android - AppCompat PreferenceActivity 在Android 4.4 中左右出现奇怪的padding

Question

我有一个扩展 AppCompatPreferenceActivity 的 SettingsActivity。

我的 pref_headers.xml 看起来像这样:

<preference-headers xmlns:android="http://schemas.android.com/apk/res/android">
    <header
        android:fragment="com.blabla.activities.fragments.ProfileFragment"
        android:icon="@drawable/ic_users"
        android:title="Profil">
    </header>
</preference-headers>

fragment 代码如下所示:

@TargetApi(Build.VERSION_CODES.HONEYCOMB)
public class ProfileFragment extends PreferenceFragment {
    @BindView(R.id.email)
    TextView email;
    @BindView(R.id.username)
    TextView username;
    @BindView(R.id.loadingPanel)
    RelativeLayout loadingPanel;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View rootView = inflater.inflate(R.layout.fragment_profile, container, false);
        ButterKnife.bind(this, rootView);

        if (setActionbarListener != null) {
            setActionbarListener.setActionbarTitle("Profil");
        }

        loadingPanel.setVisibility(View.VISIBLE);
        UsernameHandler uHandler = UsernameHandler.getInstance(new UsernameResult() {
            @Override
            public void finished(String uname) {
                username.setText(uname);
                loadingPanel.setVisibility(View.GONE);  // hide loading spinner
            }
        });
        email.setText(MainActivity.getFbUser().getEmail());

        return rootView;
    }
}

我的问题是，我正在加载的布局的左侧和右侧有一些空间。此填充绝对不是来自布局本身。在 android 8.1 中启动应用程序时，没有这样的填充/边距。

看图:

最后是SettingsActivity的代码:

public class SettingsActivity extends AppCompatPreferenceActivity implements OnSetActionbarTitleListener {

    /**
     * A preference value change listener that updates the preference's summary
     * to reflect its new value.
     */
    private static Preference.OnPreferenceChangeListener sBindPreferenceSummaryToValueListener = new Preference.OnPreferenceChangeListener() {
        @Override
        public boolean onPreferenceChange(Preference preference, Object value) {
            String stringValue = value.toString();

            if (preference instanceof ListPreference) {
                // For list preferences, look up the correct display value in
                // the preference's 'entries' list.
                ListPreference listPreference = (ListPreference) preference;
                int index = listPreference.findIndexOfValue(stringValue);

                // Set the summary to reflect the new value.
                preference.setSummary(
                        index >= 0
                                ? listPreference.getEntries()[index]
                                : null);

            } else if (preference instanceof RingtonePreference) {
                // For ringtone preferences, look up the correct display value
                // using RingtoneManager.
                if (TextUtils.isEmpty(stringValue)) {
                    // Empty values correspond to 'silent' (no ringtone).
                    preference.setSummary(R.string.pref_ringtone_silent);

                } else {
                    Ringtone ringtone = RingtoneManager.getRingtone(
                            preference.getContext(), Uri.parse(stringValue));

                    if (ringtone == null) {
                        // Clear the summary if there was a lookup error.
                        preference.setSummary(null);
                    } else {
                        // Set the summary to reflect the new ringtone display
                        // name.
                        String name = ringtone.getTitle(preference.getContext());
                        preference.setSummary(name);
                    }
                }

            } else {
                // For all other preferences, set the summary to the value's
                // simple string representation.
                preference.setSummary(stringValue);
            }
            return true;
        }
    };

    /**
     * Helper method to determine if the device has an extra-large screen. For
     * example, 10" tablets are extra-large.
     */
    private static boolean isXLargeTablet(Context context) {
        return (context.getResources().getConfiguration().screenLayout
                & Configuration.SCREENLAYOUT_SIZE_MASK) >= Configuration.SCREENLAYOUT_SIZE_XLARGE;
    }

    /**
     * Binds a preference's summary to its value. More specifically, when the
     * preference's value is changed, its summary (line of text below the
     * preference title) is updated to reflect the value. The summary is also
     * immediately updated upon calling this method. The exact display format is
     * dependent on the type of preference.
     *
     * @see #sBindPreferenceSummaryToValueListener
     */
    public static void bindPreferenceSummaryToValue(Preference preference) {
        // Set the listener to watch for value changes.
        preference.setOnPreferenceChangeListener(sBindPreferenceSummaryToValueListener);

        // Trigger the listener immediately with the preference's
        // current value.
        sBindPreferenceSummaryToValueListener.onPreferenceChange(preference,
                PreferenceManager
                        .getDefaultSharedPreferences(preference.getContext())
                        .getString(preference.getKey(), ""));
    }

