Lab7 Shared Preferences and SQLite Database (Part2)

Storing data to Shared Preferences and SQLite Database

 

1.    Create a new Android Project called DataStorage with package mdad.localdata and Activity name: DataStorage.

2.    Copy/replace activity_data_storage.xml file with the file downloaded from LMS.

<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/DStabhost" android:layout_width="match_parent"
    android:layout_height="match_parent">
    <TabWidget android:id="@android:id/tabs"
        android:layout_width="match_parent" android:layout_height="60dp" />
    <FrameLayout android:id="@android:id/tabcontent"
        android:layout_width="match_parent" android:layout_height="wrap_content" android:paddingTop="60dp">
        <LinearLayout android:id="@+id/content1"
            android:orientation="vertical" android:layout_width="match_parent"
            android:layout_height="match_parent">

            <LinearLayout
                android:layout_width="match_parent"
                android:layout_height="match_parent"
                android:layout_weight="1"
                android:orientation="horizontal">

                <EditText
                    android:id="@+id/etName"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:ems="10"
                    android:hint="Enter Player Name"
                    android:inputType="textPersonName" />

                <Button
                    android:id="@+id/btnEnterName"
                    android:layout_width="wrap_content"
                    android:layout_height="wrap_content"
                    android:layout_weight="1"
                    android:text="Submit" />



            </LinearLayout>

        </LinearLayout>



        <LinearLayout android:id="@+id/content2"
            android:orientation="vertical" android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/etIntroTab2A"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Write data into SQLite and Read name from SharedPref" >
            </TextView>
            <TextView android:id="@+id/etIntroTab2"
                android:textSize="30sp"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Enter a number from 0 to 10 "></TextView>

            <EditText
                android:id="@+id/etNum"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" >

                <requestFocus />
            </EditText>

            <Button
                android:id="@+id/btnPlay"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Play " >
            </Button>


        </LinearLayout>

        <LinearLayout android:id="@+id/content3"
            android:orientation="vertical" android:layout_width="match_parent"
            android:layout_height="match_parent">

            <TextView
                android:id="@+id/etIntroTab3"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Read data from SQLite" >
            </TextView>
            <Button
                android:id="@+id/btnShow"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Show " >
            </Button>

            <TextView
                android:id="@+id/tvDisplay"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:inputType="textMultiLine" >
            </TextView>
        </LinearLayout>


    </FrameLayout>
</TabHost>

3.    Run>Run apps and you are expected to see a messy output

4.    Edit DataStorage.java and add a method called setupTabs.

//Create a setupTabs method Within the class but outside onCreate method

private void setupTabs(){

    TabHost tabs =(TabHost) this.findViewById(R.id.DStabhost);
    tabs.setup();


    //Tab #1 SharedPreferences Example
    TabHost.TabSpec ts1 = tabs.newTabSpec("SharedPreferences");
    ts1.setIndicator("SharedPref");
    ts1.setContent(R.id.content1);
    tabs.addTab(ts1);

    //Tab #2 SQLiteDatabase Example
    TabHost.TabSpec ts2 = tabs.newTabSpec("SQLiteDatabase");
    ts2.setIndicator("SQLiteDB");
    ts2.setContent(R.id.content2);
    tabs.addTab(ts2);

    //Tab #3 Display Data from Sqlite Example
    TabHost.TabSpec ts3 = tabs.newTabSpec("DisplayAll");
    ts3.setIndicator("Display");
    ts3.setContent(R.id.content3);
    tabs.addTab(ts3);
}

Test it out/ Discussion on codes

5.    Edit DataStorage.java. Invoke the method setupTabs as shown below:

protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_data_storage);

    setupTabs();  

}

6.    Run>Apply
Changes and you are expected to see the output 
with 3 Tabs.

7.    Copy all text from activity_data_storage.xml and paste it on
Android Layout Finder at

https://www.buzzingandroid.com/tools/android-layout-finder/

      This online tools help you to create java coding very quickly for declaring variables,
       binding and all the button Listener. Copy the java codes and paste it on a notepad.

8.    Edit DataStorage.java. paste the declared variable in the DataStorage class level

Paste the methods findViews() and onClick(View v) within the class but outside onCreate() method. Use Intellisense and ALT+Enter to import class whenever necessary.

