在片段内打开相机答案

【问题标题】：Open camera inside fragment在片段内打开相机
【发布时间】：2015-08-25 13:29:25
【问题描述】：

是否可以在fragment 类似视图中使用相机，这样它就不会打开另一个应用并离开我的特殊应用？

我想要像 SurfaceView 这样的带摄像头的东西？

【问题讨论】：

标签： android camera fragment android-camera

【解决方案1】：

是的，检查这个link。

基本上覆盖SurfaceView并整合camera picture callback。

示例代码：

/* Surface on which the camera projects it's capture results.
*/
class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
        SurfaceHolder mHolder;
        Camera mCamera;

        public CameraPreview(Context context, Camera camera) {
            super(context);
            mCamera = camera;

            // Install a SurfaceHolder.Callback so we get notified when the
            // underlying surface is created and destroyed.
            mHolder = getHolder();
            mHolder.addCallback(this);
            // deprecated setting, but required on Android versions prior to 3.0
            mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        }

        public void surfaceCreated(SurfaceHolder holder) {
            // The Surface has been created, now tell the camera where to draw the preview.
            try {
                mCamera.setPreviewDisplay(holder);
                mCamera.startPreview();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        public void surfaceDestroyed(SurfaceHolder holder) {
            // empty. Take care of releasing the Camera preview in your activity.
        }

        public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
            // If your preview can change or rotate, take care of those events here.
            // Make sure to stop the preview before resizing or reformatting it.

            if (mHolder.getSurface() == null){
                // preview surface does not exist
                return;
            }

            // stop preview before making changes
            try {
                mCamera.stopPreview();
            } catch (Exception e){
                // ignore: tried to stop a non-existent preview
            }

            // set preview size and make any resize, rotate or
            // reformatting changes here

            // start preview with new settings
            try {
                mCamera.setPreviewDisplay(mHolder);
                mCamera.startPreview();

            } catch (Exception e){
                e.printStackTrace();
            }
        }
    }

带有摄像头图片回调，例如：

private Camera.PictureCallback mPicture = new Camera.PictureCallback() {

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

            File pictureFile = getOutputMediaFile();
            if (pictureFile == null){
                Toast.makeText(getActivity(), "Image retrieval failed.", Toast.LENGTH_SHORT)
                .show();
                return;
            }

            try {
                FileOutputStream fos = new FileOutputStream(pictureFile);
                fos.write(data);
                fos.close();
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    };

【讨论】：

有缺陷...缺少默认构造函数的参数和以编程方式实现视图，因为通过 XML 调用一个平淡无奇的构造函数。

【解决方案2】：

原生实现要好得多。

XML

<com.google.android.cameraview.CameraView
android:id="@+id/camera"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:keepScreenOn="true"
android:adjustViewBounds="true"
app:autoFocus="true"
app:aspectRatio="4:3"
app:facing="back"
app:flash="auto"/>

内部活动/片段

启动相机

  mCameraView.start();

停止相机

  mCameraView.stop();

Open source: Google

需要 API 级别 9。该库使用 API 级别 9-20 的 Camera 1 API 和 21 及更高级别的 Camera2。

【讨论】：

这太棒了