Java 创建未编制索引的文件夹会导致IOException
我想创建一个主文件夹,应用程序应该使用它来保存所有文件。如果目录已存在,则应忽略文件夹创建 这是我的尝试Java 创建未编制索引的文件夹会导致IOException,java,android,java-io,Java,Android,Java Io,我想创建一个主文件夹,应用程序应该使用它来保存所有文件。如果目录已存在,则应忽略文件夹创建 这是我的尝试 public static void createFolder() { String baseDir = Environment.getExternalStorageDirectory().getAbsolutePath(); String baseAppDir = "MyAppFolder"; String fileHider = ".nom
public static void createFolder() {
String baseDir = Environment.getExternalStorageDirectory().getAbsolutePath();
String baseAppDir = "MyAppFolder";
String fileHider = ".nomedia";
File mainDirectory = new File(baseDir + File.separator + baseAppDir);
if (!(mainDirectory.exists())) {
mainDirectory.mkdirs();
File outputFile = new File(mainDirectory, fileHider);
try {
FileOutputStream fos = new FileOutputStream(outputFile);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
很遗憾,此错误不起作用,请获取此错误并不创建文件夹
12-07 17:16:01.127: W/System.err(1855): java.io.FileNotFoundException: /storage/sdcard/MyAppFolder/.nomedia: open failed: ENOENT (No such file or directory)
12-07 17:16:01.167: W/System.err(1855): at libcore.io.IoBridge.open(IoBridge.java:409)
12-07 17:16:01.167: W/System.err(1855): at java.io.FileOutputStream.<init>(FileOutputStream.java:88)
12-07 17:16:01.177: W/System.err(1855): at java.io.FileOutputStream.<init>(FileOutputStream.java:73)
....
12-07 17:16:01.127:W/System.err(1855):java.io.FileNotFoundException:/storage/sdcard/MyAppFolder/.nomedia:open失败:enoint(没有这样的文件或目录)
12-07 17:16:01.167:W/System.err(1855):位于libcore.io.IoBridge.open(IoBridge.java:409)
12-07 17:16:01.167:W/System.err(1855):位于java.io.FileOutputStream.(FileOutputStream.java:88)
12-07 17:16:01.177:W/System.err(1855):位于java.io.FileOutputStream。(FileOutputStream.java:73)
....
我的舱单
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="it.myapp.test"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="14"
android:targetSdkVersion="18" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_GPS" />
<uses-permission android:name="android.permission.ACCESS_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.AUTHENTICATE_ACCOUNTS" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.FLASHLIGHT" />
<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.SEND_SMS" />
<uses-permission android:name="android.permission.CALL_PHONE" />
<uses-permission android:name="android.permission.READ_CONTACTS" />
<uses-permission android:name="android.permission.READ_CALENDAR" />
<uses-permission android:name="android.permission.VIBRATE" />
<uses-permission android:name="android.permission.USE_CREDENTIALS" />
<uses-permission android:name="android.permission.WRITE_CALENDAR" />
<uses-permission android:name="android.permission.WRITE_SOCIAL_STREAM" />
<uses-permission android:name="android.permission.WRITE_SYNC_SETTINGS" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="it.myapp.test.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
编辑
在主活动中,如果我尝试在createFolder()上使用带有printstacktrace的try catch,我会得到以下错误日志
12-07 18:28:26.090: W/dalvikvm(3335): Exception Ljava/lang/NullPointerException; thrown while initializing Lit/myapp/test/FileArchiveManager;
12-07 18:28:26.210: W/System.err(3335): java.lang.ExceptionInInitializerError
12-07 18:28:26.220: W/System.err(3335): at it.myapp.test.MainActivity.onCreate(MainActivity.java:19)
12-07 18:28:26.220: W/System.err(3335): at android.app.Activity.performCreate(Activity.java:5243)
12-07 18:28:26.230: W/System.err(3335): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
12-07 18:28:26.240: W/System.err(3335): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2140)
12-07 18:28:26.240: W/System.err(3335): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2226)
12-07 18:28:26.240: W/System.err(3335): at android.app.ActivityThread.access$700(ActivityThread.java:135)
12-07 18:28:26.250: W/System.err(3335): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1397)
12-07 18:28:26.250: W/System.err(3335): at android.os.Handler.dispatchMessage(Handler.java:102)
12-07 18:28:26.260: W/System.err(3335): at android.os.Looper.loop(Looper.java:137)
12-07 18:28:26.260: W/System.err(3335): at android.app.ActivityThread.main(ActivityThread.java:4998)
12-07 18:28:26.280: W/System.err(3335): at java.lang.reflect.Method.invokeNative(Native Method)
12-07 18:28:26.280: W/System.err(3335): at java.lang.reflect.Method.invoke(Method.java:515)
