if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED))
{
Toast.makeText(MainActivity.this,"SD卡准备就绪！",Toast.LENGTH_SHORT).show();
}
else
{
Toast.makeText(MainActivity.this,"SD卡不存在或者未挂载！",Toast.LENGTH_SHORT).show();
}
二、获取SD卡的储存情况
File ext=Environment.getExternalStorageDirectory();
long usableSpace=ext.getUsableSpace();
long totalSpace=ext.getTotalSpace();
String usableSize= Formatter.formatFileSize(MainActivity.this,usableSpace);
String totalSize=Formatter.formatFileSize(MainActivity.this,totalSpace);
Toast.makeText(MainActivity.this,"usableSize:"+usableSize+"--"+totalSize,Toast.LENGTH_SHORT).show();
三、权限问题
//在AndroidManifest中添加SD卡读写的权限
//从Android6.0开始需要动态授权
Manifest.permission.READ_EXTERNAL_STORAGE
Manifest.permission.WRITE_EXTERNAL_STORAGE
四、权限申请
//动态申请权限方法
private static final int REQUEST_EXTERNAL_STORAGE = 1;
private static String[] PERMISSIONS_STORAGE = {
"android.permission.READ_EXTERNAL_STORAGE",
"android.permission.WRITE_EXTERNAL_STORAGE" };
public static void verifyStoragePermissions(Activity activity) {
try {
//检测是否有写的权限
int permission = ActivityCompat.checkSelfPermission(activity,
"android.permission.WRITE_EXTERNAL_STORAGE");
if (permission != PackageManager.PERMISSION_GRANTED) {
// 没有写的权限，去申请写的权限，会弹出对话框
ActivityCompat.requestPermissions(activity, PERMISSIONS_STORAGE,REQUEST_EXTERNAL_STORAGE);
}
} catch (Exception e) {
e.printStackTrace();
}
}
五、写入数据
File f2=new File(ext,"test.data");
try {
verifyStoragePermissions(MainActivity.this);
OutputStream out=new FileOutputStream(f2);
out.write("test".getBytes());
out.close();
} catch (Exception e) {
e.printStackTrace();
}
六、读取数据
try {
InputStream in=new FileInputStream(f2);
byte[] buffer=new byte[64];
int len=in.read(buffer);
String str=new String(buffer,0,len);
} catch (Exception e) {
e.printStackTrace();
}
作者：大亮