Question

我在我的应用程序中使用androidx.camera.camera2库。此库适用于SDK 21及更高版本。但是我希望允许用户在没有camera2支持的情况下启动SDK 19的应用程序。我在代码中检查了SDK版本，但是应用程序启动时崩溃。我可以从旧SDK的依赖项中排除camera2吗？

05-30 12:13:42.318 2000-2000/com.myapp.android E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.myapp.android, PID: 2000
java.lang.NoClassDefFoundError: android.util.Size
    at androidx.camera.camera2.impl.Camera2DeviceSurfaceManager.<clinit>(Camera2DeviceSurfaceManager.java:53)
    at androidx.camera.camera2.Camera2AppConfig.create(Camera2AppConfig.java:58)
    at androidx.camera.camera2.impl.Camera2Initializer.onCreate(Camera2Initializer.java:44)
    at android.content.ContentProvider.attachInfo(ContentProvider.java:1591)
    at android.content.ContentProvider.attachInfo(ContentProvider.java:1562)
    at android.app.ActivityThread.installProvider(ActivityThread.java:4790)
    at android.app.ActivityThread.installContentProviders(ActivityThread.java:4385)
    at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4325)
    at android.app.ActivityThread.access$1500(ActivityThread.java:135)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:136)
    at android.app.ActivityThread.main(ActivityThread.java:5017)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:515)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
    at dalvik.system.NativeStart.main(Native Method)

Answer 1

I recently stumbled into the same issue. Diving deep into the CameraX code I found that CameraX is initialized in app startup through a content provider. Here is the content provider code where CameraX is being initialized.

public final class Camera2Initializer extends ContentProvider {
    private static final String TAG = "Camera2Initializer";
    @Override
    public boolean onCreate() {
        Log.d(TAG, "CameraX initializing with Camera2 ...");
        CameraX.init(getContext(), Camera2AppConfig.create(getContext()));
        return false;
    }
}

Im not very familiar with content providers but my first taught was, this is add at the manifest level? And indeed I was right. Looking at there manifest I found this

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="androidx.camera.camera2">
    <application>
        <provider
            android:name=".Camera2Initializer"
            android:authorities="${applicationId}.camerax-init"
            android:exported="false"
            android:initOrder="100"
            android:multiprocess="true" />
    </application>
</manifest>

There manifest gets merged into ours which will include this content provider which in the other hand initializes CameraX, we want to avoid this. So one possible way of doing so is creating our own empty content provider and adding it to our manifest with the same name. This will override there content provider. You can look into https://developer.android.com/studio/build/manifest-merge for more detail about manifest merging.

So now with there content provider overriden hopefully you can call CameraX.init(getContext(), Camera2AppConfig.create(getContext())); only when the feature gets called and not on app startup.

Im hoping this gets fixed in later versions and allows us to initialize cameraX when we want to.

带有camera2库的Android应用程序在SDK19启动时崩溃

1 个答案: