Java 如何从片段请求数据到活动在主要活动中单击按钮请求数据

是的，onAttachFragment从Android 9中被弃用，您可以使用其他方法来实现类似的功能，具体取决于代码的上下文.但到目前为止，这不是必需的，因为您没有进行任何片段转换.

方法1

通过使用公共职能

ConversationFragment.java:

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.EditText;

import androidx.fragment.app.Fragment;

public class ConversationFragment extends Fragment {

    private EditText editText;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_conversation, container, false);

        // Initialize EditText
        editText = view.findViewById(R.id.editText);

        return view;
    }

    public String getEditTextValue() {
        return editText.getText().toString();
    }
}

MainActivity.java:

import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;

import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

    private ConversationFragment conversationFragment;

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

        // Initialize the fragment
        conversationFragment = new ConversationFragment();

        // Add the fragment to the container
        getSupportFragmentManager().beginTransaction()
                .add(R.id.fragment_container, conversationFragment)
                .commit();

        // Initialize Button
        Button button = findViewById(R.id.button);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // Get EditText value from the Fragment
                String editTextValue = conversationFragment.getEditTextValue();
                onDataReceivedFromFragment(editTextValue);
            }
        });
    }

    public void onDataReceivedFromFragment(String data) {
        // Process the received data here
        Log.d("Data received in Activity", data);
    }
}

方法2

通过使用界面

ConversationFragment.java:

    import android.os.Bundle;
    import android.view.LayoutInflater;
    import android.view.View;
    import android.view.ViewGroup;
    import android.widget.EditText;

    import androidx.fragment.app.Fragment;

    public class ConversationFragment extends Fragment {

        private EditText editText;
        private EditTextValueListener listener;

        public interface EditTextValueListener {
            void onEditTextValueChanged(String value);
        }

        public void setEditTextValueListener(EditTextValueListener listener) {
            this.listener = listener;
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                Bundle savedInstanceState) {
            View view = inflater.inflate(R.layout.fragment_conversation, container, false);

            // Initialize EditText
            editText = view.findViewById(R.id.editText);

            return view;
        }

        private void sendDataToActivity(String data) {
            if (listener != null) {
                listener.onEditTextValueChanged(data);
            }
        }

        public void sendDataToActivity() {
            String data = editText.getText().toString();
            sendDataToActivity(data);
        }
    }

MainActivity.java:

    import android.os.Bundle;
    import android.util.Log;
    import android.view.View;
    import android.widget.Button;

    import androidx.appcompat.app.AppCompatActivity;

    public class MainActivity extends AppCompatActivity implements ConversationFragment.EditTextValueListener {

        private ConversationFragment conversationFragment;

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

            // Initialize the fragment
            conversationFragment = new ConversationFragment();

            // Add the fragment to the container
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.fragment_container, conversationFragment)
                    .commit();

            // Initialize Button
            Button button = findViewById(R.id.button);
            button.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    // Call method in Fragment to send EditText value
                    conversationFragment.sendDataToActivity();
                }
            });
        }

        @Override
        public void onEditTextValueChanged(String value) {
            // Process the received data here
            Log.d("Data received in Activity", value);
        }
    }

确保您也相应更新布局文件(fragment_conversation.html和activity_main.html).