Android-自定义ListView中的TextView在滚动时会丢失其内容

Question

I have came across these type of questions a lot, But none of the answers solved my problem.

I am developing a mobile shopping application model. I have a custom ListView with an ImageView , and EditText (quantity), 2 Buttons for increasing and decreasing the quantity, 3 TextView s one for item Name and other two for prices and I am dynamically loading a number of Buttons for NetWeights based on the requirement through Java code and I am implementing it using CustomAdapter(Class) extending BaseAdapter and getView().

Problem 1:

When I use the condition if(convertView==null), setTag(holder) and getTag() , the dynamically loaded Buttons are getting duplicated and gets doubled in number.

Problem 2:

While scrolling the custom ListView I am loosing my data on 2 of the TextView s while the other TextView (name) is fine because in that TextView I don't Change data on runtime. On the other two TextView s(prices) I change the data on runtime using ButtonClicks(increase and decrease) where at that time when I scroll the two TextView s, it looses its content. Actually I had this same problem with the EditText(displaying quantity), I solved it using the TextWatcher by getting the value and passing it in an array and again setting it. I used the same technique (ie) the TextWatcher for the TextView s But that did'nt Help. I also tried removing the TextWatcher and setting the text with the array and adding TextWatcher . Still I am loosing my content in those TextView s

Any Suggestions??????

Answer 1

Problem 1: While using ViewHolder (setTag(), getTag()) we will be reusing the views. For example: Let's say we have 10 listview items and the screen can display 3 items at a time. Lets say we add 2 buttons to list item 1. First time when we load the listview we will see two buttons. Lets say now we scroll down and come back to the list item 1 again, as we are reusing the views, we already have 2 buttons and if we have the code to add buttons using getTag() then 2 more buttons will be added. I think this may be causing the issue of button duplication. To add little more information, list item 1, list item 4, list item 7 and list item 10 will all use same view, as our screen in this example can display just 3 items.

Problem 2: One idea is to store all these text values in the arrayList. For example, lets assume we have one textView inside each list item that can be incremented/ decremented. Set textWatcher on this textView and whenever text changes add it to the arrrayList using 'position' as the index. Inside getView method when you do getTag() try to set the textView using previously stored text (that was stored inside the arrayList)if exists.