将值从MainActivity传递到自定义listview适配器类

Question

I want to pass a String value to my custom listview adapter class. I did it as according to the code below but it's not working.

MainActivity.java

private ArrayList<Item> generateData(String book_name)
{    
    MyAdapter adapter=new MyAdapter(getApplicationContext(),null);
    adapter.message = "hello"; 

MyAdapter.java

public class MyAdapter extends ArrayAdapter<Item> {

    public String message;

and then in the getView

@Override
    public View getView(int position, View convertView, ViewGroup parent) 
    {            
        title.setText(itemsArrayList.get(position).getTitle());
        if(message == "hello")
        {
            //do something here
        }

Thanks for the help

Answer 1

What I think is happening is that your creating the adapter which calls getView before the message is set. So in your custom adapter you change the constructor so it takes the message.

public MyAdapter(Context context, Int resource, ArrayList<value> values, String message) {
    //your current code
    this.message = message 
}

Answer 2

The problem is that your string comparision is wrong. You should use equals method instead of == . So the comparision line should looks like this:

if ("hello".equals(message)) {
    //your code here
}