java.lang.NoClassDefFoundError：解析失败：Landroidx/arch/core/util/Cancellable

Question

我将我的应用程序项目拆分为其他模块，在实现 DI 并在模块之间拆分依赖项后，出现以下异常：

java.lang.NoClassDefFoundError: Failed resolution of: Landroidx/arch/core/util/Cancellable;
        at androidx.activity.ComponentActivity.<init>(ComponentActivity.java:69)
        at androidx.fragment.app.FragmentActivity.<init>(FragmentActivity.java:118)
        at androidx.appcompat.app.AppCompatActivity.<init>(AppCompatActivity.java:77)

然后，我检查ComponentActivity班级，是的，说班级找不到Cancellable班级。

package androidx.activity;  

import static android.os.Build.VERSION.SDK_INT;  

import android.os.Build;  
import android.os.Bundle;  
import android.view.View;  
import android.view.Window;  

import androidx.annotation.CallSuper;  
import androidx.annotation.ContentView;  
import androidx.annotation.LayoutRes;  
import androidx.annotation.NonNull;  
import androidx.annotation.Nullable;  
import androidx.arch.core.util.Cancellable; // <---- This class can't be found!
import androidx.lifecycle.GenericLifecycleObserver;  
import androidx.lifecycle.Lifecycle;  
import androidx.lifecycle.LifecycleOwner;  
import androidx.lifecycle.LifecycleRegistry;  
import androidx.lifecycle.ReportFragment;  
import androidx.lifecycle.ViewModelStore;  
import androidx.lifecycle.ViewModelStoreOwner;  
import androidx.savedstate.SavedStateRegistry;  
import androidx.savedstate.SavedStateRegistryController;  
import androidx.savedstate.SavedStateRegistryOwner;  

import java.util.WeakHashMap;  

/**  
 * Base class for activities that enables composition of higher level components. * <p>  
  * Rather than all functionality being built directly into this class, only the minimal set of  
 * lower level building blocks are included. Higher level components can then be used as needed * without enforcing a deep Activity class hierarchy or strong coupling between components. */public class ComponentActivity extends androidx.core.app.ComponentActivity implements  
  LifecycleOwner,  
  ViewModelStoreOwner,  
  SavedStateRegistryOwner {

在查看了包之后，我决定添加这个依赖项：

implementation "androidx.core:core:1.1.0-alpha05"

然而，它仍然失败。

然后我在 StackOverflow 中检查了一些建议使用 Multidex 的问题，因此，我在我的build.gradle文件中启用了 mutlidex，但它仍然失败

我像这样添加了 Multidex：

implementation "androidx.multidex:multidex:2.0.0"

构建.gradle

defaultConfig {  
// Config stuff
  multiDexEnabled = true  
}

并使我的Application课程扩展MultiDexApplication课程，但它仍然失败

似乎我在这里缺少一个依赖项，但我找不到它。：C

Answer 1

根据androidx.arch.core 发行说明：

Cancellable由于缺乏可组合的基础设施以及从androidx.activity 1.0.0-alpha07. （aosp/945461）

因此，您应该升级到 Activity 1.0.0-alpha07 或更高版本，以删除 ComponentActivity 对Cancellable. 当您升级到 Fragments 1.1.0-alpha07 或更高版本时，此操作会自动完成。