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


    /**
     * Set up the {@link android.app.ActionBar}, if the API is available.
     */
    private void setupActionBar() {
        getLayoutInflater().inflate(R.layout.pref_toolbar, (ViewGroup)findViewById(android.R.id.content));
        Toolbar toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        if (toolbar != null) {
            getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        }

        setActionBarBelowContent();
    }

    private void setActionBarBelowContent() {
        int horizontalMargin = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 2, getResources().getDisplayMetrics());
        int verticalMargin = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 2, getResources().getDisplayMetrics());
        int actionBarHeight = UserInterfaceUtils.getActionBarHeight(MainActivity.context);
        getListView().setPadding(0, actionBarHeight+10, 0, verticalMargin);
    }

    @Override
    public void onHeaderClick(Header header, int position) {
        setActionBarBelowContent();
        super.onHeaderClick(header, position);
    }

    @Override
    public boolean onMenuItemSelected(int featureId, MenuItem item) {
        int id = item.getItemId();
        if (id == android.R.id.home) {
            onBackPressed();
            return true;
        }
        return super.onMenuItemSelected(featureId, item);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean onIsMultiPane() {
        return isXLargeTablet(this);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    public void onBuildHeaders(List<Header> target) {
        loadHeadersFromResource(R.xml.pref_headers, target);
    }

    /**
     * This method stops fragment injection in malicious applications.
     * Make sure to deny any unknown fragments here.
     */
    @Override
    protected boolean isValidFragment(String fragmentName) {
        return PreferenceFragment.class.getName().equals(fragmentName)
                || SettingsFragment.class.getName().equals(fragmentName)
                || FeedbackFragment.class.getName().equals(fragmentName)
                || ProfileFragment.class.getName().equals(fragmentName)
                || AGBFragment.class.getName().equals(fragmentName)
                || PrivacyFragment.class.getName().equals(fragmentName)
                || FAQFragment.class.getName().equals(fragmentName)
                || LicenseFragment.class.getName().equals(fragmentName);
    }

    @Override
    public void onBackPressed() {
        super.onBackPressed();
        setActionbarTitle("Einstellungen");
    }

    @Override
    public void setActionbarTitle(String title) {
        getSupportActionBar().setTitle(title);
    }
}

编辑 - 添加布局

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:id="@+id/item_list_item"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <android.support.v7.widget.CardView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:cardUseCompatPadding="true"
        app:cardElevation="4dp"
        app:cardCornerRadius="0dp">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_marginTop="10dp"
            android:padding="15dp"
            android:orientation="vertical">

            <LinearLayout
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:orientation="horizontal">

                <TextView
                    android:id="@+id/preUsername"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:text="Dein Benutzername:"
                    android:textAppearance="@style/profileText"
                    android:textStyle="bold"/>

                <TextView
                    android:id="@+id/username"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:textAppearance="@style/profileText"
                    android:layout_marginLeft="5dp"/>

            </LinearLayout>

            <LinearLayout
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:orientation="horizontal">

                <TextView
                    android:id="@+id/preEmail"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:textAppearance="@style/profileText"
                    android:textStyle="bold"
                    android:text="Deine Email:"/>

                <TextView
                    android:id="@+id/email"
                    android:layout_width="match_parent"
                    android:layout_height="wrap_content"
                    android:textAppearance="@style/profileText"
                    android:layout_marginLeft="5dp"/>

            </LinearLayout>

        </LinearLayout>
    </android.support.v7.widget.CardView>

    <RelativeLayout
        android:id="@+id/loadingPanel"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_gravity="center_vertical|center_horizontal"
        android:gravity="center">

        <ProgressBar
            android:id="@+id/progressBar"
            style="@style/MyProgressBarSpinner"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:indeterminate="true" />
    </RelativeLayout>

</RelativeLayout>

Answer 1

这是根据设计，即您在 KitKat 设备上获得填充的预期行为。来自 Official documentation :

On pre-Lollipop platforms, CardView does not clip the bounds of the Card for the rounded corners. Instead, it adds padding to content so that it won't overlap with the rounded corners. You can disable this behavior by setting this field to false.

解决方案:

在 XML 布局中:app:cardPreventCornerOverlap="false"

或

在 Java 中:setPreventCornerOverlap(false);

所以在你的情况下:

<android.support.v7.widget.CardView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    app:cardUseCompatPadding="true"
    app:cardElevation="4dp"
    app:cardPreventCornerOverlap="false"
    app:cardCornerRadius="0dp">

希望对您有所帮助!