如何将相机拍摄的图像保存在手机内存中以检查文件大小？

Question

我正在测试一个可以捕获高质量图像的相机应用程序。 我希望将捕获的图像保存在移动存储器（内部或外部）中以检查图像的详细信息。

我有以下用于捕获图像的代码。

import android.content.Intent;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.design.widget.BottomSheetBehavior;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewTreeObserver;
import android.view.WindowManager;
import android.widget.Toast;

import com.otaliastudios.cameraview.CameraListener;
import com.otaliastudios.cameraview.CameraLogger;
import com.otaliastudios.cameraview.CameraOptions;
import com.otaliastudios.cameraview.CameraView;
import com.otaliastudios.cameraview.SessionType;
import com.otaliastudios.cameraview.Size;

import java.io.File;


public class CameraActivity extends AppCompatActivity implements View.OnClickListener, ControlView.Callback {

    private CameraView camera;
    private ViewGroup controlPanel;

    private boolean mCapturingPicture;
    private boolean mCapturingVideo;

    // To show stuff in the callback
    private Size mCaptureNativeSize;
    private long mCaptureTime;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED,
                WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED);
        setContentView(R.layout.activity_camera);
        CameraLogger.setLogLevel(CameraLogger.LEVEL_VERBOSE);

        camera = findViewById(R.id.camera);
        camera.addCameraListener(new CameraListener() {
            public void onCameraOpened(CameraOptions options) { onOpened(); }
            public void onPictureTaken(byte[] jpeg) { onPicture(jpeg); }

            @Override
            public void onVideoTaken(File video) {
                super.onVideoTaken(video);
                onVideo(video);
            }
        });

        findViewById(R.id.edit).setOnClickListener(this);
        findViewById(R.id.capturePhoto).setOnClickListener(this);
        findViewById(R.id.captureVideo).setOnClickListener(this);
        findViewById(R.id.toggleCamera).setOnClickListener(this);

        controlPanel = findViewById(R.id.controls);
        ViewGroup group = (ViewGroup) controlPanel.getChildAt(0);
        Control[] controls = Control.values();
        for (Control control : controls) {
            ControlView view = new ControlView(this, control, this);
            group.addView(view, ViewGroup.LayoutParams.MATCH_PARENT,
                    ViewGroup.LayoutParams.WRAP_CONTENT);
        }

        controlPanel.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                BottomSheetBehavior b = BottomSheetBehavior.from(controlPanel);
                b.setState(BottomSheetBehavior.STATE_HIDDEN);
            }
        });
    }

    private void message(String content, boolean important) {
        int length = important ? Toast.LENGTH_LONG : Toast.LENGTH_SHORT;
        Toast.makeText(this, content, length).show();
    }

    private void onOpened() {
        ViewGroup group = (ViewGroup) controlPanel.getChildAt(0);
        for (int i = 0; i < group.getChildCount(); i++) {
            ControlView view = (ControlView) group.getChildAt(i);
            view.onCameraOpened(camera);
        }
    }

    private void onPicture(byte[] jpeg) {
        mCapturingPicture = false;
        long callbackTime = System.currentTimeMillis();
        if (mCapturingVideo) {
            message("Captured while taking video. Size="+mCaptureNativeSize, false);
            return;
        }

        // This can happen if picture was taken with a gesture.
        if (mCaptureTime == 0) mCaptureTime = callbackTime - 300;
        if (mCaptureNativeSize == null) mCaptureNativeSize = camera.getPictureSize();

        PicturePreviewActivity.setImage(jpeg);
        Intent intent = new Intent(CameraActivity.this, PicturePreviewActivity.class);
        intent.putExtra("delay", callbackTime - mCaptureTime);
        intent.putExtra("nativeWidth", mCaptureNativeSize.getWidth());
        intent.putExtra("nativeHeight", mCaptureNativeSize.getHeight());
        startActivity(intent);

        mCaptureTime = 0;
        mCaptureNativeSize = null;
    }

    private void onVideo(File video) {
        mCapturingVideo = false;
        Intent intent = new Intent(CameraActivity.this, VideoPreviewActivity.class);
        intent.putExtra("video", Uri.fromFile(video));
        startActivity(intent);
    }

    @Override
    public void onClick(View view) {
        switch (view.getId()) {
            case R.id.edit: edit(); break;
            case R.id.capturePhoto: capturePhoto(); break;
            case R.id.captureVideo: captureVideo(); break;
            case R.id.toggleCamera: toggleCamera(); break;
        }
    }

    @Override
    public void onBackPressed() {
        BottomSheetBehavior b = BottomSheetBehavior.from(controlPanel);
        if (b.getState() != BottomSheetBehavior.STATE_HIDDEN) {
            b.setState(BottomSheetBehavior.STATE_HIDDEN);
            return;
        }
        super.onBackPressed();
    }

    private void edit() {
        BottomSheetBehavior b = BottomSheetBehavior.from(controlPanel);
        b.setState(BottomSheetBehavior.STATE_COLLAPSED);
    }

    private void capturePhoto() {
        if (mCapturingPicture) return;
        mCapturingPicture = true;
        mCaptureTime = System.currentTimeMillis();
        mCaptureNativeSize = camera.getPictureSize();
        message("Capturing picture...", false);
        camera.capturePicture();
    }

    private void captureVideo() {
        if (camera.getSessionType() != SessionType.VIDEO) {
            message("Can't record video while session type is 'picture'.", false);
            return;
        }
        if (mCapturingPicture || mCapturingVideo) return;
        mCapturingVideo = true;
        message("Recording for 8 seconds...", true);
        camera.startCapturingVideo(null, 8000);
    }

    private void toggleCamera() {
        if (mCapturingPicture) return;
        switch (camera.toggleFacing()) {
            case BACK:
                message("Switched to back camera!", false);
                break;

            case FRONT:
                message("Switched to front camera!", false);
                break;
        }
    }

