Question

我得到了一个代码，如果看起来它的宽度太宽，我会压缩并调整位图大小。该代码有效，但我知道位图，调整大小和压缩是一项昂贵的任务，我担心我的代码可能无法以正确的方式执行。

你能看一下并提交更好的方法吗？

谢谢，

安迪

以下是代码：

 // Max Width size
        final int destWidth = 2300;


        // Compress the Image
        ByteArrayOutputStream bytes = new ByteArrayOutputStream();
        Bitmap bitmap = null;
        Bitmap resizedBitmap = null;
        String path = null;

        try {
            bitmap = MediaStore.Images.Media.getBitmap(getActivity().getContentResolver(), imageUri);
            bitmap.compress(Bitmap.CompressFormat.JPEG, 20, bytes);
            path = MediaStore.Images.Media.insertImage(getActivity().getContentResolver(), bitmap, imageUri.getEncodedQuery(), null);

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

        if (bitmap != null) {
            if (bitmap.getWidth() > destWidth) {
                final int desHeight = bitmap.getHeight() / (bitmap.getWidth() / destWidth);
                resizedBitmap = Bitmap.createScaledBitmap(bitmap, destWidth, desHeight,false);
                resizedBitmap.compress(Bitmap.CompressFormat.JPEG, 20, bytes);
                path = MediaStore.Images.Media.insertImage(getActivity().getContentResolver(), resizedBitmap, imageUri.getEncodedQuery(), null);
            }
        }

        final Uri uri = Uri.parse(path);


        // Clean up
        try {
            bitmap.recycle();
            bytes.close();

            if (resizedBitmap != null) {
                resizedBitmap.recycle();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }

Answer 1

您可以使用以下java类来实现。这是完全优化的。

请在项目中记住导入compile 'io.reactivex:rxandroid:1.2.1'。

<强> FileUtil.java

import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.provider.MediaStore;
import android.provider.OpenableColumns;
import android.util.Log;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * Created by aupadhyay on 1/31/17.
 */

public class FileUtil {
    static final String FILES_PATH = "CompressImage";
    private static final int EOF = -1;
    private static final int DEFAULT_BUFFER_SIZE = 1024 * 4;

    private FileUtil() {

    }

    public static File from(Context context, Uri uri) throws IOException {
        InputStream inputStream = context.getContentResolver().openInputStream(uri);
        String fileName = getFileName(context, uri);
        String[] splitName = splitFileName(fileName);
        File tempFile = File.createTempFile(splitName[0], splitName[1]);
        tempFile = rename(tempFile, fileName);
        tempFile.deleteOnExit();
        FileOutputStream out = null;
        try {
            out = new FileOutputStream(tempFile);
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        if (inputStream != null) {
            copy(inputStream, out);
            inputStream.close();
        }

        if (out != null) {
            out.close();
        }
        return tempFile;
    }

    static String[] splitFileName(String fileName) {
        String name = fileName;
        String extension = "";
        int i = fileName.lastIndexOf(".");
        if (i != -1) {
            name = fileName.substring(0, i);
            extension = fileName.substring(i);
        }

        return new String[]{name, extension};
    }

    static String getFileName(Context context, Uri uri) {
        String result = null;
        if (uri.getScheme().equals("content")) {
            Cursor cursor = context.getContentResolver().query(uri, null, null, null, null);
            try {
                if (cursor != null && cursor.moveToFirst()) {
                    result = cursor.getString(cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME));
                }
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if (cursor != null) {
                    cursor.close();
                }
            }
        }
        if (result == null) {
            result = uri.getPath();
            int cut = result.lastIndexOf(File.separator);
            if (cut != -1) {
                result = result.substring(cut + 1);
            }
        }
        return result;
    }

    static String getRealPathFromURI(Context context, Uri contentUri) {
        Cursor cursor = context.getContentResolver().query(contentUri, null, null, null, null);
        if (cursor == null) {
            return contentUri.getPath();
        } else {
            cursor.moveToFirst();
            int index = cursor.getColumnIndex(MediaStore.Images.ImageColumns.DATA);
            String realPath = cursor.getString(index);
            cursor.close();
            return realPath;
        }
    }

