渲染错误Cardview android studio 3.1和appCompact主题错误

Question

我在android studio中遇到了关于cardview渲染错误和appCompact主题错误的问题。这是屏幕截图和gradle代码

Android Notification

App Theme error

I have tried this solution and still doesn't work

----这是gradle代码----

apply plugin: 'com.android.application'
android {  
    compileSdkVersion 27  
    defaultConfig {  
        applicationId "com.example.shirazikudou.firebase4"  
        minSdkVersion 23  
        targetSdkVersion 27  
        versionCode 1  
        versionName "1.0"    
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"  
    }  
    buildTypes {  
        release {  
            minifyEnabled false  
            proguardFiles getDefaultProguardFile('proguard-      android.txt'), 'proguard-rules.pro'  
        }  
    }  
}  

dependencies {  
    implementation fileTree(dir: 'libs', include: ['*.jar'])  
    androidTestImplementation('com.android.support.test.espresso:espresso-      core:2.2.2', {  
        exclude group: 'com.android.support', module: 'support-    annotations'  
    })  
    api 'com.android.support:appcompat-v7:27.1.1'  
    implementation 'com.android.support.constraint:constraint-    layout:1.1.0'  
    implementation 'com.google.firebase:firebase-auth:11.8.0'  
    implementation 'com.google.firebase:firebase-database:11.8.0'  
    testImplementation 'junit:junit:4.12'  
    androidTestImplementation 'com.android.support.test:runner:1.0.2'  
    androidTestImplementation 'com.android.support.test.espresso:espresso-    core:3.0.2'  
    implementation 'com.android.support:cardview-v7:27.+'  
    implementation 'com.android.support:design:27.1.1'  
}  

apply plugin: 'com.google.gms.google-services'