    @Override
    public boolean onValueChanged(Control control, Object value, String name) {
        if (!camera.isHardwareAccelerated() && (control == Control.WIDTH || control == Control.HEIGHT)) {
            if ((Integer) value > 0) {
                message("This device does not support hardware acceleration. " +
                        "In this case you can not change width or height. " +
                        "The view will act as WRAP_CONTENT by default.", true);
                return false;
            }
        }
        control.applyValue(camera, value);
        BottomSheetBehavior b = BottomSheetBehavior.from(controlPanel);
        b.setState(BottomSheetBehavior.STATE_HIDDEN);
        message("Changed " + control.getName() + " to " + name, false);
        return true;
    }

    //region Boilerplate

    @Override
    protected void onResume() {
        super.onResume();
        camera.start();
    }

    @Override
    protected void onPause() {
        super.onPause();
        camera.stop();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        camera.destroy();
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        boolean valid = true;
        for (int grantResult : grantResults) {
            valid = valid && grantResult == PackageManager.PERMISSION_GRANTED;
        }
        if (valid && !camera.isStarted()) {
            camera.start();
        }
    }

    //endregion
}

我还添加了读取和写入外部存储的权限。 但我只想知道图片保存后的大小。

添加代码以保存图像 -

    public void KickOut(String filename,Bitmap bitmap){

        ActivityCompat.requestPermissions(PicturePreviewActivity.this,new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},1);
        OutputStream outputStream;
        File filepath=Environment.getExternalStorageDirectory();
//        File dir=new File(filepath+"/Olaa/");
        File dir=new File("/Environment.getExternalStoragePublicDirectory/Imgs/");
        dir.mkdirs();
        File file=new File(dir,"filename.png");
        Toast.makeText(PicturePreviewActivity.this, file + " -> saved" , Toast.LENGTH_SHORT).show();
        try{
            outputStream=new FileOutputStream(file);
            bitmap.compress(Bitmap.CompressFormat.PNG,100,outputStream);
            outputStream.flush();outputStream.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
//        Toast.makeText(PicturePreviewActivity.this, filepath + " -> path" , Toast.LENGTH_SHORT).show();
    }

Answer 1

您可以检查捕获图像的大小，也可以将文件保存在自定义文件夹中。

您可以在 onActivityResult() 中获取结果并从包中获取图像并将其转换为字节，lengthbmp_KB 将为您提供以 kb 为单位的大小。

if (resultCode == RESULT_OK) {

        //Image capture
        if (requestCode == 1) {
            Bitmap thumbnail = (Bitmap) data.getExtras().get("data");
            ByteArrayOutputStream bytes = new ByteArrayOutputStream();
            thumbnail.compress(Bitmap.CompressFormat.JPEG, 100, bytes);
            byte[] imageInByte = bytes.toByteArray();
            long lengthbmp = imageInByte.length;
            // save on custom folder
            File destination1 = createDirectoryAndSaveFile(thumbnail, System.currentTimeMillis() + ".jpg");

          /*  File destination = new File(Environment.getExternalStorageDirectory(),
                    System.currentTimeMillis() + ".jpg");*/
            picturePath = "" + destination1;
            // show image on gallery
            scanGallery(getActivity(), picturePath);

            long lengthbmp_KB = lengthbmp / 1024;
            long length_MB = lengthbmp_KB / 1024;

        }

您可以将文件保存在您自己的文件夹中

 private File createDirectoryAndSaveFile(Bitmap imageToSave, String fileName) {
    File direct = new File(Environment.getExternalStorageDirectory() + "/My Images");
    if (!direct.exists()) {
        File wallpaperDirectory = new File("/sdcard/MYfolder Images/");
        wallpaperDirectory.mkdirs();
    }
    File file = new File(new File("/sdcard/Myfolder Images/"), fileName);
  /*  if (file.exists()) {
        file.delete();
    }*/
    try {
        FileOutputStream out = new FileOutputStream(file);
        imageToSave.compress(Bitmap.CompressFormat.JPEG, 100, out);
        out.flush();
        out.close();
    } catch (Exception e) {
        e.printStackTrace();
    }
    return file;
}

您可以使用此 MediaScannerConnection 在图库中查看您的图像

 private void scanGallery(Context cntx, String path) {
    try {
        MediaScannerConnection.scanFile(cntx, new String[]{path}, null, new MediaScannerConnection.OnScanCompletedListener() {
            public void onScanCompleted(String path, Uri uri) {
            }
        });
    } catch (Exception e) {
        e.printStackTrace();
    }
}

并在 onActivityResult() 中使用此方法

Answer 2

要检查保存在手机内存中的图像大小，您可以使用 Bitmapfactory.option

**BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(filename, options);
int imageHeight = options.outHeight;
int imageWidth = options.outWidth;**

Answer 3

您可以使用它来保存文件，前提是您已在清单中授予权限。

static final int REQUEST_TAKE_PHOTO = 1;

private void dispatchTakePictureIntent() {
    Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    // Ensure that there's a camera activity to handle the intent
    if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
        // Create the File where the photo should go
        File photoFile = null;
        try {
            photoFile = createImageFile();
        } catch (IOException ex) {
            // Error occurred while creating the File
            ...
        }
        // Continue only if the File was successfully created
        if (photoFile != null) {
            Uri photoURI = FileProvider.getUriForFile(this,
                                                  "com.example.android.fileprovider",
                                                  photoFile);
            takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, photoURI);
            startActivityForResult(takePictureIntent, REQUEST_TAKE_PHOTO);
        }
    }
}

也看看这里的文档。