我的代码曾经工作，但现在我甚至无法创建目录。 （请注意，“1”不会打印到logcat。）我不知道我打破了什么。我想在我创建的文件夹中保存图像，这是我的代码：
String storedir = "/sdcard";
String separator = "/";
String mDateTime = formatter.format(cal.getTime());
File newdir1 = new File(storedir + "/" + mDateTime);
if (newdir1.mkdir())
System.out.println("1");
File newdir2 = new File(storedir + "/" + mDateTime + "/");
if (newdir2.mkdir())
System.out.println("2");
// Fall into the catch because of ;
if (fileNameLower.indexOf(".jpeg") > 0)
fileExt = ".jpeg";
String rand_fileName = Long.toString(System.currentTimeMillis());// +fileExt;
String last_fileName = rand_fileName + fileExt;
File storefile = new File(storedir + "/" + mDateTime + "/" + separator
+ last_fileName);
String picAddress = storedir + "/" + mDateTime + "/" + separator
+ rand_fileName + ".png";
System.out.println("135 : [" + storefile.toString() + "]/n");
BufferedOutputStream bos = null;
BufferedInputStream bis = null;
try {
Log.w("Process : " , "Starting to download process.");
bos = new BufferedOutputStream(new FileOutputStream(storefile));
bis = new BufferedInputStream(in);
int c;
while ((c = bis.read()) != -1) {
bos.write(c);
bos.flush();
}
Log.w("Process : " , "The image is downloaded.");
} catch (Exception exception) {
exception.printStackTrace();
throw new Exception("151 : !");
} finally
{
bos.close();
bis.close();
}
04-29 21:29:20.648: W/The image's type(5733): .jpeg
04-29 21:29:20.648: I/System.out(5733): log : [.jpeg]/n
04-29 21:29:20.652: I/System.out(5733): log : [/sdcard/2012-04-29/1335734960650.jpeg]/n
04-29 21:29:20.652: W/Process :(5733): Starting to download process.
04-29 21:29:20.652: W/System.err(5733): java.io.FileNotFoundException: /sdcard/2012-04-29/1335734960650.jpeg (Permission denied)
04-29 21:29:20.672: W/System.err(5733): at org.apache.harmony.luni.platform.OSFileSystem.open(Native Method)
04-29 21:29:20.672: W/System.err(5733): at dalvik.system.BlockGuard$WrappedFileSystem.open(BlockGuard.java:232)
04-29 21:29:20.682: W/System.err(5733): at java.io.FileOutputStream.<init>(FileOutputStream.java:94)
04-29 21:29:20.682: W/System.err(5733): at java.io.FileOutputStream.<init>(FileOutputStream.java:66)
04-29 21:29:20.682: W/System.err(5733): at com.mobil.eposta.Baglanti.saveFile(Baglanti.java:345)
04-29 21:29:20.692: W/System.err(5733): at com.mobil.eposta.Baglanti.saveAttachMent(Baglanti.java:255)
04-29 21:29:20.692: W/System.err(5733): at com.mobil.eposta.Baglanti.EkiKaydet(Baglanti.java:235)
04-29 21:29:20.692: W/System.err(5733): at com.mobil.eposta.Baglanti.Position(Baglanti.java:224)
04-29 21:29:20.692: W/System.err(5733): at com.mobil.eposta.GoruntuleActivity$1.onClick(GoruntuleActivity.java:75)
04-29 21:29:20.707: W/System.err(5733): at android.view.View.performClick(View.java:2485)
04-29 21:29:20.707: W/System.err(5733): at android.view.View$PerformClick.run(View.java:9080)
04-29 21:29:20.712: W/System.err(5733): at android.os.Handler.handleCallback(Handler.java:587)
04-29 21:29:20.712: W/System.err(5733): at android.os.Handler.dispatchMessage(Handler.java:92)
04-29 21:29:20.712: W/System.err(5733): at android.os.Looper.loop(Looper.java:123)
04-29 21:29:20.712: W/System.err(5733): at android.app.ActivityThread.main(ActivityThread.java:3683)
04-29 21:29:20.712: W/System.err(5733): at java.lang.reflect.Method.invokeNative(Native Method)
04-29 21:29:20.712: W/System.err(5733): at java.lang.reflect.Method.invoke(Method.java:507)
04-29 21:29:20.722: W/System.err(5733): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
04-29 21:29:20.732: W/System.err(5733): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
04-29 21:29:20.732: W/System.err(5733): at dalvik.system.NativeStart.main(Native Method)
我应该怎样做sdcard的挂载情况？
在此代码中，结果为“NOT GOOD”语句。我该如何改变这种情况？
private static boolean checkExternalMedia()
{
boolean mExternalStorageAvailable = false;
boolean mExternalStorageWriteable = false;
String state = Environment.getExternalStorageState();
if (Environment.MEDIA_MOUNTED.equals(state)) {
// We can read and write the media
mExternalStorageAvailable = mExternalStorageWriteable = true;
} else if (Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {
// We can only read the media
mExternalStorageAvailable = true;
mExternalStorageWriteable = false;
} else {
// Something else is wrong. It may be one of many other states,
// to know is we can neither read nor write
Log.i("TAG","State="+state+" Not good");
mExternalStorageAvailable = mExternalStorageWriteable = false;
}
Log.i("TAG","Available="+mExternalStorageAvailable+"Writeable="+mExternalStorageWriteable+" State"+state);
return (mExternalStorageAvailable && mExternalStorageWriteable);
}
答案 0 :(得分：1)
你需要
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
。请参阅有关stackoverflow的其他问题，例如Permission to write to the SD card
答案 1 :(得分：1)
Environment.getExternalStorageDirectory().getAbsolutePath() 这将为您提供SD卡根路径（在某些设备中可能不仅仅是“/ sdcard”
通常是“/ mnt / sdcard”，而不是“/ sdcard”。如果你想尝试一些事情，首先要做的就是直截了当。
您初始化了一个“分隔符”常量，但您继续使用“/”来创建路径。这是从您粘贴的问题代码中引用的：
File storefile = new File（storedir +“/”+ mDateTime + “/”+ separator + last_fileName）;
你能看到它有什么问题吗？
答案 2 :(得分：0)
使用File类来构建路径更加安全和简单。
以这种方式尝试：
if (!checkExternalMedia()) {
// show error dialog here.
return;
}
File storedir = Environment.getExternalStorageDirectory();
String mDateTime = formatter.format(cal.getTime());
File savedir = new File (storedir, mDateTime);
if (fileNameLower.indexOf(".jpeg") > 0) {
fileExt = ".jpeg";
}
String rand_fileName = Long.toString(System.currentTimeMillis());// +fileExt;
String last_fileName = rand_fileName + fileExt;
File storefile = new File(storedir, last_fileName);
// create all directories required for that file
if (!storefile.mkdirs()) {
Log.e("Process", "can't create directories:" + storefile.getParent());
// return here too
}
// here be streams