android中bitmap与字节流之间的相互转换

将字节数组转换为ImageView可调用的Bitmap对象,图片缩放,把字节数组保存为一个文件,把Bitmap转Byte
import java.io.BufferedOutputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;

public class ImageDispose {



    /**
     * @param 将图片内容解析成字节数组
     * @param inStream
     * @return byte[]
     * @throws Exception
     */
    public static byte[] readStream(InputStream inStream) throws Exception {
        byte[] buffer = new byte[1024];
        int len = -1;
        ByteArrayOutputStream outStream = new ByteArrayOutputStream();
        while ((len = inStream.read(buffer)) != -1) {
            outStream.write(buffer, 0, len);
        }
        byte[] data = outStream.toByteArray();
        outStream.close();
        inStream.close();
        return data;

    }
    /**
     * @param 将字节数组转换为ImageView可调用的Bitmap对象
     * @param bytes
     * @param opts
     * @return Bitmap
     */
    public static Bitmap getPicFromBytes(byte[] bytes,
            BitmapFactory.Options opts) {
        if (bytes != null)
            if (opts != null)
                return BitmapFactory.decodeByteArray(bytes, 0, bytes.length,
                        opts);
            else
                return BitmapFactory.decodeByteArray(bytes, 0, bytes.length);
        return null;
    }
    /**
     * @param 图片缩放
     * @param bitmap 对象
     * @param w 要缩放的宽度
     * @param h 要缩放的高度
     * @return newBmp 新 Bitmap对象
     */
    public static Bitmap zoomBitmap(Bitmap bitmap, int w, int h){
        int width = bitmap.getWidth();
        int height = bitmap.getHeight();
        Matrix matrix = new Matrix();
        float scaleWidth = ((float) w / width);
        float scaleHeight = ((float) h / height);
        matrix.postScale(scaleWidth, scaleHeight);
        Bitmap newBmp = Bitmap.createBitmap(bitmap, 0, 0, width, height,
                matrix, true);
        return newBmp;
    }

    /**
     * 把Bitmap转Byte
     */
    public static byte[] Bitmap2Bytes(Bitmap bm){
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        bm.compress(Bitmap.CompressFormat.PNG, 100, baos);
        return baos.toByteArray();
    }
    /**
     * 把字节数组保存为一个文件
     */
    public static File getFileFromBytes(byte[] b, String outputFile) {
        BufferedOutputStream stream = null;
        File file = null;
        try {
            file = new File(outputFile);
            FileOutputStream fstream = new FileOutputStream(file);
            stream = new BufferedOutputStream(fstream);
            stream.write(b);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (stream != null) {
                try {
                    stream.close();
                } catch (IOException e1) {
                    e1.printStackTrace();
                }
            }
        }
        return file;
    }

}