You need to use a Theme.AppCompat theme (or descendant) with this activity

• 具体错误

2021-11-01 20:03:17.567 14095-14095/com.serenegiant.usbcameratest E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.serenegiant.usbcameratest, PID: 14095
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.serenegiant.usbcameratest/com.serenegiant.usbcameratest.MainActivity}: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3483)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3655)
        at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
        at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
        at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2108)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:236)
        at android.app.ActivityThread.main(ActivityThread.java:7879)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:656)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:967)
     Caused by: java.lang.IllegalStateException: You need to use a Theme.AppCompat theme (or descendant) with this activity.
        at androidx.appcompat.app.AppCompatDelegateImpl.createSubDecor(AppCompatDelegateImpl.java:696)
        at androidx.appcompat.app.AppCompatDelegateImpl.ensureSubDecor(AppCompatDelegateImpl.java:659)
        at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:552)
        at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:161)
        at com.serenegiant.usbcameratest.MainActivity.onCreate(MainActivity.java:63)

• 解决办法一

由继承自AppCompatActivity改为继承自Activity

• 解决办法二

第一步：在当前应用的build.gradle，添加红色加粗这两句：

dependencies {

    compile 'com.android.support:design:25.0.0'     compile 'com.android.support.constraint:constraint-layout:1.0.0-beta5' } 第二步：在对应的activity中添加红色加粗这一句：

第三步：在style.xml添加红色加粗这三句：