1、创建弹框的公共类
import android.app.AlertDialog;
import android.content.Context;

public class DialogBase {
public static void showmessage(Context context, String message,String FirstBtn)
{
AlertDialog.Builder ab = new AlertDialog.Builder(context);
ab.setTitle("消息标题");
ab.setMessage(message);
ab.setPositiveButton(FirstBtn, null);
ab.show();
}

}

2、调用DialogBase 方法

btnlogin.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (etname.getText().toString().isEmpty()) {
DialogBase.showmessage(LogInActivity.this, "请输入账号信息！", "确定");
return;
}
if (etpwd.getText().toString().isEmpty()) {
DialogBase.showmessage(LogInActivity.this, "请输入密码信息！", "确定");
return;
}
if (etname.getText().toString().equals("admin") && etpwd.getText().toString().equals("123")) {//判断是否选中记住密码
getckpwd();

                Intent intent = new Intent(LogInActivity.this, TabBottom.class);
                startActivity(intent);
            } else {
                DialogBase.showmessage(LogInActivity.this, "用户名或密码有误！", "确定");
            }
        }
    });