    static File rename(File file, String newName) {
        File newFile = new File(file.getParent(), newName);
        if (!newFile.equals(file)) {
            if (newFile.exists()) {
                if (newFile.delete()) {
                    Log.d("FileUtil", "Delete old " + newName + " file");
                }
            }
            if (file.renameTo(newFile)) {
                Log.d("FileUtil", "Rename file to " + newName);
            }
        }
        return newFile;
    }

    static int copy(InputStream input, OutputStream output) throws IOException {
        long count = copyLarge(input, output);
        if (count > Integer.MAX_VALUE) {
            return -1;
        }
        return (int) count;
    }

    static long copyLarge(InputStream input, OutputStream output)
            throws IOException {
        return copyLarge(input, output, new byte[DEFAULT_BUFFER_SIZE]);
    }

    static long copyLarge(InputStream input, OutputStream output, byte[] buffer)
            throws IOException {
        long count = 0;
        int n;
        while (EOF != (n = input.read(buffer))) {
            output.write(buffer, 0, n);
            count += n;
        }
        return count;
    }
}

<强> ImageUtil.java

import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.media.ExifInterface;
import android.net.Uri;
import android.text.TextUtils;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * Created by aupadhyay on 1/31/17.
 */

class ImageUtil {

    private ImageUtil() {

    }

    static Bitmap getScaledBitmap(Context context, Uri imageUri, float maxWidth, float maxHeight, Bitmap.Config bitmapConfig) {
        String filePath = FileUtil.getRealPathFromURI(context, imageUri);
        Bitmap scaledBitmap = null;

        BitmapFactory.Options options = new BitmapFactory.Options();

        //by setting this field as true, the actual bitmap pixels are not loaded in the memory. Just the bounds are loaded. If
        //you try the use the bitmap here, you will get null.
        options.inJustDecodeBounds = true;
        Bitmap bmp = BitmapFactory.decodeFile(filePath, options);
        if (bmp == null) {

            InputStream inputStream = null;
            try {
                inputStream = new FileInputStream(filePath);
                BitmapFactory.decodeStream(inputStream, null, options);
                inputStream.close();
            } catch (FileNotFoundException exception) {
                exception.printStackTrace();
            } catch (IOException exception) {
                exception.printStackTrace();
            }
        }

        int actualHeight = options.outHeight;
        int actualWidth = options.outWidth;

        if (actualWidth < 0 || actualHeight < 0) {
            Bitmap bitmap2 = BitmapFactory.decodeFile(filePath);
            actualWidth = bitmap2.getWidth();
            actualHeight = bitmap2.getHeight();
        }

        float imgRatio = (float) actualWidth / actualHeight;
        float maxRatio = maxWidth / maxHeight;

        //width and height values are set maintaining the aspect ratio of the image
        if (actualHeight > maxHeight || actualWidth > maxWidth) {
            if (imgRatio < maxRatio) {
                imgRatio = maxHeight / actualHeight;
                actualWidth = (int) (imgRatio * actualWidth);
                actualHeight = (int) maxHeight;
            } else if (imgRatio > maxRatio) {
                imgRatio = maxWidth / actualWidth;
                actualHeight = (int) (imgRatio * actualHeight);
                actualWidth = (int) maxWidth;
            } else {
                actualHeight = (int) maxHeight;
                actualWidth = (int) maxWidth;
            }
        }

        //setting inSampleSize value allows to load a scaled down version of the original image
        options.inSampleSize = calculateInSampleSize(options, actualWidth, actualHeight);

        //inJustDecodeBounds set to false to load the actual bitmap
        options.inJustDecodeBounds = false;

        //this options allow android to claim the bitmap memory if it runs low on memory
        options.inPurgeable = true;
        options.inInputShareable = true;
        options.inTempStorage = new byte[16 * 1024];

        try {
            //load the bitmap from its path
            bmp = BitmapFactory.decodeFile(filePath, options);
            if (bmp == null) {

