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 "com.itheima27.sutdentmanager.MainActivity" "@string/app_name" > <intent-filter> <action "android.intent.action.MAIN" />
<category "android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application>
</manifest> |
3 编写布局文件activity_main.xml
<LinearLayout android:layout_width="match_parent" android:layout_height=android:background="@android:color/white" android:orientation="vertical" >
<TextView "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 "fill_parent" "5dip" android:padding="5dip">
<TextView android:id="@+id/tv_name" android:paddingLeft="15dip" android:paddingRight="15dip" 姓名"18sp" />
<"@+id/tv_sex" android:layout_marginLeft=android:layout_toRightOf="@id/tv_name" 性别"@+id/tv_age" "@id/tv_sex" 年龄"18sp" />
<!-- 在姓名的下面 --> <EditText "@+id/et_name" android:layout_alignLeft=android:layout_alignRight=android:layout_below=android:singleLine="true" />
在性别的下面"@+id/et_sex" "true" />
<EditText "@+id/et_age" "@id/tv_age" android:inputType="number" Button "@+id/btn_add_student" android:layout_alignBaseline="@id/et_age" "@id/et_age" 添加学生"20sp" /> </RelativeLayout>
<ScrollView "fill_parent" "wrap_content" android:layout_weight="1" >
<LinearLayout "@+id/ll_student_list" "fill_parent" android:layout_margin="1dip" "vertical" "5dip" > </LinearLayout> </ScrollView>
<"horizontal" >
<"@+id/btn_save" "1" 保存数据"20sp" />
<"@+id/btn_restore" 恢复数据LinearLayout> </LinearLayout> |
4 编写Student实体
package com.itheima27.sutdentmanager.entities;
public class Student { private String name; sex; private Integer age;
public Student() { super(); } public Student(String name,String sex,Integer age) { super(); this.name = name; sex = sex; age = age; } public String getName() { return name; } void setName(String name) { name = name; } public String getSex() { sex; } void setSex(String sex) { sex = sex; } public Integer getAge() { age; } void setAge(Integer age) { age = age; } @Override public String toString() { return "Student [name=" + name + ",sex=" + sex + + 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;
class MainActivity extends ActionBarActivity implements OnClickListener {
private EditText etName; etSex; etAge; private LinearLayout llStudentList; private List<Student> studentList; private String filePath;
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(btn_add_student).setOnClickListener(this);
studentList = new ArrayList<Student>(); filePath = Environment.getExternalStorageDirectory().getPath() + "/student.xml"; }
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(保存失败 } } else { Toast.makeText(当前没有数据 } break; btn_restore: if(restoreStudentFromLocal()) { Toast.makeText(恢复成功 } 恢复失败 } break; btn_add_student: addStudent(); default: break; } } /** * 从xml中读出Student数据 * @return */ boolean restoreStudentFromLocal() { try { XmlPullParser parser = Xml.newPullParser(); parser.setInput(new FileInputStream(filePath),255); font-family: Consolas; font-size: 11pt; mso-font-kerning: 0pt;">"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 "name".equals(nodeName)) { student.setName(parser.nextText()); } "sex".equals(nodeName)) { student.setSex(parser.nextText()); } "age".equals(nodeName)) { student.setAge(Integer.valueOf(parser.nextText())); } break; END_TAG: "student".equals(nodeName)) { studentList.add(student); } default: break; } eventType = parser.next(); } refreshStudentList(); return true; } catch (Exception e) { e.printStackTrace(); } false; } 恢复student的List列表 void 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); } } boolean saveStudent2Local() { try { XmlSerializer serializer = Xml.newSerializer(); serializer.setOutput(new FileOutputStream("utf-8"); serializer.startDocument("utf-8",true); serializer.startTag(null,255); font-family: Consolas; font-size: 11pt; mso-font-kerning: 0pt;">"infos"); for (Student stu : studentList) { serializer.startTag("student"); serializer.startTag("name"); serializer.text(stu.getName()); serializer.endTag("name"); serializer.startTag("sex"); serializer.text(stu.getSex()); serializer.endTag("sex"); serializer.startTag("age"); serializer.text(String.valueOf(stu.getAge())); serializer.endTag("age"); serializer.endTag("student"); } serializer.endTag("infos"); serializer.endDocument(); false; } 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 = " + name + " + sex + " + age); llStudentList.addView(childView); } else { Toast.makeText(请正确输入 } } } |