Android之文件管理_SDcard基本操作

做软件的时候 也许要存数据要用到SD卡 所以在用之前 最好检测下 SD卡是否可用

详解地址传送门 http://www.runoob.com/w3cnote/android-tutorial-file.html

Android判断SD卡是否可用，可按以下方式：

首先要在AndroidManifest.xml中增加SD卡访问权限

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

2.判断SD卡是否存在

private boolean ExistSDCard() {  
if (Environment.getExternalStorageState().equals(  
   Environment.MEDIA_MOUNTED)) {  
  return true;  
} else  
  return false;  
}  

官网代码

//判断是否可写
/* Checks if external storage is available for read and write */
public boolean isExternalStorageWritable() {
    String state = Environment.getExternalStorageState();
    if (Environment.MEDIA_MOUNTED.equals(state)) {
        return true;
    }
    return false;
}

//判断是否可读
/* Checks if external storage is available to at least read */
public boolean isExternalStorageReadable() {
    String state = Environment.getExternalStorageState();
    if (Environment.MEDIA_MOUNTED.equals(state) ||
        Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {
        return true;
    }
    return false;
}

Android中判断SD卡状态

String status = Environment.getExternalStorageState();
if (status.equalsIgnoreCase(Environment.MEDIA_MOUNTED)) {
    Toast.makeText(TechoLite.this, "SD卡存在", Toast.LENGTH_LONG).show();
    // 此时SD是可读写的
} else if (status.equalsIgnoreCase(Environment.MEDIA_MOUNTED_READ_ONLY)) {
    Toast.makeText(TechoLite.this, "虽然SD存在，但是为只读状态", Toast.LENGTH_LONG).show();
} else if (status.equalsIgnoreCase(Environment.MEDIA_REMOVED)) {
    Toast.makeText(TechoLite.this, "SD不存在", Toast.LENGTH_LONG).show();
} else if (status.equalsIgnoreCase(Environment.MEDIA_SHARED)) {
    Toast.makeText(TechoLite.this, "虽然SD卡存在，但是正与PC等相连接", Toast.LENGTH_LONG).show();
} else if (status.equalsIgnoreCase(Environment.MEDIA_BAD_REMOVAL)) {
    Toast.makeText(TechoLite.this, "SD卡在挂载状态下被错误取出", Toast.LENGTH_LONG).show();
} else if (status.equalsIgnoreCase(Environment.MEDIA_CHECKING)) {
    Toast.makeText(TechoLite.this, "正在检查SD卡", Toast.LENGTH_LONG).show();
} else if (status.equalsIgnoreCase(Environment.MEDIA_NOFS)) {
    Toast.makeText(TechoLite.this, "虽然SD卡存在，但其文件系统不被支持", Toast.LENGTH_LONG).show();
} else if (status.equalsIgnoreCase(Environment.MEDIA_UNMOUNTABLE)) {
    Toast.makeText(TechoLite.this, "虽然SD卡存在，但是无法被挂载", Toast.LENGTH_LONG).show();
} else if (status.equalsIgnoreCase(Environment.MEDIA_UNMOUNTED)) {
    Toast.makeText(TechoLite.this, "虽然SD卡存在，但是未被挂载", Toast.LENGTH_LONG).show();
} else {
    Toast.makeText(TechoLite.this, "其他原因", Toast.LENGTH_LONG).show();
}