为什么在XML Android Studio中看不到我的设计？

Question

I'm a beginner and after searching on the net for a long time I found no satisfactory and permanent solution.

The problem is I can't see my design in Android Studio 3.0.1.

I get a screen like this:

My STYLE.XML code

<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>

My CONTENT CONTACT.XML code

<?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>

My XML code:

<?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>

My BUILD.GRADLE code (app)

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'
}

My activity_contact.xml (maybe this is coordinator layout?)

<?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>

I don't think there's a problem with Java code as I took this from a Learning course that I enrolled in Recently.

EDIT: NOW I CAN SEE MY LAYOUT BUT I HAVE A GRADLE PROJECT SYNC FAILED. APPRECIATE ANY HELP

My New Gradle code -

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

Just try it, Changes on Gradle file.

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

As I can see this post is quite old but I thought would be good if in case someone else get the same issue

Just go to style.xml file (which is under value) and give extension to your theme with 'Base' For exmaple:

change

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

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

Answer 3

You might be getting this error

You need to use a Theme.AppCompat theme (or descendant) with the design library.

I found a work around for this that requires you to explicitly define a theme for Coordinator layout

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

Make sure that the theme you use is child of Theme.AppCompat