Android代碼無法訪問手機相機...怎麼回事？

Question

我無法使相機預覽正常工作。任何想法發生了什麼？我不認爲我的代碼可以在手機上連接/查找相機...我在編程方面很新穎。

這裏的錯誤信息：

07-31 22:10:29.940 26291-26291/user.cameratest W/CameraBase: An error occurred while connecting to camera: 0 
07-31 22:10:30.168 26291-26320/user.cameratest E/Surface: getSlotFromBufferLocked: unknown buffer: 0xb9bfa3e8 
07-31 22:10:30.191 26291-26291/user.cameratest W/CameraBase: An error occurred while connecting to camera: 0 
07-31 22:10:36.957 26291-26320/user.cameratest E/Surface: getSlotFromBufferLocked: unknown buffer: 0xb9c89198 
07-31 22:10:40.458 26291-26320/user.cameratest E/Surface: getSlotFromBufferLocked: unknown buffer: 0xb9b47570 

下面是代碼：

AndroidManifest.xml中

<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
package="user.cameratest"> 

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

<uses-permission android:name="android.permission.CAMERA" /> 
<uses-permission android:name="android.hardware.camera.autofocus" /> 
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" /> 
<!--uses-permission android:name="android.permission.INTERNET" /> 
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /--> 

<application 
    android:icon="@mipmap/ic_launcher" 
    android:label="@string/app_name" > 
    <activity 
     android:label="@string/app_name" 
     android:name=".cameraActivity" 
     android:screenOrientation="landscape" > 
     <intent-filter > 
      <action android:name="android.intent.action.MAIN" /> 

      <category android:name="android.intent.category.LAUNCHER" /> 
     </intent-filter> 
    </activity> 
</application> 

cameraActivity.java

package user.cameratest; 

import java.io.File; 
import java.io.FileNotFoundException; 
import java.io.FileOutputStream; 
import java.io.IOException; 

import android.app.Activity; 
import android.content.Context; 
import android.content.Intent; 
import android.hardware.Camera; 
import android.hardware.Camera.PictureCallback; 
import android.hardware.Camera.ShutterCallback; 
import android.net.Uri; 
import android.os.AsyncTask; 
import android.os.Bundle; 
import android.os.Environment; 
import android.util.Log; 
import android.view.SurfaceView; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.view.ViewGroup.LayoutParams; 
import android.view.Window; 
import android.view.WindowManager; 
import android.widget.Button; 
import android.widget.FrameLayout; 
import android.widget.Toast; 

public class cameraActivity extends Activity { // 
    private static final String TAG = "cameraActivity"; 
    cameraPreview preview; 
    Button buttonClick; 
    Camera camera; // 
    Activity act; 
    Context ctx; 

    @Override 
    public void onCreate(Bundle savedInstanceState) { // 
     super.onCreate(savedInstanceState); // 
     ctx = this; 
     act = this; 
     requestWindowFeature(Window.FEATURE_NO_TITLE); // 
     getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN); // 

     setContentView(R.layout.camera_layout); // 

     preview = new cameraPreview(this, (SurfaceView)findViewById(R.id.surfaceView)); 
     preview.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT)); 
     ((FrameLayout) findViewById(R.id.layout)).addView(preview); 
     preview.setKeepScreenOn(true); 

     preview.setOnClickListener(new OnClickListener() { 

      @Override 
      public void onClick(View arg0) { 
       camera.takePicture(shutterCallback, rawCallback, jpegCallback); 
      } 
     }); 

     Toast.makeText(ctx, getString(R.string.take_photo_help), Toast.LENGTH_LONG).show(); 

     //  buttonClick = (Button) findViewById(R.id.btnCapture); 
     // 
     //  buttonClick.setOnClickListener(new OnClickListener() { 
     //   public void onClick(View v) { 
     ////    preview.camera.takePicture(shutterCallback, rawCallback, jpegCallback); 
     //    camera.takePicture(shutterCallback, rawCallback, jpegCallback); 
     //   } 
     //  }); 
     // 
     //  buttonClick.setOnLongClickListener(new OnLongClickListener(){ 
     //   @Override 
     //   public boolean onLongClick(View arg0) { 
     //    camera.autoFocus(new AutoFocusCallback(){ 
     //     @Override 
     //     public void onAutoFocus(boolean arg0, Camera arg1) { 
     //      //camera.takePicture(shutterCallback, rawCallback, jpegCallback); 
     //     } 
     //    }); 
     //    return true; 
     //   } 
     //  }); 
    } 

