Android图片回调数据为空

Question

我在拍摄图片后使用相机代码为byte [] imageData参数为null,我不知道为什么.

package com.pictures;

import java.io.BufferedOutputStream;
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.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.PixelFormat;
import android.graphics.Bitmap.CompressFormat;
import android.hardware.Camera;
import android.os.Bundle;
import android.util.Log;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.view.View.OnClickListener;
import android.view.View.OnTouchListener;

public class CamaraView extends Activity implements SurfaceHolder.Callback,
        OnClickListener {
    static final int FOTO_MODE = 0;
    private static final String TAG = "CameraTest";
    Camera mCamera;
    boolean mPreviewRunning = false;
    private Context mContext = this;

    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);

        Log.e(TAG, "onCreate");

        Bundle extras = getIntent().getExtras();

        getWindow().setFormat(PixelFormat.TRANSLUCENT);
        requestWindowFeature(Window.FEATURE_NO_TITLE);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
        setContentView(R.layout.main);
        mSurfaceView = (SurfaceView) findViewById(R.id.surface_camera);
        mSurfaceView.setOnClickListener(this);
        mSurfaceHolder = mSurfaceView.getHolder();
        mSurfaceHolder.addCallback(this);
        mSurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
    }

    Camera.PictureCallback mPictureCallback = new Camera.PictureCallback() {
        public void onPictureTaken(byte[] imageData, Camera c) {

            if (imageData != null) {

                Intent mIntent = new Intent();

                StoreByteImage(mContext, imageData, 50,
                        "ImageName");
                mCamera.startPreview();

                setResult(FOTO_MODE, mIntent);
                finish();

            }
        }
    };

    protected void onResume() {
        Log.e(TAG, "onResume");
        super.onResume();
    }

    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
    }

    protected void onStop() {
        Log.e(TAG, "onStop");
        super.onStop();
    }

    public void surfaceCreated(SurfaceHolder holder) {
        Log.e(TAG, "surfaceCreated");
        mCamera = Camera.open();

    }

    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
        Log.e(TAG, "surfaceChanged");


        // XXX stopPreview() will crash if preview is not running
        if (mPreviewRunning) {
            mCamera.stopPreview();
        }

        Camera.Parameters p = mCamera.getParameters();
        p.setPreviewSize(w, h);
        mCamera.setParameters(p);

        try {
            mCamera.setPreviewDisplay(holder);
        } catch (IOException e) {
            // TODO Auto-generated catch block
            System.out.println("Caught exception in surface chagned");
            e.printStackTrace();
        }
        mCamera.startPreview();
        mPreviewRunning = true;

    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        Log.e(TAG, "surfaceDestroyed");
        mCamera.stopPreview();
        mPreviewRunning = false;
        mCamera.release();
    }

    private SurfaceView mSurfaceView;
    private SurfaceHolder mSurfaceHolder;

    public void onClick(View arg0) {

        mCamera.takePicture(null, mPictureCallback, mPictureCallback);

    }

    public static boolean StoreByteImage(Context mContext, byte[] imageData,
            int quality, String expName) {

        File sdImageMainDirectory = new File("/sdcard");
        FileOutputStream fileOutputStream = null;
        String nameFile;
        try {

            BitmapFactory.Options options=new BitmapFactory.Options();
            options.inSampleSize = 5;

            Bitmap myImage = BitmapFactory.decodeByteArray(imageData, 0,
                    imageData.length,options);


            fileOutputStream = new FileOutputStream(
                    sdImageMainDirectory.toString() +"/image.jpg");


            BufferedOutputStream bos = new BufferedOutputStream(
                    fileOutputStream);

            myImage.compress(CompressFormat.JPEG, quality, bos);

            bos.flush();
            bos.close();

        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return true;
    }

}

Answer 1

好的,我看到了问题.您正在重复使用原始和jpeg回调的图片回调.来自javadoc你可以阅读:

触发异步图像捕获.随着图像捕获的进行,相机服务将启动对应用程序的一系列回调.捕获图像后发生快门回调.这可以用于触发声音以让用户知道已捕获图像.原始图像数据可用时发生原始回调(注意:如果没有可用的原始图像回调缓冲区或原始图像回调缓冲区不足以容纳原始图像,则数据将为null).当缩放的,完全处理的postview图像可用时,会发生postview回调(注意:并非所有硬件都支持此功能).当压缩图像可用时,将发生jpeg回调.如果应用程序不需要特定的回调,则可以传递null而不是回调方法.

因此,如果它被称为原始回调,则数据可以为null.如果您不喜欢原始数据,只需使用:

 mCamera.takePicture(null, null, mPictureCallback);