05_学生管理系统，xml读写，布局的综合应用



1. 最终要做的项目目标：

2、编写Android清单文件AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"

package="com.itheima27.sutdentmanager"

android:versionCode="1"

android:versionName="1.0" >

<uses-sdk

android:minSdkVersion="8"

android:targetSdkVersion="19" />

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

<application

android:allowBackup="true"

android:icon="@drawable/ic_launcher"

android:label="@string/app_name"

android:theme="@style/AppTheme" >

<activity

android:name="com.itheima27.sutdentmanager.MainActivity"

android:label="@string/app_name" >

<intent-filter>

<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />

</intent-filter>

</activity>

</application>

</manifest>

3 编写布局文件activity_main.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:background="@android:color/white"

android:orientation="vertical" >

<TextView

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_gravity="center_horizontal"

android:layout_marginTop="5dip"

android:text="学生管理系统"

android:textColor="#99CCFF"

android:textSize="23sp"/>

<RelativeLayout

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:layout_marginTop="5dip"

android:padding="5dip">

<TextView

android:id="@+id/tv_name"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:paddingLeft="15dip"

android:paddingRight="15dip"

android:text="姓名"

android:textSize="18sp" />

<TextView

android:id="@+id/tv_sex"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginLeft="5dip"

android:layout_toRightOf="@id/tv_name"

android:paddingLeft="15dip"

android:paddingRight="15dip"

android:text="性别"

android:textSize="18sp" />

<TextView

android:id="@+id/tv_age"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_marginLeft="5dip"

android:layout_toRightOf="@id/tv_sex"

android:paddingLeft="15dip"

android:paddingRight="15dip"

android:text="年龄"

android:textSize="18sp" />

<!-- 在姓名的下面 -->

<EditText

android:id="@+id/et_name"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignLeft="@id/tv_name"

android:layout_alignRight="@id/tv_name"

android:layout_below="@id/tv_name"

android:singleLine="true" />

<!-- 在性别的下面 -->

<EditText

android:id="@+id/et_sex"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignLeft="@id/tv_sex"

android:layout_alignRight="@id/tv_sex"

android:layout_below="@id/tv_sex"

android:singleLine="true" />

<EditText

android:id="@+id/et_age"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignLeft="@id/tv_age"

android:layout_alignRight="@id/tv_age"

android:layout_below="@id/tv_age"

android:inputType="number"

android:singleLine="true" />

<Button

android:id="@+id/btn_add_student"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_alignBaseline="@id/et_age"

android:layout_toRightOf="@id/et_age"

android:text="添加学生"

android:textSize="20sp" />

</RelativeLayout>

<ScrollView

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:layout_weight="1" >

<LinearLayout

android:id="@+id/ll_student_list"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:layout_margin="1dip"

android:orientation="vertical"

android:padding="5dip" >

</LinearLayout>

</ScrollView>

<LinearLayout

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:layout_marginTop="5dip"

android:orientation="horizontal" >

<Button

android:id="@+id/btn_save"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_weight="1"

android:text="保存数据"

android:textSize="20sp" />

<Button

android:id="@+id/btn_restore"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_weight="1"

android:text="恢复数据"

android:textSize="20sp" />

</LinearLayout>

</LinearLayout>

4 编写Student实体

package com.itheima27.sutdentmanager.entities;

public class Student {

private String name;

private String sex;

private Integer age;

public Student() {

super();

}

public Student(String name, String sex, Integer age) {

super();

this.name = name;

this.sex = sex;

this.age = age;

}

public String getName() {

return name;

}

public void setName(String name) {

this.name = name;

}

public String getSex() {

return sex;

}

public void setSex(String sex) {

this.sex = sex;

}

public Integer getAge() {

return age;

}

public void setAge(Integer age) {

this.age = age;

}

@Override

public String toString() {

return "Student [name=" + name + ", sex=" + sex + ", age=" + age + "]";

}

}

5 编写MainActivity

package com.itheima27.sutdentmanager;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.util.ArrayList;

import java.util.List;

import org.xmlpull.v1.XmlPullParser;

import org.xmlpull.v1.XmlSerializer;

import android.graphics.Color;

import android.os.Bundle;

import android.os.Environment;

import android.support.v7.app.ActionBarActivity;

import android.text.TextUtils;

import android.util.Xml;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.EditText;

import android.widget.LinearLayout;

import android.widget.TextView;

import android.widget.Toast;

import com.itheima27.sutdentmanager.entities.Student;

public class MainActivity extends ActionBarActivity implements OnClickListener {

private EditText etName;

private EditText etSex;

private EditText etAge;

private LinearLayout llStudentList;

private List<Student> studentList;

private String filePath;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

init();

