Button in Custom View

xspotlivin · by **xspotlivin** » Mon Apr 06, 2009 12:23 am

I'm trying to create a button in a custom view that I've created. I'm looping through an XML document and drawing certain things. I want to be able to also create buttons to go in certain locations depending on the xml data. I'd like to do it in the view because I want to be able to call invalidate() on my view to redraw things and replace the buttons when new xml data is available.

The problem is that I put my code in the view class, the activity crashes because the button is "null". Here is a subset of my code:

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        @Override
 
        protected void onDraw(Canvas canvas) {          
 
                // Clock-size rectangle to draw compliance windows
 
                RectF clockRect = new RectF(86, 6, 394, 314);
 
                // Create a node list containing each reminder
 
                NodeList reminderNodes = this.clockXML.getElementsByTagName("AdherenceInterval");
 
                int reminderLength = reminderNodes.getLength();
 
                Button checkbox = (Button) findViewById(R.id.checkbox);
 
        checkbox.setLayoutParams(new AbsoluteLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT, 0, 0));
 
        checkbox.setOnClickListener(new Button.OnClickListener() {
 
                public void onClick(View v) {
 
                        Context context = v.getContext();
 
                        Intent i = new Intent(context, ReportMedications.class);
 
                        context.startActivity(i);
 
                }
 
        });
 
Parsed in 0.033 seconds,  using GeSHi 1.0.8.4

I know this code works for creating buttons because I can put it in my activity class and it works just fine. Any suggestions? I thought about relocating the button in the activity, but I can't figure out how to do this when new data is available.

WarrenFaith · by **WarrenFaith** » Tue Apr 07, 2009 8:03 am

findViewById(R.id.mything) returns null in two cases:
1. there is no content view (method setContentView(R.layout.whatever) was never called)
or 2. there is simply no R.id.mything

Button in Custom View

Button in Custom View

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