為什么在XML Android Studio中看不到我的設計？

Question

我是一個初學者，經過長時間的網上搜索后，我發現沒有令人滿意的永久解決方案。

問題是我在Android Studio 3.0.1中看不到我的設計。

我得到這樣的屏幕：

我的STYLE.XML代碼

<resources>

    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>
    </style>

    <style name="AppTheme.NoActionBar">
        <item name="windowActionBar">false</item>
        <item name="windowNoTitle">true</item>
    </style>

    <style name="AppTheme.AppBarOverlay" parent="ThemeOverlay.AppCompat.Dark.ActionBar" />

    <style name="AppTheme.PopupOverlay" parent="ThemeOverlay.AppCompat.Light" />

</resources>

我的CONTENT CONTACT.XML代碼

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="hk.ust.cse.comp107x.chatclient.Contacts"
    tools:showIn="@layout/activity_contacts">

    <ListView
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:id="@+id/friendListView"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true" />
</RelativeLayout>

我的XML代碼：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="hk.ust.cse.comp107x.chatclient.ChatClient">

    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_centerHorizontal="true"
        android:padding="5pt"
        android:id="@+id/linearLayout"
        android:background="#ffffff"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_margin="0pt">

        <EditText
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:id="@+id/messageText"
            android:layout_gravity="bottom"
            android:layout_weight="1"
            android:hint="@string/messagehint" />


        <ImageButton
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:id="@+id/sendButton"
            android:src="@drawable/ic_send_black_36dp"
            android:background="@android:drawable/btn_default_small" />
    </LinearLayout>

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentTop="true"
        android:layout_alignParentEnd="true"
        android:layout_above="@+id/linearLayout"
        android:padding="5pt"
        android:background="@null">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/messageList"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:background="@null"
            android:divider="@null"
            android:scrollbars="vertical"
            android:stackFromBottom="true"
            android:transcriptMode="alwaysScroll" />
    </LinearLayout>

</RelativeLayout>

我的BUILD.GRADLE代碼（應用程序）

apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.3"

    defaultConfig {
        applicationId "myappID"
        minSdkVersion 18
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    androidTestCompile 'com.android.support.test:runner:0.4.1'
    // Set this dependency to use JUnit 4 rules
    androidTestCompile 'com.android.support.test:rules:0.4.1'
    // Set this dependency to build and run Espresso tests
    androidTestCompile 'com.android.support.test.espresso:espresso-core:2.2.1'
    // Set this dependency to build and run UI Automator tests
    androidTestCompile 'com.android.support.test.uiautomator:uiautomator-v18:2.1.2'
    androidTestCompile 'com.android.support:support-annotations:23.4.0'
    // Optional -- Hamcrest library
    androidTestCompile 'org.hamcrest:hamcrest-library:1.3'
    compile 'com.android.support:appcompat-v7:23.4.0'
    compile 'com.android.support:design:23.4.0'
    compile 'com.android.support:cardview-v7:23.4.0'
    compile 'com.android.support:recyclerview-v7:23.4.0'
}

我的activity_contact.xml （也許這是協調器布局？）

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:fitsSystemWindows="true"
    tools:context="hk.ust.cse.comp107x.chatclient.Contacts">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:popupTheme="@style/AppTheme.PopupOverlay" />

    </android.support.design.widget.AppBarLayout>

    <include layout="@layout/content_contacts" />

    <android.support.design.widget.FloatingActionButton
        android:id="@+id/fab"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|end"
        android:layout_margin="@dimen/fab_margin"
        android:src="@android:drawable/ic_input_add" />

</android.support.design.widget.CoordinatorLayout>

我認為Java代碼沒有問題，因為我是從最近參加的學習課程中學到的。

編輯：現在，我可以看到我的布局，但是我有一個失敗的項目同步失敗。 感謝任何幫助

我的新Gradle代碼-

apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.3"

    defaultConfig {
        applicationId "hk.ust.cse.comp107x.chatclient"
        minSdkVersion 18
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    androidTestCompile 'com.android.support.test:runner:0.4.1'
    // Set this dependency to use JUnit 4 rules
    androidTestCompile 'com.android.support.test:rules:0.4.1'
    // Set this dependency to build and run Espresso tests
    androidTestCompile 'com.android.support.test.espresso:espresso-core:2.2.1'
    // Set this dependency to build and run UI Automator tests
    androidTestCompile 'com.android.support.test.uiautomator:uiautomator-v18:2.1.2'
    androidTestCompile 'com.android.support:support-annotations:23.4.0'
    // Optional -- Hamcrest library
    androidTestCompile 'org.hamcrest:hamcrest-library:1.3'
    compile 'com.android.support:appcompat-v7:25.3.1'
    compile 'com.android.support:design:25.3.1'
    compile 'com.android.support:cardview-v7:23.4.0'
    compile 'com.android.support:recyclerview-v7:23.4.0'
}

Answer 1

只需嘗試一下，更改Gradle文件即可。

compileSdkVersion 27
buildToolsVersion "27.0.0"

//noinspection GradleCompatible
implementation 'com.android.support:appcompat-v7:27.0.0'
implementation 'com.android.support:design:27.0.0'

testImplementation 'junit:junit:4.12'

Answer 2

正如我所看到的，這篇文章已經很老了，但我認為如果其他人遇到同樣的問題，那會很好

只需轉到style.xml文件（該文件處於價值之下），然后用“ Base”為您的主題擴展即可。例如：

更改

<style name="AppTheme" parent="Theme.AppCompat.Light.NoActionBar">

<style name="AppTheme" parent="Base.Theme.AppCompat.Light.NoActionBar"> 

Answer 3

您可能會收到此錯誤

您需要在設計庫中使用Theme.AppCompat主題（或后代）。

我找到了解決此問題的方法，該方法要求您顯式定義Coordinator布局的主題

<android.support.design.widget.CoordinatorLayout
    android:theme="@style/AppTheme.NoActionBar"
    ...
    ...>

確保您使用的主題是Theme.AppCompat的子主題