Question

我使用的是Android Studio 3.4，并且正在使用Material Design。当我在布局中添加按钮时，我得到的是java.lang.ClassCastException@11378fc8，在删除按钮之前，我将无法再使用布局编辑器。

我已经尝试过“无效/重新启动”，进行重建，清理和构建。

这是我的树结构： Tree structure

Build.Gradle：

apply plugin: 'com.android.application'

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "fr.aurelien.test_dessin_android"
        minSdkVersion 24
        targetSdkVersion 28
        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:1.0.0-beta01'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    implementation 'androidx.legacy:legacy-support-v4:1.0.0-beta01'
    implementation 'com.google.android.material:material:1.1.0-alpha06'
    implementation 'com.google.code.gson:gson:2.8.5'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test:runner:1.1.0-alpha4'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.0-alpha4'
}

类强制转换异常：

java.lang.IllegalArgumentException: java.lang.ClassCastException@126d0c4
    at sun.reflect.GeneratedMethodAccessor1380.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at android.animation.PropertyValuesHolder_Delegate.callMethod(PropertyValuesHolder_Delegate.java:108)
    at android.animation.PropertyValuesHolder_Delegate.nCallFloatMethod(PropertyValuesHolder_Delegate.java:143)
    at android.animation.PropertyValuesHolder.nCallFloatMethod(PropertyValuesHolder.java)
    at android.animation.PropertyValuesHolder.access$400(PropertyValuesHolder.java:38)
    at android.animation.PropertyValuesHolder$FloatPropertyValuesHolder.setAnimatedValue(PropertyValuesHolder.java:1387)
    at android.animation.ObjectAnimator.animateValue(ObjectAnimator.java:990)
    at android.animation.ValueAnimator.setCurrentFraction(ValueAnimator.java:674)
    at android.animation.ValueAnimator.start(ValueAnimator.java:1071)
    at android.animation.ValueAnimator.start(ValueAnimator.java:1088)
    at android.animation.ObjectAnimator.start(ObjectAnimator.java:852)
    at android.animation.ValueAnimator.startWithoutPulsing(ValueAnimator.java:1081)
    at android.animation.AnimatorSet.handleAnimationEvents(AnimatorSet.java:1142)
    at android.animation.AnimatorSet.doAnimationFrame(AnimatorSet.java:1046)
    at android.animation.AnimationHandler.doAnimationFrame(AnimationHandler.java:146)
    at android.animation.AnimationHandler.access$100(AnimationHandler.java:37)
    at android.animation.AnimationHandler$1.doFrame(AnimationHandler.java:54)
    at android.view.Choreographer$CallbackRecord.run(Choreographer.java:947)
    at android.view.Choreographer.doCallbacks(Choreographer.java:761)
    at android.view.Choreographer_Delegate.doFrame(Choreographer_Delegate.java:66)
    at com.android.layoutlib.bridge.impl.RenderSessionImpl.renderAndBuildResult(RenderSessionImpl.java:563)
    at com.android.layoutlib.bridge.impl.RenderSessionImpl.render(RenderSessionImpl.java:425)
    at com.android.layoutlib.bridge.BridgeRenderSession.render(BridgeRenderSession.java:120)
    at com.android.ide.common.rendering.api.RenderSession.render(RenderSession.java:151)
    at com.android.ide.common.rendering.api.RenderSession.render(RenderSession.java:133)
    at com.android.tools.idea.rendering.RenderTask.lambda$null$8(RenderTask.java:755)
    at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1590)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)

MainActivity：

package fr.aurelien.test_dessin_android;

import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
        fragmentTransaction.add(R.id.frameLayout, new SimpleFragment());
        fragmentTransaction.commit();
    }
}

片段类：

package fr.aurelien.test_dessin_android;

import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class SimpleFragment extends Fragment {

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View retView = inflater.inflate(R.layout.fragment_layout, container, false);
        return retView;
    }
}

Manifest.xml：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="fr.aurelien.test_dessin_android">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme.default">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

XML代码：

<?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">

    <TextView
        android:id="@+id/textView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="70dp"
        android:layout_marginTop="16dp"
        android:text="TextView"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="55dp"
        android:layout_marginTop="31dp"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/textView"
        app:srcCompat="@mipmap/ic_launcher" />

    <Button
        android:id="@+id/button5"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="16dp"
        android:text="Button"
        app:layout_constraintTop_toTopOf="parent"
        tools:layout_editor_absoluteX="189dp" />

</androidx.constraintlayout.widget.ConstraintLayout>

Answer 1

这是Android Studio中的错误。您可以在此处跟踪它，它显然已针对3.5.2 https://issuetracker.google.com/issues/132316448

进行了固定

Answer 2

如果要使用材质组件，则需要将styles.xml中的默认主题从 Theme.AppCompat 更改为 Theme.MaterialComponents。 别忘了添加 implementation 'com.google.android.material:material:1.1.0'在您的应用程序级别build.gradle

中

Answer 3

您是否尝试过使用androidx.appcompat.widget.AppCompatButton而不是Button？

为什么在android studio中添加按钮时出现类强制转换异常？

3 个答案: