android实现图片压缩

import static android.os.Environment.DIRECTORY_DOWNLOADS;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Environment;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class PhotoCompresser {
    /**
     *
     * @param inSampleSize  可以根据需求计算出合理的inSampleSize
     */
    public static void compress(int inSampleSize) {
        File sdFile = new File(String.valueOf(Environment.getExternalStoragePublicDirectory(DIRECTORY_DOWNLOADS)));
        File originFile = new File(sdFile, "a.jpg");
        BitmapFactory.Options options = new BitmapFactory.Options();
        //设置此参数是仅仅读取图片的宽高到options中，不会将整张图片读到内存中，防止oom
        options.inJustDecodeBounds = true;
        Bitmap emptyBitmap = BitmapFactory.decodeFile(originFile.getAbsolutePath(), options);
        options.inJustDecodeBounds = false;
        options.inSampleSize = inSampleSize;
        Bitmap resultBitmap = BitmapFactory.decodeFile(originFile.getAbsolutePath(), options);
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        resultBitmap.compress(Bitmap.CompressFormat.JPEG, 100, bos);
        try {
            FileOutputStream fos = new FileOutputStream(new File(sdFile, "resultImg.jpg"));
            fos.write(bos.toByteArray());
            fos.flush();
            fos.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

使用，参数是压缩率，图片放在Download，名字是a.jpg

PhotoCompresser.compress(5);

权限

   <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
    <uses-permission
        android:name="android.permission.WRITE_EXTERNAL_STORAGE"
        android:maxSdkVersion="28" />
    <uses-permission android:name="android.permission.MANAGE_EXTERNAL_STORAGE"
        tools:ignore="ScopedStorage" />

GitHub地址 下载前给star