SQLite database Use

1, the dialog box added

Add a dialog box for a previous app

Tasks that need to be completed:

1) Create Datepickerfragment

@Override
Public Dialog Oncreatedialog (Bundle savedinstancestate) {
    
    return new Alertdialog.builder (Getactivity ())
            . Setview (V)
            . Settitle (R.string.date_picker_title)
            . Setpositivebutton (Android. R.string.ok,null)
            . Create ();
}

2) Display dialog box with Fragmentmanager

To pass crime to datepickerfragment need to create a new

Newinstance (Date) method:

public class Datepickerfragment extends Dialogfragment {

private static final String arg_date = "DATE";
Private DatePicker Mdatepicker;
public static datepickerfragment newinstance (date date) {

    Bundle args = new bundle ();
    Args.putserializable (Arg_date, DATE);

    Datepickerfragment fragment = new Datepickerfragment ();
    Fragment.setarguments (args);
    return fragment;
}

Also add a string to the String.xml:

<string name= "Date_picker_title" >date of crime:</string>

Responses to dialog boxes:

public void Onactivityresult (int requestcode, int resultcode, Intent data) {
    if (resultcode! = ACTIVITY.RESULT_OK) {
        Return
    }

    if (Requestcode = = request_date) {
        Date date = (date) data
                . Getserializableextra (Datepickerfragment.extra_date);
        Mcrime.setdate (date);
        Updatecrime ();
        Updatedate ();
    }

2. Toolbars and menus

1) Generate icon:

Right-click the drawable directory and select New→image Asset

Click Next to enter the preview screen:

2) Response menu item selection

Need to be in crimelistfragment.

Implementing the Onoptionsitemselected (MenuItem) method

@Override
public boolean onoptionsitemselected (MenuItem item) {
    Switch (Item.getitemid ()) {
        Case R.id.new_crime:
            Crime Crime = new Crime ();
            Crimelab.get (Getactivity ()). Addcrime (crime);
            UpdateUI ();
            mcallbacks.oncrimeselected (crime);
            return true;
        Default
            return super.onoptionsitemselected (item);
    }
}

In the Crimelistfragment

Response SHOW SUBTITLE menu item Click event

Case R.id.show_subtitle:
    msubtitlevisible =!msubtitlevisible;
    Getactivity (). Invalidateoptionsmenu ();
    Updatesubtitle ();
    return true;

3. SQLite database

1) Create the initial database

Create the Crimebasehelper class with the following code:

public class Crimebasehelper extends Sqliteopenhelper {
    private static final int VERSION = 1;
    private static final String database_name = "CRIMEBASE.DB";
    Public Crimebasehelper (Context context) {
        Super (context, database_name, NULL, VERSION);
    }
    @Override
    public void OnCreate (Sqlitedatabase db) {
    }
    @Override
    public void Onupgrade (sqlitedatabase db, int oldversion, int newversion) {
    }
}

2) write SQL to create the initial code

Db.execsql ("CREATE TABLE" + Crimetable.name + "(" +
        "_id Integer primary Key autoincrement," +
        CrimeTable.Cols.UUID + "," +
        CrimeTable.Cols.TITLE + "," +
        CrimeTable.Cols.DATE + "," +
        CrimeTable.Cols.SOLVED + "," +
        CrimeTable.Cols.SUSPECT +
        ")"
);

The code needs to import crimetable, in the word crimetable,

Press ALT + ENTER to select the Prompt option

3) Read the database

Call Query (...) Method Query Record

Private Crimecursorwrapper Querycrimes (String whereclause, string[] whereargs) {
    cursor cursor = Mdatabase.query (
            Crimetable.name,
            NULL,//Columns-null selects all Columns
            Whereclause,
            Whereargs,
            NULL,//GroupBy
            NULL,//having
            Null  //By
    );
    return new Crimecursorwrapper (cursor);
}

SQLite database Use