android如何往SDCard中存取图片

引用

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

import android.graphics.Bitmap;
import android.os.Environment;
import android.util.Log;

/**
 * 保存图片的类
 * 
 * 
 */
public class SaveBitmap {

	private final static String CACHE = "/css";

	/**
	 * 保存图片的方法 保存到sdcard
	 * 
	 * @throws Exception
	 * 
	 */
	public static void saveImage(Bitmap bitmap, String imageName)
			throws Exception {
		String filePath = isExistsFilePath();
		FileOutputStream fos = null;
		File file = new File(filePath, imageName);
		try {
			fos = new FileOutputStream(file);
			if (null != fos) {
				bitmap.compress(Bitmap.CompressFormat.PNG, 90, fos);
				fos.flush();
				fos.close();
			}
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	/**
	 * 获取sd卡的缓存路径， 一般在卡中sdCard就是这个目录
	 * 
	 * @return SDPath
	 */
	public static String getSDPath() {
		File sdDir = null;
		boolean sdCardExist = Environment.getExternalStorageState().equals(
				android.os.Environment.MEDIA_MOUNTED); // 判断sd卡是否存在
		if (sdCardExist) {
			sdDir = Environment.getExternalStorageDirectory();// 获取根目录
		} else {
			Log.e("ERROR", "没有内存卡");
		}
		return sdDir.toString();
	}

	/**
	 * 获取缓存文件夹目录 如果不存在创建 否则则创建文件夹
	 * 
	 * @return filePath
	 */
	private static String isExistsFilePath() {
		String filePath = getSDPath() + CACHE;
		File file = new File(filePath);
		if (!file.exists()) {
			file.mkdirs();
		}
		return filePath;
	}
	/**
	 * 获取SDCard文件
	 * 
	 * @return Bitmap
	 */
	public static Bitmap getImageFromSDCard(String imageName) {
		String filepath = getSDPath() + CACHE  + "/" + imageName;
		File file = new File(filepath);
		if (file.exists()) {
			Bitmap bm = BitmapFactory.decodeFile(filepath);
			return bm;
		}
		return null;
	}
}