Android应用添加工具栏导致异常

Question

我想我应该添加一个工具栏，因为我需要一个 设置 按钮。

所以我将此添加到我的main_activity.xml

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        app:title="PSA MFD"
        app:subtitle="Multi functional display for Citroen and Peugeot"
        app:logo="@android:drawable/ic_menu_call"
        app:navigationIcon="@drawable/ic_fan"
 />

但现在我的应用无法运行，因为：

    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.rwb.psamfd/com.rwb.psamfd.MainActivity}: android.view.InflateException: Binary XML file line #10: Binary XML file line #10: Error inflating class android.support.v7.widget.Toolbar
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2646)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707)
        at android.app.ActivityThread.-wrap12(ActivityThread.java)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:154)
        at android.app.ActivityThread.main(ActivityThread.java:6077)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)
     Caused by: android.view.InflateException: Binary XML file line #10: Binary XML file line #10: Error inflating class android.support.v7.widget.Toolbar
     Caused by: android.view.InflateException: Binary XML file line #10: Error inflating class android.support.v7.widget.Toolbar
     Caused by: java.lang.ClassNotFoundException: Didn't find class "android.support.v7.widget.Toolbar" on path: DexPathList[[zip file "/data/app/com.rwb.psamfd-2/base.apk"],nativeLibraryDirectories=[/data/app/com.rwb.psamfd-2/lib/x86, /system/lib, /vendor/lib]]
        at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:380)
        at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
        at android.view.LayoutInflater.createView(LayoutInflater.java:609)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:787)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:727)
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:858)
        at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:821)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:518)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:426)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:377)
        at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:555)
        at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:161)
        at com.rwb.psamfd.MainActivity.onCreate(MainActivity.kt:31)
        at android.app.Activity.performCreate(Activity.java:6662)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1118)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2599)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2707)
        at android.app.ActivityThread.-wrap12(ActivityThread.java)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1460)
        at android.os.Handler.dispatchMessage(Handler.java:102)
        at android.os.Looper.loop(Looper.java:154)
        at android.app.ActivityThread.main(ActivityThread.java:6077)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:866)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:756)

我需要做什么？我完全不知道。 （我是 Android 开发新手——与 C# 相比，这非常困难）。

Answer 1

方法一：

将以下内容添加到 build.gradle 文件中的依赖项中：

dependencies {
  ...
  **implementation 'androidx.appcompat:appcompat:1.0.0'**
}

并将您的工具栏更改为：

<androidx.appcompat.widget.Toolbar
  ....
  Your contents
  ....>
<androidx.appcompat.widget.Toolbar/>

方法二：

你可以直接迁移到androidx。

希望你能找到解决办法。