捕获后，Android Camera API无法在目录中显示图像？

Question

我使用Java制作了自己的Android相机应用程序，一切似乎工作正常，但是当我捕获图像时，它不会显示在我的目录中 - 我 - 我从同一目录中删除一个或多个要删除的文件。你们知道为什么会这样吗？

我通过手机图片库和Windows 10文件管理器（通过USB线）查看了我的目录。

这是我的代码：

CameraDemo.java

package nl.arjenvangaal.takepicturev2;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;

import android.app.Activity;
import android.hardware.Camera;
import android.hardware.Camera.PictureCallback;
import android.hardware.Camera.ShutterCallback;
import android.os.Bundle;
import android.os.Environment;
import android.view.View;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.Toast;

public class CameraDemo extends Activity {
    Preview preview;
    Button saveButton;


    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main); //load layout file

        preview = new Preview(this); //create new camera preview
        ((FrameLayout) findViewById(R.id.preview)).addView(preview); //display new preview

        //button listener
        saveButton = (Button)findViewById(R.id.saveButton);
        saveButton.setOnClickListener(new Button.OnClickListener() {
            public void onClick(View v) {
                preview.camera.takePicture(shutterCallback, rawCallback, jpegCallback);
            }
        });

    }

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

        }
    };

    /** Handles data for raw picture */
    PictureCallback rawCallback = new PictureCallback() {
        public void onPictureTaken(byte[] data, Camera camera) {

        }
    };


    /** Handles data for jpeg picture */
    PictureCallback jpegCallback = new PictureCallback() {
        public void onPictureTaken(byte[] data, Camera camera) {
            SimpleDateFormat dateFormat = new SimpleDateFormat("yyyymmddhhmmss", Locale.US);
            String date = dateFormat.format(new Date());
            String photoFile = "Foto_"+ date + ".jpg";
            File sdDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES); //mapje

            String filename =sdDir + File.separator + photoFile; //mapje + / + filenaam
            File pictureFile = new File(filename);  //uiteindelijke bestandslocatie

            FileOutputStream outStream; //me create new output

            try {
                outStream = new FileOutputStream(pictureFile);
                outStream.write(data);
                outStream.close();

                Toast.makeText(getApplicationContext(), "Foto opgeslagen.", Toast.LENGTH_LONG).show();

            } catch (IOException e) {
                Toast.makeText(getApplicationContext(), "Foto kon niet worden opgeslagen.", Toast.LENGTH_LONG).show();
            }
        }
    };
}

Preview.java

package nl.arjenvangaal.takepicturev2;

import java.io.IOException;
import java.util.List;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.hardware.Camera;
import android.hardware.Camera.PreviewCallback;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;


class Preview extends SurfaceView implements SurfaceHolder.Callback {
    private static final String TAG = "Preview";

    SurfaceHolder mHolder;
    public Camera camera;

    Preview(Context context) {
        super(context);

        // Install a SurfaceHolder.Callback so we get notified when the
        // underlying surface is created and destroyed.
        mHolder = getHolder();
        mHolder.addCallback(this);
        mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

    public void surfaceCreated(SurfaceHolder holder) {
        // The Surface has been created, acquire the camera and tell it where
        // to draw.
        camera = Camera.open();
        try {
            camera.setPreviewDisplay(holder);
            camera.setDisplayOrientation(90); //Roteer het beeld 90 graden zodat het goed wordt weergegeven
            camera.setPreviewCallback(new PreviewCallback() {
                public void onPreviewFrame(byte[] data, Camera arg1) {
                    Preview.this.invalidate();
                }
            });
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        // Surface will be destroyed when we return, so stop the preview.
        // Because the CameraDevice object is not a shared resource, it's very
        // important to release it when the activity is paused.
        camera.stopPreview();
;
        //voorkom error als je het programma afsluit en heropent
        if (camera != null) {
            camera.release();
        }
    }

    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
        Camera.Parameters parameters = camera.getParameters();
        List<Camera.Size> previewSizes = parameters.getSupportedPreviewSizes();

        // You need to choose the most appropriate previewSize for your app
        Camera.Size previewSize = previewSizes.get(0); // .... select one of previewSizes here
        parameters.setPreviewSize(previewSize.width, previewSize.height);
        camera.setParameters(parameters);

        //voorkom error als je het programma afsluit en heropent
        if (mHolder.getSurface() == null) {
            return;
        }
        try {
            camera.stopPreview();
        } catch (Exception e) {
            //You can ignore this, because this means the Preview doesn't Exist
            //So, no need to try stopping
        }
        try {
            camera.setPreviewDisplay(mHolder);
            camera.startPreview();
        } catch (Exception e) {
            //Catch this
        }
    }

    @Override
    public void draw(Canvas canvas) {
        super.draw(canvas);
        Paint p= new Paint(Color.RED);
        Log.d(TAG, "draw");
        canvas.drawText("PREVIEW", canvas.getWidth() / 2, canvas.getHeight() / 2, p);
    }
}

activity_main

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

    <FrameLayout
        android:id="@+id/preview"
        android:layout_weight="1" android:layout_width="fill_parent"
        android:layout_height="fill_parent">
    </FrameLayout>

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Save" android:layout_gravity="center"
        android:id="@+id/saveButton"
        />
</LinearLayout>