安卓中对数据库的操作(增删改查)

效果图如下：

MainActivity类如下：

package com.example.sqlitecrud;import java.util.List;import com.example.sqlitecrud.db.dao.StedentDao;import com.example.sqlitecrud.domain.Student;import android.app.Activity;import android.graphics.Color;import android.os.Bundle;import android.text.TextUtils;import android.view.Gravity;import android.view.View;import android.view.View.OnClickListener;import android.view.Window;import android.widget.Button;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 etAge;private EditText etDeleteName;private EditText etUpdateProName;private EditText etUpdateBackName;private EditText etQueryOne;private Button btAdd;private Button btDelete;private Button btUpdate;private Button btQuery;private Button btQueryAll;private Button btDeleteAll;private LinearLayout llContent;private TextView tv;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);// 去掉标题requestWindowFeature(Window.FEATURE_NO_TITLE);setContentView(R.layout.activity_main);initView();initEvent();}private void initView() {etName = (EditText) this.findViewById(R.id.et_name);etAge = (EditText) this.findViewById(R.id.et_age);etDeleteName = (EditText) this.findViewById(R.id.et_delete_name);etUpdateProName = (EditText) this.findViewById(R.id.et_update_pro_name);etUpdateBackName = (EditText) this.findViewById(R.id.et_update_back_name);etQueryOne = (EditText) this.findViewById(R.id.et_query_one);btAdd = (Button) this.findViewById(R.id.bt_add);btDelete = (Button) this.findViewById(R.id.bt_delete);btUpdate = (Button) this.findViewById(R.id.bt_update);btQuery = (Button) this.findViewById(R.id.bt_query);btDeleteAll = (Button) this.findViewById(R.id.bt_delete_all);btQueryAll = (Button) this.findViewById(R.id.bt_query_all);llContent = (LinearLayout) this.findViewById(R.id.ll_content);}private void initEvent() {btAdd.setOnClickListener(this);btDelete.setOnClickListener(this);btUpdate.setOnClickListener(this);btQuery.setOnClickListener(this);btQueryAll.setOnClickListener(this);btDeleteAll.setOnClickListener(this);}@Overridepublic void onClick(View v) {switch (v.getId()) {case R.id.bt_add:String name = etName.getText().toString().trim();String age = etAge.getText().toString().trim();if (!TextUtils.isEmpty(name) && !TextUtils.isEmpty(age)) {StedentDao dao = new StedentDao(this);long line = dao.insert(name, Integer.valueOf(age));Toast.makeText(this, "插入到数据库成功,影响在" + line + "行",Toast.LENGTH_SHORT).show();} else {Toast.makeText(this, "输入不能为空,请重新输入", Toast.LENGTH_SHORT).show();}break;case R.id.bt_delete:String deleteName = etDeleteName.getText().toString().trim();if (!TextUtils.isEmpty(deleteName)) {StedentDao dao = new StedentDao(this);int line = dao.delete(deleteName);if (line == 0) {Toast.makeText(this, "删除失败,数据库中不存在该人,请重新输入," + deleteName,Toast.LENGTH_SHORT).show();} else {Toast.makeText(this, "数据删除成功,影响到" + line + "行",Toast.LENGTH_SHORT).show();}} else {Toast.makeText(this, "删除数据输入不能为空,请重新输入", Toast.LENGTH_SHORT).show();}break;case R.id.bt_update:String updateProName = etUpdateProName.getText().toString().trim();String updateBackName = etUpdateBackName.getText().toString().trim();if (!TextUtils.isEmpty(updateProName)&& !TextUtils.isEmpty(updateBackName)) {StedentDao dao = new StedentDao(this);int line = dao.update(updateProName, updateBackName);if (line == 0) {Toast.makeText(this,"修改失败,数据库中不存在该人,请重新输入," + updateProName,Toast.LENGTH_SHORT).show();} else {Toast.makeText(this,"数据修改成功,将" + updateProName + "修改为" + updateBackName+ "影响在数据库中的" + line + "行",Toast.LENGTH_SHORT).show();}} else {Toast.makeText(this, "修改数据输入不能为空,请重新输入", Toast.LENGTH_SHORT).show();}break;case R.id.bt_query:String queryOneName = etQueryOne.getText().toString().trim();if (!TextUtils.isEmpty(queryOneName)) {StedentDao dao = new StedentDao(this);Student student = dao.query(queryOneName);if (student != null) {// 动态刷新界面llContent.removeAllViews();tv = new TextView(this);tv.setText("姓名:" + student.getName() + "年龄:"+ student.getAge());tv.setTextSize(25);tv.setTextColor(Color.GRAY);llContent.addView(tv);} else {Toast.makeText(this, "未查询到任何数据", Toast.LENGTH_SHORT).show();// 给出没有数据的提示信息llContent.removeAllViews();tv = new TextView(this);tv.setText("当前没有查询到任何数据");tv.setTextSize(25);tv.setTextColor(Color.RED);tv.setGravity(Gravity.CENTER);llContent.addView(tv);}} else {Toast.makeText(this, "查询数据输入不能为空,请重新输入", Toast.LENGTH_SHORT).show();}case R.id.bt_query_all:llContent.removeAllViews();StedentDao dao = new StedentDao(this);List<Student> studentLists = dao.queryAll();if (studentLists != null) {for (Student student : studentLists) {tv = new TextView(this);tv.setText("姓名:" + student.getName() + "年龄:"+ student.getAge());tv.setTextSize(25);tv.setTextColor(Color.MAGENTA);llContent.addView(tv);}} else {// 给出没有数据的提示信息llContent.removeAllViews();tv = new TextView(this);tv.setText("当前没有查询到任何数据");tv.setTextSize(25);tv.setTextColor(Color.YELLOW);tv.setGravity(Gravity.CENTER);llContent.addView(tv);Toast.makeText(this, "当前未查询到任何数据", Toast.LENGTH_SHORT).show();}break;case R.id.bt_delete_all:llContent.removeAllViews();StedentDao deleteDao = new StedentDao(this);int line = deleteDao.deleteAll();if (line == 0) {Toast.makeText(this, "所有数据删除成功", Toast.LENGTH_SHORT).show();} else {Toast.makeText(this, "当前没有数据", Toast.LENGTH_SHORT).show();}break;default:break;}}}

