05_学生管理系统，xml读写，布局的综合应用

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(); } } }