如何使用新的Android-xapi从当前的PreferenceFragment打开一个新的PreferenceFragment?

你在1)中尝试的方法是正确的,但你不应该使用 <PreferenceScreen>

您的XML资源应该如下所示:

<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">

    <Preference
        app:key="screen_preference" 
        app:summary="Shows another screen of preferences"
        app:title="Screen preference"
        app:fragment="com.example.user.myapplication.MainActivity$PrefsFragment2"/>

</PreferenceScreen>

另外,如果您使用的首选项版本早于 androidx.preference:preference:1.1.0-alpha01 ,则需要实现onPreferenceStartFragment来处理片段事务(在1.1.0 alpha01中,此方法有一个默认实现,但仍鼓励您使用自己的实现自定义任何动画/过渡)

这应该看起来像:

override fun onPreferenceStartFragment(
        caller: PreferenceFragmentCompat,
        pref: Preference
): Boolean {
    // Instantiate the new Fragment
    val args = pref.extras
    val fragment = supportFragmentManager.fragmentFactory.instantiate(
            classLoader,
            pref.fragment,
            args
    ).apply {
        arguments = args
        setTargetFragment(caller, 0)
    }
    // Replace the existing Fragment with the new Fragment
    supportFragmentManager.beginTransaction()
            .replace(R.id.settings, fragment)
            .addToBackStack(null)
            .commit()
    return true
}

Settings 指导 以及 AndroidX Preference Sample

here .

here ) :

主要活动.kt

class MainActivity : AppCompatActivity(), PreferenceFragmentCompat.OnPreferenceStartFragmentCallback {
    override fun onPreferenceStartFragment(caller: PreferenceFragmentCompat, pref: Preference): Boolean {
        //Note: this whole function won't be needed when using new version of fragment dependency (1.1.0 and above)
        val fragment = Fragment.instantiate(this, pref.fragment, pref.extras)
        fragment.setTargetFragment(caller, 0)
        supportFragmentManager.beginTransaction().replace(android.R.id.content, fragment).addToBackStack(null).commit()
        return true
    }

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        supportActionBar!!.setDisplayHomeAsUpEnabled(true)
        if (savedInstanceState == null)
            supportFragmentManager.beginTransaction().replace(android.R.id.content, PrefsFragment()).commit()
    }

    class PrefsFragment : PreferenceFragmentCompat() {
        override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
            setPreferencesFromResource(R.xml.preferences, rootKey)
        }
    }

    class PrefsFragment2 : PreferenceFragmentCompat() {
        override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
            setPreferencesFromResource(R.xml.preferences2, null)
        }
    }
}

首选项.xml

  <PreferenceScreen xmlns:app="http://schemas.android.com/apk/res-auto">

    <Preference
      app:fragment="com.example.user.myapplication.MainActivity$PrefsFragment2" app:key="screen_preference" app:summary="Shows another screen of preferences"
      app:title="Screen preference"/>

  </PreferenceScreen>

首选项2.xml

<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" android:title="Demo">

  <PreferenceCategory android:title="Category">
    <CheckBoxPreference
      android:key="next_screen_checkbox_preference" android:summary="AAAA" android:title="Toggle preference"/>
  </PreferenceCategory>

</PreferenceScreen>

渐变相关性:

implementation 'androidx.appcompat:appcompat:1.0.2'
implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
implementation 'androidx.preference:preference:1.0.0'

好吧,我找到了两个可能的,但很奇怪的解决方案。

解决方案1

在主设置首选项XML文件中,为每个子 PreferenceScreen Preference 标签。

首选项.xml

<PreferenceScreen
    android:key="screen_preference" android:summary="Shows another screen of preferences"
    android:title="Screen preference">
    <Preference/>
</PreferenceScreen>

我将的第二个参数传递null setPreferencesFromResource

以下是代码(项目可用) here ) :

class MainActivity : AppCompatActivity(), PreferenceFragmentCompat.OnPreferenceStartScreenCallback {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        supportActionBar!!.setDisplayHomeAsUpEnabled(true)
        if (savedInstanceState == null)
            supportFragmentManager.beginTransaction().replace(android.R.id.content, PrefsFragment()).commit()
    }

    override fun onPreferenceStartScreen(caller: PreferenceFragmentCompat, pref: PreferenceScreen): Boolean {
        supportFragmentManager.beginTransaction().replace(android.R.id.content, PrefsFragment2()).addToBackStack(null).commit()
        return true
    }

    class PrefsFragment : PreferenceFragmentCompat() {
        override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
            setPreferencesFromResource(R.xml.preferences, rootKey)
        }
    }

    class PrefsFragment2 : PreferenceFragmentCompat() {
        override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
            setPreferencesFromResource(R.xml.preferences2, null)
        }
    }
}

当然,这需要修改,以便您知道要创建和添加哪个片段。。。

解决方案2

我用普通的 而不是每个 ,对于每一个,我选择在单击时添加片段(项目可用) here

首选项.xml

<Preference
    android:key="screen_preference" android:summary="Shows another screen of preferences"
    android:title="Screen preference"/>

