Android Studio(Kotlin&XML)：RecyclerView卡片集成Switch及选中项同步至汇总页

需求概述 #

我正在开发一款医疗提醒App，核心流程与待实现功能如下：

1. 首页支持选择治疗类别
2. 进入对应类别页后，通过RecyclerView卡片内的Switch选择具体治疗项
3. 选中治疗项后，点击「医疗包」图标进入汇总页，需实现：
   • 开启Switch时，汇总页自动生成带对应治疗名称和颜色的卡片
   • 汇总页支持为每个治疗项设置提醒频率

项目资源 #

• 项目仓库：medminder-android
• 页面截图：
  • 首页：
  • 治疗页：
  • 汇总页：

分步实现方案 #

1. 定义数据模型与状态管理 #

首先统一治疗项的数据结构，确保跨页面数据一致性：

// 治疗项数据类，包含核心属性
data class TreatmentItem(
    val id: String,
    val name: String,
    val colorHex: String,
    var isSelected: Boolean = false,
    var reminderFrequency: Int = 0 // 可定义为小时/天单位，根据需求调整
)

使用全局ViewModel维护选中状态，实现跨页面实时同步：

class TreatmentViewModel : ViewModel() {
    private val _selectedTreatments = MutableLiveData<MutableList<TreatmentItem>>()
    val selectedTreatments: LiveData<MutableList<TreatmentItem>> = _selectedTreatments

    init {
        // 初始化时可加载本地存储数据（见下文持久化部分）
        _selectedTreatments.value = mutableListOf()
    }

    // 更新治疗项选中状态
    fun updateTreatmentSelection(item: TreatmentItem) {
        val currentList = _selectedTreatments.value ?: mutableListOf()
        if (item.isSelected) {
            currentList.add(item)
        } else {
            currentList.removeIf { it.id == item.id }
        }
        _selectedTreatments.postValue(currentList)
        // 同步保存到本地（见下文持久化部分）
        saveSelectedTreatments(currentList)
    }
}

2. 治疗页Switch状态绑定与监听 #

在治疗页的RecyclerView Adapter中，绑定Switch状态并同步到ViewModel：

class TreatmentAdapter(
    private val treatmentList: List<TreatmentItem>,
    private val viewModel: TreatmentViewModel
) : RecyclerView.Adapter<TreatmentAdapter.ViewHolder>() {

    inner class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        val card: CardView = itemView.findViewById(R.id.treatment_card)
        val nameTv: TextView = itemView.findViewById(R.id.treatment_name)
        val selectSwitch: Switch = itemView.findViewById(R.id.select_switch)
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        val view = LayoutInflater.from(parent.context).inflate(R.layout.item_treatment_card, parent, false)
        return ViewHolder(view)
    }

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        val item = treatmentList[position]
        // 绑定UI属性
        holder.card.setCardBackgroundColor(Color.parseColor(item.colorHex))
        holder.nameTv.text = item.name
        holder.selectSwitch.isChecked = item.isSelected

        // 监听Switch状态变化
        holder.selectSwitch.setOnCheckedChangeListener { _, isChecked ->
            item.isSelected = isChecked
            viewModel.updateTreatmentSelection(item)
        }
    }

    override fun getItemCount() = treatmentList.size
}

3. 汇总页实时展示与频率设置 #

在汇总页监听ViewModel的LiveData，实时更新RecyclerView：

class SummaryActivity : AppCompatActivity() {
    private lateinit var viewModel: TreatmentViewModel
    private lateinit var adapter: SummaryAdapter

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_summary)
        viewModel = ViewModelProvider(this)[TreatmentViewModel::class.java]
        initRecyclerView()
        observeSelectedTreatments()
    }

    private fun observeSelectedTreatments() {
        viewModel.selectedTreatments.observe(this) { items ->
            adapter.updateItems(items)
        }
    }

    private fun initRecyclerView() {
        adapter = SummaryAdapter(mutableListOf()) { item, newFrequency ->
            // 更新治疗项的提醒频率
            item.reminderFrequency = newFrequency
            viewModel.updateTreatmentSelection(item)
        }
        findViewById<RecyclerView>(R.id.summary_recycler).apply {
            adapter = this@SummaryActivity.adapter
            layoutManager = LinearLayoutManager(this@SummaryActivity)
        }
    }
}

汇总页Adapter实现频率设置功能：

class SummaryAdapter(
    private var items: MutableList<TreatmentItem>,
    private val onFrequencyChanged: (TreatmentItem, Int) -> Unit
) : RecyclerView.Adapter<SummaryAdapter.ViewHolder>() {

    fun updateItems(newItems: MutableList<TreatmentItem>) {
        items = newItems
        notifyDataSetChanged()
    }

    inner class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        val card: CardView = itemView.findViewById(R.id.summary_card)
        val nameTv: TextView = itemView.findViewById(R.id.treatment_name)
        val frequencySpinner: Spinner = itemView.findViewById(R.id.frequency_spinner)
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        val view = LayoutInflater.from(parent.context).inflate(R.layout.item_summary_card, parent, false)
        return ViewHolder(view)
    }

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        val item = items[position]
        holder.card.setCardBackgroundColor(Color.parseColor(item.colorHex))
        holder.nameTv.text = item.name

        // 绑定频率选择器
        holder.frequencySpinner.setSelection(item.reminderFrequency)
        holder.frequencySpinner.onItemSelectedListener = object : AdapterView.OnItemSelectedListener {
            override fun onItemSelected(parent: AdapterView<*>?, view: View?, position: Int, id: Long) {
                onFrequencyChanged(item, position)
            }
            override fun onNothingSelected(parent: AdapterView<*>?) {}
        }
    }

    override fun getItemCount() = items.size
}

4. 持久化存储（可选但推荐） #

避免App重启后数据丢失，将选中项序列化存储到SharedPreferences：

// 保存选中项到本地
fun saveSelectedTreatments(items: List<TreatmentItem>) {
    val gson = Gson()
    val json = gson.toJson(items)
    getSharedPreferences("MedMinderPrefs", Context.MODE_PRIVATE)
        .edit()
        .putString("selected_treatments", json)
        .apply()
}

// 从本地加载选中项
fun loadSelectedTreatments(context: Context): List<TreatmentItem> {
    val json = context.getSharedPreferences("MedMinderPrefs", Context.MODE_PRIVATE)
        .getString("selected_treatments", "")
    return if (json.isNullOrEmpty()) {
        emptyList()
    } else {
        Gson().fromJson(json, object : TypeToken<List<TreatmentItem>>() {}.type)
    }
}

在ViewModel初始化时加载本地数据：

init {
    val savedItems = loadSelectedTreatments(context).toMutableList()
    _selectedTreatments.value = savedItems
}

内容的提问来源于stack exchange，提问作者MobileMilin