Inside Android: January 2015

After a pretty long timegap I am back again with Android development work. Today I add an opportunity to look into android application. Today I focus on key functionality such as

1. Custom View Display
2. Singleton Sqlite DB Connection across multiple threads

I have written a sample application, I am pasting code snippets which will explain both.

Note: There could be typo please correct it or put your comments so that I can correct it back

DBHelper.java

public class DBHelper extends SQLiteOpenHelper{
private static final String DB_NAME="Billing";

public DBHelper(Context context) {
super(context, DB_NAME, null, 1);
}

@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
db.execSQL("create table particular " + "(id integer primary key, particulars text, qty text, price text, date text)");
}

@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// TODO Auto-generated method stub
db.execSQL("DROP TABLE IF EXISTS particular");
onCreate(db);
}
}

DatabaseManager.java

public class DatabaseManager {

private AtomicInteger mOpenCounter = new AtomicInteger();

private static DatabaseManager instance;

private static SQLiteOpenHelper mDatabaseHelper;

private SQLiteDatabase mDatabase;

public static synchronized void initializeInstance(SQLiteOpenHelper helper) {

if (instance == null) {

instance = new DatabaseManager();

mDatabaseHelper = helper;

}

public static synchronized DatabaseManager getInstance() {

if (instance == null) {

throw new IllegalStateException(

DatabaseManager.class.getSimpleName()

+ " is not initialized, call initializeInstance(..) method first.");

}

return instance;

}

public synchronized SQLiteDatabase openDatabase() {

if (mOpenCounter.incrementAndGet() == 1) {

// Opening new database

mDatabase = mDatabaseHelper.getWritableDatabase();

}

return mDatabase;

}

public synchronized SQLiteDatabase openReadDatabase() {

if (mOpenCounter.incrementAndGet() == 1) {

// Opening new database

mDatabase = mDatabaseHelper.getReadableDatabase();

}

return mDatabase;

}

public synchronized void closeDatabase() {

if (mOpenCounter.decrementAndGet() == 0) {

// Closing database

mDatabase.close();

}

Particular.java(Is the MainActivity)

package com.example.billtracking;

import java.text.SimpleDateFormat;

import java.util.ArrayList;

import java.util.Date;

import java.util.HashMap;

import java.util.List;

import java.util.Map;

import android.app.ActionBar;

import android.app.Dialog;

import android.app.ProgressDialog;

import android.content.ContentValues;

import android.content.Intent;

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;

import android.os.AsyncTask;

import android.os.Bundle;

import android.support.v7.app.ActionBarActivity;

import android.util.Log;

import android.view.KeyEvent;

import android.view.Menu;

import android.view.MenuItem;

import android.view.View;

import android.widget.Button;

import android.widget.EditText;

import android.widget.ListView;

import android.widget.Toast;

public class Particular extends ActionBarActivity {

EditText edtDate;

Button bAccept;

Button bClear;

public EditText edtParticular;

public EditText edtQty;

public EditText edtPrice;

public ListView listView;

ListViewAdapterHelper adapter;

static Map<Integer, List<String>> map = new HashMap<Integer, List<String>>();

static int i = 1;

private MenuItem menuItem;

public EditText edtSearch;

private ProgressDialog prgDialog;

public static final int progress_bar_type = 0;

* FragmentManager fm; private boolean isTaskRunning = false;

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.main);

final ActionBar actionBar = getActionBar();

edtDate = (EditText) findViewById(R.id.date);

Date myDate = new Date();

edtDate.setText(new SimpleDateFormat("dd/MM/yyyy").format(myDate));

edtParticular = (EditText) findViewById(R.id.particular);

edtQty = (EditText) findViewById(R.id.qty);

edtPrice = (EditText) findViewById(R.id.price);

listView = (ListView) findViewById(R.id.list);

bAccept = (Button) findViewById(R.id.accept);

bClear = (Button) findViewById(R.id.clear);

actionBar.setDisplayOptions(ActionBar.DISPLAY_SHOW_HOME

| ActionBar.DISPLAY_SHOW_TITLE | ActionBar.DISPLAY_SHOW_CUSTOM);

bAccept.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

listView.setAdapter(null);

// Create Inner Thread Class

Thread background = new Thread(new Runnable() {

public void run() {

DatabaseManager.initializeInstance(new DBHelper(

getApplicationContext()));

SQLiteDatabase dbSqlite = DatabaseManager.getInstance()

.openDatabase();

ContentValues contentValues = new ContentValues();

contentValues.put("particulars", edtParticular

.getText().toString().trim());

contentValues.put("qty", edtQty.getText().toString()