                InputStream inputStream = null;
                try {
                    inputStream = new FileInputStream(filePath);
                    BitmapFactory.decodeStream(inputStream, null, options);
                    inputStream.close();
                } catch (FileNotFoundException exception) {
                    exception.printStackTrace();
                } catch (IOException exception) {
                    exception.printStackTrace();
                }
            }
        } catch (OutOfMemoryError exception) {
            exception.printStackTrace();
        }
        try {
            scaledBitmap = Bitmap.createBitmap(actualWidth, actualHeight, bitmapConfig);
        } catch (OutOfMemoryError exception) {
            exception.printStackTrace();
        }

        float ratioX = actualWidth / (float) options.outWidth;
        float ratioY = actualHeight / (float) options.outHeight;

        Matrix scaleMatrix = new Matrix();
        scaleMatrix.setScale(ratioX, ratioY, 0, 0);

        Canvas canvas = new Canvas(scaledBitmap);
        canvas.setMatrix(scaleMatrix);
        canvas.drawBitmap(bmp, 0, 0, new Paint(Paint.FILTER_BITMAP_FLAG));

        //check the rotation of the image and display it properly
        ExifInterface exif;
        try {
            exif = new ExifInterface(filePath);
            int orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, 0);
            Matrix matrix = new Matrix();
            if (orientation == 6) {
                matrix.postRotate(90);
            } else if (orientation == 3) {
                matrix.postRotate(180);
            } else if (orientation == 8) {
                matrix.postRotate(270);
            }
            scaledBitmap = Bitmap.createBitmap(scaledBitmap, 0, 0,
                    scaledBitmap.getWidth(), scaledBitmap.getHeight(),
                    matrix, true);
        } catch (IOException e) {
            e.printStackTrace();
        }

        return scaledBitmap;
    }

    static File compressImage(Context context, Uri imageUri, float maxWidth, float maxHeight,
                              Bitmap.CompressFormat compressFormat, Bitmap.Config bitmapConfig,
                              int quality, String parentPath, String prefix, String fileName) {
        FileOutputStream out = null;
        String filename = generateFilePath(context, parentPath, imageUri, compressFormat.name().toLowerCase(), prefix, fileName);
        try {
            out = new FileOutputStream(filename);

            //write the compressed bitmap at the destination specified by filename.
            ImageUtil.getScaledBitmap(context, imageUri, maxWidth, maxHeight, bitmapConfig).compress(compressFormat, quality, out);

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } finally {
            try {
                if (out != null) {
                    out.close();
                }
            } catch (IOException ignored) {
            }
        }

        return new File(filename);
    }

    private static String generateFilePath(Context context, String parentPath, Uri uri,
                                           String extension, String prefix, String fileName) {
        File file = new File(parentPath);
        if (!file.exists()) {
            file.mkdirs();
        }
        /** if prefix is null, set prefix "" */
        prefix = TextUtils.isEmpty(prefix) ? "" : prefix;
        /** reset fileName by prefix and custom file name */
        fileName = TextUtils.isEmpty(fileName) ? prefix + FileUtil.splitFileName(FileUtil.getFileName(context, uri))[0] : fileName;
        return file.getAbsolutePath() + File.separator + fileName + "." + extension;
    }

    private static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
        final int height = options.outHeight;
        final int width = options.outWidth;
        int inSampleSize = 1;

        if (height > reqHeight || width > reqWidth) {
            final int heightRatio = Math.round((float) height / (float) reqHeight);
            final int widthRatio = Math.round((float) width / (float) reqWidth);
            inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
        }

        final float totalPixels = width * height;
        final float totalReqPixelsCap = reqWidth * reqHeight * 2;

        while (totalPixels / (inSampleSize * inSampleSize) > totalReqPixelsCap) {
            inSampleSize++;
        }

        return inSampleSize;
    }
}

<强> CompressImage.java

import android.content.Context;
import android.graphics.Bitmap;
import android.net.Uri;

import java.io.File;

import rx.Observable;
import rx.functions.Func0;

