Android SD card Read/write

Package com.jredu.zuiyou.activity;

Import Android.os.Bundle;
Import android.os.Environment;
Import android.support.v7.app.AppCompatActivity;
Import Android.view.View;
Import Android.widget.Button;
Import Android.widget.Toast;

Import COM.JREDU.ZUIYOU.R;
Import com.jredu.zuiyou.entity.Student;

Import Java.io.File;
Import Java.io.FileInputStream;
Import Java.io.FileOutputStream;
Import java.io.IOException;
Import Java.io.ObjectInputStream;
Import Java.io.ObjectOutputStream;

public class Sdactivity extends Appcompatactivity {
ObjectOutputStream oos = null;
ObjectInputStream ois = null;

@Override
protected void OnCreate (Bundle savedinstancestate) {
Super.oncreate (savedinstancestate);
Setcontentview (R.LAYOUT.ACTIVITY_SD);
Button write = (button) Findviewbyid (r.id.write);
Write.setonclicklistener (New View.onclicklistener () {
@Override
public void OnClick (View v) {
Writetosd ();
}
});
Button read = (button) Findviewbyid (R.id.read);
Read.setonclicklistener (New View.onclicklistener () {
@Override
public void OnClick (View v) {
READFROMSD ();
}
});
}
public void Writetosd () {
String state = Environment.getexternalstoragestate ();
if (State.equals (environment.media_mounted)) {
File root = Environment.getexternalstoragedirectory ();
File TargetDir = new file (Root,super.getpackagename ());
if (! Targetdir.exists ()) {
Targetdir.mkdir ();
}
try {
Oos = new ObjectOutputStream (new FileOutputStream (New File (TargetDir, "yxl.txt"));
Student Student = new Student ("Xiaoming", 18);
Oos.writeobject (student);
Toast.maketext (Getapplication (), "Write succeeded", Toast.length_short). Show ();
} catch (IOException e) {
E.printstacktrace ();
} finally {
try {
Oos.flush ();
Oos.close ();
} catch (IOException e) {
E.printstacktrace ();
}
}
}else {
Toast.maketext (Getapplication (), "No SD card found", Toast.length_short). Show ();
}
}
public void Readfromsd () {
String state = Environment.getexternalstoragestate ();
if (State.equals (environment.media_mounted)) {
File root = Environment.getexternalstoragedirectory ();
File TargetDir = new file (Root,super.getpackagename ());
if (! Targetdir.exists ()) {
Targetdir.mkdir ();
}
try {
OIS = new ObjectInputStream (new FileInputStream (New File (TargetDir, "/yxl.txt"));
Student Student = (Student) ois.readobject ();
Toast.maketext (Getapplication (), Student.getname (). toString () + "," +student.getage (), Toast.length_short). Show ();

} catch (IOException e) {
E.printstacktrace ();
} catch (ClassNotFoundException e) {
E.printstacktrace ();
}finally {
try {
Ois.close ();
} catch (IOException e) {
E.printstacktrace ();
}
}
}else {
Toast.maketext (Getapplication (), "No SD card found", Toast.length_short). Show ();
}
}
}

Android SD card Read/write