}

private void init() {

etName = (EditText) findViewById(R.id.et_name);

etSex = (EditText) findViewById(R.id.et_sex);

etAge = (EditText) findViewById(R.id.et_age);

llStudentList = (LinearLayout) findViewById(R.id.ll_student_list);

findViewById(R.id.btn_save).setOnClickListener(this);

findViewById(R.id.btn_restore).setOnClickListener(this);

findViewById(R.id.btn_add_student).setOnClickListener(this);

studentList = new ArrayList<Student>();

filePath = Environment.getExternalStorageDirectory().getPath() + "/student.xml";

}

public void onClick(View v) {

switch (v.getId()) {

case R.id.btn_save:

if(studentList.size() > 0) {

//将信息写到xml文件中

if(saveStudent2Local()) {

Toast.makeText(this, "保存成功", 0).show();

} else {

Toast.makeText(this, "保存失败", 0).show();

}

} else {

Toast.makeText(this, "当前没有数据", 0).show();

        }

break;

case R.id.btn_restore:

if(restoreStudentFromLocal()) {

Toast.makeText(this, "恢复成功", 0).show();

} else {

Toast.makeText(this, "恢复失败", 0).show();

}

break;

case R.id.btn_add_student:

addStudent();

break;

default:

break;

}

}

/**

* 从xml中读出Student数据

* @return

*/

private boolean restoreStudentFromLocal() {

try {

XmlPullParser parser = Xml.newPullParser();

parser.setInput(new FileInputStream(filePath), "utf-8");

int eventType = parser.getEventType();

studentList.clear();

Student student = null;

String nodeName = null;

while(eventType != XmlPullParser.END_DOCUMENT) {

nodeName = parser.getName();

switch (eventType) {

case XmlPullParser.START_TAG:

if("student".equals(nodeName)) {

student = new Student();

} else if("name".equals(nodeName)) {

student.setName(parser.nextText());

} else if("sex".equals(nodeName)) {

student.setSex(parser.nextText());

} else if("age".equals(nodeName)) {

student.setAge(Integer.valueOf(parser.nextText()));

}

break;

case XmlPullParser.END_TAG:

if("student".equals(nodeName)) {

studentList.add(student);

}

break;

default:

break;

}

eventType = parser.next();

}

refreshStudentList();

return true;

} catch (Exception e) {

e.printStackTrace();

}

return false;

}

/**

* 恢复student的List列表

*/

private void refreshStudentList() {

llStudentList.removeAllViews();

TextView childView;

for (Student student : studentList) {

childView = new TextView(this);

childView.setTextSize(23);

childView.setTextColor(Color.BLACK);

childView.setText("　　" + student.getName() + "　　" + student.getSex() + "　　" + student.getAge());

llStudentList.addView(childView);

}

}

private boolean saveStudent2Local() {

try {

XmlSerializer serializer = Xml.newSerializer();

serializer.setOutput(new FileOutputStream(filePath), "utf-8");

serializer.startDocument("utf-8", true);

serializer.startTag(null, "infos");

for (Student stu : studentList) {

serializer.startTag(null, "student");

serializer.startTag(null, "name");

serializer.text(stu.getName());

serializer.endTag(null, "name");

serializer.startTag(null, "sex");

serializer.text(stu.getSex());

serializer.endTag(null, "sex");

serializer.startTag(null, "age");

serializer.text(String.valueOf(stu.getAge()));

serializer.endTag(null, "age");

serializer.endTag(null, "student");

}

serializer.endTag(null, "infos");

serializer.endDocument();

return true;

} catch (Exception e) {

e.printStackTrace();

}

return false;

}

private void addStudent() {

String name = etName.getText().toString();

String sex = etSex.getText().toString();

String age = etAge.getText().toString();

if(!TextUtils.isEmpty(name)

&& !TextUtils.isEmpty(sex)

&& !TextUtils.isEmpty(age)) {

studentList.add(new Student(name, sex, Integer.valueOf(age)));

TextView childView = new TextView(this);

childView.setTextSize(23);

childView.setTextColor(Color.BLACK);

childView.setText("　　" + name + "　　" + sex + "　　" + age);

llStudentList.addView(childView);

} else {

Toast.makeText(this, "请正确输入", 0).show();

}

}

}