12-07 18:28:26.280: W/System.err(3335): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777)
12-07 18:28:26.290: W/System.err(3335): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593)
12-07 18:28:26.290: W/System.err(3335): at dalvik.system.NativeStart.main(Native Method)
12-07 18:28:26.300: W/System.err(3335): Caused by: java.lang.NullPointerException: name == null
12-07 18:28:26.310: W/System.err(3335): at java.io.File.<init>(File.java:150)
12-07 18:28:26.310: W/System.err(3335): at java.io.File.<init>(File.java:124)
12-07 18:28:26.320: W/System.err(3335): at android.os.Environment.buildPath(Environment.java:812)
12-07 18:28:26.320: W/System.err(3335): at android.os.Environment.buildPaths(Environment.java:796)
12-07 18:28:26.330: W/System.err(3335): at android.os.Environment$UserEnvironment.buildExternalStoragePublicDirs(Environment.java:199)
12-07 18:28:26.330: W/System.err(3335): at android.os.Environment.getExternalStoragePublicDirectory(Environment.java:538)
12-07 18:28:26.340: W/System.err(3335): at it.myapp.test.utility.FileArchiveManager.<clinit>(FileArchiveManager.java:17)
12-07 18:28:26.340: W/System.err(3335): ... 15 more
12-0718:28:26.090:W/dalvikvm(3335):异常Ljava/lang/NullPointerException;初始化Lit/myapp/test/FileArchiveManager时抛出;
12-07 18:28:26.210:W/System.err(3335):java.lang.exceptionininitializerror
12-07 18:28:26.220:W/System.err(3335):at-it.myapp.test.MainActivity.onCreate(MainActivity.java:19)
12-07 18:28:26.220:W/System.err(3335):位于android.app.Activity.performCreate(Activity.java:5243)
12-07 18:28:26.230:W/System.err(3335):位于android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
12-07 18:28:26.240:W/System.err(3335):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2140)
12-07 18:28:26.240:W/System.err(3335):位于android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2226)
12-07 18:28:26.240:W/System.err(3335):在android.app.ActivityThread.access$700(ActivityThread.java:135)
12-07 18:28:26.250:W/System.err(3335):在android.app.ActivityThread$H.handleMessage(ActivityThread.java:1397)
12-07 18:28:26.250:W/System.err(3335):位于android.os.Handler.dispatchMessage(Handler.java:102)
12-07 18:28:26.260:W/System.err(3335):位于android.os.Looper.loop(Looper.java:137)
12-07 18:28:26.260:W/System.err(3335):位于android.app.ActivityThread.main(ActivityThread.java:4998)
12-07 18:28:26.280:W/System.err(3335):位于java.lang.reflect.Method.invokenactive(本机方法)
12-07 18:28:26.280:W/System.err(3335):位于java.lang.reflect.Method.invoke(Method.java:515)
12-07 18:28:26.280:W/System.err(3335):在com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777)
12-07 18:28:26.290:W/System.err(3335):位于com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593)
12-07 18:28:26.290:W/System.err(3335):在dalvik.System.NativeStart.main(本机方法)
12-07 18:28:26.300:W/System.err(3335):由以下原因引起:java.lang.NullPointerException:name==null
12-07 18:28:26.310:W/System.err(3335):位于java.io.File.(File.java:150)
12-07 18:28:26.310:W/System.err(3335):位于java.io.File.(File.java:124)
12-07 18:28:26.320:W/System.err(3335):位于android.os.Environment.buildPath(Environment.java:812)
12-07 18:28:26.320:W/System.err(3335):位于android.os.Environment.buildpath(Environment.java:796)
12-07 18:28:26.330:W/System.err(3335):在android.os.Environment$UserEnvironment.buildExternalStoragePublicDirs(Environment.java:199)
12-07 18:28:26.330:W/System.err(3335):在android.os.Environment.getExternalStoragePublicDirectory(Environment.java:538)上
12-07 18:28:26.340:W/System.err(3335):at-it.myapp.test.utility.FileArchiveManager。(FileArchiveManager.java:17)
12-07 18:28:26.340:带系统错误(3335):。。。还有15个
您的代码将仅适用于根设备。要解决此问题,您必须将文件放在标准目录(
Environment.getExternalStoragePublicDirectory()
)中。添加WRITE\u EXTERNAL\u STORAGE
权限。如果您的应用程序可以写入getExternalFilesDir()
,但不能在外部存储上的其他位置写入,这意味着:
权限
首先,请不要将用户外部存储的根目录弄乱。将文件放在标准目录(
Environment.getExternalStoragePublicDirectory()
)或指定的应用程序特定目录(getExternalFilesDir()
上的Context
)中。除此之外,请解释“不工作”是什么意思。@Commonware应用程序不创建任何文件夹,请参阅日志。如果我尝试在基本路径中使用getExternalStorageDirectory创建一个简单的文本文件,那么如果手机不是root用户,该文件也会成功创建如果我使用getExternalStorageDirectory()创建一个文件有效,所以原因应该不同。应用程序具有permission@AndreaF:请编辑您的问题并粘贴到您的清单中。@AndreaF:嗯,看起来确实不错。我没有解释你看到的行为。我添加了其他信息。如果你有时间,请看一下我编辑的问题。谢谢。@AndreaF:您的新堆栈跟踪与您的代码不一致。堆栈跟踪使用getExternalStoragePublicDirectory()
(您可能正在向其传递null
),而源代码使用的是getExternalStorageDirectory()
。