允许在SD卡上的android写 [英] Permission to write on SD card android

问题描述

编辑：问题解决了，FileOutputStream中uncorrectly定义，更改为：

Problem solved, FileOutputStream defined uncorrectly, change to:

FOS =新的FileOutputStream（根+/+ saveFileName）;

fos = new FileOutputStream( root + "/" + saveFileName );

您好，我有一个问题写入SD卡，这里是code： （很抱歉的code中的布局，只需复制pased吧）

Hello, I have a problem writing to the SD card, here is the code: (Sorry about the layout of the code, just copy pased it )

public class SaveAndReadManager {

 private String result;
 private String saveFileName = "eventlist_savefile";

 public String writeToFile( ArrayList<Event> arrlEvents ){
  FileOutputStream fos = null;
  ObjectOutputStream out = null;

  try{
   File root = Environment.getExternalStorageDirectory();

   if( root.canWrite() ){
    fos = new FileOutputStream( saveFileName );
    out = new ObjectOutputStream( fos );
    out.writeObject( arrlEvents );

    result = "File written";

    out.close();
   }else{
    result = "file cant write";
   }
  }catch( IOException e ){
   e.printStackTrace();
   result = "file not written";
  }

  return result;
 }

 public boolean readFromFile(){
  return false;
 }
}

我还没有实现的readFromFile（）呢。 问题是，root.canWrite（）返回false，所有的时间。 这里是清单文件：

I have not implemented the readFromFile() yet. The problem is that root.canWrite() returns false all the time. Here is the manifest file:

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

<application android:icon="@drawable/icon" android:label="@string/app_name">
    <activity android:name=".InfoScreen"
           android:label="@string/app_name">
      <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>

    <activity android:name=".EventCalendar"
              android:label="@string/app_name" />

    <activity android:name=".MakeEvent"
              android:label="@string/app_name" />

    <activity android:name=".ViewEvent"
              android:label="@string/app_name" />

</application>
<uses-sdk android:minSdkVersion="8" />

我问的写权限，并在我的AVD，如果我去设置 - > SD卡和手机存储，它告诉我，我有1 GB的SD卡上写上。请大家帮帮忙。

I've asked for the permission to write, and on my avd, if i go to settings -> SD card and phone storage, it tells me i have 1 gb on the sd card to write on. Please help.

感谢：）

推荐答案

而导致你看到的将writeToFile retunred？ 文件没有写或档案着写？

Which result are you seeing retunred from writeToFile? "file not written" or "file cant write"?

当我跑到你的code则下降到与文件没有写的结果抓IOException异常块。这样做的原因是，果寡糖的定义不正确：

When I ran your code it dropped into the catch IOException block with the result of "file not written". The reason for this was that fos was defined incorrectly:

fos = new FileOutputStream( saveFileName );

应该是：

fos = new FileOutputStream( root + "/" saveFileName );

在我改变了这一行，我接到了将writeToFile文件写入返回的结果。

After I changed this line, I got the result "File written" returned from writeToFile.

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