» CS 491 Lecture 9 – On Today and JSON

CS 491 Lecture 9 – On Today and JSON

October 1, 2013 by Chris Johnson. Filed under cs491 mobile, fall 2013, lectures.

Agenda

what ?s
tracking memories on this day in history
database
getting and putting memories through $_REQUEST
exchanging data with JSON
an Android client

Code

schema.sql

DROP TABLE IF EXISTS memory;

CREATE TABLE memory (
  id INT AUTO_INCREMENT PRIMARY KEY,
  year INT,
  month INT,
  day INT,
  log TEXT
);

put.php

<?php

require_once('globals.php');

$feedback = array();
$_REQUEST = json_decode(file_get_contents("php://input"), true);

$db = new mysqli('localhost', 'twodeeor_vanuser', PASSWORD, 'twodeeor_ontoday');
if ($db->connect_errno) {
  $feedback['ok'] = false;
  $feedback['error'] = $db->connect_errno;
} else {

  // Editing existing...
  if ($_REQUEST['id'] < 0) {
    $statement = $db->prepare("INSERT INTO memory (year, month, day, log) VALUES (?, ?, ?, ?)");
    if ($statement) {
      $statement->bind_param('iiis', $_REQUEST['year'], $_REQUEST['month'], $_REQUEST['day'], $_REQUEST['log']);
    }
  }

  // Adding new...
  else {
    $statement = $db->prepare("UPDATE memory SET year = ?, month = ?, day = ?, log = ? WHERE id = ?");
    if ($statement) {
      $statement->bind_param('iiisi', $_REQUEST['year'], $_REQUEST['month'], $_REQUEST['day'], $_REQUEST['log'], $_REQUEST['id']);
    }
  }

  if (!$statement) {
    $feedback['ok'] = false;
    $feedback['error'] = $db->error;
  } else {
    $ok = $statement->execute();
    $statement->free_result();
    $feedback['ok'] = true;
  }

  $db->close();
}

echo json_encode($feedback);

?>

get.php

<?php

require_once('globals.php');

$feedback = array();

$_REQUEST = json_decode(file_get_contents("php://input"), true);
$db = new mysqli('localhost', 'twodeeor_vanuser', PASSWORD, 'twodeeor_ontoday');

if ($db->connect_errno) {
  $feedback['ok'] = false;
  $feedback['error'] = $db->connect_errno;
} else {

  $statement = $db->prepare("SELECT * FROM memory WHERE month = ? AND day = ? ORDER BY year DESC");
  if (!$statement) {
    $feedback['ok'] = false;
    $feedback['error'] = $db->error;
  } else {
    $statement->bind_param('ii', $_REQUEST['month'], $_REQUEST['day']);
    $ok = $statement->execute();
    $statement->bind_result($id, $year, $month, $day, $log);
    $feedback['memories'] = array();
    while ($statement->fetch()) {
      $memory = array();
      $memory['id'] = $id;
      $memory['year'] = $year;
      $memory['month'] = $month;
      $memory['day'] = $day;
      $memory['log'] = $log;
      array_push($feedback['memories'], $memory);
    }
    $statement->free_result();
    $feedback['ok'] = true;
  }

  $db->close();
}

echo json_encode($feedback);

?>

edit.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:orientation="vertical"
  android:layout_width="match_parent"
  android:layout_height="match_parent">
  <EditText
    android:id="@+id/logEditor"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:ems="10"
    android:hint="Enter memory..."
    android:lines="5"
    android:inputType="textMultiLine">
    <requestFocus />
  </EditText>

</LinearLayout>

activity_main.xml

<RelativeLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  tools:context=".MainActivity">
  <DatePicker
    android:id="@+id/datePicker"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true"
    android:layout_marginTop="18dp" />
  <Button
    android:id="@+id/addTodayButton"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/datePicker"
    android:layout_marginTop="20dp"
    android:text="Add today's memory" />
  <ListView
    android:id="@+id/logView"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/addTodayButton"></ListView>
</RelativeLayout>

Memory.java

package org.twodee.ontoday;

import org.json.JSONException;
import org.json.JSONObject;

public class Memory {
  private int id;
  private int year;
  private int month;
  private int day;
  private String log;

  public Memory(int id,
                int year,
                int month,
                int day,
                String log) {
    super();
    this.id = id;
    this.year = year;
    this.month = month;
    this.day = day;
    this.log = log;
  }

  public int getId() {
    return id;
  }

  public int getYear() {
    return year;
  }

  public int getMonth() {
    return month;
  }

  public int getDay() {
    return day;
  }

  public String getLog() {
    return log;
  }

  public void setLog(String log) {
    this.log = log;
  }

  public String toString() {
    return year + " - " + log;
  }

  public JSONObject toJSON() {
    JSONObject object = new JSONObject();
    try {
      object.put("id", id);
      object.put("year", year);
      object.put("month", month);
      object.put("day", day);
      object.put("log", log);
    } catch (JSONException e) {
      e.printStackTrace();
    }
    return object;
  }

  public String getDateString() {
    return String.format("%d/%d/%d", year, month, day);
  }
}

