New items in Gridview added at runtime

Question

I have a problem with my shoping list application. I implemented a button adapter from this tutorial which I will use for adding products to list. Each buuton in my gridview will be a product and each product will have context menu where I can add it to list or delete the product.

Problem is that user should have ability to add new products or categories and I don't know how to add items to gridview at runtime. I thought that I could create some dynamic array like list in c++ but i'm new to android and java so I have no idea how to implement something like that.

I tried to implement stack but every time I try to push something app crashes. The same is with array list.

ButtonAdapter :

ButtonAdapter(Context c, ArrayList<String> array){
  mContext = c; 
  arrayInAdapter = array; } 


public int getCount() {  
    int a;
    a = arrayInAdapter.size();
 return a;  
}  

public View getView(int position, View convertView, ViewGroup parent) {  
 Button btn;  

 if (convertView == null) {  
  //if it's not recycled, initialize some attributes  
  btn = new Button(mContext);  
  btn.setLayoutParams(new GridView.LayoutParams(130, 130));  
  btn.setPadding(8, 8, 8, 8);  
 }  
 else {  
 btn = (Button) convertView;  
 }  
 btn.setText(arrayInAdapter.get(position));   
 btn.setTextColor(Color.RED);  
 btn.setBackgroundResource(R.drawable.sample_0);  
 btn.setId(position); 
 btn.setOnClickListener(new MyOnClickListener(position));

 return btn;  
}  

}

and in Grid Activity i have another arraylist

public static ArrayList<String> arrayInGrid;

in onCreate:

gridView.setAdapter(new ButtonAdapter(this,arrayInGrid ));  

but when i try to send new item to array program crashes.

arrayInGrid.add("new");

In fact it crashes at

arrayInAdapter.size();  

in button adapter.

any ideas what is wrong?

Solution

You can pass the values in your dynamic array to the BaseAdapter for that GridView. Here's a tutorial, Hope it will help you. http://www.mkyong.com/android/android-gridview-example/