    @Override 
    protected void onResume() { 
     super.onResume(); 
     int numCams = Camera.getNumberOfCameras(); 
     if(numCams > 0){ 
      try{ 
       camera = Camera.open(0); 
       camera.startPreview(); 
       preview.setCamera(camera); 
      } catch (RuntimeException ex){ 
       Toast.makeText(ctx, getString(R.string.camera_not_found), Toast.LENGTH_LONG).show(); 
      } 
     } 
    } 

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

    private void resetCam() { 
     camera.startPreview(); 
     preview.setCamera(camera); 
    } 

    private void refreshGallery(File file) { 
     Intent mediaScanIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE); 
     mediaScanIntent.setData(Uri.fromFile(file)); 
     sendBroadcast(mediaScanIntent); 
    } 

    ShutterCallback shutterCallback = new ShutterCallback() { 
     public void onShutter() { 
      //   Log.d(TAG, "onShutter'd"); 
     } 
    }; 

    PictureCallback rawCallback = new PictureCallback() { 
     public void onPictureTaken(byte[] data, Camera camera) { 
      //   Log.d(TAG, "onPictureTaken - raw"); 
     } 
    }; 

    PictureCallback jpegCallback = new PictureCallback() { 
     public void onPictureTaken(byte[] data, Camera camera) { 
      new SaveImageTask().execute(data); 
      resetCam(); 
      Log.d(TAG, "onPictureTaken - jpeg"); 
     } 
    }; 

    private class SaveImageTask extends AsyncTask<byte[], Void, Void> { 

     @Override 
     protected Void doInBackground(byte[]... data) { 
      FileOutputStream outStream = null; 

      // Write to SD Card 
      try { 
       File sdCard = Environment.getExternalStorageDirectory(); 
       File dir = new File (sdCard.getAbsolutePath() + "/camtest"); 
       dir.mkdirs(); 

       String fileName = String.format("%d.jpg", System.currentTimeMillis()); 
       File outFile = new File(dir, fileName); 

       outStream = new FileOutputStream(outFile); 
       outStream.write(data[0]); 
       outStream.flush(); 
       outStream.close(); 

       Log.d(TAG, "onPictureTaken - wrote bytes: " + data.length + " to " + outFile.getAbsolutePath()); 

       refreshGallery(outFile); 
      } catch (FileNotFoundException e) { 
       e.printStackTrace(); 
      } catch (IOException e) { 
       e.printStackTrace(); 
      } finally { 
      } 
      return null; 
     } 

    } 
} 

cameraPreview.java

package user.cameratest; 

/** 
* @author Jose Davis Nidhin 
*/ 

import java.io.IOException; 
import java.util.List; 

import android.content.Context; 
import android.hardware.Camera; 
import android.hardware.Camera.Size; 
import android.util.Log; 
import android.view.SurfaceHolder; 
import android.view.SurfaceView; 
import android.view.View; 
import android.view.ViewGroup; 

class cameraPreview extends ViewGroup implements SurfaceHolder.Callback { // 
    private final String TAG = "cameraPreview"; // 

    SurfaceView mSurfaceView; // 
    SurfaceHolder mHolder; // 
    Size mPreviewSize; // 
    List<Size> mSupportedPreviewSizes; // 
    Camera mCamera; // 

    cameraPreview(Context context, SurfaceView sv) { // 
     super(context); // 

     mSurfaceView = sv; // 
//  addView(mSurfaceView); 

     mHolder = mSurfaceView.getHolder(); // 
     mHolder.addCallback(this); // 
     mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS); // 
    } 

    public void setCamera(Camera camera) { // 
     mCamera = camera; // 
     if (mCamera != null) { // 
      mSupportedPreviewSizes = mCamera.getParameters().getSupportedPreviewSizes(); // 
      requestLayout(); // 

      // get Camera parameters 
      Camera.Parameters params = mCamera.getParameters(); // 

