自定义 Android 对话框中的 EditText returns 空

Question

所以我根据 Android 开发者网站 (http://developer.android.com/guide/topics/ui/dialogs.html#CustomLayout) 上的当前指南创建了一个自定义对话框，并希望将用户输入从 EditText 传回 MainActivity；但事实证明 MainActivity 收到 null。我不明白为什么。

非常感谢任何帮助。

这是我的代码：

MainActivity.java

public class MainActivity extends AppCompatActivity implements NewItemFragment.NoticeDialogListener {

private final static String TAG = "tag";

RecyclerView recyclerView;
RecyclerView.LayoutManager manager;
RecyclerView.Adapter adapter;
FloatingActionButton fab;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    fab = (FloatingActionButton) findViewById(R.id.fab);

    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            NewItemFragment dialog = new NewItemFragment();
            dialog.show(getSupportFragmentManager(), "newitem");
        }
    });

    manager = new LinearLayoutManager(this);

    recyclerView = (RecyclerView) findViewById(R.id.recycler);
    recyclerView.setLayoutManager(manager);

    initialiseData();
    initialiseAdapter();
}

@Override
public void onDialogPositiveClick(DialogFragment dialogFragment) {
    LayoutInflater inflater = getLayoutInflater();
    View view = inflater.inflate(R.layout.new_item_dialog, null);
    EditText editText = (EditText) view.findViewById(R.id.newitem);
    String input = editText.getText().toString();
    EditText result = (EditText) findViewById(R.id.textedit);
    int i = entries.size();
    if (input.equals("")) {
        result.setText("Fail");
    } else {
        entries.add(new Items(input));
        adapter.notifyItemInserted(i + 1);
    }
}

@Override
public void onDialogNegativeClick(DialogFragment dialogFragment) {
}

}

NewItemFragment.java

public class NewItemFragment extends DialogFragment {

public interface NoticeDialogListener {
    public void onDialogPositiveClick(DialogFragment dialogFragment);
    public void onDialogNegativeClick(DialogFragment dialogFragment);
}

NoticeDialogListener listener;

@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);
    try {
        listener = (NoticeDialogListener) activity;
    } catch (ClassCastException e) {
        throw new ClassCastException(activity.toString()
            + " must implement NoticeDialogListener");
    }
}


@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
    final LayoutInflater inflater = getActivity().getLayoutInflater();
    final View view = inflater.inflate(R.layout.new_item_dialog, null);
    builder.setView(view)
            .setPositiveButton(R.string.add, new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    listener.onDialogPositiveClick(NewItemFragment.this);
                }
            })
            .setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() {
                @Override
                public void onClick(DialogInterface dialog, int which) {
                    NewItemFragment.this.getDialog().cancel();
                }
            });
    return builder.create();
}

}

最后 new_item_dialog.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:paddingTop="24dp"
    android:paddingStart="24dp"
    android:paddingEnd="24dp">
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="24sp"
        android:textColor="#000000"
        android:text="@string/new_item"
        android:layout_marginBottom="20dp"/>
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/newitem"
        android:hint="@string/hint"
        android:layout_marginBottom="24dp"/>
</LinearLayout>

谢谢，乔什

Answer 1

我会这样更改 NoticeDialogListener，因为您只需要 EditText

的内容

public interface NoticeDialogListener {
    public void onDialogPositiveClick(final String input);
    public void onDialogNegativeClick();
}

并且当 setPositiveButton 被调用时，

.setPositiveButton(R.string.add, new DialogInterface.OnClickListener() {
      @Override
      public void onClick(DialogInterface dialog, int which) {
           listener.onDialogPositiveClick( ((TextVew)view.findViewById(R.id.newitem)).getText().toStrig());
      }

自定义 Android 对话框中的 EditText returns 空

EditText in custom Android Dialog returns null

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