利用LeanCloud移动服务端，简单的登录注册

注册代码

//判断输入的内容是否为空
if (password.equals(again_password)) {//判断两次密码是否相同
    if (!username.isEmpty()) { //用户名
        if (!password.isEmpty()) {//密码
            if (!e_mail.isEmpty()) {//邮箱

                AVUser user = new AVUser();
                user.setUsername(username);
                user.setPassword(password);
                user.setEmail(e_mail);
                //其他的属性可以这样添加
                //user.put("phone","18689898");
                //添加到数据库
                user.signUpInBackground(new SignUpCallback() {
                    @Override
                    public void done(AVException e) {
                        if (e == null) {
                            //成功
                            Intent i = new Intent(RegisterActivity.this, LoginActivity.class);
                            startActivity(i);
                        } else { //注册失败分为很多种方法
                            switch (e.getCode()) {
                                case 202:
                                    Toast.makeText(RegisterActivity.this, "用户名已被注册，请重新填写", Toast.LENGTH_LONG).show();
                                    break;
                                case 203:
                                    Toast.makeText(RegisterActivity.this, "邮箱已被注册，请重新填写", Toast.LENGTH_LONG).show();
                                    break;
                                default:
                                    Toast.makeText(RegisterActivity.this, "网络错误，请检查您的网络连接", Toast.LENGTH_LONG).show();
                                    break;
                            }

                        }
                    }
                });

            } else {
                Toast.makeText(RegisterActivity.this, "请输入邮箱", Toast.LENGTH_LONG).show();
            }
        } else {
            Toast.makeText(RegisterActivity.this, "请输入密码", Toast.LENGTH_LONG).show();
        }
    } else {
        Toast.makeText(RegisterActivity.this, "请输入用户名", Toast.LENGTH_LONG).show();
    }

} else {
    Toast.makeText(RegisterActivity.this, "两次密码不一致", Toast.LENGTH_LONG).show();
}

登录代码

public void Login(View view) {

    String Username = name.getText().toString();
    System.out.println(Username);
    String password = et_password.getText().toString();
    System.out.println(password);
    System.out.println(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<");

    //判断用户名和密码是否为空
    if (Username.isEmpty()) {//判断是否为空，如果为空，返回true
        Toast.makeText(LoginActivity.this,"请输入用户名",Toast.LENGTH_LONG).show();
        return;
    }
    if (password.isEmpty()) {
        Toast.makeText(LoginActivity.this,"请输入密码",Toast.LENGTH_LONG).show();
        return;
    }

    AVUser.logInInBackground(Username,password, new LogInCallback<AVUser>() {
        @Override
        public void done(AVUser avUser, AVException e) {
            if (e == null) {
                Intent i = new Intent(LoginActivity.this,MainActivity.class);
                startActivity(i);
                finish();
            }else {
                Toast.makeText(LoginActivity.this,"登录失败",Toast.LENGTH_LONG).show();
            }
        }
    });
}

源码：http://pan.baidu.com/s/1gegSYaf