Render error android studio failed to load appcompat action bar, even after matching library versions

Question

apply plugin: 'com.android.application'
android {
compileSdkVersion 28
defaultConfig {
    applicationId "com.app.newzubair.yld"
    minSdkVersion 15
    targetSdkVersion 28
    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'])
implementation 'com.android.support:appcompat-v7:28.0.0-alpha3'
implementation 'com.android.support:support-v4:28.0.0-alpha3'
implementation 'com.android.support:support-media-compat:28.0.0-alpha3'
implementation 'com.android.support.constraint:constraint-layout:1.1.2'
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.google.firebase:firebase-core:16.0.0'}
apply plugin: 'com.google.gms.google-services'    

So this is my gradle build, now I have corrected the android support library versions(as the chosen solution on this community suggested) I still cannot see the changes I make in XML rendered onto the emulation.

This is the screenshot

Answer 1

com.android.support:appcompat-v7:28.0.0-alpha3 has few bugs

change

implementation 'com.android.support:appcompat-v7:28.0.0-alpha3'

to

implementation 'com.android.support:appcompat-v7:28.0.0-alpha1'

Answer 2

在您的LinearLayout标签中添加以下行android:orientation="vertical"