android - 如何监听 SwitchPreferenceCompat 变化

Question

我正在尝试将 onCLick 监听器添加到我的 PreferenceScreen 上的开关，但它不起作用。我尝试了 Java 教程中的代码并将其转换为 Kotlin，但由于某种原因它无法正常工作。

这是我的 AdbSettingsFragment:

package com.wrssmithjr04.systemuituner

import android.content.SharedPreferences.OnSharedPreferenceChangeListener
import android.os.Bundle
import android.util.Log
import androidx.preference.Preference
import androidx.preference.PreferenceFragmentCompat


class AdbSettingsFragment : PreferenceFragmentCompat() {

    private val key1 = "adb_switch"

    private var preferenceChangeListener: OnSharedPreferenceChangeListener? = null

    override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
        setPreferencesFromResource(R.xml.adb_prefs, rootKey)

        preferenceChangeListener =
            OnSharedPreferenceChangeListener { sharedPreferences, key ->
                if (rootKey == key1) {
                    Log.d("Test", rootKey)
                    val adbPref = findPreference<Preference>(key)
                    // Doesn't get to this part
                    Log.d("Test", key1 + "was pressed")
                }
            }
    }

    override fun onResume() {
        super.onResume()
        preferenceScreen.sharedPreferences
            .registerOnSharedPreferenceChangeListener(preferenceChangeListener)
    }

    override fun onPause() {
        super.onPause()
        preferenceScreen.sharedPreferences
            .unregisterOnSharedPreferenceChangeListener(preferenceChangeListener)
    }

}

感谢您的帮助!

Answer 1

我不知道你为什么要检查 key1 和 rootKey 是否相等。然而，更好的模式是先检查首选项的类型(导致隐式智能转换)，然后检查其键:

preferenceChangeListener = OnSharedPreferenceChangeListener { sharedPreferences, key ->
    val preference = findPreference<Preference>(key)
    when (preference) {
        is SwitchPreferenceCompat -> {
            if (key == "adb_switch") {
                Log.d("Test", "${preference.key} : ${preference.isChecked}")
            }
        }
        is CheckBoxPreference -> {
            // do sth else
        }
        is ListPreference -> {
            // do sth else
        }
    }
}