android 手机拍照流程

 

android 拍照API流程

 

1. 在布局文件中添加一个 surfaceView (摄影平面)

2.根据 SurfaceView  获得 Holder (固定器)

3.给固定器设置 SurfaceHolder.Callback ; 这个 Callback 有一系列的周期方法,

比如:surfaceCreated,surfaceChanged,surfaceDestroyed等方法.

①.在surfaceDestroyed 中 打开相机,设置预览效果 ;

②.在surfaceChanged中可以初始化相机( Camera );比如相机的参数: 像素, 大小,格式,开始预览,等等

③.在surfaceDestroyed可以可以停止相机拍摄;释放相机资源

4. 相机自动对焦 的回调处理

Camera.autoFocus( AutoFocusCallback )

	AutoFocusCallback 有个接口方法
	 public void onAutoFocus(boolean focused, Camera camera) {
                    /* 对到焦点拍照 */
                    if (focused) {
                            takePicture();//见第5步
                    }
            }

 

5.Camera.takePicture(ShutterCallback shutter/*摄像*/, PictureCallback raw/*拍照*/, PictureCallback jpeg/*照片*/)

查看API或者源码,可以发现,这些callback里面都有包含摄像,或者被拍照时的byte[]数据,而这些数据可以根据BitmapFactory变成Bitmap图片.

 

见源代码如下：

 

public class ScanBarZBarActivity extends Activity implements SurfaceHolder.Callback{
	private static String TAG = "ScanBarZBarActivity";
	 private Camera mCamera;
    private Button mButton, mButton1, mButton2;
    private SurfaceView mSurfaceView;
    private SurfaceHolder holder;
    private AutoFocusCallback mAutoFocusCallback = new AutoFocusCallback();
    private String path = "WXJSMyPhoto";
    private String path1;
    private Bitmap bmp;
    private int cnt = 1;
    private Calendar c;
    public native String getISBN(Bitmap bmp);
    private int flag=5;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            /* 隐藏状态栏 */
            this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                            WindowManager.LayoutParams.FLAG_FULLSCREEN);
            /* 隐藏标题栏 */
            requestWindowFeature(Window.FEATURE_NO_TITLE);
            /* 设定屏幕显示为横向 */
            this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);

            setContentView(R.layout.camera);
            /* SurfaceHolder设定 */
            mSurfaceView = (SurfaceView) findViewById(R.id.mSurfaceView);
            holder = mSurfaceView.getHolder();
            holder.addCallback(ScanBarZBarActivity.this);
            holder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
            c = Calendar.getInstance();

            /* Button初始化 */
            mButton = (Button) findViewById(R.id.myButton);
            mButton1 = (Button) findViewById(R.id.myButton1);
            mButton2 = (Button) findViewById(R.id.myButton2);
            /* 拍照Button的事件处理 */
            mButton.setOnClickListener(new Button.OnClickListener() {
                    @Override
                    public void onClick(View arg0) {
                            /* 告动对焦后拍照 */
                            mCamera.autoFocus(mAutoFocusCallback);
                    }
            });
            /* Button的事件处理 */
            mButton1.setOnClickListener(new Button.OnClickListener() {
                    @Override
                    public void onClick(View arg0) {
                            /* 保存文件 */
                   	 Log.i(TAG,"click button2");
                            if (bmp != null) {
                                    /* 检查SDCard是否存在 */
                                    if (!Environment.MEDIA_MOUNTED.equals(Environment
                                                    .getExternalStorageState())) {
                                            /* SD卡不存在，显示Toast信息 */
                                            Toast.makeText(ScanBarZBarActivity.this,
                                                            "SD卡不存在!无法保存相片,请插入SD卡。", Toast.LENGTH_LONG)
                                                            .show();
                                    } else {
                                            try {
                                                    /* 文件不存在就创建 */
                                                    File f = new File(Environment
                                                                    .getExternalStorageDirectory(), path);
                                                    Log.i(TAG,"click button2:" + f.getAbsolutePath());
                                                    if (!f.exists()) {
                                                            f.mkdir();
                                                    }
                                                    /* 保存相片文件 */
                                                    path1 = String.valueOf(c.get(Calendar.MILLISECOND))
                                                                    + "camera.jpg";
                                                    File n = new File(f, path1);
                                                    FileOutputStream bos = new FileOutputStream(n
                                                                    .getAbsolutePath());
                                                    /* 文件转换 */
                                                    bmp.compress(Bitmap.CompressFormat.JPEG, 100, bos);
                                                    /* 调用flush()方法，更新BufferStream */
                                                    bos.flush();
                                                    /* 结束OutputStream */
                                                    bos.close();
                                                    Toast.makeText(ScanBarZBarActivity.this,
                                                                    path1 + "保存成功!", Toast.LENGTH_LONG).show();
                                                    cnt++;
                                            } catch (Exception e) {
                                                    e.printStackTrace();
                                            }
                                    }
                            }

