Question

我正在开发一个Android应用程序。在我决定在主题中使用材料设计之前，一切似乎都很完美。添加材料设计主题后，布局预览不会显示预览，但是在手机上构建时效果很好。删除xml中使用的材料设计组件时，一切工作正常。

附加我的代码：

activity_home.xml

     <?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
        android:background="@color/background"
        tools:context=".home.Home">


        <com.google.android.material.button.MaterialButton
            android:layout_width="match_parent"
            android:layout_height="50dp"
            android:layout_centerInParent="true"
            android:id="@+id/logout"
            android:text="LOG OUT"
            />
    </RelativeLayout>

HomeActivity.java

package com.****.*****.home;


import androidx.appcompat.app.AppCompatActivity;
import com.hashimshafiq.prepup.R;
import butterknife.OnClick;

public class Home extends AppCompatActivity  {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_home);
        ButterKnife.bind(this);
    }

    @OnClick(R.id.logout) void onClickLogout(){

    }


}

build.graple（应用程序模块）

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

android {
    compileSdkVersion 28
    defaultConfig {
        applicationId "com.****.*****"
        minSdkVersion 19
        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'
        }

        compileOptions {
            sourceCompatibility JavaVersion.VERSION_1_8
            targetCompatibility JavaVersion.VERSION_1_8
        }
    }
    buildToolsVersion = '28.0.3'
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'androidx.appcompat:appcompat:1.0.2'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'
    implementation 'com.android.support:appcompat-v7:28.0.0'
    implementation 'com.android.support:design:28.0.0'
    implementation 'androidx.annotation:annotation:1.1.0'
    implementation 'androidx.lifecycle:lifecycle-extensions:2.0.0'
    implementation 'com.google.firebase:firebase-database:16.0.4'
    implementation 'com.google.firebase:firebase-auth:16.0.5'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test:runner:1.2.0'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'
    implementation "com.google.android.material:material:1.1.0-alpha09"
    implementation 'com.jakewharton:butterknife:10.1.0'
    annotationProcessor 'com.jakewharton:butterknife-compiler:10.1.0'
    implementation 'com.facebook.android:facebook-android-sdk:5.2.0'
}

build.gradle（Prepup）

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    repositories {
        google()
        jcenter()

    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.4.2'
        classpath 'com.google.gms:google-services:4.2.0'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        google()
        jcenter()
        mavenCentral()

    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

styles.xml

<resources>

    <!-- Base application theme. -->
    <style name="AppTheme" parent="Theme.MaterialComponents.Light.NoActionBar">
        <!-- Customize your theme here. -->
        <item name="colorPrimary">@color/colorPrimary</item>
        <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
        <item name="colorAccent">@color/colorAccent</item>

    </style>


    <style name="AppTextField" parent="Widget.MaterialComponents.TextInputLayout.OutlinedBox">

        <item name="boxBackgroundColor">@color/background</item>
        <item name="boxStrokeColor">@android:color/white</item>
        <item name="hintTextColor">@android:color/white</item>


    </style>




</resources>

主要在布局预览中出现的错误

java.lang.IllegalArgumentException：java.lang.ClassCastException@b83d5b8 在sun.reflect.GeneratedMethodAccessor509.invoke（未知来源）在sun.reflect.DelegatingMethodAccessorImpl.invoke（DelegatingMethodAccessorImpl.java:43）在java.lang.reflect.Method.invoke（Method.java:498）在android.animation.PropertyValuesHolder_Delegate.callMethod（PropertyValuesHolder_Delegate.java:108）在android.animation.PropertyValuesHolder_Delegate.nCallFloatMethod（PropertyValuesHolder_Delegate.java:143）在android.animation.PropertyValuesHolder.nCallFloatMethod（PropertyValuesHolder.java）在android.animation.PropertyValuesHolder.access $ 400（PropertyValuesHolder.java:38）在android.animation.PropertyValuesHolder $ FloatPropertyValuesHolder.setAnimatedValue（PropertyValuesHolder.java:1387）在android.animation.ObjectAnimator.animateValue（ObjectAnimator.java:990）在android.animation.ValueAnimator.setCurrentFraction（ValueAnimator.java:674）在android.animation.ValueAnimator.setCurrentPlayTime（ValueAnimator.java:637）在android.animation.ValueAnimator.start（ValueAnimator.java:1069）在android.animation.ValueAnimator.start（ValueAnimator.java:1088）在android.animation.ObjectAnimator.start（ObjectAnimator.java:852）在android.animation.ValueAnimator.startWithoutPulsing（ValueAnimator.java:1081）在android.animation.AnimatorSet.handleAnimationEvents（AnimatorSet.java:1142）在android.animation.AnimatorSet.startAnimation（AnimatorSet.java:1227）在android.animation.AnimatorSet.start（AnimatorSet.java:729）在android.animation.AnimatorSet.start（AnimatorSet.java:684）在android.animation.StateListAnimator.start（StateListAnimator.java:188）在android.animation.StateListAnimator.setState（StateListAnimator.java:181）在android.view.View.drawableStateChanged（View.java:21105）在android.widget.TextView.drawableStateChanged（TextView.java:5283）在androidx.appcompat.widget.AppCompatButton.drawableStateChanged（AppCompatButton.java:156）在android.view.View.refreshDrawableState（View.java:21160）在android.view.View.dispatchAttachedToWindow（View.java:18379）在android.view.ViewGroup.dispatchAttachedToWindow（ViewGroup.java:3404）在android.view.ViewGroup.dispatchAttachedToWindow（ViewGroup.java:3404）在android.view.ViewGroup.dispatchAttachedToWindow（ViewGroup.java:3404）在android.view.ViewGroup.dispatchAttachedToWindow（ViewGroup.java:3404）在android.view.AttachInfo_Accessor.setAttachInfo（AttachInfo_Accessor.java:42）在com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate（RenderSessionImpl.java:335）在com.android.layoutlib.bridge.Bridge.createSession（Bridge.java:391）在com.android.tools.idea.layoutlib.LayoutLibrary.createSession（LayoutLibrary.java:195）在com.android.tools.idea.rendering.RenderTask.createRenderSession（RenderTask.java:540）在com.android.tools.idea.rendering.RenderTask.lambda $ inflate $ 5（RenderTask.java:666）在java.util.concurrent.CompletableFuture $ AsyncSupply.run（CompletableFuture.java:1590）在java.util.concurrent.ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1142）在java.util.concurrent.ThreadPoolExecutor $ Worker.run（ThreadPoolExecutor.java:617）在java.lang.Thread.run（Thread.java:745）

注意：应用程序在Moble上运行正常，但是布局预览无法显示布局，这就是问题所在。

谢谢。

修改我已经完成了以下解决方案，但没有任何反应，错误仍然存在。

使缓存无效并重新启动
清洁版本
将材料设计还原为1.0.0版

Answer 1

在进行以下更改后刷新布局：

1）从文件 activity_home.xml 中的父布局中删除行tools:context=".home.Home"。

2）将文件 HomeActivity.java 中的类 Home 的名称更改为 HomeActivity 。

3）使用gradle文件重新同步项目。

编辑：

这不是由于XML /后端代码中的错误引起的。这是由于Android Studio中的一个错误引起的，here可以在3.6 Canary 3版本（API 29和material_version ='1.1.0-alpha08'）中得到修复。

添加材料设计后，布局预览不会显示布局

1 个答案:

编辑：