.trim());

contentValues.put("price", edtPrice.getText()

.toString().trim());

contentValues.put("date", edtDate.getText().toString()

.trim());

dbSqlite.insert("particular", null, contentValues);

DatabaseManager.getInstance().closeDatabase();

runOnUiThread(new Runnable() {

public void run() {

Toast.makeText(getApplicationContext(),

"Successfully inserted",

Toast.LENGTH_SHORT).show();

}

});

}

});

background.start();

List<String> arraylist = new ArrayList<String>();

arraylist.add(edtParticular.getText().toString().trim());

arraylist.add(edtQty.getText().toString().trim());

arraylist.add(edtPrice.getText().toString().trim());

arraylist.add(edtDate.getText().toString().trim());

map.put(i++, arraylist);

listView.setAdapter(new ListViewAdapterHelper(getBaseContext(),

map));

}

});

bClear.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

// TODO Auto-generated method stub

if (map.size() > 0) {

map.clear();

i = 1;

listView.setAdapter(null);

}

});

}

@Override

public void onResume() {

super.onResume();

if (map.size() > 0) {

listView.setAdapter(new ListViewAdapterHelper(getBaseContext(), map));

}

@Override

public void onPause() {

super.onPause();

listView.setAdapter(null);

}

@Override

public void onDestroy() {

super.onDestroy();

listView.setAdapter(null);

}

@Override

public boolean onCreateOptionsMenu(Menu menu) {

// Inflate the menu; this adds items to the action bar if it is present.

getMenuInflater().inflate(R.menu.main, menu);

return super.onCreateOptionsMenu(menu);

}

@Override

protected Dialog onCreateDialog(int id) {

switch (id) {

case progress_bar_type:

prgDialog = new ProgressDialog(this);

prgDialog.setMessage("Displaying Usage Statistics...");

prgDialog.setIndeterminate(false);

prgDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);

prgDialog.setCancelable(true);

prgDialog.show();

return prgDialog;

default:

return null;

}

@Override

public boolean onOptionsItemSelected(MenuItem item) {

switch (item.getItemId()) {

case R.id.search_action:

menuItem = item;

menuItem.setActionView(R.layout.search_layout);

menuItem.collapseActionView();

edtSearch = (EditText) item.getActionView().findViewById(

R.id.txt_search);

edtSearch.setOnKeyListener(new View.OnKeyListener() {

@Override

public boolean onKey(View v, int keyCode, KeyEvent event) {

if ((event.getAction() == KeyEvent.ACTION_DOWN)

&& (keyCode == KeyEvent.KEYCODE_ENTER)) {

if (!edtSearch.getText().toString().trim().equals("")) {

/*ThreadProcess tp = new ThreadProcess();

tp.execute(edtSearch.getText().toString().trim());*/

}

return false;

}

});

break;

default:

break;

}

return true;

}

/* class ThreadProcess extends AsyncTask<String, String, String> {

@Override

protected void onPreExecute() {

* int currentOrientation =

* getResources().getConfiguration().orientation; if

* (currentOrientation == Configuration.ORIENTATION_PORTRAIT) {

* setRequestedOrientation

* (ActivityInfo.SCREEN_ORIENTATION_PORTRAIT); } else {

* setRequestedOrientation

* (ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE); }

showDialog(progress_bar_type);

}

@Override

protected void onPostExecute(String result) {

// setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_SENSOR);

dismissDialog(progress_bar_type);

Intent intent = new Intent(Particular.this, SearchResultsActivity.class);

startActivity(intent);

}

@Override

protected String doInBackground(String... params) {

// TODO Auto-generated method stub

try {

Thread.sleep(7000);

Map<String, Double> map = new HashMap<String, Double>();

DatabaseManager.initializeInstance(new DBHelper(

getApplicationContext()));

SQLiteDatabase dbSqlite = DatabaseManager.getInstance().openReadDatabase();

//where particulars=? ORDER BY date"

Cursor cursor = dbSqlite.rawQuery("select * from particular where particulars=? ORDER BY date", params);

Log.d("com.example.billtracking", "cursor getCount = "+cursor.getCount());

if (cursor.getCount() > 0) {

cursor.moveToFirst();

do {

String key = cursor.getString(cursor

.getColumnIndex("date"));

Double value = Double.parseDouble(cursor

.getString(cursor.getColumnIndex("qty")));

String[] sDate = key.split("/");

Double qtyTemp;

// Calculate total qty of an item within same month

if (map.containsKey(sDate[1])) {

qtyTemp = map.get(sDate[1]);

map.put(sDate[1], qtyTemp + value);

