Android 实现拍照功能

解析：
1）判断是否有摄像头checkCameraHardware(this)
2）获得相机camera = Camera.open(0);
3）把相机添加到mPreView = new SurfacePreView(this, mCamera);
4）实现拍照 mCamera.autoFocus
5）在拍照后使用mCamera.takePicture(null, null, mPicture);方法把图片保存到sdcard

代码实现:

/** * 使用照相机拍照 * @author chen.lin * */
public class CameraActivity extends Activity {
    private Camera mCamera;//相机
    private SurfacePreView mPreView;//视图
    private FrameLayout mFrameLayout;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_camera_takephoto);
        mFrameLayout = (FrameLayout) findViewById(R.id.framelayout);

        if (checkCameraHardware(this)) {
            mCamera = getCamera();
            mPreView = new SurfacePreView(this, mCamera);
            mFrameLayout.addView(mPreView);
        }
    }

    /** * 拍照对焦 * @param view */
    public void takephoto(View view){
        mCamera.autoFocus(new AutoFocusCallback() {
            @Override
            public void onAutoFocus(boolean success, Camera camera) {
                mCamera.takePicture(null, null, mPicture);
            }
        });
    }

    /** * 拍照后的图片保存 */
    private PictureCallback mPicture = new PictureCallback() {

        @Override
        public void onPictureTaken(byte[] data, Camera camera) {
            try {
                File file = new File("/sdcard/file/aa.jpg");
                if (!file.exists()) {
                    file.mkdirs();
                }
                FileOutputStream fos = new FileOutputStream(file);
                fos.write(data);
                fos.close();
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    };

    /** * 判断照相机是否存在 * @param context * @return */
    private boolean checkCameraHardware(Context context){
        if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
            return true;
        }
        return false; 
    }

    /** * 初始化照相机 * @return */
    public static Camera getCamera(){
        Camera camera = null;
        try {
            camera = Camera.open(0);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return camera;
    }
    /** * 实现拍照视图 */
    @SuppressWarnings("deprecation")
    private class SurfacePreView extends SurfaceView implements SurfaceHolder.Callback{
        private Camera mCamera;
        private SurfaceHolder mHolder;

        public SurfacePreView(Context context, Camera camera) {
            super(context);
            mCamera = camera;
            mHolder = getHolder();
            mHolder.addCallback(this);
            mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        }

        @Override
        public void surfaceCreated(SurfaceHolder holder) {
            try {
                mCamera.setPreviewDisplay(mHolder);
                mCamera.startPreview();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        @Override
        public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
            if (holder.getSurface() == null) {
                return;
            }
            try {
                mCamera.stopPreview();
                mCamera.setPreviewDisplay(mHolder);
                mCamera.startPreview();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        @Override
        public void surfaceDestroyed(SurfaceHolder holder) {
            //
            mCamera = null;
        }

    }
}

布局：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" >

    <FrameLayout  android:id="@+id/framelayout" android:layout_width="wrap_content" android:layout_height="0dp" android:layout_weight="1" >
    </FrameLayout>

    <Button  android:id="@+id/button1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:onClick="takephoto" android:text="拍照" />

</LinearLayout>