Checkbox Text List :: Extension of Iconified Text tutorial

Checkbox Text List :: Extension of Iconified Text tutorial


What you will learn:How to create a list of items with Checkboxes

Difficulty:2.0 / 5


What it will look like:

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:

publicclassCheckBoxifiedTextimplementsComparable{

privateStringmText ="";
privatebooleanmChecked;
publicCheckBoxifiedText(Stringtext,booleanchecked){
/* 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:

publicViewgetView(intposition,ViewconvertView, ViewGroup parent){
CheckBoxifiedTextView btv;
if(convertView ==null){
btv =newCheckBoxifiedTextView(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());
}
returnbtv;
}

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

Java:

publicvoidselectAll(){
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:

publicCheckBoxifiedTextView(Contextcontext, CheckBoxifiedText aCheckBoxifiedText){
super(context);

/* First CheckBox and the Text to the right (horizontal),
* not above and below (vertical) */
this.setOrientation(HORIZONTAL);
mCheckBoxText = aCheckBoxifiedText;
mCheckBox =newCheckBox(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,newLinearLayout.LayoutParams(
LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));

mText =newTextView(context);
mText.setText(aCheckBoxifiedText.getText());
//mText.setPadding(0, 0, 15, 0);
addView(mText,newLinearLayout.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:

publicclassCheckboxextendsListActivity{
/** Called when the activity is first created. */

privateCheckBoxifiedTextListAdapter cbla;
// Create CheckBox List Adapter, cbla
privateString[]items ={"Box 1","Box 2","Box 3","Box 4"};
// Array of string we want to display in our list

@Override
publicvoidonCreate(Bundle icicle){
super.onCreate(icicle);
setContentView(R.layout.main);

cbla =newCheckBoxifiedTextListAdapter(this);
for(intk=0; klength; k++)
{
cbla.addItem(newCheckBoxifiedText(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.