how to connect esp8266 softAp with android app

On Android side it's just network communication without any features. Take a look at Official Documentation and tutorials like this. Everything depends on esp8266 firmware:

• if it implements HTTP web server You can use HttpUrlConnection and GET or POST requests on Android side and corresponding script on esp8266 side;

• if it implements ServerSocket You can use Socket connection an implement Socket Client on Android side.

Update:

Socket communication with esp8266 You should do it in separate (not UI) thread. Full example is something like that:

class SocketClientThread implements Runnable {
        DataInputStream dis;
        DataOutputStream dos;
        String strResponseData;

        @Override
        public void run() {
            try {
                InetAddress serverAddr = InetAddress.getByName("<address>");
                clientSocket = new Socket(serverAddr, <port_number - 80 in your example>);
                dos = new DataOutputStream(clientSocket.getOutputStream());
                dis = new DataInputStream(clientSocket.getInputStream());

                // now you can write data to stream
                dos.writeUTF("Hello");

                // you can also read data from stream
                strResponseData = dis.readUTF();


            } catch (UnknownHostException ignore) {
            } catch (IOException ignore) {
            }

            finally{
                if (clientSocket != null){
                    try {
                        clientSocket.close();
                    } 
                    catch (IOException ignore) {
                    }
                }
            }
        }
}

And than You can use SocketClientThread this way:

Thread socketClientThread;
socketClientThread = new Thread(new SocketClientThread());
socketClientThread.start();