Android Support库和AndroidX冲突问题

项目运行重新编译，编译到一半就报错了，真是一脸懵逼。好好的怎么就突然报错了？错误信息如下：

• Error

Manifest merger failed : Attribute application@appComponentFactory value=(android.support.v4.app.CoreComponentFactory) from [com.android.support:support-compat:28.0.0] AndroidManifest.xml:22:18-91
is also present at [androidx.core:core:1.0.0] AndroidManifest.xml:22:18-86 value=(androidx.core.app.CoreComponentFactory).
Suggestion: add 'tools:replace="android:appComponentFactory"' to <application> element at AndroidManifest.xml:6:5-21:19 to override.

按照日志提示添加在<application>标签里面加上：tools:replace="android:appComponentFactory"

<application
        android:name=".application.MyApplication"
        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"
        tools:replace="android:appComponentFactory">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

添加完后，重新编译依旧错误：

Caused by: java.lang.RuntimeException: Manifest merger failed with multiple errors, see logs
    at com.android.builder.core.AndroidBuilder.mergeManifestsForApplication(AndroidBuilder.java:556)
    at com.android.build.gradle.tasks.ProcessApplicationManifest.doFullTaskAction(ProcessApplicationManifest.java:198)
    at com.android.build.gradle.internal.tasks.IncrementalTask.taskAction(IncrementalTask.java:106)
    at sun.reflect.GeneratedMethodAccessor378.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:73)
    at org.gradle.api.internal.project.taskfactory.IncrementalTaskAction.doExecute(IncrementalTaskAction.java:50)
    at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:39)
    at org.gradle.api.internal.project.taskfactory.StandardTaskAction.execute(StandardTaskAction.java:26)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$1.run(ExecuteActionsTaskExecuter.java:131)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:300)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor$RunnableBuildOperationWorker.execute(DefaultBuildOperationExecutor.java:292)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor.execute(DefaultBuildOperationExecutor.java:174)
    at org.gradle.internal.operations.DefaultBuildOperationExecutor.run(DefaultBuildOperationExecutor.java:90)
    at org.gradle.internal.operations.DelegatingBuildOperationExecutor.run(DelegatingBuildOperationExecutor.java:31)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeAction(ExecuteActionsTaskExecuter.java:120)
    at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:99)
    ... 115 more

几番折腾后，发现是 Androidx库和 Android Support库不能共存的问题，一山不容二虎。可是项目并没迁移Androidx库，怎么会出现 Androidx库呢？

依赖架包

• Solution

No1. 转换成Androidx
在AS 3.2 及以上版本提供了更加方便快捷的方法一键迁移到 AndroidX。选择菜单上的ReFactor —— Migrate to AndroidX... 即可；

AndroidX 迁移

No2. 转换成Android Support
1）在 Terminal 中输入gradlew :app:dependencies命令，查看第三方库的依赖树并找出引用了 androidx的库；

查看依赖树

2）经查找发现是implementation 'com.github.chrisbanes:PhotoView:latest.release'引用了 Androidx库；

androidx引用库

3）进入PhotoView 项目地址，查看更新内容；

PhotoView地址

4）根据更新内容发现，从2.2.0版本开始引用 androidx库，那我们尝试回退到2.1.4版本；implementation 'com.github.chrisbanes:PhotoView:2.1.4'

PhotoView更新版本

5）点击 Sync now 重新编译，发现Gradle编译成功，依赖 androidx库也消失了。

编译成功

• Notes
  1）许多第三方库并没有迁移 androidx库，所以项目在使用 androidx库时应当注意兼容问题；
  2）在引用依赖库的时候，尽量避免使用latest.release或+方式，而是使用具体的版本。以免出现新旧库兼容，编译时间久等问题。