可以从对话框textview获取文本，但无法从对话框edittext获取文本

Posted 2021-04-18

我使用自定义DialogFragment和界面创建了一个对话框，以及将单击事件传递回对话框主机（MainActivity）的自定义布局。但是我的问题是，当我尝试在对话框中的EditText中输入文本时，它会以空字符串形式返回。有任何想法吗？我能够从对话框中的TextView获取文本，而不是EditText。

add_class_dialog.xml：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:padding="10dp">
    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center">
        <TextView
            android:id="@+id/viewClassName"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Class: "
            android:textSize="25sp"
            android:textColor="@color/textColor"/>
        <EditText
            android:id="@+id/editClassName"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:hint="Enter class"
            android:textSize="25sp"
            android:textColor="@color/textColor"
            android:layout_gravity="center"/>
    </LinearLayout>
</LinearLayout>

main activity.Java:

public class MainActivity extends FragmentActivity implements AddClassDialogFragment.AddClassDialogListener {

TextView nameView;
EditText editName;

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

    View vi = getLayoutInflater().inflate(R.layout.add_class_dialog, null);
    nameView = vi.findViewById(R.id.viewClassName);
    editName = vi.findViewById(R.id.editClassCredits);

}
public void addClass(View view) {
    AddClassDialogFragment acdf = new AddClassDialogFragment();
    acdf.show(getFragmentManager(), "ac");
}
@Override
public void onDialogPositiveClick(DialogFragment dialog) {
    Toast.makeText(this, nameView.getText().toString(), Toast.LENGTH_SHORT).show();
    Toast.makeText(this, editName.getText().toString(), Toast.LENGTH_SHORT).show();

}
@Override
public void onDialogNegativeClick(DialogFragment dialog) {
    Toast.makeText(this, "Cancel", Toast.LENGTH_SHORT).show();
}
}

add class dialog fragment.Java:

public class AddClassDialogFragment extends DialogFragment {
public interface AddClassDialogListener {
    void onDialogPositiveClick(DialogFragment dialog);
    void onDialogNegativeClick(DialogFragment dialog);
}
AddClassDialogListener mListener;

@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);
    try {
        mListener = (AddClassDialogListener) 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();
    builder.setView(inflater.inflate(R.layout.add_class_dialog, null));
    builder.setPositiveButton("Add", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialogInterface, int i) {
            mListener.onDialogPositiveClick(AddClassDialogFragment.this);
        }
    });
    builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialogInterface, int i) {
            mListener.onDialogNegativeClick(AddClassDialogFragment.this);
        }
    });
    return builder.create();
}
}

答案

您获得TextView值的原因是因为您在布局中对其进行了硬编码。 android:text="Class: "你的代码有几个问题。如果布局用于对话框，则不应在“活动”中对其进行充气。这是你想要实现它的方式。您无需在“活动”中夸大布局。应该在对话框中夸大布局，并且活动应该不知道该布局具有什么或做了什么。无论活动需要知道什么，都应该通过回调来实现。

package com.soulpatch.stackoverflow;

import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;

public class MainActivity extends FragmentActivity implements AddClassDialogFragment.AddClassDialogListener {
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    final AddClassDialogFragment acdf = new AddClassDialogFragment();
    acdf.show(getSupportFragmentManager(), "abc");
}

@Override
public void onDialogPositiveClick(TextView textView, EditText editText) {
    Toast.makeText(this, textView.getText(), Toast.LENGTH_SHORT).show();
    Toast.makeText(this, editText.getText() == null ? "" : editText.getText().toString(), Toast.LENGTH_SHORT).show();
}

@Override
public void onDialogNegativeClick(TextView textView, EditText editText) {
    Toast.makeText(this, textView.getText(), Toast.LENGTH_SHORT).show();
    Toast.makeText(this, editText.getText() == null ? "" : editText.getText().toString(), Toast.LENGTH_SHORT).show();
}
}

DialogFragment将通过您在此处声明的界面定义需要返回活动的内容。我已将其更改为采用TextView和EditText。您可以根据您的要求进行更改。

package com.soulpatch.stackoverflow;

import android.app.Activity;    
import android.app.AlertDialog;
import android.app.Dialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.support.v4.app.DialogFragment;
import android.view.LayoutInflater;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.TextView;

public class AddClassDialogFragment extends DialogFragment {
public interface AddClassDialogListener {
    void onDialogPositiveClick(TextView textView, EditText editText);

    void onDialogNegativeClick(TextView textView, EditText editText);
}

AddClassDialogListener mListener;

@Override
public void onAttach(Activity activity) {
    super.onAttach(activity);
    try {
        mListener = (AddClassDialogListener) 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 LinearLayout linearLayout = (LinearLayout) inflater.inflate(R.layout.add_class_dialog, null);
    final TextView textView = linearLayout.findViewById(R.id.viewClassName);
    final EditText editText = linearLayout.findViewById(R.id.editClassName);
    builder.setView(linearLayout);
    builder.setPositiveButton("Add", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialogInterface, int i) {
            mListener.onDialogPositiveClick(textView, editText);
        }
    });
    builder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialogInterface, int i) {
            mListener.onDialogNegativeClick(textView, editText);
        }
    });
    return builder.create();
}
}

另一答案

您刚刚为Edittext引用了错误的ID。

public class MainActivity extends FragmentActivity implements AddClassDialogFragment.AddClassDialogListener {

TextView nameView;
EditText editName;

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

    View vi = getLayoutInflater().inflate(R.layout.add_class_dialog, null);
    nameView = vi.findViewById(R.id.viewClassName);
    editName = vi.findViewById(R.id.editClassName);

}
public void addClass(View view) {
    AddClassDialogFragment acdf = new AddClassDialogFragment();
    acdf.show(getFragmentManager(), "ac");
}
@Override
public void onDialogPositiveClick(DialogFragment dialog) {
    Toast.makeText(this, nameView.getText().toString(), Toast.LENGTH_SHORT).show();
    Toast.makeText(this, editName.getText().toString(), Toast.LENGTH_SHORT).show();

}
@Override
public void onDialogNegativeClick(DialogFragment dialog) {
    Toast.makeText(this, "Cancel", Toast.LENGTH_SHORT).show();
}
}