                            mButton.setVisibility(View.VISIBLE);
                            mButton1.setVisibility(View.VISIBLE);
                            mButton2.setVisibility(View.VISIBLE);
                            /* 重新设定Camera */
                            stopCamera();
                            initCamera();
                    }
            });
            /* 放弃Button的事件处理 */
            mButton2.setOnClickListener(new Button.OnClickListener() {
                    @Override
                    public void onClick(View arg0) {
                            mButton.setVisibility(View.VISIBLE);
                            mButton1.setVisibility(View.VISIBLE);
                            mButton2.setVisibility(View.VISIBLE);
                            /* 重新设定Camera */
                            stopCamera();
                            initCamera();
                    }
            });
    }

    @Override
    public void surfaceCreated(SurfaceHolder surfaceholder) {
            try {
                    /* 打开相机， */
                    mCamera = Camera.open();
                    mCamera.setPreviewDisplay(holder);
            } catch (IOException exception) {
                    mCamera.release();
                    mCamera = null;
            }
    }

    @Override
    public void surfaceChanged(SurfaceHolder surfaceholder, int format, int w,
                    int h) {
            /* 相机初始化 */
    		Log.i(TAG,"init camera");
            initCamera();
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder surfaceholder) {
    		Log.i(TAG,"destoryed camera");
            stopCamera();
            mCamera.release();
            mCamera = null;
    }

    /* 拍照的method */
    private void takePicture() {
            if (mCamera != null) {
            	Log.i(TAG,"takePicture");
                    mCamera.takePicture(shutterCallback, rawCallback, jpegCallback);
            }
    }

    private ShutterCallback shutterCallback = new ShutterCallback() {
            public void onShutter() {

            }
    };

    private PictureCallback rawCallback = new PictureCallback() {
            public void onPictureTaken(byte[] _data, Camera _camera) {
            }
    };

    private PictureCallback jpegCallback = new PictureCallback() {
            public void onPictureTaken(byte[] _data, Camera _camera) {
                    /* 取得相仞 */
                    try {
                            /* 设定Button?视性 */
                            mButton.setVisibility(View.GONE);
                            mButton1.setVisibility(View.VISIBLE);
                            mButton2.setVisibility(View.VISIBLE);
                            /* 取得相仞Bitmap对象 */
                            bmp = BitmapFactory.decodeByteArray(_data, 0, _data.length);
                            //发送给isbn分析
                           // String isbn = getISBN(bmp);获得图片解析后的信息
                          //  Log.i(TAG, "isbn:" + flag + isbn);
                            flag--;
                            if(flag>0){
                            	mCamera.autoFocus(mAutoFocusCallback);
                            }
                           
                    } catch (Exception e) {
                            e.printStackTrace();
                    }
            }
    };

    /* 告定义class AutoFocusCallback */
    public final class AutoFocusCallback implements
                    android.hardware.Camera.AutoFocusCallback {
            public void onAutoFocus(boolean focused, Camera camera) {
                    /* 对到焦点拍照 */
                    if (focused) {
                            takePicture();
                    }
            }
    };

    /* 相机初始化的method */
    private void initCamera() {
            if (mCamera != null) {
                    try {
                            Camera.Parameters parameters = mCamera.getParameters();
                            /*
                             * 设定相片大小为1024*768， 格式为JPG
                             */
                            parameters.setPictureFormat(PixelFormat.JPEG);
                            parameters.setPictureSize(1024, 768);
                            mCamera.setParameters(parameters);
                            /* 开启预览画面 */
                            mCamera.startPreview();
                    } catch (Exception e) {
                            e.printStackTrace();
                    }
            }
    }

    /* 停止相机的method */
    private void stopCamera() {
            if (mCamera != null) {
                    try {
                            /* 停止预览 */
                            mCamera.stopPreview();
                    } catch (Exception e) {
                            e.printStackTrace();
                    }
            }
    }
}

 

 

评论

1 楼 enefry 2011-05-24  

不能修改对焦和曝光时间啊.