java.lang.RuntimeException: 无法连接到相机服务。在 Camera.open() 上；

Question

我正在尝试打开前置摄像头，完全没有添加（只是预览），立即拍照并将其上传到某个地方。但是我的应用程序在我调用 "Camera.open();" 时崩溃了。这是我的代码：

CameraActivity.java:

package eu.andret.remotesilentphoto;

import android.app.Activity;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.os.Bundle;
import android.util.Log;
import android.view.Window;
import android.widget.FrameLayout;

public class CameraActivity extends Activity {

    private static CameraActivity instance;

    private Camera camera;
    @Override
    protected synchronized void onCreate(Bundle savedInstanceState) {
        instance = this;
        super.onCreate(savedInstanceState);
        getWindow().requestFeature(Window.FEATURE_NO_TITLE);
        setContentView(R.layout.activity_camera);
        boolean front = getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FRONT);
        new Alert("" + front).show(this);
        if (!front) {
            finish();
            return;
        }
        try {
            camera = Camera.open();
            Log.d("AC", camera + "");
            FrameLayout f = (FrameLayout)findViewById(R.id.frameLayout1);
            f.addView(new CameraPreview(this, camera));
        } catch (Exception ex) {
            ex.printStackTrace();
            stackTrace(ex);
        }
    }

    public static CameraActivity getInstance() {
        return instance;
    }

    public final void stackTrace(Exception e) {
        for (StackTraceElement s:e.getStackTrace()) {
            if (s.getClassName().startsWith("eu.andret")) {
                new Alert("Error: " + e.getClass().getName() + ": " + e.getMessage() + " at " + s.getClassName() + ".java:" + s.getLineNumber() + ".").show(this);
            }
        }
    }

    @Override
    protected void onPause() {
        super.onPause();
        camera.release();
    }

    @Override
    protected void onResume() {
        super.onResume();
        try {
            camera = Camera.open();
            Log.d("AC", camera + "");
            FrameLayout f = (FrameLayout)findViewById(R.id.frameLayout1);
            f.addView(new CameraPreview(this, camera));
        } catch (Exception ex) {
            ex.printStackTrace();
            stackTrace(ex);
        }
    }
}

CameraPreview.java:

package eu.andret.remotesilentphoto;

import java.io.IOException;

import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ByteArrayEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.EntityUtils;

import android.content.Context;
import android.hardware.Camera;
import android.hardware.Camera.PictureCallback;
import android.os.AsyncTask;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
    private Camera camera;
    private SurfaceHolder surfaceHolder;

    private PictureCallback camPictureCallback = new PictureCallback() {
        @Override
        public void onPictureTaken(byte[] data, Camera camera) {
            new UploadPhoto().execute(data);
            camera.startPreview();
        }
    };

    @SuppressWarnings("deprecation")
    public CameraPreview(Context context, Camera camera) {
        super(context);
        this.camera = camera;
        surfaceHolder = getHolder();
        surfaceHolder.addCallback(this);
        surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        try {
            camera.setPreviewDisplay(surfaceHolder);
            camera.setDisplayOrientation(180);
            camera.takePicture(null, null, camPictureCallback);
        } catch (IOException ex) {
            ex.printStackTrace();
        }
        camera.startPreview();
    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        try {
            camera.setPreviewDisplay(surfaceHolder);
            camera.setDisplayOrientation(180);
        } catch (IOException ex) {
            ex.printStackTrace();
        }
        camera.startPreview();
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        if (camera != null) {
            camera.stopPreview();
            camera.setPreviewCallback(null);
            camera.release();
            camera = null;
        }
    }

    public class UploadPhoto extends AsyncTask<byte[], Void, String> {
        @Override
        protected String doInBackground(byte[]... params) {
            try {
                HttpPost httpPost = new HttpPost("some link here");
                httpPost.setEntity(new ByteArrayEntity(params[0]));
                DefaultHttpClient httpClient = new DefaultHttpClient();
                HttpResponse httpResponse = httpClient.execute(httpPost);
                String result = EntityUtils.toString(httpResponse.getEntity(), HTTP.UTF_8);
                new Alert("0" + result).show(CameraActivity.getInstance());
            } catch (Exception e) {
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(String result) {
            new Alert("1" + result).show(CameraActivity.getInstance());
        }
    }
}

AndroidManifest.xml:

<uses-sdk
    android:minSdkVersion="11"
    android:targetSdkVersion="21" />
<uses-permission android:name="android.permission.CAMERA" />

<uses-feature android:name="android.hardware.camera" />
<uses-feature android:name="android.hardware.camera.front" />

一个例外是：

An error occurred while connecting to camera: 0
java.lang.RuntimeException: Fail to connect to camera service
    at android.hardware.Camera.native_setup(Native Method)
    at android.hardware.Camera.<init>(Camera.java:351)
    at android.hardware.Camera.open(Camera.java:325)
    at eu.andret.remotesilentphoto.CameraActivity.onResume(CameraActivity.java:62)
    at android.app.Instrumentation.callActivityOnResume(Instrumentation.java:1192)
    at android.app.Activity.performResume(Activity.java:5310)
    at android.app.ActivityThread.performResumeActivity(ActivityThread.java:2764)
    at android.app.ActivityThread.handleResumeActivity(ActivityThread.java:2803)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2238)
    at android.app.ActivityThread.access0(ActivityThread.java:135)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:136)
    at android.app.ActivityThread.main(ActivityThread.java:5001)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:515)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)

如何摆脱这个异常？我正在通过 GenyMotion 在 Android 4.4.4 (API 19) 上编译。

Answer 1

问题是您正在创建两个 Camera 实例（即 Camera.open()），但在 onPause 方法中只释放一个实例。

这样做-

if(camera != null)
{
    camera = Camera.open();
}

java.lang.RuntimeException: 无法连接到相机服务。在 Camera.open() 上；

java.lang.RuntimeException: Fail to connect to camera service. on Camera.open();

java

camera

android

runtimeexception