Question

我认为我正在做一切正确的事情来创建一个文件夹我可以在我的应用程序中稍后写，但它似乎没有工作。关于我如何失败的任何线索？

它正确地尝试创建/ mnt / sdcard / gradebook

我有use-permission android：name =“android.permission.WRITE_EXTERNAL_STORAGE” 在我的清单中。我正在运行一个真正的设备（三星Galaxy S），我没有使用 sdcard作为存储，当它连接到我的电脑。

    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;
        Toast.makeText(this,"This Application needs a writable external storage (sdcard).",Toast.LENGTH_SHORT).show();
        finish();
    } else {
        // Something else is wrong. It may be one of many other states, but all we need
        //  to know is we can neither read nor write
        mExternalStorageAvailable = mExternalStorageWriteable = false;
        Toast.makeText(this,"This Application needs a mounted external storage (sdcard).",Toast.LENGTH_SHORT).show();
        finish();

    }


    File folder = new File(Environment.getExternalStorageDirectory () + "/gradeBook");
    boolean success = false;
    if(!folder.exists()){
         success = folder.mkdir();
    }
    if (!success) {
        Log.e("FILE", "can't create " + folder);
    }
    else 
    {
        Log.i("FILE", "directory is created"); 
    }

这是清单

<?xml version="1.0" encoding="utf-8"?>
  <manifest xmlns:android="http://schemas.android.com/apk/res/android" 
    package="com.ulsanonline.gradebook" 
    android:versionName="@string/version" 
    android:installLocation="auto" 
    android:versionCode="2">
    <uses-sdk android:minSdkVersion="8"></uses-sdk> 
    <application 
        android:icon="@drawable/icon" 
        android:debuggable="true" 
        android:persistent="false" 
        android:hasCode="true"
        android:minSdkVersion="8">
        <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
        <uses-permission android:name="android.permission.CAMERA" />
        <activity 
            android:name=".CourseWork" 
            android:label="@string/app_name" 
            android:screenOrientation="portrait">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

Answer 1

uses-permission必须直接作为<manifest>子项放置，因此应该是：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
    package="com.ulsanonline.gradebook" 
    android:versionName="@string/version" 
    android:installLocation="auto" 
    android:versionCode="2">
    <uses-sdk android:minSdkVersion="8"></uses-sdk> 
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.CAMERA" />
    <application 
        android:icon="@drawable/icon" 
        android:debuggable="true" 
        android:persistent="false"

Answer 2

试试这个，

//Declare a string 

String NewFolder = "/myNewFolder";
String extStorageDirectory;

//external storage directory path
    extStorageDirectory = Environment.getExternalStorageDirectory().toString();    
//creating a new folder
File mkTarDir=new File(extStorageDirectory + NewFolder);
  mkTarDir.mkdir();
//path to save a image              
File file = new File(extStorageDirectory + NewFolder ,"myimage"+String.valueOf(System.currentTimeMillis()) + ".PNG");

无法在/ mnt / sdcard中创建文件夹

2 个答案: