[英]Android Studio Preview is blank or shows android…CoordinatorLayout
[英]Not able to use CoordinatorLayout in Android Studio
我的問題是,盡管在 build.gradle 文件中添加了所有可能的依賴項,但我無法在 Android Studio 中使用 CoordinatorLayout。 該類未實例化。 這是我的 build.gradle:
apply plugin: 'com.android.application'
android {
compileSdkVersion 29
buildToolsVersion "29.0.2"
defaultConfig {
applicationId "com.example.uiuxpractical4materialdesign"
minSdkVersion 21
targetSdkVersion 29
versionCode 1
versionName "1.0"
testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'androidx.appcompat:appcompat:1.1.0'
implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'androidx.test.ext:junit:1.1.1'
androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
implementation 'androidx.recyclerview:recyclerview:1.1.0'
implementation 'com.google.android.material:material:1.0.0'
implementation 'androidx.coordinatorlayout:coordinatorlayout:1.1.0'
}
活動_main.xml:
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
tools:context=".MainActivity">
<androidx.coordinatorlayout.widget.CoordinatorLayout
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginStart="16dp"
android:layout_marginTop="16dp"
android:layout_marginEnd="16dp"
android:layout_marginBottom="16dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>
錯誤:
java.lang.NoClassDefFoundError: androidx/coordinatorlayout/R$attr
at androidx.coordinatorlayout.widget.CoordinatorLayout.<init>(CoordinatorLayout.java:211)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
at org.jetbrains.android.uipreview.ViewLoader.createNewInstance(ViewLoader.java:403)
at org.jetbrains.android.uipreview.ViewLoader.loadClass(ViewLoader.java:186)
at org.jetbrains.android.uipreview.ViewLoader.loadView(ViewLoader.java:144)
at com.android.tools.idea.rendering.LayoutlibCallbackImpl.loadView(LayoutlibCallbackImpl.java:309)
at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:418)
at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:429)
at android.view.BridgeInflater.createViewFromTag(BridgeInflater.java:333)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:730)
at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:863)
at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:72)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:837)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:824)
at android.view.LayoutInflater.inflate(LayoutInflater.java:515)
at android.view.LayoutInflater.inflate(LayoutInflater.java:394)
at com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:323)
at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:394)
at com.android.tools.idea.layoutlib.LayoutLibrary.createSession(LayoutLibrary.java:200)
at com.android.tools.idea.rendering.RenderTask.createRenderSession(RenderTask.java:572)
at com.android.tools.idea.rendering.RenderTask.lambda$inflate$5(RenderTask.java:698)
at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1590)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at java.lang.Thread.run(Thread.java:748)
由於這個原因,這個類沒有被實例化,我得到了這樣的東西:- 另外,這里也有一張錯誤的小圖片:- 感謝大家幫助那里解決這個問題。 如果您還需要其他任何東西,也請告知。
嘗試在build.gradle的依賴項中添加這一行
implementation 'androidx.appcompat:appcompat:1.0.2'
implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
implementation 'com.android.support:design:29.0.2'
不用擔心 com.android..... 和 androidx.... 這個實現 androidx. 如果您的 android studio 高於 3.2,則自動遷移實現。
你可以檢查這個鏈接。 https://stackoverflow.com/a/58619780/10075771它也將幫助您了解情況:) 希望我能幫助您 :)
嘗試添加以下依賴項實現 'com.android.support:appcompat-v7:23.1.1' 實現 'com.android.support:design:23.1.1'
希望這對你有用。
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