业务操作Dao了类：

package com.example.sqlitecrud.db.dao;import java.util.ArrayList;import java.util.List;import android.content.ContentValues;import android.content.Context;import android.database.Cursor;import android.database.SQLException;import android.database.sqlite.SQLiteDatabase;import com.example.sqlitecrud.db.StudentSqliteOpenHelp;import com.example.sqlitecrud.domain.Student;public class StedentDao {private StudentSqliteOpenHelp sSOpenHelper;public StedentDao(Context context) {sSOpenHelper = new StudentSqliteOpenHelp(context);}/** * 往数据库中添加数据 *  * @param name *            姓名 * @param age *            年龄 * @return 添加到的行 */public long insert(String name, int age) {SQLiteDatabase db = sSOpenHelper.getWritableDatabase();ContentValues values = new ContentValues();values.put("name", name);values.put("age", age);return db.insert("student", null, values);}/** * 从数据库中根据名字删除数据 *  * @param name *            名字 * @return 删除的行 */public int delete(String name) {SQLiteDatabase db = sSOpenHelper.getWritableDatabase();return db.delete("student", "name = ?", new String[] { name });}/** * 修改数据库中的数据 *  * @param name *            要修改的名字 * @param newName *            修改后的名字 * @return 修改的行数 */public int update(String name, String newName) {SQLiteDatabase db = sSOpenHelper.getWritableDatabase();ContentValues values = new ContentValues();values.put("name", newName);return db.update("student", values, "name = ?", new String[] { name });}private Student student = null;/** * 根据姓名查询数据 *  * @param name *            姓名 * @return 学生实体 */public Student query(String name) {SQLiteDatabase db = sSOpenHelper.getReadableDatabase();// String[] columns = {"id","name","age"};Cursor cursor = db.query("student",new String[] { "id", "name", "age" }, "name = ?",new String[] { name }, null, null, null);if (cursor != null && cursor.getCount() > 0) {if (cursor.moveToFirst()) {student = new Student();student.setId(cursor.getInt(0));student.setName(cursor.getString(1));student.setAge(cursor.getInt(2));// int id = cursor.getInt(0);// String studentName = cursor.getString(1);// int age = cursor.getInt(2);}}return student;}// 存储数据的集合private List<Student> studentList = null;/** * 查询所有数据 *  * @return 数据集合 */public List<Student> queryAll() {SQLiteDatabase db = sSOpenHelper.getReadableDatabase();Cursor cursor = db.query("student",new String[] { "id", "name", "age" }, null, null, null, null,null);if (cursor != null && cursor.getCount() > 0) {studentList = new ArrayList<Student>();while (cursor.moveToNext()) {student = new Student();student.setId(cursor.getInt(0));student.setName(cursor.getString(1));student.setAge(cursor.getInt(2));studentList.add(student);}}return studentList;}/** * 删除所有数据 * @return0 删除成功，1删除失败 */public int deleteAll() {try {SQLiteDatabase db = sSOpenHelper.getWritableDatabase();// return db.delete("student", null, null);String sql = "delete from student";db.execSQL(sql);return 0;} catch (SQLException e) {// TODO Auto-generated catch blocke.printStackTrace();}return 1;}}

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