学生管理系统

package com.itheima27.sutdentmanager.entities;public class Student {	private String name;	private String sex;	private Integer age;	public Student(String name, String sex, Integer age) {		super();		this.name = name;		this.sex = sex;		this.age = age;	}	public Student() {		super();		// TODO Auto-generated constructor stub	}	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 + "]";	}}

package com.itheima27.sutdentmanager;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.util.ArrayList;import java.util.List;import org.xmlpull.v1.XmlPullParser;import org.xmlpull.v1.XmlPullParserException;import org.xmlpull.v1.XmlSerializer;import com.itheima27.sutdentmanager.entities.Student;import android.os.Bundle;import android.os.Environment;import android.app.Activity;import android.graphics.Color;import android.text.TextUtils;import android.util.Xml;import android.view.Menu;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;public class MainActivity extends Activity implements OnClickListener {    private EditText etName;	private EditText etSex;	private EditText etAge;	private LinearLayout llStudentList;	private List
    
      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
     
      ();		filePath = Environment.getExternalStorageDirectory().getPath() + "/student.xml";	}	@Override	public void onClick(View v) {		switch (v.getId()) {		case R.id.btn_save:			if(studentList.size() > 0) {				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;		}	}		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;	}		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();		}	}}
     
    

动态刷新界面

package com.itheima28.refreshview;import android.os.Bundle;import android.app.Activity;import android.view.Menu;import android.view.View;import android.widget.LinearLayout;import android.widget.TextView;public class MainActivity extends Activity {	private LinearLayout llGroup;	@Override	protected void onCreate(Bundle savedInstanceState) {		super.onCreate(savedInstanceState);		setContentView(R.layout.activity_main);				llGroup = (LinearLayout) findViewById(R.id.ll);	}	public void onClick(View view) {				// 添加一个TextView向llGroup				// 定义一个textview对象		TextView tv = new TextView(this);		tv.setText("张三　　　女　　　34");				// 把textview对象添加到linearlayout中		llGroup.addView(tv);	}}