//Within the class but outside onCreate

private void findViews() {
    TabWidget tabs = (TabWidget)findViewById( android.R.id.tabs );

    etName = (EditText)findViewById( R.id.etName );
    btnEnterName = (Button)findViewById( R.id.btnEnterName );

    etNum = (EditText)findViewById( R.id.etNum );
    btnPlay = (Button)findViewById( R.id.btnPlay );

    btnShow = (Button)findViewById( R.id.btnShow );
    tvDisplay = (TextView)findViewById( R.id.tvDisplay );
    btnEnterName.setOnClickListener( this );
    btnPlay.setOnClickListener( this );
    btnShow.setOnClickListener( this );
}

//Within the class but outside onCreate

 public void onClick(View v) {
  if ( v == btnEnterName ) {
   // Handle clicks for btnEnterName
  } else if ( v == btnPlay ) {
   // Handle clicks for btnPlay
  } else if ( v == btnShow ) {
   // Handle clicks for btnShow
  }
 }

9.    Edit DataStorage.java

 

You are expected to see this error >

To solve this error

Type the highlighted code and this will implements the listener interface

public class DataStorage extends AppCompatActivity implements View.OnClickListener {

10.     Edit DataStorage.java
Given the partial codes, put it in the correct sections.

//#1 Declare Class variables db

SQLiteDatabase db;

int score=100; int rnum;

//#2 inside onCreate method

setContentView(R.layout.activity_data_storage);

    setupTabs();

    findViews();

   
  //#3 Create Sqlite Database and Table

String sqlStatement="create table if not exists gamedata (recID integer PRIMARY KEY autoincrement, pname text, score integer)";

db = openOrCreateDatabase("NumberGame.db", MODE_PRIVATE, null);

db.execSQL(sqlStatement);


//#3 Read value from SharedPreferences

SharedPreferences myPrefs = getSharedPreferences("SPREF_NAME",0);

SharedPreferences.Editor myEditor = myPrefs.edit();

String pName  = myPrefs.getString("pName","");

if (pName.equals (""))  //If user first time running app or never set name before

{    }  //do nothing

else

    etName.setText(pName) ;  //else show the name set previously which was stored in SharedPreference


//#4 create a random number

rnum=(int)(Math.random()*10); //random number from 0 to 10

Log.d("rnum","rnum is "+rnum);  //write to Logcat (Press ALT+6 to see Logcat)

11.    Edit DataStorage.java


    The following codes is written when user click on submit button and it will


write the playername to the local phone memory, SharedPreferences with the
Filename SPREF_NAME and variable name pName

//if ( v == btnEnterName ) {

String playerName = etName.getText().toString();

SharedPreferences myPrefs = getSharedPreferences("SPREF_NAME",0);
SharedPreferences.Editor myEditor = myPrefs.edit();
myEditor.putString("pName", playerName);
myEditor.commit();

Toast toast = Toast.makeText(getApplicationContext(), 
"playerName" +" entered.", Toast.LENGTH_SHORT);
// Set the Gravity to Top and Left
toast.setGravity(Gravity.TOP | Gravity.LEFT, 100, 800);
toast.show();










Test it out/ Discussion on codes






 The following codes is written when user click on Play button and it will compare

the number entered by the user and check if it is correct, if wrong score minus
10. When user gets it right, it will write the player name (get from
SharedPreference memory)  and the score to the Sqlite table.
//else if ( v == btnPlay ) 


int num = 0;
    try {
        num= Integer.parseInt(etNum.getText().toString());
    }
    catch(Exception e)
    {    num = 0;       }
    
    if(num==rnum)
    {
        etNum.setText("");
        etNum.setHint("Bravo!  Score: "+score);

        //Read value from SharedPreferences
        SharedPreferences myPrefs = getSharedPreferences("SPREF_NAME",0);
        SharedPreferences.Editor myEditor = myPrefs.edit();
        String playerName  = myPrefs.getString("pName","No name set");

        try {
              db.beginTransaction();
              db.execSQL("insert into gamedata(pname,score) values('"+playerName+"','"+score+"');");
              db.setTransactionSuccessful();
              db.endTransaction();
        }
        catch (Exception e) {
            Toast.makeText(DataStorage.this, e.getMessage(),Toast.LENGTH_LONG).show();
        }

        //Reset Score and start new random number
        rnum=(int)(Math.random()*10); //random number from 0 to 10
        Log.d("rnum","rnum is "+rnum);
        score=100; //reset score to initial value of 100

    }else{


        etNum.setText("");
        if (num>rnum)
            etNum.setHint("Try smaller number..." );
        else
            etNum.setHint("Try bigger number..." );
        score-=10; //reduce score by 10 points
        if(score<0) score=0;//lowest score is 0
    }








Test it out/ Discussion on codes








The following codes is written when user click on Display Tab and Show button and
it display the names and the score from Sqlite memory.



//else if ( v == btnShow )


try {
    Cursor c1 = db.rawQuery("select * from gamedata", null);
    String s1, s2, sc="";
    while(c1.moveToNext())
    {
        s1=c1.getString(1);
        s2=c1.getString(2);
        sc+=s1+"\t"+s2+"\n";
    }
    tvDisplay.setText("Scoreboard\n"+sc);
}
catch (Exception e) {
    Toast.makeText(DataStorage.this, e.getMessage()
, Toast.LENGTH_LONG).show();
}



Test it out/ Discussion on codes






LAB 7: Mobile Device Application (Part B)

Modify DataStorage.java such that score is displayed from highest to lowest score