ImageUtils.java

package com.dingmouren.dingdingmusic.utils;

import android.content.ContentResolver;
import android.content.ContentUris;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.ParcelFileDescriptor;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import rx.Observable;

/**
 * Created by dingmouren on 2017/2/10.
 */

public class ImageUtils {
    private static final BitmapFactory.Options sBitmapOptionsCache = new BitmapFactory.Options();
    private static final Uri sArtworkUri = Uri.parse("content://media/external/audio/albumart");

    public static Bitmap getArtworkQuick(Context context, long album_id, int w,int h) {
        w -= 1;
        ContentResolver res = context.getContentResolver();
        Uri uri = ContentUris.withAppendedId(sArtworkUri, album_id);

        if (uri != null) {
            ParcelFileDescriptor fd = null;
            try {
                fd = res.openFileDescriptor(uri, "r");
                if (fd == null) {
                    return null;
                }
                int sampleSize = 1;

                sBitmapOptionsCache.inJustDecodeBounds = true;
                BitmapFactory.decodeFileDescriptor(fd.getFileDescriptor(),
                        null, sBitmapOptionsCache);
                int nextWidth = sBitmapOptionsCache.outWidth >> 1;
                int nextHeight = sBitmapOptionsCache.outHeight >> 1;
                while (nextWidth > w && nextHeight > h) {
                    sampleSize <<= 1;
                    nextWidth >>= 1;
                    nextHeight >>= 1;
                }

                sBitmapOptionsCache.inSampleSize = sampleSize;
                sBitmapOptionsCache.inJustDecodeBounds = false;
                Bitmap b = BitmapFactory.decodeFileDescriptor(
                        fd.getFileDescriptor(), null, sBitmapOptionsCache);

                if (b != null) {
                    if (sBitmapOptionsCache.outWidth != w
                            || sBitmapOptionsCache.outHeight != h) {
                        Bitmap tmp = Bitmap.createScaledBitmap(b, w, h, true);
                        if (tmp != b)
                            b.recycle();
                        b = tmp;
                    }
                }

                return b;
            } catch (FileNotFoundException e) {
            } finally {
                try {
                    if (fd != null)
                        fd.close();
                } catch (IOException e) {
                }
            }
        }
        return null;
    }

}