Checkbox Text List

Checkbox Text List :: Extension of Iconified Text tutorial

What you will learn:How to create a list of items with Checkboxes
Description:
This tutorial grew from another tutorial here which dealt with making lists with icons attached to each list item. (IconifiedTextView tutorial).

1.In order to make a List which includes checkboxes, we need to modify a few things. InCheckBoxifiedText.java, we made a String to hold the text of our list item. We also need a boolean value to keep track of the status of the checkbox (checked = true, unchecked = false). The constructor will initialize the checkbox to be checked or unchecked.

Java:

public class CheckBoxifiedText implements Comparable { private String mText = ""; private boolean mChecked; public CheckBoxifiedText ( String text, boolean checked ) { /* constructor */ mText = text; mChecked = checked; }

2.Second, we need to look atCheckboxifiedTextViewAdapter.java. We need to add code to support our checkbox.(src.getChecked()will tell us whether our box is checked or not.

Java:

public View getView ( int position, View convertView, ViewGroup parent ) { CheckBoxifiedTextView btv; if (convertView == null ) { btv = new CheckBoxifiedTextView (mContext, mItems. get (position ) ); } else { // Reuse/Overwrite the View passed // We are assuming(!) that it is castable! CheckBoxifiedText src = mItems. get (position ); btv = (CheckBoxifiedTextView ) convertView; btv. setCheckBoxState (src. getChecked ( ) ); btv = (CheckBoxifiedTextView ) convertView; btv. setText (mItems. get (position ). getText ( ) ); } return btv; }

We also want to add some methods for doing things like getting the state of the checkbox, or selecting all the items.

Java:

public void selectAll ( ) { for (CheckBoxifiedText cboxtxt: mItems ) cboxtxt. setChecked ( true ); /* Things have changed, do a redraw. */ this. notifyDataSetInvalidated ( ); }

3.Open upCheckBoxifiedTextView.java. We need to set up where we want the checkbox to be located, the text location, and whether the box is checked or not.

Java:

public CheckBoxifiedTextView ( Context context, CheckBoxifiedText aCheckBoxifiedText ) { super (context ); /* First CheckBox and the Text to the right (horizontal), * not above and below (vertical) */ this. setOrientation (HORIZONTAL ); mCheckBoxText = aCheckBoxifiedText; mCheckBox = new CheckBox (context ); mCheckBox. setPadding ( 0, 0, 20, 0 ); // 5px to the right /* Set the initial state of the checkbox. */ mCheckBox. setChecked (aCheckBoxifiedText. getChecked ( ) ); /* At first, add the CheckBox to ourself * (! we are extending LinearLayout) */ addView (mCheckBox, new LinearLayout. LayoutParams ( LayoutParams. WRAP_CONTENT, LayoutParams. WRAP_CONTENT ) ); mText = new TextView (context ); mText. setText (aCheckBoxifiedText. getText ( ) ); //mText.setPadding(0, 0, 15, 0); addView (mText, new LinearLayout. LayoutParams ( LayoutParams. WRAP_CONTENT, LayoutParams. WRAP_CONTENT ) ); }

4.Finally, we can look at our ListActivity code which will be using the classes we just made. In the attached source code, this is theCheckbox.javafile. For this example, i am using an array of strings which contain the text we want in each list item. We create a checkboxlist adapter, cbla, first.

Then, we loop through each item in the array and add it to the list adapter (usingcbla.addItem()). I am setting all the checkboxes to initially be unchecked by passing the value of FALSE.

Java:

public class Checkbox extends ListActivity { /** Called when the activity is first created. */ private CheckBoxifiedTextListAdapter cbla; // Create CheckBox List Adapter, cbla private String [ ] items = { "Box 1", "Box 2", "Box 3", "Box 4" }; // Array of string we want to display in our list @Override public void onCreate (Bundle icicle ) { super. onCreate (icicle ); setContentView (R. layout. main ); cbla = new CheckBoxifiedTextListAdapter ( this ); for ( int k= 0; k length; k++ ) { cbla. addItem ( new CheckBoxifiedText (items [k ], false ) ); } // Display it setListAdapter (cbla ); } }

Thats pretty much it. Not much work! Attached are all the source files you will need for this tutorial. I have also added functions such as select all, and deselect all which will come in handy.