Android Studio Palette/Component Tree

Question

Palette items have question mark on them .

SCREENSHOT

this is mine build.gradle script

    compileSdkVersion 27
        minSdkVersion 19
        targetSdkVersion 27

dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    implementation 'com.android.support.constraint:constraint-layout:1.1.3'
    implementation 'junit:junit:4.12'
    implementation 'junit:junit:4.12'
    implementation 'com.android.support.test.espresso:espresso-core:3.0.2'
    implementation 'com.android.support.test:runner:1.0.2'
    implementation 'com.android.support:recyclerview-v7:27.1.1'
    implementation 'com.android.support:appcompat-v7:27.1.1'
    implementation 'com.android.support:design:27.1.1'
    implementation 'com.android.support:cardview-v7:27.1.1'
    implementation 'com.android.support:support-v4:27.1.1'
}

Answer 1

That just means that Android Studio is not being able to provide you a preview icon of these views at the moment. It doesn't mean there is some explicit problem with Android Studio or that these components won't work. You can place the view on a layout to see how the view actually looks like rather than relying on a preview icon.

On the contrary, you shouldn't actually be using the palette to drag-and-drop and make your layout but rather be writing your layout using XML. That would avoid unnecessary offsets or fixed positions of certain elements and will help you ensure your layout looks good on all devices.

Note: if your layouts don't work or Android Studio is not being able to show you a preview of your layout, that's a complete separate question and should be asked separately.