layout_height="49dp"
android:layout_marginBottom="8dp"
android:layout_marginEnd="8dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
android:layout_marginStart="8dp"
android:layout_marginTop="8dp"
android:src="@android:drawable/ic_input_add"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="1.0"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="1.0" />
<com.baoyz.swipemenulistview.SwipeMenuListView
android:id="@+id/listView"
android:layout_width="392dp"
android:layout_height="514dp"
app:layout_constraintDimensionRatio="1:1"
tools:layout_editor_absoluteX="0dp"
tools:layout_editor_absoluteY="0dp">
</com.baoyz.swipemenulistview.SwipeMenuListView>
</android.support.constraint.ConstraintLayout>

Answer 1

AppCompatDialogFragment继承自Fragment，因此这基本上是一个嵌套片段，形式为DialogFragment。您可以有一个接口，并在"父"片段上实现它。我不想说太多细节，因为这里已经全部解释了。这通常被称为事件回调。链接答案的道具：(