android 读取,写入图片到sd卡源码

<pre name="code" class="html"><!--<span style="font-family: Arial, Helvetica, sans-serif;">在AndroidMainfest.xml文件中添加</span><span style="font-family: Arial, Helvetica, sans-serif;">--></span>

<!-- 在SDCard中创建与删除文件权限 --> <uses-permission android:name="android.permission.MOUNT_UNMOUNT_FILESYSTEMS" ></uses-permission> <!-- 往SDCard写入数据权限 --> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" ></uses-permission><uses-permission android:name="android.permission.RESTART_PACKAGES" ></uses-permission>

<!--<span style="font-family: Arial, Helvetica, sans-serif;">注意：在<application...></application>前添加</span><span style="font-family: Arial, Helvetica, sans-serif;">--></span>

/**
* Save Bitmap to a file.保存图片到SD卡。
*
* @param bitmap
* @param file
* @return error message if the saving is failed. null if the saving is
*         successful.
* @throws IOException
*/
public static void saveBitmapToFile(Bitmap bitmap, String _file)
throws IOException {//_file = <span style="font-family: Arial, Helvetica, sans-serif;">getSDPath()+"</span><span style="font-family: Arial, Helvetica, sans-serif;">/xx自定义文件夹</span><span style="font-family: Arial, Helvetica, sans-serif;">/hot.png</span><span style="font-family: Arial, Helvetica, sans-serif;">"</span>
BufferedOutputStream os = null;
try {
File file = new File(_file);
// String _filePath_file.replace(File.separatorChar +
// file.getName(), "");
int end = _file.lastIndexOf(File.separator);
String _filePath = _file.substring(0, end);
File filePath = new File(_filePath);
if (!filePath.exists()) {
filePath.mkdirs();
}
file.createNewFile();
os = new BufferedOutputStream(new FileOutputStream(file));
bitmap.compress(Bitmap.CompressFormat.PNG, 100, os);
} finally {
if (os != null) {
try {
os.close();
} catch (IOException e) {
Log.e(TAG_ERROR, e.getMessage(), e);
}
}
}
}

<pre name="code" class="java">//读取
public class MainAct extends Activity {
/** Called when the activity is first created. */
private ImageView img;
//SD图片路径
private String filepath = <span style="font-family: Arial, Helvetica, sans-serif;">getSDPath()+"</span><span style="font-family: Arial, Helvetica, sans-serif;">/xx自定义文件夹</span><span style="font-family: Arial, Helvetica, sans-serif;">/hot.png</span><span style="font-family: Arial, Helvetica, sans-serif;">"</span>

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
img = (ImageView) findViewById(R.id.img);
File file = new File(filepath);
if (file.exists()) {
Bitmap bm = BitmapFactory.decodeFile(filepath);
//将图片显示到ImageView中
img.setImageBitmap(bm);
}
}
}

/*** 获取SDK路径* @return*/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();//获取跟目录}return sdDir.toString();}