5
我正在学习Android Studio中的原型，并且我遇到了一个我似乎无法找到答案的障碍。从活动AlertDialog添加到片段ArrayAdapter
我有一个活动，显示一个自定义ArrayAdapter作为ListView。我可以编辑ListView中的项目，方法是单击它们并键入AlertDialog。还有一个我可以按下的添加按钮，它带来了一个类似的AlertDialog，但是当我保存时没有任何东西被添加到ListView中。如何让AlertDialog文本输入保存为新的ArrayAdapter项目？
我发现的大多数例子都直接在Activity中实例化了ArrayAdapter，而不是像我做过的那样通过Fragment。
MainActivity.java
public class MainActivity extends AppCompatActivity {
private static final String TAG = "MainActivity";
@Override
protected void onCreate(Bundle savedInstanceState) { //initialize the activity
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main); //establish where the layout will come from
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); //creates a toolbar
setSupportActionBar(toolbar);
if (findViewById(R.id.fragment_container) != null) {
if (savedInstanceState != null) {
return;
}
//creates the first fragment dynamically, so it can be replaced
Fragment firstFragment = new MainActivityFragment();
firstFragment.setArguments(getIntent().getExtras());
getSupportFragmentManager().beginTransaction()
.add(R.id.fragment_container, firstFragment).commit();
}
//This creates the Floating Action Button
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
createDialog();
}
private void createDialog() {
ArrayList<User> users = new ArrayList<User>();
// create an AlertDialog that'll come up when the add button is clicked
AlertDialog.Builder alertDialog = new AlertDialog.Builder(MainActivity.this);
// set title
alertDialog.setTitle("Add item");
final EditText input = new EditText(MainActivity.this); //uses the EditText from dialog_set
input.setInputType(InputType.TYPE_CLASS_TEXT); //makes the dialog ask for plain text input
alertDialog.setView(input);
// set up buttons
alertDialog.setPositiveButton("Save", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
String textInput = input.getText().toString(); //saves user text as a string
Log.d(TAG, textInput); // records input as a log
CustomUsersAdapter.this.add(textInput);
}
});
alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
// show it
alertDialog.show();
}
});
}
MainActivityFragment.java
public class MainActivityFragment extends Fragment {
@BindView(R.id.lvUsers) ListView listView;
public MainActivityFragment() {
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_main, container, false);
ButterKnife.bind(this, view);
ArrayList<User> arrayOfUsers = new ArrayList<User>();
arrayOfUsers.add(new User("Person 1", "Hometown 1"));
arrayOfUsers.add(new User("Person 2", "Hometown 2"));
arrayOfUsers.add(new User("Person 3", "Hometown 3"));
arrayOfUsers.add(new User("Person 4", "Hometown 4"));
arrayOfUsers.add(new User("Person 5", "Hometown 5"));
// Create the adapter to convert the array to views
CustomUsersAdapter adapter = new CustomUsersAdapter(getContext(), arrayOfUsers);
// Attach the adapter to a ListView
listView.setAdapter(adapter);
return view;
}
CustomUsersAdapter.java
public class CustomUsersAdapter extends ArrayAdapter<User> {
private ArrayList<User> users;
public CustomUsersAdapter(Context context, ArrayList<User> users) {
super(context, 0, users);
this.users = users;
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
// Get the data item for this position
User user = getItem(position);
// Check if an existing view is being reused, otherwise inflate the view
if (convertView == null) {
convertView = LayoutInflater.from(getContext()).inflate(R.layout.item_user, parent, false);
}
// Lookup view for data population
TextView tvName = (TextView) convertView.findViewById(R.id.tvName);
TextView tvHome = (TextView) convertView.findViewById(R.id.tvHometown);
// Populate the data into the template view using the data object
tvName.setText(user.name);
tvHome.setText(user.hometown);
convertView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
createDialog(position);
}
});
// Return the completed view to render on screen
return convertView;
}
protected void add(String textInput) {
add(new User(textInput, "Incomplete"));
}
private void createDialog(final int position) {
// create an AlertDialog that'll come up when text is clicked
AlertDialog.Builder alertDialog = new AlertDialog.Builder(
getContext());
// set title
alertDialog.setTitle("Edit item");
final EditText input = new EditText(getContext()); //uses the EditText from dialog_set
input.setInputType(InputType.TYPE_CLASS_TEXT); //makes the dialog ask for plain text input
alertDialog.setView(input);
// set up buttons
alertDialog.setPositiveButton("Save", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
String textInput = input.getText().toString(); //saves user text as a string
users.get(position).name = textInput;
notifyDataSetChanged();
}
});
alertDialog.setNeutralButton("Complete", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
users.get(position).hometown = "Complete";
notifyDataSetChanged();
}
});
alertDialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
dialog.cancel();
}
});
// show it
alertDialog.show();
}
ListView的布局（从fragment_main.xml）
<ListView
android:id="@+id/lvUsers"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_alignParentLeft="true"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true" >
</ListView>
'我可以通过单击它们来编辑ArrayAdapter中的项目。不可能。数组适配器不是gui元素，没有视图，因此不可点击。请重新说明。 – greenapps
是否有一个原因，你在活动中的FAB与片段？ – BlackHatSamurai
@greenapps，我改了一下措辞 - 现在更清楚了吗？ – songbird813