我正在尝试使用Camera2创建手电筒。我遇到了错误。当我尝试打开或关闭手电筒时，出现错误消息：
android.hardware.camera2.CameraAccessExeption：摄像头设备遇到严重错误。
主要活动
package com.nettport.lommelykt;
import android.Manifest;
import android.content.pm.PackageManager;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.ToggleButton;
import android.content.Context;
import android.graphics.SurfaceTexture;
import android.hardware.camera2.CameraAccessException;
import android.hardware.camera2.CameraCaptureSession;
import android.hardware.camera2.CameraCharacteristics;
import android.hardware.camera2.CameraDevice;
import android.hardware.camera2.CameraManager;
import android.hardware.camera2.CameraMetadata;
import android.hardware.camera2.CaptureRequest;
import android.util.Size;
import android.view.Surface;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
CameraManager cameraManager;
CameraCharacteristics cameraCharacteristics;
CameraDevice mCameraDevice;
CameraCaptureSession mSession;
CaptureRequest.Builder mBuilder;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Initialize camera
initCamera();
// Click button on or off
ToggleButton onOffButton = (ToggleButton) findViewById(R.id.toggleButton);
onOffButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// your click actions go here
if (((ToggleButton) v).isChecked()) {
changeTextAndIcon(1);
turnOnFlashLight();
} else {
changeTextAndIcon(0);
turnOffFlashLight();
}
}
});
}
/*- Change text and icon ------------------------------------- */
// modus = 1 -> turn on
// modus = 0 -> turn off
void changeTextAndIcon(int modus) {
// Change text
TextView statusText = (TextView) findViewById(R.id.textView);
if (modus == 1) {
statusText.setText("Lommelykten er på"); // Flash is on
} else {
statusText.setText("Lommelykten er av"); // Flash is off
}
// Change icon to off
ImageView flashlightIcon = (ImageView) findViewById(R.id.imageView);
if (modus == 1) {
flashlightIcon.setImageResource(R.drawable.flashlight_on);
} else {
flashlightIcon.setImageResource(R.drawable.flashlight_off);
}
}
private void initCamera() {
cameraManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
try {
String[] id = cameraManager.getCameraIdList();
if (id != null && id.length > 0) {
cameraCharacteristics = cameraManager.getCameraCharacteristics(id[0]);
boolean isFlash = cameraCharacteristics.get(CameraCharacteristics.FLASH_INFO_AVAILABLE);
if (isFlash) {
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
cameraManager.openCamera(id[0], new MyCameraDeviceStateCallback(), null);
Toast.makeText(this, "Camera initialized", Toast.LENGTH_LONG).show();
}
}
}
catch (CameraAccessException e)
{
e.printStackTrace();
Toast.makeText(this, "Camera initialization error:\n" + e.toString(), Toast.LENGTH_LONG).show();
}
}
class MyCameraDeviceStateCallback extends CameraDevice.StateCallback
{
@Override
public void onOpened(CameraDevice camera)
{
mCameraDevice = camera;
// get builder
try
{
mBuilder = camera.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
List<Surface> list = new ArrayList<Surface>();
SurfaceTexture mSurfaceTexture = new SurfaceTexture(1);
Size size = getSmallestSize(mCameraDevice.getId());
mSurfaceTexture.setDefaultBufferSize(size.getWidth(), size.getHeight());
Surface mSurface = new Surface(mSurfaceTexture);
list.add(mSurface);
mBuilder.addTarget(mSurface);
camera.createCaptureSession(list, new MyCameraCaptureSessionStateCallback(), null);
}
catch (CameraAccessException e)
{
e.printStackTrace();
}
}
@Override
public void onDisconnected(CameraDevice camera)
{
}
@Override
public void onError(CameraDevice camera, int error)
{
}
}
private Size getSmallestSize(String cameraId) throws CameraAccessException
{
Size[] outputSizes = cameraManager.getCameraCharacteristics(cameraId).get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP).getOutputSizes(SurfaceTexture.class);
if (outputSizes == null || outputSizes.length == 0)
{
throw new IllegalStateException("Camera " + cameraId + "doesn't support any outputSize.");
}
Size chosen = outputSizes[0];
for (Size s : outputSizes)
{
if (chosen.getWidth() >= s.getWidth() && chosen.getHeight() >= s.getHeight())
{
chosen = s;
}
}
return chosen;
}
class MyCameraCaptureSessionStateCallback extends CameraCaptureSession.StateCallback
{
@Override
public void onConfigured(CameraCaptureSession session)
{
mSession = session;
try
{
mSession.setRepeatingRequest(mBuilder.build(), null, null);
}
catch (CameraAccessException e)
{
e.printStackTrace();
}
}
@Override
public void onConfigureFailed(CameraCaptureSession session)
{
}
}
public void turnOnFlashLight()
{
try
{
mBuilder.set(CaptureRequest.FLASH_MODE, CameraMetadata.FLASH_MODE_TORCH);
mSession.setRepeatingRequest(mBuilder.build(), null, null);
Toast.makeText(this, "Flash activated", Toast.LENGTH_LONG).show();
}
catch (Exception e)
{
e.printStackTrace();
Toast.makeText(this, "Flash failed:\n" + e.toString(), Toast.LENGTH_LONG).show();
}
}
public void turnOffFlashLight()
{
try
{
mBuilder.set(CaptureRequest.FLASH_MODE, CameraMetadata.FLASH_MODE_OFF);
mSession.setRepeatingRequest(mBuilder.build(), null, null);
Toast.makeText(this, "Flash disabled", Toast.LENGTH_LONG).show();
}
catch (Exception e)
{
e.printStackTrace();
Toast.makeText(this, "Flash failed:\n" + e.toString(), Toast.LENGTH_LONG).show();
}
}
private void close()
{
Toast.makeText(this, "Camera closed", Toast.LENGTH_LONG).show();
if (mCameraDevice == null || mSession == null)
{
return;
}
mSession.close();
mCameraDevice.close();
mCameraDevice = null;
mSession = null;
}
}
Android清单
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.nettport.lommelykt">
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme"
>
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
<!-- Allows access to the flashlight -->
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.FLASHLIGHT" />
<uses-feature android:name="android.hardware.camera" />
<uses-feature android:name="android.hardware.camera.autofocus" />
<uses-feature android:name="android.hardware.camera.flash" />
</manifest>
您没有坚持使用SurfaceTexture。由此创建的Surface大致等于一个弱指针，并且不会阻止SurfaceTexture被垃圾回收。
查看将SurfaceTexture存储在MainActivity中是否可以解决您的问题。如果不是，您将需要提供崩溃的日志（不仅仅是应用程序日志记录，整个系统），以更详细地了解相机服务所抱怨的问题。
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