3.18

public class SignUpActivity extends AppCompatActivity {

    private EditText id;
    private EditText name;
    private EditText phone;
    private EditText className;
    private EditText password;

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_register);

        id = findViewById(R.id.StudentIdEdit);
        name = findViewById(R.id.NameEdit);
        phone = findViewById(R.id.PhoneEdit);
        className = findViewById(R.id.ClassEdit);
        password = findViewById(R.id.PasswordEdit);


        Button backLoginButton = findViewById(R.id.BackLoginButton);
        backLoginButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // 返回到 MainActivity
                Intent intent = new Intent(SignUpActivity.this, MainActivity.class);
                startActivity(intent);
                finish();
            }
        });

    }

    public void register(View view){

        String id1 = id.getText().toString();
        String name1 = name.getText().toString();
        String phone1 = phone.getText().toString();
        String className1 = className.getText().toString();
        String password1 = password.getText().toString();

        Student student = new Student();

        student.setId(id1);
        student.setName(name1);
        student.setPhone(phone1);
        student.setClassName(className1);
        student.setPassword(password1);
        student.setSetGoal(0);
        student.setSetRecord(0);

        new Thread(){
            @Override
            public void run() {

                int msg = 0;
                StudentDao studentDao = new StudentDao();

                Student s = studentDao.findStudent(student.getId());
                if(s != null){
                    msg = 1;
                }
                else{
                    boolean flag = studentDao.register(student);
                    if(flag){
                        msg = 2;
                    }
                }
                hand.sendEmptyMessage(msg);
            }
        }.start();
    }
    @SuppressLint("HandlerLeak")
    final Handler hand = new Handler()
    {
        public void handleMessage(Message msg) {
            if(msg.what == 0) {
                Toast.makeText(getApplicationContext(),"注册失败",Toast.LENGTH_LONG).show();
            } else if(msg.what == 1) {
                Toast.makeText(getApplicationContext(),"该账号已经存在，请换一个账号",Toast.LENGTH_LONG).show();
            } else if(msg.what == 2) {
                Toast.makeText(getApplicationContext(), "注册成功", Toast.LENGTH_LONG).show();
                Intent intent = new Intent();
                //将想要传递的数据用putExtra封装在intent中
                intent.putExtra("a","注册");
                setResult(RESULT_CANCELED,intent);
                finish();
            }
        }
    };
}