package com.example.myapplication;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
class MyHelper extends SQLiteOpenHelper {
public MyHelper(Context context) {
super(context, "itcast.db", null, 1);
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL("CREATE TABLE information(_id INTEGER PRIMARY KEY AUTOINCREMENT, name VARCHAR(20), phone VARCHAR(20))");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
}
}
package com.example.myapplication;
import android.text.TextUtils;
import android.content.ContentValues;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import androidx.appcompat.app.AppCompatActivity ;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
MyHelper myHelper;
private EditText mEtName;
private EditText mEtPriter;
private EditText mEtPhone;
private TextView mTvShow;
private Button mBtnAdd;
private Button mBtnQuery;
private Button mBtnUpdate;
private Button mBtnDelete;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myHelper = new MyHelper(this);
init();
}
private void init() {
mEtName = (EditText) findViewById(R.id.et_name);
mEtPhone = (EditText) findViewById(R.id.et_phone);
mEtPriter=(EditText) findViewById(R.id.et_priter);
mTvShow = (TextView) findViewById(R.id.tv_show);
mBtnAdd = (Button) findViewById(R.id.btn_add);
mBtnQuery = (Button) findViewById(R.id.btn_query);
mBtnUpdate = (Button) findViewById(R.id.btn_update);
mBtnDelete = (Button) findViewById(R.id.btn_delete);
mBtnAdd.setOnClickListener(this);
mBtnQuery.setOnClickListener(this);
mBtnUpdate.setOnClickListener(this);
mBtnDelete.setOnClickListener(this);
}
@Override
public void onClick(View v) {
String name, phone;
SQLiteDatabase db;
ContentValues values;
String s1=mEtPriter.getText().toString();
switch (v.getId()) {
case R.id.btn_add: //添加数据
name = mEtName.getText().toString();
phone = mEtPhone.getText().toString();
db = myHelper.getWritableDatabase();//获取可读写SQLiteDatabse对象
if (TextUtils.isEmpty(name)) {
Toast.makeText(this, "点击错误", Toast.LENGTH_SHORT).show();
}else {
values = new ContentValues(); //创建ContentValues对象
values.put("name", name); //将数据添加到ContentValues对象
values.put("phone", phone);
db.insert("information", null, values);
Toast.makeText(this, "信息已添加", Toast.LENGTH_SHORT).show();
}
db.close();
break;
case R.id.btn_query: //查询数据
db = myHelper.getReadableDatabase();
Cursor cursor = db.query("information", null, "name=?", new String[] {s1}, null,
null, null);
if (cursor.getCount() == 0) {
mTvShow.setText("");
Toast.makeText(this, "请在框内输入姓名", Toast.LENGTH_SHORT).show();
} else {
cursor.moveToFirst();
mTvShow.setText("Name : " + cursor.getString(1) +
" ；Tel : " + cursor.getString(2));
}
while (cursor.moveToNext()) {
mTvShow.append("\n" + "Name : " + cursor.getString(1) +
" ；Tel : " + cursor.getString(2));
}
cursor.close();
db.close();
break;
case R.id.btn_update: //修改数据
db = myHelper.getWritableDatabase();
values = new ContentValues(); // 要修改的数据
values.put("phone", phone = mEtPhone.getText().toString());
db.update("information", values, "name=?",
new String[]{mEtName.getText().toString()}); // 更新并得到行数
Toast.makeText(this, "信息已修改", Toast.LENGTH_SHORT).show();
db.close();
break;
case R.id.btn_delete: //删除数据
db = myHelper.getWritableDatabase();
db.delete("information", "name=?", new String[] {s1});
Toast.makeText(this, "信息已删除", Toast.LENGTH_SHORT).show();
mTvShow.setText("");
db.close();
break;
}
}
}
