在Java Fragment中集成并控制Jetpack Compose对话框

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <!-- 其他传统布局元素 -->
    <!-- ... -->

    <!-- 用于承载Compose对话框的隐藏ComposeView -->
    <androidx.compose.ui.platform.ComposeView
        android:id="@+id/compose_dialog_host"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.compose.runtime.State;
import androidx.compose.runtime.livedata.observeAsState; // 用于LiveData与Compose的互操作
import androidx.compose.ui.platform.ComposeView;
import androidx.fragment.app.Fragment;
import androidx.lifecycle.MutableLiveData; // 用于Java Fragment管理Compose对话框状态

import kotlin.Unit; // Kotlin Unit类型，用于Java中调用Kotlin Lambda
import kotlin.jvm.functions.Function0; // Kotlin无参数Lambda的Java接口

// 假设您有一个Kotlin文件ComposeDialogs.kt，其中定义了MyAlertDialog Composable
// Kotlin编译器会为顶层函数生成一个静态类，例如 ComposeDialogsKt
// import com.yourpackage.ComposeDialogsKt;

public class MyJavaFragment extends Fragment {

    private ComposeView composeDialogHost;
    // 使用MutableLiveData来作为Compose对话框的可见性状态
    // Fragment可以通过setValue()更新它，Compose可以通过observeAsState()观察它
    private MutableLiveData<Boolean> showComposeDialog = new MutableLiveData<>(false);

    private static final int REQUEST_CODE_EXAMPLE = 1001; // 示例请求码

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_your, container, false);
        composeDialogHost = view.findViewById(R.id.compose_dialog_host);
        return view;
    }

    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        // 设置ComposeView的内容
        composeDialogHost.setContent(
            () -> {
                // 在Compose中，通过observeAsState()将LiveData转换为Compose的State
                // 当LiveData的值变化时，Composable会自动重组
                State<Boolean> showDialogState = showComposeDialog.observeAsState(false);

                if (Boolean.TRUE.equals(showDialogState.getValue())) {
                    // 调用您的Compose对话框 Composable
                    // MyAlertDialog是Kotlin中定义的Composable函数
                    // onDismissRequest是一个Lambda，用于在对话框关闭时更新状态
                    ComposeDialogsKt.MyAlertDialog(
                        "操作确认",
                        "您确定要执行此操作吗？",
                        new Function0<Unit>() { // 使用Function0接口来表示Kotlin的无参数Lambda
                            @Override
                            public Unit invoke() {
                                showComposeDialog.setValue(false); // 关闭对话框
                                return Unit.INSTANCE; // Kotlin Lambda需要返回Unit.INSTANCE
                            }
                        }
                    );
                }
                return Unit.INSTANCE; // setContent Lambda需要返回Unit.INSTANCE
            }
        );

        // 示例：在某个操作后显示对话框 (例如，点击事件)
        // 您可以根据实际需求在这里添加按钮或其他触发器
        // Button myButton = view.findViewById(R.id.my_button);
        // myButton.setOnClickListener(v -> showComposeDialog.setValue(true));

        // 示例：启动一个Activity并等待结果
        // Intent intent = new Intent(getActivity(), SomeOtherActivity.class);
        // startActivityForResult(intent, REQUEST_CODE_EXAMPLE);
    }

    // 示例：在onActivityResult中根据结果显示Compose对话框
    @Override
    public void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == REQUEST_CODE_EXAMPLE && resultCode == Activity.RESULT_OK) {
            // 当接收到特定结果时，触发显示Compose对话框
            showComposeDialog.setValue(true);
        }
    }
}

package com.yourpackage // 确保包名与Java Fragment的引用一致

import androidx.compose.material3.AlertDialog
import androidx.compose.material3.Text
import androidx.compose.material3.Button
import androidx.compose.runtime.Composable
import androidx.compose.ui.tooling.preview.Preview

/**
 * 一个简单的Jetpack Compose风格的对话框。
 *
 * @param title 对话框的标题。
 * @param message 对话框中显示的消息。
 * @param onDismissRequest 当对话框需要被关闭时调用的回调。
 */
@Composable
fun MyAlertDialog(
    title: String,
    message: String,
    onDismissRequest: () -> Unit // Kotlin的无参数Lambda
) {
    AlertDialog(
        onDismissRequest = onDismissRequest, // 用户点击对话框外部或按返回键时触发
        title = { Text(text = title) },
        text = { Text(text = message) },
        confirmButton = {
            Button(onClick = onDismissRequest) {
                Text("确定")
            }
        },
        dismissButton = {
            Button(onClick = onDismissRequest) {
                Text("取消")
            }
        }
    )
}

@Preview(showBackground = true)
@Composable
fun PreviewMyAlertDialog() {
    // 预览Compose对话框，不实际显示，仅用于设计时查看
    MyAlertDialog(
        title = "预览标题",
        message = "这是一个预览消息。",
        onDismissRequest = {}
    )
}