What to do if Android cannot connect to mysql

The solution to the failure of Android to connect to mysql: first, customize the listening event in Activty; then create a sub-thread in the custom listening event; finally change the definition of coonection to “DriverManager.getConnection(… )” is enough.

Recommendation: “Mysql Video Tutorial”

Android Studio connects to MySQL: problem solving: virtual machine cannot connect to local SQL, coon is always Empty

Connect to the database in the child thread

First, customize the listening event in Activty

/  /write in Activity
 private Button mBtn;
   @Override
  protected void onCreate(Bundle savedInstanceState)
     {
         super.onCreate(savedInstanceState);
         setContentView(R. layout. activity_main);
         SetListener();//Custom listener event
         }

Create a child thread in the custom listening event, pay attention to the last .start()

private void SetListener()
     {
         mBtnadmin.setOnClickListener(new View.OnClickListener()
         {
             @Override
             public void onClick(View view) {
                 new Thread(new Runnable() {
                     @Override
                     public void run() {
                         Connection cOnn=null;//Create a connection
                         Statement stmt=null;//Used to execute SQL statements
                         try {
                         //register driver
                             Class.forName("com.mysql.jdbc.Driver");
                         // Execution statement of the database
                             String sql="insert into demo values(6666,6666)";
  //Get the connection object. If localhost fails here, change it to 10.0.2.2. This is the address of the computer on the virtual machine. Note that it is a virtual machine, which is used for virtual machine testing
                             cOnn=DriverManager.getConnection("jdbc:mysql://10.0.2.2:3306/logindata","root","666666");
                             stmt=conn.createStatement();
                             stmt. executeUpdate(sql);
                             }
                         } catch (Exception e)
                         {
                             e.printStackTrace();
                         } finally {
                      stmt. close();
                      conn. close();
                            // JDBCUtils.Close(stmt,conn);
                         }
                     }
                 }).start();
              }
         });
     }

Because the virtual machine has been used for testing, the definition of coonection has always been

 cOnn= DriverManager.getConnection("jdbc  :mysql://localhost/logindata","root","666666");

Every time the connection result is reported: coon=null, finally multi-party debugging found this problem, the virtual machine corresponds The ip of your computer should be 10.0.2.2, that is, change the definition of coonection to

cOnn= DriverManager.getConnection("jdbc:mysql://10.0.2.2  :3306/logindata","root","666666");

Success! I was worried about the code problem before, so I didn’t connect to MySQL on the server, now I can try it!

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