      List<String> focusModes = params.getSupportedFocusModes(); // 
      if (focusModes.contains(Camera.Parameters.FOCUS_MODE_AUTO)) { // 
       // set the focus mode 
       params.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO); // 
       // set Camera parameters 
       mCamera.setParameters(params); // 
      } 
     } 
    } 

    @Override 
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { // 
     // We purposely disregard child measurements because act as a 
     // wrapper to a SurfaceView that centers the camera preview instead 
     // of stretching it. 
     final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec); // 
     final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec); // 
     setMeasuredDimension(width, height); // 

     if (mSupportedPreviewSizes != null) { // 
      mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width, height); // 
     } 
    } 

    @Override 
    protected void onLayout(boolean changed, int l, int t, int r, int b) { // 
     if (changed && getChildCount() > 0) { 
      final View child = getChildAt(0); 

      final int width = r - l; 
      final int height = b - t; 

      int previewWidth = width; 
      int previewHeight = height; 
      if (mPreviewSize != null) { 
       previewWidth = mPreviewSize.width; 
       previewHeight = mPreviewSize.height; 
      } 

      // Center the child SurfaceView within the parent. 
      if (width * previewHeight > height * previewWidth) { 
       final int scaledChildWidth = previewWidth * height/previewHeight; 
       child.layout((width - scaledChildWidth)/2, 0, 
         (width + scaledChildWidth)/2, height); 
      } else { 
       final int scaledChildHeight = previewHeight * width/previewWidth; 
       child.layout(0, (height - scaledChildHeight)/2, 
         width, (height + scaledChildHeight)/2); 
      } 
     } 
    } 

    public void surfaceCreated(SurfaceHolder holder) { 
     // The Surface has been created, acquire the camera and tell it where 
     // to draw. 
     try { 
      if (mCamera != null) { 
       mCamera.setPreviewDisplay(holder); 
      } 
     } catch (IOException exception) { 
      Log.e(TAG, "IOException caused by setPreviewDisplay()", exception); 
     } 
    } 

    public void surfaceDestroyed(SurfaceHolder holder) { 
     // Surface will be destroyed when we return, so stop the preview. 
     if (mCamera != null) { 
      mCamera.stopPreview(); 
     } 
    } 


    private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) { 
     final double ASPECT_TOLERANCE = 0.1; 
     double targetRatio = (double) w/h; 
     if (sizes == null) return null; 

     Size optimalSize = null; 
     double minDiff = Double.MAX_VALUE; 

     int targetHeight = h; 

     // Try to find an size match aspect ratio and size 
     for (Size size : sizes) { 
      double ratio = (double) size.width/size.height; 
      if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) continue; 
      if (Math.abs(size.height - targetHeight) < minDiff) { 
       optimalSize = size; 
       minDiff = Math.abs(size.height - targetHeight); 
      } 
     } 

     // Cannot find the one match the aspect ratio, ignore the requirement 
     if (optimalSize == null) { 
      minDiff = Double.MAX_VALUE; 
      for (Size size : sizes) { 
       if (Math.abs(size.height - targetHeight) < minDiff) { 
        optimalSize = size; 
        minDiff = Math.abs(size.height - targetHeight); 
       } 
      } 
     } 
     return optimalSize; 
    } 

    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) { 
     if(mCamera != null) { 
      Camera.Parameters parameters = mCamera.getParameters(); 
      parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height); 
      requestLayout(); 

      mCamera.setParameters(parameters); 
      mCamera.startPreview(); 
     } 
    } 

} 

camera_layout.xml

<?xml version="1.0" encoding="utf-8"?> 
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:id="@+id/layout" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" > 

    <SurfaceView 
     android:id="@+id/surfaceView" 
     android:layout_width="match_parent" 
     android:layout_height="match_parent" /> 

    <!-- Button 
     android:id="@+id/btnCapture" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_gravity="center_horizontal" 
     android:background="@drawable/round_button" 
     android:text="@string/btn_capture" /--> 

</FrameLayout> 

Answer 1

你要求的權限？： https://developer.android.com/training/permissions/requesting.html

對於相機，其許可權限爲Manifest.permission.CAMERA。

另外，android.hardware.camera已經過時，你應該使用android.hardware.camera2 https://developer.android.com/reference/android/hardware/camera2/package-summary.html