启用后新的 PreferenceScreen 打不开

Question

我一直在为我的项目使用 AndroidX Preference 库。该项目有主菜单和子菜单。我已经设置了主菜单中的 CheckBoxPreference 和子菜单中的 PreferenceScreen 之间的依赖关系。 CheckBox 被选中时，PreferenceScreen 被启用，但我无法打开子菜单。

如果我删除依赖项，一切正常！

<?xml version="1.0" encoding="utf-8"?>
<androidx.preference.PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
    <CheckBoxPreference
        android:key="checkbox1"
        android:summaryOff="Description of checkbox 1 off"
        android:summaryOn="Description of checkbox 1 on"
        android:title="CheckBox 1">
    </CheckBoxPreference>
    <ListPreference
        android:dependency="checkbox1"
        android:entries="@array/entries"
        android:entryValues="@array/entry_values"
        android:key="list"
        android:summary="Description of list"
        android:title="List">
    </ListPreference>
    <CheckBoxPreference
        android:key="checkbox2"
        android:summary="Description of checkbox 2"
        android:title="CheckBox 2">
    </CheckBoxPreference>
    <PreferenceScreen
        android:key="screen"
        android:dependency="checkbox2"
        android:summary="Description of screen"
        android:title="Screen">
        <CheckBoxPreference
            android:key="checkbox3"
            android:summary="Description of checkbox 3"
            android:title="CheckBox 3">
        </CheckBoxPreference>
        <PreferenceCategory
            android:key="category1"
            android:summary="Description of category 1"
            android:title="Category 1">
            <CheckBoxPreference
                android:key="checkbox4"
                android:summary="Description of checkbox 4"
                android:title="CheckBox 4">
            </CheckBoxPreference>
        </PreferenceCategory>
        <PreferenceCategory
            android:key="category2"
            android:dependency="checkbox3"
            android:summary="Description of category 2"
            android:title="Category 2">
            <CheckBoxPreference
                android:key="chb5"
                android:summary="Description of checkbox 5"
                android:title="CheckBox 5">
            </CheckBoxPreference>
            <CheckBoxPreference
                android:key="chb6"
                android:summary="Description of checkbox 6"
                android:title="CheckBox 6">
            </CheckBoxPreference>
        </PreferenceCategory>
    </PreferenceScreen>
</androidx.preference.PreferenceScreen>

PreferencesFragment.java

public class PreferencesFragment extends PreferenceFragmentCompat {

    CheckBoxPreference checkBoxPreference;
    PreferenceCategory preferenceCategory;


    public static final String FRAGMENT_TAG = "my_preference_fragment";

    public PreferencesFragment(){

    }

    @Override
    public void onCreatePreferences(Bundle savedInstanceState, String rootKey) {
        setPreferencesFromResource(R.xml.preferences, rootKey);

        checkBoxPreference = findPreference("checkbox3");
        preferenceCategory = findPreference("category2");
        preferenceCategory.setEnabled(checkBoxPreference.isChecked());

        checkBoxPreference.setOnPreferenceClickListener(new Preference.OnPreferenceClickListener() {
            @Override
            public boolean onPreferenceClick(Preference preference) {
                preferenceCategory.setEnabled(checkBoxPreference.isChecked());
                return false;
            }
        });
    }
}

PreferencesActivity.java

public class PreferencesActivity extends AppCompatActivity
        implements PreferenceFragmentCompat.OnPreferenceStartScreenCallback{

    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        if (savedInstanceState == null) {
            Fragment fragment = getSupportFragmentManager()
                    .findFragmentByTag(PreferencesFragment.FRAGMENT_TAG);
            if (fragment == null) {
                fragment = new PreferencesFragment();
            }
        }

        getSupportFragmentManager()
                .beginTransaction()
                .replace(android.R.id.content, new PreferencesFragment())
                .commit();

    }

    @Override
    public boolean onPreferenceStartScreen(PreferenceFragmentCompat caller,
                                           PreferenceScreen preferenceScreen) {
        FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
        PreferencesFragment preferencesFragment = new PreferencesFragment();
        Bundle args = new Bundle();
        args.putString(PreferenceFragmentCompat.ARG_PREFERENCE_ROOT, preferenceScreen.getKey());
        preferencesFragment.setArguments(args);
        fragmentTransaction.replace(android.R.id.content, preferencesFragment,
                preferenceScreen.getKey());
        fragmentTransaction.addToBackStack(preferenceScreen.getKey());
        fragmentTransaction.commit();
        return true;
    }

}

我希望开始一个新的偏好，但实际上我得到了这个：

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: edu.allexfiloenko.lesson62_preferences_enable, PID: 9233
    java.lang.IllegalStateException: Dependency "checkbox2" not found for preference "screen" (title: "Screen"
        at androidx.preference.Preference.registerDependency(Preference.java:1393)
        at androidx.preference.Preference.onAttached(Preference.java:1357)
        at androidx.preference.PreferenceGroup.onAttached(PreferenceGroup.java:444)
        at androidx.preference.PreferenceFragmentCompat.bindPreferences(PreferenceFragmentCompat.java:484)
        at androidx.preference.PreferenceFragmentCompat.onViewCreated(PreferenceFragmentCompat.java:272)
        at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:892)
        at androidx.fragment.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManagerImpl.java:1238)
        at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManagerImpl.java:1303)
        at androidx.fragment.app.BackStackRecord.executeOps(BackStackRecord.java:439)
        at androidx.fragment.app.FragmentManagerImpl.executeOps(FragmentManagerImpl.java:2076)
        at androidx.fragment.app.FragmentManagerImpl.executeOpsTogether(FragmentManagerImpl.java:1866)
        at androidx.fragment.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManagerImpl.java:1821)
        at androidx.fragment.app.FragmentManagerImpl.execPendingActions(FragmentManagerImpl.java:1727)
        at androidx.fragment.app.FragmentManagerImpl.run(FragmentManagerImpl.java:150)
        at android.os.Handler.handleCallback(Handler.java:790)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:164)
        at android.app.ActivityThread.main(ActivityThread.java:6494)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)

Answer 1

这实际上不是受支持的用例，一般不再建议嵌套 PreferenceScreen。

相反，我会推荐一个单独的片段，具有单独的层次结构。您可以在第一个屏幕中使用首选项，以 link 进入第二个屏幕。那么这个 Preference 就会有依赖，这应该可以正常工作。

为了兴趣，我认为这里的实际问题是，当你移动到新屏幕后，外部层次结构不再存在，但是作为新根的 PreferenceScreen 仍然有这个依赖，所以它寻找不再存在的偏好 "checkbox2" :)

有关详细信息，请参阅 Settings guide。

启用后新的 PreferenceScreen 打不开

New PreferenceScreen doesn't open after enabling

java

android

android-preferences

androidx