2024.4.1（周一）进度

完善地铁app的查询功能，截止到今天已完成线路查询、站点查询、起终点查询

package com.example.beijingsubway;

import android.os.Bundle;
import android.annotation.SuppressLint;
import android.os.Handler;
import android.os.Message;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import com.google.android.material.snackbar.Snackbar;

import androidx.appcompat.app.AppCompatActivity;

import android.widget.EditText;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;

public class FpsActivity extends AppCompatActivity implements View.OnClickListener {
    private Button fps_find;
    private TextView textView;
    private EditText linename;
    private static final int TEST_USER_SELECT = 1;

    @SuppressLint("HandlerLeak")
    private Handler handler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            int SubwayID;
            switch (msg.what) {
                case TEST_USER_SELECT:
                    Subway subway = (Subway) msg.obj;
                    SubwayID = subway.getId();
                    System.out.println("***********");
                    System.out.println("***********");
                    System.out.println("id:" + SubwayID);
                    textView.setText(Integer.toString(SubwayID));
                    break;
            }
        }
    };

    @SuppressLint("MissingInflatedId")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_fps);
        fps_find = findViewById(R.id.fps_find);
        textView = findViewById(R.id.fps_result);
        linename = findViewById(R.id.line_name);

        fps_find.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        if (view.getId() == R.id.fps_find) {
            String lineNameText = linename.getText().toString();
            if (!lineNameText.isEmpty()) {
                int inputId = Integer.parseInt(lineNameText);
                new Thread(new Runnable() {
                    @Override
                    public void run() {
                        try {
                            Connection conn = DBOpenHelper.getConn();
                            if (conn != null) {
                                String sql = "SELECT * FROM subway WHERE id = ?";
                                try (PreparedStatement pst = conn.prepareStatement(sql)) {
                                    pst.setInt(1, inputId);
                                    try (ResultSet rs = pst.executeQuery()) {
                                        StringBuilder resultText = new StringBuilder();
                                        while (rs.next()) {
                                            int id = rs.getInt("id");
                                            String s_station = rs.getString("s_station");
                                            String e_station = rs.getString("e_station");
                                            String path = rs.getString("path");

                                            resultText.append("线路: ").append(id)
                                                    .append("\n起点站: ").append(s_station)
                                                    .append("\n终点站: ").append(e_station)
                                                    .append("\n路线: ").append(path)
                                                    .append("\n\n");
                                        }

                                        runOnUiThread(new Runnable() {
                                            @Override
                                            public void run() {
                                                textView.setText(resultText.toString());
                                            }
                                        });
                                    }
                                }
                                conn.close();
                            } else {
                                runOnUiThread(new Runnable() {
                                    @Override
                                    public void run() {
                                        Snackbar.make(fps_find, "无法连接到数据库", Snackbar.LENGTH_SHORT).show();
                                    }
                                });
                            }
                        } catch (SQLException e) {
                            e.printStackTrace();
                            runOnUiThread(new Runnable() {
                                @Override
                                public void run() {
                                    Snackbar.make(fps_find, "查询操作失败", Snackbar.LENGTH_SHORT).show();
                                }
                            });
                        }
                    }
                }).start();
            } else {
                Snackbar.make(fps_find, "请输入线路名称", Snackbar.LENGTH_SHORT).show();
            }
        }
    }
}