所花时间：4h
代码量：430
博客量：1
了解的知识点：1.Android连接Mysql数据库教程以及增删改查_android 访问 mysql 增删查改 源码-CSDN博客
更新数据
第一步，修改activity_main.xml文件（添加一个更新按钮和输入框）
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">
<Button
android:id="@+id/bt_send"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="查询数据表"/>
<TextView
android:id="@+id/tv_response"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textStyle="bold" />
<Button
android:id="@+id/bt_delete"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="删除数据"/>
<EditText
android:id="@+id/ed_insert"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="请输入要插入的数据"
android:maxLines="2"/>
<Button
android:id="@+id/bt_insert"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="插入数据"/>
<EditText
android:id="@+id/ed_update"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="请输入更新的内容"
android:maxLines="2"/>
<Button
android:id="@+id/bt_update"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="更新数据"/>
</LinearLayout>
第二步，修改MainActivity.java
package com.example.mysqlconnectiontest;
import android.annotation.SuppressLint;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
private Button button,button_delete,button_insert,button_update;
private TextView textView;
private static final int TEST_USER_SELECT = 1;
int i =0,d=0,z=0;
private EditText editText,editText_update;
@SuppressLint("HandlerLeak")
private Handler handler = new Handler(){
@Override
public void handleMessage(Message msg) {
String user;
switch (msg.what){
case TEST_USER_SELECT:
Test test = (Test) msg.obj;
user = test.getUser();
System.out.println("***********");
System.out.println("***********");
System.out.println("user:"+user);
textView.setText(user);
break;
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = (Button) findViewById(R.id.bt_send);
textView = (TextView) findViewById(R.id.tv_response);
button_delete = (Button) findViewById(R.id.bt_delete);
button_insert = (Button) findViewById(R.id.bt_insert);
button_update = (Button) findViewById(R.id.bt_update);
editText_update = (EditText) findViewById(R.id.ed_update);
}
@Override
protected void onStart() {
super.onStart();
button.setOnClickListener(this);
button_delete.setOnClickListener(this);
button_insert.setOnClickListener(this);
button_update.setOnClickListener(this);
}
@Override
public void onClick(View view) {
switch (view.getId()){
case R.id.bt_send:
//执行查询操作
//通多点击buttoni自增长查询对应id的name
if (i<=3){
i++;
}else {
i=1;
}
//连接数据库进行操作需要在主线程操作
new Thread(new Runnable() {
@Override
public void run() {
Connection conn = null;
conn =(Connection) DBOpenHelper.getConn();
String sql = "select name from test_one where id='"+i+"'";
Statement st;
try {
st = (Statement) conn.createStatement();
ResultSet rs = st.executeQuery(sql);
while (rs.next()){
//因为查出来的数据试剂盒的形式，所以我们新建一个javabean存储
Test test = new Test();
test.setUser(rs.getString(1));
Message msg = new Message();
msg.what =TEST_USER_SELECT;
msg.obj = test;
handler.sendMessage(msg);
}
st.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}).start();
break;
case R.id.bt_delete:
//new一个线程执行删除数据库数据
d++;
new Thread(new Runnable() {
@Override
public void run() {
Connection conn = null;
int u = 0;
conn =(Connection) DBOpenHelper.getConn();
String sql = "delete from test_one where id='"+d+"'";
PreparedStatement pst;
try {
pst = (PreparedStatement) conn.prepareStatement(sql);
u = pst.executeUpdate();
pst.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}).start();
break;
case R.id.bt_insert:
//执行插入操作
new Thread(new Runnable() {
@Override
public void run() {
Connection conn = null;
int u = 0;
conn =(Connection) DBOpenHelper.getConn();
String sql = "insert into test_one (name) values(?)";
PreparedStatement pst;
try {
pst = (PreparedStatement) conn.prepareStatement(sql);
//将输入的edit框的值获取并插入到数据库中
pst.setString(1,editText.getText().toString());
u = pst.executeUpdate();
pst.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}).start();
break;
case R.id.bt_update:
//new一个线程执行删除数据库数据
z++;
new Thread(new Runnable() {
@Override
public void run() {
Connection conn = null;
int u = 0;
conn =(Connection) DBOpenHelper.getConn();
String sql = "update test_one set name='"+editText_update.getText().toString()+"' where id='"+z+"'";
PreparedStatement pst;
try {
pst = (PreparedStatement) conn.prepareStatement(sql);
u = pst.executeUpdate();
pst.close();
conn.close();
} catch (SQLException e) {
e.printStackTrace();
}
}
}).start();
break;
default:
}
}
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