主要活动.kt

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        supportActionBar!!.setDisplayHomeAsUpEnabled(true)
        if (savedInstanceState == null)
            supportFragmentManager.beginTransaction().replace(android.R.id.content, PrefsFragment()).commit()
    }

    class PrefsFragment : PreferenceFragmentCompat() {
        override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
            setPreferencesFromResource(R.xml.preferences, rootKey)
            setPreferenceToOpenFragmentAsNewPage(findPreference("screen_preference"), PrefsFragment2::class.java)
        }

        private fun setPreferenceToOpenFragmentAsNewPage(pref: Preference, java: Class<out PreferenceFragmentCompat>) {
            pref.onPreferenceClickListener = Preference.OnPreferenceClickListener {
                val fragment = java.newInstance()
                val args = Bundle(1)
                args.putString(PreferenceFragmentCompat.ARG_PREFERENCE_ROOT, pref.key)
                fragment.arguments = args
                activity!!.supportFragmentManager.beginTransaction().replace(android.R.id.content, fragment).addToBackStack(null).commit()
                true
            }
        }
    }

    class PrefsFragment2 : PreferenceFragmentCompat() {
        override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
            setPreferencesFromResource(R.xml.preferences2, null)
        }
    }
}

编辑:对第二个解决方案稍加修改就可以让它变得更好:

<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android" android:title="Demo">

    <Preference
        android:fragment="com.example.user.myapplication.MainActivity$PrefsFragment2" android:key="screen_preference"
        android:summary="Shows another screen of preferences" android:title="Screen preference"/>

</PreferenceScreen>

主要活动.kt

class MainActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        supportActionBar!!.setDisplayHomeAsUpEnabled(true)
        if (savedInstanceState == null)
            supportFragmentManager.beginTransaction().replace(android.R.id.content, PrefsFragment()).commit()
    }

    class PrefsFragment : PreferenceFragmentCompat() {
        override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
            setPreferencesFromResource(R.xml.preferences, rootKey)
            setPreferenceToOpenFragmentAsNewPage(findPreference("screen_preference"))
        }

        private fun setPreferenceToOpenFragmentAsNewPage(pref: Preference) {
            pref.onPreferenceClickListener = Preference.OnPreferenceClickListener {
                val clazz = Class.forName(pref.fragment)
                val fragment: PreferenceFragmentCompat = clazz.newInstance() as PreferenceFragmentCompat
                val args = Bundle(1)
                args.putString(PreferenceFragmentCompat.ARG_PREFERENCE_ROOT, pref.key)
                fragment.arguments = args
                activity!!.supportFragmentManager.beginTransaction().replace(android.R.id.content, fragment).addToBackStack(null).commit()
                true
            }
        }
    }

    class PrefsFragment2 : PreferenceFragmentCompat() {
        override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
            setPreferencesFromResource(R.xml.preferences2, null)
        }
    }

}

请注意,您需要将此添加到Proguard规则:

-keepnames public class * extends androidx.preference.PreferenceFragmentCompat

class PrefsFragment : BasePreferenceFragment() {
    override fun onCreatePreferences(savedInstanceState: Bundle?, rootKey: String?) {
        setPreferencesFromResource(R.xml.preferences_headers, rootKey)
        val preferenceScreen = preferenceScreen
        val preferenceCount = preferenceScreen.preferenceCount
        for (i in 0 until preferenceCount) {
            val pref = preferenceScreen.getPreference(i)
            val fragmentClassName = pref.fragment
            if (fragmentClassName.isNullOrEmpty())
                continue
            pref.setOnPreferenceClickListener {
                showPreferenceFragment(activity!!, fragmentClassName)
                true
            }
        }
    }
}

companion object {
    @JvmStatic
    private fun showPreferenceFragment(activity: FragmentActivity, fragmentClassName: String) {
        val clazz = Class.forName(fragmentClassName)
        val fragment: PreferenceFragmentCompat = clazz.newInstance() as PreferenceFragmentCompat
        val fragmentsCount = activity.supportFragmentManager.fragments.size
        val transaction = activity.supportFragmentManager.beginTransaction().replace(android.R.id.content, fragment)
        if (fragmentsCount > 0)
            transaction.addToBackStack(null)
        transaction.commit()
    }
}

编辑:似乎第一个解决方案是正确的,但需要改变。核对答案 here . 提供完整样品 here .

仅供参考,如果您使用的是导航抽屉+androidx.appcompat,则可以:

1) 将每个PreferenceScreen子级拆分为preference.xml文件: ie“Pref\u general.xml”将是主要首选项,“Pref\u ServerSettings.xml”包含服务器设置的首选项屏幕子项。 2) 为每个preference.xml创建PreferenceFragmentCompat:

“预碎片常规”

在PrefFragmentGeneral.xml文件中,为任何子xml添加首选项,而不是像下面这样的首选项屏幕:

<Preference
    android:key="pref_serverPref"
    android:summary="@string/settings_serverPrefSum"
    android:title="@string/settings_serverPrefTitle"
    />

“预碎片服务器”

public class PrefFragmentGeneral extends PreferenceFragmentCompat {
    @Override
    public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
        setPreferencesFromResource(R.xml.Pref_general, rootKey);
        //find your preference(s) using the same key
        Preference serverPref=findPreference("pref_serverPref");
        if(serverPref!=null){
            //Assign the click listener to navigate to the fragment using the navigation controller
            serverPref.setOnPreferenceClickListener(preference -> {
                NavController navController = Navigation.findNavController(getActivity(), R.id.nav_host_fragment);
                navController.navigate(R.id.nav_PrefFragmentServer);
                return true;
            });
        }
    }
//and the PrefFragmentServer 
public class PrefFragmentServer extends PreferenceFragmentCompat {
    @Override
    public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
        setPreferencesFromResource(R.xml.pref_ServerSettings,rootKey);
     }
}

3) 在导航抽屉中注册所有片段:

好好享受吧!

优点:当你导航回来,你回到“一般”偏好,好像你回到一个偏好活动的孩子! 你不会得到一个异常告诉你片段不是FragmentManager的一部分。