/**
 * Created by aupadhyay on 1/31/17.
 */

public class CompressImage {
    private static volatile CompressImage INSTANCE;
    private Context context;
    //max width and height values of the compressed image is taken as 612x816
    private float maxWidth = 612.0f;
    private float maxHeight = 816.0f;
    private Bitmap.CompressFormat compressFormat = Bitmap.CompressFormat.JPEG;
    private Bitmap.Config bitmapConfig = Bitmap.Config.ARGB_8888;
    private int quality = 80;
    private String destinationDirectoryPath;
    private String fileNamePrefix;
    private String fileName;


    private CompressImage(Context context) {
        this.context = context;
        destinationDirectoryPath = context.getCacheDir().getPath() + File.pathSeparator + FileUtil.FILES_PATH;
    }

    public static CompressImage getDefault(Context context) {
        if (INSTANCE == null) {
            synchronized (CompressImage.class) {
                if (INSTANCE == null) {
                    INSTANCE = new CompressImage(context);
                }
            }
        }
        return INSTANCE;
    }

    public File compressToFile(File file) {
        return ImageUtil.compressImage(context, Uri.fromFile(file), maxWidth, maxHeight,
                compressFormat, bitmapConfig, quality, destinationDirectoryPath,
                fileNamePrefix, fileName);
    }

    public Bitmap compressToBitmap(File file) {
        return ImageUtil.getScaledBitmap(context, Uri.fromFile(file), maxWidth, maxHeight, bitmapConfig);
    }

    public Observable<File> compressToFileAsObservable(final File file) {
        return Observable.defer(new Func0<Observable<File>>() {
            @Override
            public Observable<File> call() {
                return Observable.just(compressToFile(file));
            }
        });
    }

    public Observable<Bitmap> compressToBitmapAsObservable(final File file) {
        return Observable.defer(new Func0<Observable<Bitmap>>() {
            @Override
            public Observable<Bitmap> call() {
                return Observable.just(compressToBitmap(file));
            }
        });
    }

    public static class Builder {
        private CompressImage compressImage;

        public Builder(Context context) {
            compressImage = new CompressImage(context);
        }

        public Builder setMaxWidth(float maxWidth) {
            compressImage.maxWidth = maxWidth;
            return this;
        }

        public Builder setMaxHeight(float maxHeight) {
            compressImage.maxHeight = maxHeight;
            return this;
        }

        public Builder setCompressFormat(Bitmap.CompressFormat compressFormat) {
            compressImage.compressFormat = compressFormat;
            return this;
        }

        public Builder setBitmapConfig(Bitmap.Config bitmapConfig) {
            compressImage.bitmapConfig = bitmapConfig;
            return this;
        }

        public Builder setQuality(int quality) {
            compressImage.quality = quality;
            return this;
        }

        public Builder setDestinationDirectoryPath(String destinationDirectoryPath) {
            compressImage.destinationDirectoryPath = destinationDirectoryPath;
            return this;
        }

        public Builder setFileNamePrefix(String prefix) {
            compressImage.fileNamePrefix = prefix;
            return this;
        }

        public Builder setFileName(String fileName) {
            compressImage.fileName = fileName;
            return this;
        }

        public CompressImage build() {
            return compressImage;
        }
    }
}

现在要压缩您的图片，您可以使用以下代码段：

        // Compress image using RxJava in background thread
        CompressImage.getDefault(this)
                .compressToFileAsObservable(actualImage)
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(new Action1<File>() {
                    @Override
                    public void call(File file) {
                        compressedImage = file;
                        // use compressedImage or pass in any function.
                    }
                }, new Action1<Throwable>() {
                    @Override
                    public void call(Throwable throwable) {
                        //throwable.getMessage();
                    }
                });

我们将actualImage和compressedImage作为文件对象。

private File actualImage;
private File compressedImage;

**更新

意图打开图片库：

Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
        intent.setType("image/*");
        startActivityForResult(intent, PICK_IMAGE_REQUEST); // private static final int PICK_IMAGE_REQUEST = 1;

你可以使用onActivityResult：

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == PICK_IMAGE_REQUEST && resultCode == RESULT_OK) {
        if (data == null) {
            //Failed to open picture!
            return;
        }
        try {
            actualImage = FileUtil.from(this, data.getData());// conversion to file is important.

        } catch (IOException e) {
            //Failed to read picture data!
            e.printStackTrace();
        }
    }
}

现在我认为你不应该得到错误。

位图调整大小和压缩优化

1 个答案: