android:exported needs to be explicitly specified for <activity>

目录	场景错误提示解决思路问题解决

场景：

正在按《第一行代码——Android（第3版）》写Kotlin代码，写了一个 HelloWorld，点击“运行”时报错

错误提示：

> Task :app:processDebugAndroidTestManifest FAILED
E:\AndroidProject\app\build\intermediates\tmp\manifest\androidTest\debug\tempFile1ProcessTestManifest1257258968881101446.xml Error:
    android:exported needs to be explicitly specified for <activity>. Apps targeting Android 12 and higher are required to specify an explicit value for `android:exported` when the corresponding component has an intent filter defined. See https://developer.android.com/guide/topics/manifest/activity-element#exported for details.
E:\AndroidProject\app\build\intermediates\tmp\manifest\androidTest\debug\tempFile1ProcessTestManifest1257258968881101446.xml Error:
    android:exported needs to be explicitly specified for <activity>. Apps targeting Android 12 and higher are required to specify an explicit value for `android:exported` when the corresponding component has an intent filter defined. See https://developer.android.com/guide/topics/manifest/activity-element#exported for details.
E:\AndroidProject\app\build\intermediates\tmp\manifest\androidTest\debug\tempFile1ProcessTestManifest1257258968881101446.xml Error:
    android:exported needs to be explicitly specified for <activity>. Apps targeting Android 12 and higher are required to specify an explicit value for `android:exported` when the corresponding component has an intent filter defined. See https://developer.android.com/guide/topics/manifest/activity-element#exported for details.

解决思路：

（1）通过以 --debug 选项运行，重新查看更加详细的错误信息（点击下图 --debug option，将自动再以该选项运行）

（2）得到更加详细的错误提示：

2021-11-12T07:57:44.384+0800 [INFO] [org.gradle.api.Task] Merging library manifest C:\Users\BensonLaur\.gradle\caches\transforms-3\ee2f476fa0c3550d01ea1b26bf917f27\transformed\monitor-1.3.0\AndroidManifest.xml
2021-11-12T07:57:44.384+0800 [INFO] [org.gradle.api.Task] Merging manifest with lower [androidx.test:monitor:1.3.0] AndroidManifest.xml:17:1-24:12
2021-11-12T07:57:44.384+0800 [INFO] [org.gradle.api.Task] uses-sdk defined in both files...
2021-11-12T07:57:44.384+0800 [INFO] [org.gradle.api.Task] Merging uses-sdk with lower [androidx.test:monitor:1.3.0] AndroidManifest.xml:20:5-22:41
2021-11-12T07:57:44.384+0800 [INFO] [org.gradle.api.Task] Merging library manifest C:\Users\BensonLaur\.gradle\caches\transforms-3\eba7c60eedbe1207821675fbca04aee1\transformed\espresso-idling-resource-3.3.0\AndroidManifest.xml
2021-11-12T07:57:44.384+0800 [INFO] [org.gradle.api.Task] Merging manifest with lower [androidx.test.espresso:espresso-idling-resource:3.3.0] AndroidManifest.xml:17:1-24:12
2021-11-12T07:57:44.384+0800 [INFO] [org.gradle.api.Task] uses-sdk defined in both files...
2021-11-12T07:57:44.384+0800 [INFO] [org.gradle.api.Task] Merging uses-sdk with lower [androidx.test.espresso:espresso-idling-resource:3.3.0] AndroidManifest.xml:20:5-22:41
2021-11-12T07:57:44.385+0800 [ERROR] [org.gradle.api.Task] E:\AndroidProject\app\build\intermediates\tmp\manifest\androidTest\debug\tempFile1ProcessTestManifest1866872685080210847.xml Error:
    android:exported needs to be explicitly specified for <activity>. Apps targeting Android 12 and higher are required to specify an explicit value for `android:exported` when the corresponding component has an intent filter defined. See https://developer.android.com/guide/topics/manifest/activity-element#exported for details.
2021-11-12T07:57:44.385+0800 [ERROR] [org.gradle.api.Task] E:\AndroidProject\app\build\intermediates\tmp\manifest\androidTest\debug\tempFile1ProcessTestManifest1866872685080210847.xml Error:
    android:exported needs to be explicitly specified for <activity>. Apps targeting Android 12 and higher are required to specify an explicit value for `android:exported` when the corresponding component has an intent filter defined. See https://developer.android.com/guide/topics/manifest/activity-element#exported for details.
2021-11-12T07:57:44.385+0800 [ERROR] [org.gradle.api.Task] E:\AndroidProject\app\build\intermediates\tmp\manifest\androidTest\debug\tempFile1ProcessTestManifest1866872685080210847.xml Error:
    android:exported needs to be explicitly specified for <activity>. Apps targeting Android 12 and higher are required to specify an explicit value for `android:exported` when the corresponding component has an intent filter defined. See https://developer.android.com/guide/topics/manifest/activity-element#exported for details.
2021-11-12T07:57:44.385+0800 [INFO] [org.gradle.api.Task] -- Merging decision tree log ---