我一直在努力以不会产生以下错误的方式在我的应用程序中实现相机功能：
E/ContextImpl: 试图从一个非可视上下文访问可视化服务WindowManager：com.camtest.App@385f002 可视化服务，例如WindowManager、WallpaperService或LayoutInflater应该从Activity或其他可视化上下文访问。使用通过 Context#createWindowContext(int, Bundle) 创建的 Activity 或 Context，它们会根据屏幕上某个区域的配置和视觉边界进行调整。java.lang.IllegalAccessException：试图从非可视上下文访问可视服务 WindowManager：com.camtest.App@385f002
该错误是由这一行触发的：
final ListenableFuture<ProcessCameraProvider> cameraProviderFuture = ProcessCameraProvider.getInstance(this);
我createWindowContext按照错误提示进行了实施，但一些目标设备较旧，不符合升级到 Android 11 的条件，因此createWindowContext不是一个选择。
第一次，我跟随其中一个 CodeLabs 来实现 CameraX。相机按预期运行，但触发了异常。所以我找到了一个实现CameraX的不同例子，但我得到了同样的IllegalAccessException例外。
有什么建议么？
package com.camtest;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.camera.core.Camera;
import androidx.camera.core.CameraSelector;
import androidx.camera.core.ImageCapture;
import androidx.camera.core.ImageCaptureException;
import androidx.camera.core.Preview;
import androidx.camera.lifecycle.ProcessCameraProvider;
import androidx.camera.view.PreviewView;
import androidx.core.app.ActivityCompat;
import androidx.core.content.ContextCompat;
import androidx.lifecycle.LifecycleOwner;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.view.View;
import android.widget.ImageView;
import android.widget.Toast;
import com.google.common.util.concurrent.ListenableFuture;
import java.io.File;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
public class CamTest extends AppCompatActivity {
private Executor executor = Executors.newSingleThreadExecutor();
private int REQUEST_CODE_PERMISSIONS = 9001;
private final String[] REQUIRED_PERMISSIONS = new String[]{"android.permission.CAMERA", "android.permission.WRITE_EXTERNAL_STORAGE"};
PreviewView mPreviewView;
ImageView captureImage;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.camera_test);
mPreviewView = findViewById(R.id.camera);//was previewView
captureImage = findViewById(R.id.captureImg);
if(allPermissionsGranted()){
startCamera(); //start camera if permission has been granted by user
} else{
ActivityCompat.requestPermissions(this, REQUIRED_PERMISSIONS, REQUEST_CODE_PERMISSIONS);
}
}
private void startCamera() {
final ListenableFuture<ProcessCameraProvider> cameraProviderFuture = ProcessCameraProvider.getInstance(this); //This line triggers `E/ContextImpl: Tried to access visual service WindowManager from a non-visual Context`
cameraProviderFuture.addListener(new Runnable() {
@Override
public void run() {
try {
ProcessCameraProvider cameraProvider = cameraProviderFuture.get();
bindPreview(cameraProvider);
} catch (ExecutionException | InterruptedException e) {
// No errors need to be handled for this Future.
// This should never be reached.