} else

map.put(sDate[1], value);

} while (cursor.moveToNext());

}

DatabaseManager.getInstance().closeDatabase();

} catch (InterruptedException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

return null;

}

}*/

}

listview_row.xml

<?xml version="1.0" encoding="utf-8"?>

<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:layout_gravity="top"

android:paddingTop="0dip"

android:stretchColumns="*"

android:shrinkColumns="*">

<TableLayout

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:layout_gravity="top"

android:paddingTop="0dip" >

<TextView

android:id="@+id/textParticular"

android:layout_width="wrap_content"

android:layout_weight="1"

android:layout_height="wrap_content"

android:textColor="#000000"

android:layout_gravity="left|top"

android:layout_marginLeft="10dip"

android:layout_marginTop="2dip"

android:gravity="left" />

<TextView

android:id="@+id/textQty"

android:layout_width="wrap_content"

android:layout_weight="1"

android:textColor="#000000"

android:layout_height="wrap_content"

android:layout_gravity="top|right"

android:layout_marginRight="10dip"

android:gravity="right"

android:layout_marginTop="2dip" />

</TableRow>

<TextView

android:id="@+id/textPrice"

android:layout_width="wrap_content"

android:textColor="#000000"

android:layout_weight="1"

android:layout_height="wrap_content"

android:layout_gravity="bottom|left"

android:layout_marginLeft="10dip"

android:layout_marginTop="4dip"

android:gravity="left"

android:text="" />

<TextView

android:id="@+id/textDate"

android:layout_width="wrap_content"

android:layout_weight="1"

android:textColor="#000000"

android:layout_height="wrap_content"

android:layout_gravity="bottom|right"

android:layout_marginRight="10dip"

android:layout_marginTop="4dip"

android:gravity="right"

android:text="" />

</TableRow>

</TableLayout>

</TableRow>

</TableLayout>

search_layout.xml

<?xml version="1.0" encoding="utf-8"?>

<EditText xmlns:android="http://schemas.android.com/apk/res/android"

android:id="@+id/txt_search"

android:layout_width="fill_parent"

android:layout_height="wrap_content"

android:inputType="text"

android:textColor="#ffffff"

android:drawableLeft="@drawable/ic_action_search"

android:hint="Usage Statistics"

android:focusableInTouchMode="true"

</EditText>

main.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:layout_width="match_parent"

android:layout_height="match_parent"

android:orientation="vertical"

android:paddingLeft="16dp"

android:paddingRight="16dp" >

<EditText

android:id="@+id/particular"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:hint="@string/particular" />

<LinearLayout

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:orientation="horizontal" >

<EditText

android:id="@+id/qty"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:hint="@string/qty" />

<EditText

android:id="@+id/price"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:hint="@string/price"

android:maxLines="1" />

</LinearLayout>

<LinearLayout

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:orientation="horizontal"

<EditText

android:id="@+id/date"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:hint="@string/date"

android:inputType="date"

android:maxLines="1" />

<Button

android:id="@+id/accept"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:hint="@string/accept"

android:paddingBottom="0dp"/>

<Button

android:id="@+id/clear"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:hint="@string/clear"

android:paddingBottom="0dp"/>

</LinearLayout>

<ListView

android:id="@+id/list"

android:layout_width="fill_parent"

android:layout_height="fill_parent"

android:layout_weight="1"/>

</LinearLayout>

menu/main.xml

<menu xmlns:android="http://schemas.android.com/apk/res/android"

xmlns:billtracking="http://schemas.android.com/apk/res-auto"

xmlns:tools="http://schemas.android.com/tools"

tools:context="com.example.billtracking.MainActivity" >

<item

android:id="@+id/search_action"

android:actionViewClass="android.widget.SearchView"

android:icon="@drawable/ic_action_search"

android:title="@string/action_search"

billtracking:showAsAction="collapseActionView|ifRoom"/>

<item

android:id="@+id/empty"

android:icon="@drawable/ic_action_overflow"

android:title="@string/overflow_menu"

billtracking:showAsAction="always">

<!-- <menu>

<item

android:id="@+id/rate"

android:icon="@drawable/ic_menu_friendslist"

android:showAsAction="always|withText"

android:title="List"/>

</menu> -->

</item>

<item

android:id="@+id/action_settings"

android:orderInCategory="100"

android:title="@string/action_settings"

billtracking:showAsAction="never"/>

</menu>

Inside Android

Wednesday, January 7, 2015

Android.mk for C++ native library compilation

Android Application: Thread Safe DB Access & Custom View display