MainActivity.java

package org.twodee.ontoday;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Scanner;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicHeader;
import org.apache.http.protocol.HTTP;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.DatePicker.OnDateChangedListener;
import android.widget.EditText;
import android.widget.ListView;

public class MainActivity extends Activity {
  private ListView logView;
  private ArrayAdapter<Memory> logAdapter;
  private DatePicker datePicker;

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    datePicker = (DatePicker) findViewById(R.id.datePicker);
    logView = (ListView) findViewById(R.id.logView);

    final Button addButton = (Button) findViewById(R.id.addTodayButton);
    addButton.setOnClickListener(new OnClickListener() {
      @Override
      public void onClick(View view) {
        edit(new Memory(-1, datePicker.getYear(), datePicker.getMonth() + 1, datePicker.getDayOfMonth(), ""));
      }
    });

    logAdapter = new ArrayAdapter<Memory>(this, android.R.layout.simple_list_item_1);
    logView.setAdapter(logAdapter);

    final Calendar today = Calendar.getInstance();

    datePicker.init(today.get(Calendar.YEAR), today.get(Calendar.MONTH), today.get(Calendar.DAY_OF_MONTH), new OnDateChangedListener() {
      @Override
      public void onDateChanged(DatePicker picker,
                                int year,
                                int month,
                                int day) {
        load(month + 1, day);
      }
    });

    load(10, 1);
  }

  protected void load(final int month,
                      final int day) {
    new AsyncTask<Void, Void, ArrayList<Memory>>() {
      @Override
      protected ArrayList<Memory> doInBackground(Void... args) {
        ArrayList<Memory> memories = new ArrayList<Memory>();

        try {
          JSONObject json = new JSONObject();
          json.put("month", month);
          json.put("day", day);
          json = makeRequest("http://www.twodee.org/ontoday/get.php", json);

          if (json.has("memories")) {
            JSONArray memoriesJSON = json.getJSONArray("memories");
            for (int i = 0; i < memoriesJSON.length(); ++i) {
              JSONObject memoryJSON = memoriesJSON.getJSONObject(i);
              memories.add(new Memory(memoryJSON.getInt("id"),
                                      memoryJSON.getInt("year"),
                                      memoryJSON.getInt("month"),
                                      memoryJSON.getInt("day"),
                                      memoryJSON.getString("log")));
            }
          }
        } catch (JSONException e) {
          Log.d("FOO", "Bad JSON Parsing");
        }

        return memories;
      }

      @Override
      protected void onPostExecute(ArrayList<Memory> memories) {
        logAdapter.clear();
        logAdapter.addAll(memories);
      }
    }.execute();
  }

  private void edit(final Memory memory) {
    AlertDialog.Builder dialog = new AlertDialog.Builder(this);

    dialog.setTitle("Memory for " + memory.getDateString());
    View body = LayoutInflater.from(this).inflate(R.layout.edit, null);
    final EditText logEditor = (EditText) body.findViewById(R.id.logEditor);
    dialog.setView(body);

    dialog.setPositiveButton("OK", new DialogInterface.OnClickListener() {
      @Override
      public void onClick(DialogInterface dialog,
                          int which) {
        memory.setLog(logEditor.getText().toString());
        upload(memory);
      }
    });

    dialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
      @Override
      public void onClick(DialogInterface dialog,
                          int which) {
        dialog.cancel();
      }
    });

    dialog.show();
  }

  private void upload(final Memory memory) {
    new AsyncTask<Void, Void, Void>() {
      @Override
      protected Void doInBackground(Void... arg0) {
        makeRequest("http://www.twodee.org/ontoday/put.php", memory.toJSON());
        return null;
      }

      @Override
      protected void onPostExecute(Void result) {
        load(datePicker.getMonth() + 1, datePicker.getDayOfMonth());
      }
    }.execute();
  }

  private JSONObject makeRequest(String url, JSONObject json) {
    try {
      URI uri = new URI(String.format(url));
      HttpPost post = new HttpPost(uri);
      StringEntity entity = new StringEntity(json.toString());

      Log.d("FOO", "sending " + json.toString());

      entity.setContentType(new BasicHeader(HTTP.CONTENT_TYPE, "application/json"));
      post.setEntity(entity);

      HttpClient client = new DefaultHttpClient();
      HttpResponse response = client.execute(post);

      Scanner in = new Scanner(response.getEntity().getContent());
      in.useDelimiter("\\Z");
      String body = in.next();
      in.close();

      Log.d("FOO", body);

      return new JSONObject(body);
    } catch (URISyntaxException e) {
      e.printStackTrace();
    } catch (UnsupportedEncodingException e) {
      e.printStackTrace();
    } catch (ClientProtocolException e) {
      e.printStackTrace();
    } catch (IOException e) {
      e.printStackTrace();
    } catch (JSONException e) {
      e.printStackTrace();
    }

    return null;
  }
}

Haiku

Mom feared the teen years
“Grow, but let’s not stop talking.”
She named me JSON