在定制的相机应用程序中按下按钮切换到前置摄像头

Question

我正在制作一个自定义相机应用程序，它将拍照并将其保存在图库中。 我有两个问题： 1：我无法访问前置摄像头。我添加了另一个按钮并添加了前置摄像头代码，但它不起作用。所以有人可以告诉我应该做什么才能切换到前置摄像头。

2：我的第二个问题是当我的图像被保存时，它的方向变为横向。

here is my code :

public class MainActivity extends AppCompatActivity {
public final static String DEBUG_TAG = "MainActivity";
private Camera mCamera = null;
private Camera.PreviewCallback previewCb;
private Camera.AutoFocusCallback autoFocusCb;
private CameraView mCameraView = null;
public static final int MEDIA_TYPE_IMAGE = 0;
public static int i = 0;
private static final int CAMERA_REQUEST = 1888;
public final static int PICK_PHOTO_CODE = 1046;
ImageButton button;
static final int REQUEST_IMAGE_CAPTURE = 1;
ImageView mImageView;
private int cameraId = 0;


protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
    mImageView = (ImageView) findViewById(R.id.imageView);
    try {
        mCamera = Camera.open();
    } catch (Exception e) {
        Log.d("ERROR", "Failed to get camera: " + e.getMessage());
    }

    if (mCamera != null) {
mCameraView = new CameraView(this, mCamera, previewCb,autoFocusCb);

FrameLayout camera_view = (FrameLayout)  findViewById(R.id.camera_view);

        camera_view.addView(mCameraView);//add the SurfaceView to the layout
    }

}


public void OnBtnClick(View view) {
    mCamera.autoFocus(new Camera.AutoFocusCallback() {

        public void onAutoFocus(boolean success, Camera camera)

        {

                           mCamera.startPreview();
mCamera.takePicture(null, null, new PhotoHandler(getApplicationContext()));

        }

    });

}


public void OnBtn1Click(View view) {

}
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == CAMERA_REQUEST && resultCode == Activity.RESULT_OK) {

        Bitmap photo = (Bitmap) data.getExtras().get("data");
        mImageView.setImageBitmap(photo);

    }
}



}

我的相机预览课程

public class CameraView extends SurfaceView implements  SurfaceHolder.Callback{
public final static String DEBUG_TAG = "MainActivity";
private SurfaceHolder mHolder;
private Camera.AutoFocusCallback autoFocusCallback;
private int cameraId = 0;
private Camera mCamera;
int currentZoomLevel = 0;
private Camera.PreviewCallback previewCallback;
public CameraView(Context context, Camera camera, Camera.PreviewCallback previewCb,Camera.AutoFocusCallback autoFocusCb){
    super(context);
    previewCallback = previewCb;
    autoFocusCallback = autoFocusCb;
    mCamera = camera;
    mCamera.setDisplayOrientation(90);
    mHolder = getHolder();
    mHolder.addCallback(this);
    mHolder.setType(SurfaceHolder.SURFACE_TYPE_NORMAL);

}



@Override
public void surfaceCreated(SurfaceHolder surfaceHolder) {
    try{
        mCamera.setPreviewDisplay(surfaceHolder);
        mCamera.startPreview();
    } catch (IOException e) {
        Log.d("ERROR", "Camera error on surfaceCreated " + e.getMessage());
    }
}

@Override
public void surfaceChanged(SurfaceHolder surfaceHolder, int i, int i2, int i3) {

    if(mHolder.getSurface() == null)
        return;

    try{
        mCamera.stopPreview();
    } catch (Exception e){

    }
    try{
        mCamera.setDisplayOrientation(90);
        mCamera.setPreviewCallback(previewCallback);
        mCamera.setPreviewDisplay(mHolder);
        mCamera.startPreview();
        mCamera.autoFocus(autoFocusCallback);
        mCamera.autoFocus(autoFocusCallback);
    } catch (IOException e) {
        Log.d("ERROR", "Camera error on surfaceChanged " + e.getMessage());
    }
}



@Override
public void surfaceDestroyed(SurfaceHolder surfaceHolder) {
    mCamera.stopPreview();
    mCamera.release();
}

}

和我的xml文件：

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">

<FrameLayout
    android:id="@+id/camera_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/imageView"
        android:layout_gravity="center_horizontal" />

</FrameLayout>

<ImageButton
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/button"
    android:onClick="OnBtnClick"
    android:layout_gravity="center_horizontal|bottom"
    android:background = "@drawable/roundedbutton"
    android:src="@drawable/btn_capture" />

<ImageButton
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:id="@+id/imgClose"
    android:layout_gravity="right|top"
    android:background="@android:drawable/ic_menu_close_clear_cancel"
    android:padding="20dp"/>

<ImageButton
    android:layout_width="113dp"
    android:layout_height="94dp"
    android:id="@+id/imageButton"
    android:layout_gravity="left|bottom"
    android:background = "@drawable/roundedbutton"
    android:src="@drawable/front"
    android:onClick="OnBtn1Click"/>

</FrameLayout>