}
}
}, ContextCompat.getMainExecutor(this));
}
void bindPreview(@NonNull ProcessCameraProvider cameraProvider) {
Preview preview = new Preview.Builder().build();
ImageCapture imageCapture = new ImageCapture.Builder()
.setCaptureMode(ImageCapture.CAPTURE_MODE_MINIMIZE_LATENCY)
.build();
CameraSelector cameraSelector = new CameraSelector.Builder()
.requireLensFacing(CameraSelector.LENS_FACING_BACK)
.build();
Camera camera = cameraProvider.bindToLifecycle(
((LifecycleOwner) this),
cameraSelector,
preview,
imageCapture);
preview.setSurfaceProvider(
mPreviewView.getSurfaceProvider());
captureImage.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
SimpleDateFormat mDateFormat = new SimpleDateFormat("yyyyMMddHHmmss", Locale.US);
File file = new File(getBatchDirectoryName(), mDateFormat.format(new Date())+ ".jpg");
ImageCapture.OutputFileOptions outputFileOptions = new ImageCapture.OutputFileOptions.Builder(file).build();
imageCapture.takePicture(outputFileOptions, executor, new ImageCapture.OnImageSavedCallback () {
@Override
public void onImageSaved(@NonNull ImageCapture.OutputFileResults outputFileResults) {
new Handler().post(new Runnable() {
@Override
public void run() {
Toast.makeText(CamTest.this, "Image Saved successfully", Toast.LENGTH_SHORT).show();
}
});
}
@Override
public void onError(@NonNull ImageCaptureException error) {
error.printStackTrace();
}
});
}
});
}
public String getBatchDirectoryName() {
String app_folder_path = "";
app_folder_path = Environment.getExternalStorageDirectory().toString() + "/images";
File dir = new File(app_folder_path);
if (!dir.exists() && !dir.mkdirs()) {
}
return app_folder_path;
}
private boolean allPermissionsGranted(){
for(String permission : REQUIRED_PERMISSIONS){
if(ContextCompat.checkSelfPermission(this, permission) != PackageManager.PERMISSION_GRANTED){
return false;
}
}
return true;
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
if(requestCode == REQUEST_CODE_PERMISSIONS){
if(allPermissionsGranted()){
startCamera();
} else{
Toast.makeText(this, "Permissions not granted by the user.", Toast.LENGTH_SHORT).show();
this.finish();
}
}
}
}
此活动由 MainActivity 的 onCreate 中的以下代码启动：
Button button_test = findViewById(R.id.button_test);
button_test.setOnClickListener(view -> {
Intent intent = new Intent(MainActivity.this, CamTest.class);
startActivityForResult(intent,0);
});
编辑：完整的堆栈跟踪-
E/ContextImpl: Tried to access visual service WindowManager from a non-visual Context:com.camtest.App@dd90e6b Visual services, such as WindowManager, WallpaperService or LayoutInflater should be accessed from Activity or other visual Context. Use an Activity or a Context created with Context#createWindowContext(int, Bundle), which are adjusted to the configuration and visual bounds of an area on screen.
java.lang.IllegalAccessException: Tried to access visual service WindowManager from a non-visual Context:com.camtest.App@dd90e6b
at android.app.ContextImpl.getSystemService(ContextImpl.java:1914)
at android.content.ContextWrapper.getSystemService(ContextWrapper.java:803)
at androidx.camera.camera2.internal.Camera2UseCaseConfigFactory.<init>(Camera2UseCaseConfigFactory.java:50)
at androidx.camera.camera2.Camera2Config.lambda$defaultConfig$1(Camera2Config.java:60)
at androidx.camera.camera2.-$$Lambda$Camera2Config$g_hY10kZhqC56um0PalOLTzuFlU.newInstance(Unknown Source:0)
at androidx.camera.core.CameraX.lambda$initAndRetryRecursively$9$CameraX(CameraX.java:575)
at androidx.camera.core.-$$Lambda$CameraX$u-Xx2b6YXY5GXNXRh-mDiDnHdpQ.run(Unknown Source:10)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
at java.lang.Thread.run(Thread.java:923)
编辑#2：为了重现此错误，必须启用 VmPolicy 的 StrictMode。下面的代码被添加到 MainActivity.onCreate：
if( BuildConfig.BUILD_TYPE.contentEquals( "debug" ) ){
/*StrictMode.setThreadPolicy( new StrictMode.ThreadPolicy.Builder()
.detectAll()
.penaltyLog()
.build());*/
StrictMode.setVmPolicy( new StrictMode.VmPolicy.Builder()
.detectAll()//.detectNonSdkApiUsage()
.penaltyLog()
.build());
}
编辑 #3：从 CameraX 版本 1.0.0-beta12 更新到 1.0.0-rc1 （截至今天的当前版本）没有效果