Question

我已经尝试过谷歌很多但是找不到单一的解决方案当我在我的设备上运行它时，它提供了以下异常，从本网站获取本教程，用前置摄像头捕获图像而不在屏幕上显示图片here is the link

logcat的

    04-09 07:35:13.181  12257-12257/com.example22.dell.magicgoodapp E/AndroidRuntime﹕ FATAL EXCEPTION: main
    Process: com.example22.dell.magicgoodapp, PID: 12257
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example22.dell.magicgoodapp/com.example22.dell.magicgoodapp.MainActivity}: java.lang.RuntimeException: Fail to connect to camera service
            at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2338)
            at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2390)
            at android.app.ActivityThread.access$800(ActivityThread.java:151)
            at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1321)
            at android.os.Handler.dispatchMessage(Handler.java:110)
            at android.os.Looper.loop(Looper.java:193)
            at android.app.ActivityThread.main(ActivityThread.java:5292)
            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:824)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:640)
            at dalvik.system.NativeStart.main(Native Method)
     Caused by: java.lang.RuntimeException: Fail to connect to camera service
            at android.hardware.Camera.native_setup(Native Method)
            at android.hardware.Camera.<init>(Camera.java:469)
            at android.hardware.Camera.open(Camera.java:424)
            at com.example22.dell.magicgoodapp.MainActivity.onCreate(Unknown Source)
            at android.app.Activity.performCreate(Activity.java:5264)
            at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1088)
              at android.app.ActivityThread.performLaunchActivity
     (ActivityThread.java:2302)
              at  android.app.ActivityThread.handleLaunchActivity
      (ActivityThread.java:2390)
              at android.app.ActivityThread.access$800\
     (ActivityThread.java:151)
              at   android.app.ActivityThread$H.handleMessage
     (ActivityThread.java:1321)
              at android.os.Handler.dispatchMessage(Handler.java:110)
              at android.os.Looper.loop(Looper.java:193)
              at android.app.ActivityThread.main(ActivityThread.java:5292)
              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:824)
               at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:640)
              at dalvik.system.NativeStart.main(Native Method)

MainActivity

package com.example22.dell.magicgoodapp;
import android.app.Activity;
import android.content.pm.PackageManager;
import android.hardware.Camera;
import android.hardware.Camera.CameraInfo;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Toast;

public class MainActivity extends Activity {
    final static String DEBUG_TAG = "MainActivity";
    private Camera camera;
    private int cameraId = 0;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // do we have a camera?
        if (!getPackageManager()
                .hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
            Toast.makeText(this, "No camera on this device", Toast.LENGTH_LONG)
                    .show();
        } else {
            cameraId = findFrontFacingCamera();
            if (cameraId < 0) {
                Toast.makeText(this, "No front facing camera found.",
                        Toast.LENGTH_LONG).show();
            } else {
                camera = Camera.open(cameraId);
            }
        }
    }

    public void onClick(View view) {
        camera.takePicture(null, null,
                new PhotoHandler(getApplicationContext()));
    }

    private int findFrontFacingCamera() {
        int cameraId = -1;
        // Search for the front facing camera
        int numberOfCameras = Camera.getNumberOfCameras();
        for (int i = 0; i < numberOfCameras; i++) {
            CameraInfo info = new CameraInfo();
            Camera.getCameraInfo(i, info);
            if (info.facing == CameraInfo.CAMERA_FACING_FRONT) {
                Log.d(DEBUG_TAG, "Camera found");
                cameraId = i;
                break;
            }
        }
        return cameraId;
    }

    @Override
    protected void onPause() {
        if (camera != null) {
            camera.release();
            camera = null;
        }
        super.onPause();
    }

   }

PhotoHandler类

package com.example22.dell.magicgoodapp;

/**
 * Created by DELL on 1/21/2015.
 */
import java.io.File;
import java.io.FileOutputStream;
import java.text.SimpleDateFormat;
import java.util.Date;

import android.content.Context;
import android.hardware.Camera;
import android.hardware.Camera.PictureCallback;
import android.os.Environment;
import android.util.Log;
import android.widget.Toast;

public class PhotoHandler implements PictureCallback {

    private final Context context;

    public PhotoHandler(Context context) {
        this.context = context;
    }

    @Override
    public void onPictureTaken(byte[] data, Camera camera) {

        File pictureFileDir = getDir();

        if (!pictureFileDir.exists() && !pictureFileDir.mkdirs()) {

            Log.d(MainActivity.DEBUG_TAG, "Can't create directory to save image.");
            Toast.makeText(context, "Can't create directory to save image.",
                    Toast.LENGTH_LONG).show();
            return;

        }

        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyymmddhhmmss");
        String date = dateFormat.format(new Date());
        String photoFile = "Picture_" + date + ".jpg";

        String filename = pictureFileDir.getPath() + File.separator + photoFile;

        File pictureFile = new File(filename);

        try {
            FileOutputStream fos = new FileOutputStream(pictureFile);
            fos.write(data);
            fos.close();
            Toast.makeText(context, "New Image saved:" + photoFile,
                    Toast.LENGTH_LONG).show();
        } catch (Exception error) {
            Log.d(MainActivity.DEBUG_TAG, "File" + filename + "not saved: "
                    + error.getMessage());
            Toast.makeText(context, "Image could not be saved.",
                    Toast.LENGTH_LONG).show();
        }
    }

    private File getDir() {
        File sdDir = Environment
                .getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
        return new File(sdDir, "CameraAPIDemo");
    }
}

Answer 1

我认为您尚未在清单中声明权限

<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />
<uses-feature android:name="android.hardware.camera.autofocus" />

Answer 2

已建议检查权限。

如果相机没有通过相机访问的其他尝试释放相机，它也可能处于不良状态。这发生在早期开发中。

使用当前设置重新启动手机是否值得查看相机是否已按住。或者检查默认相机，看它是否加载或出错。这是一个很好的检查机制。

您目前在onPause（）生命周期中有一个版本，这应该是您希望在正确的时间停止它的内容。但也许你在最初的开发过程中并没有这样做，现在处于糟糕的状态。

Android活动无法启动Componentinfo

2 个答案: