android - 在 Android 的“PreferenceScreen”中调整边距/填充

不幸的是，我认为您不会找到比您在Android 中发现的更好的答案：如何最大化 PreferenceFragment 宽度（或摆脱边距）？. 我将解释原因并为您提供一种替代方法，您可能认为该替代方法比您参考的答案中提供的更糟糕。

首选项屏幕下方是我们将识别的每个项目的布局。这些是我们将使用的首选项库依赖项：

implementation 'com.android.support:preference-v7:27.1.1'
implementation 'com.android.support:preference-v14:27.1.1'

主题的preferenceTheme属性定义了首选项的外观。

<style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">
    ...
    <!-- Theme for the preferences -->
    <item name="preferenceTheme">@style/PreferenceThemeOverlay.v14.Material</item>
</style>

PreferenceThemeOverlay.v14.Material从我们看到的向上父链（ctrl-B）

<style name="PreferenceThemeOverlay.v14.Material">
...
<item name="preferenceStyle">@style/Preference.Material</item>
...
</style>

Preference.Material定义为：

<style name="Preference.Material">
    <item name="android:layout">@layout/preference_material</item>
</style>

首选项的布局是preference_material.xml。这里是来源。

此布局的以下部分让我们感兴趣：

...
<RelativeLayout
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_weight="1"
    android:paddingTop="16dp"
    android:paddingBottom="16dp">
    <TextView android:id="@+id/title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:singleLine="true"
        android:textAppearance="?attr/textAppearanceListItem"
        android:ellipsize="marquee" />
    <TextView android:id="@+id/summary"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/title"
        android:layout_alignStart="@id/title"
        android:textAppearance="?attr/textAppearanceListItemSecondary"
        android:textColor="?attr/textColorSecondary"
        android:maxLines="10"
        android:ellipsize="end" />
</RelativeLayout>
...

如您所见，的顶部和底部填充RelativeLayout是硬编码的。由于没有使用样式属性，因此无法覆盖填充。由于这种硬编码，您有两种选择：

使用您找到的答案中概述的“非常糟糕的解决方法” ，其中涉及 Java 代码来修改填充，或者，
android:layout="@layout/custom_preference"通过在 XML 中定义您的偏好来使用您自己的布局。您可以复制 Android 布局并进行修改。

每种方法都有缺点，因此请选择您认为最能应对的方法。

以下是演示首选项布局替换的小应用程序的关键组件。

MainActivity.java
为方便起见，此活动在首选项片段中滚动。

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        if (savedInstanceState == null) {
            Fragment preferenceFragment = new PrefsFragment();
            FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
            ft.add(R.id.prefContainer, preferenceFragment);
            ft.commit();
        }
    }

    public static class PrefsFragment extends PreferenceFragmentCompat {

        @Override
        public void onCreatePreferences(Bundle bundle, String s) {
            addPreferencesFromResource(R.xml.app_preferences);
        }
    }
}

app_preference.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.preference.PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
    <android.support.v7.preference.Preference
        android:key="preference"
        android:layout="@layout/custom_pref_layout"
        android:summary="Doesn't really do anything."
        android:title="Preference Title" />

    <android.support.v7.preference.EditTextPreference
        android:defaultValue="Default EditTextPreference value"
        android:dialogMessage="EditTextPreference Dialog Message"
        android:inputType="number"
        android:key="editTextPreference"
        android:layout="@layout/custom_pref_layout"
        android:summary="EditTextPreference Summary"
        android:title="EditTextPreference Title" />

    <android.support.v7.preference.SwitchPreferenceCompat
        android:defaultValue="true"
        android:key="switchPreference"
        android:layout="@layout/custom_pref_layout"
        android:summary="SwitchPreference Summary"
        android:title="SwitchPreference Title" />

    <android.support.v7.preference.CheckBoxPreference
        android:defaultValue="true"
        android:key="checkBoxPreference"
        android:layout="@layout/custom_pref_layout"
        android:summary="CheckBoxPreference Summary"
        android:title="CheckBoxPreference Title" />

    <android.support.v7.preference.ListPreference
        android:defaultValue="180"
        android:entries="@array/pref_sync_frequency_titles"
        android:entryValues="@array/pref_sync_frequency_values"
        android:key="list_preference"
        android:layout="@layout/custom_pref_layout"
        android:negativeButtonText="@null"
        android:positiveButtonText="@null"
        android:title="List Preference Title" />

</android.support.v7.preference.PreferenceScreen>

activity_main.xml
简单地为偏好片段定义一个主页。

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/prefContainer"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.preferencecustomlayout.MainActivity" />

custom_pref_layout.xml
进行了一些修改以适应此文件的使用，主要更新?attr/somthing为?android:attr/something.

<?xml version="1.0" encoding="utf-8"?>
<!-- Copyright (C) 2014 The Android Open Source Project
     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
     You may obtain a copy of the License at
          http://www.apache.org/licenses/LICENSE-2.0
     Unless required by applicable law or agreed to in writing, software
     distributed under the License is distributed on an "AS IS" BASIS,
     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     See the License for the specific language governing permissions and
     limitations under the License.
-->
<!-- Layout for a Preference in a PreferenceActivity. The
     Preference is able to place a specific widget for its particular
     type in the "widget_frame" layout. -->

<!-- Modified from the original to accommodate usage as a local layout file. -->
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="?android:attr/activatedBackgroundIndicator"
    android:clipToPadding="false"
    android:gravity="center_vertical"
    android:minHeight="?attr/listPreferredItemHeightSmall"
    android:paddingEnd="?android:attr/listPreferredItemPaddingEnd"
    android:paddingStart="?android:attr/listPreferredItemPaddingStart">

    <LinearLayout
        android:id="@+id/icon_frame"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="-4dp"
        android:gravity="start|center_vertical"
        android:minWidth="60dp"
        android:orientation="horizontal"
        android:paddingBottom="4dp"
        android:paddingEnd="12dp"
        android:paddingTop="4dp">

        <com.android.internal.widget.PreferenceImageView
            android:id="@+id/icon"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:maxHeight="48dp"
            android:maxWidth="48dp" />
    </LinearLayout>

    <RelativeLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight="1"
        android:paddingBottom="16dp"
        android:paddingTop="16dp">

        <TextView
            android:id="@android:id/title"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:ellipsize="marquee"
            android:singleLine="true"
            android:textAppearance="?attr/textAppearanceListItem" />

        <TextView
            android:id="@android:id/summary"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignStart="@android:id/title"
            android:layout_below="@android:id/title"
            android:ellipsize="end"
            android:maxLines="10"
            android:textAppearance="?attr/textAppearanceListItemSecondary"
            android:textColor="?android:attr/textColorSecondary" />
    </RelativeLayout>
    <!-- Preference should place its actual preference widget here. -->
    <LinearLayout
        android:id="@android:id/widget_frame"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:gravity="end|center_vertical"
        android:orientation="vertical"
        android:paddingStart="16dp" />
</LinearLayout>

摇篮文件

apply plugin: 'com.android.application'

android {
    compileSdkVersion 27
    buildToolsVersion '27.0.3'

    defaultConfig {
        applicationId "com.example.preferencecustomlayout"
        minSdkVersion 18
        targetSdkVersion 27
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    testImplementation 'junit:junit:4.12'
    implementation 'com.android.support:appcompat-v7:27.1.1'
    implementation 'com.android.support:preference-v7:27.1.1'
    implementation 'com.android.support:preference-v14:27.1.1'
}

android - 在 Android 的“PreferenceScreen”中调整边距/填充

问题描述

解决方案

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