启用后无法打开新首选项屏幕

Question

我一直在为我的项目使用 AndroidX 首选项库。该项目有主菜单和子菜单。我已经设置了主菜单中的复选框首选项和子菜单中的首选项屏幕之间的依赖关系。选中复选框后，首选项屏幕将启用，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>

首选项片段.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;
            }
        });
    }
}

首选项活动.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，但实际上我有这个：

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$2.run(FragmentManagerImpl.java:150)
        at android.os.Handler.handleCallback(Handler.java:790)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:164)
        at android.app.ActivityThread.main(ActivityThread.java:6494)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)

Answer 1

这不是一个真正受支持的用例，通常不再建议嵌套首选项屏幕。

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来链接到第二个屏幕。然后，此首选项将具有依赖关系，这应该可以正常工作。

出于兴趣起见，我认为这里的实际问题是，在您移动到新屏幕后，外部层次结构不再存在，但是作为新根的首选项屏幕仍然具有此依赖项，因此它会查找不再存在的首选项"checkbox2":)

有关详细信息，请参阅设置指南。