Android检查SD卡是否可读写详解编程语言

因为external storage可能是不可用的，比如遇到SD卡被拔出等情况时。因此在访问之前应对其可用性进行检查。我们可以通过执 行 getExternalStorageState()来查询external storage的状态。若返回状态为MEDIA_MOUNTED, 则 可以读写。

/* 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; 
} 
  
/* 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; 
}