unity中Image显示android手机SD卡中的图片

using UnityEngine;
using System.Collections;
using UnityEngine.UI;
using System.IO;

public class ImageManager : MonoBehaviour {

private string imagePath;
private Image image;
private Texture2D m_Tex;

void Start()
{
LoadImage();
}

private void LoadImage()
{
imagePath = Application.persistentDataPath + "/tackPhoto/1.jpg";
Debug.Log(imagePath);
image = GameObject.Find ("TakePhoto").GetComponent<Image>();

// WWW www = new WWW(imagePath);
// yield return www;
//byte[] by= www.texture.EncodeToJPG();
LoadFromFile(imagePath);
Sprite tempSprite = new Sprite();
tempSprite = Sprite.Create(m_Tex, new Rect(0, 0, m_Tex.width, m_Tex.height), new Vector2(0, 0));
image.sprite = tempSprite;

}

private void LoadFromFile(string path)
{
m_Tex = new Texture2D(1, 1);
m_Tex.LoadImage(ReadPNG(path));

}

private byte[] ReadPNG(string path)
{
FileStream fileStream = new FileStream(path, FileMode.Open, System.IO.FileAccess.Read);

fileStream.Seek(0, SeekOrigin.Begin);

byte[] binary = new byte[fileStream.Length]; //创建文件长度的buffer
fileStream.Read(binary, 0, (int)fileStream.Length);

fileStream.Close();

fileStream.Dispose();

fileStream = null;

return binary;
}

}