Android ListView Optimization Best Practices

This blog teaches you how to use convertView and viewHolder(static) to improve ListView lag. However, when ListView loads a large number of complex layouts and pictures, ListView still lags even with convertView and viewHolder. This article mainly discusses how to ensure the smoothness of ListView while loading complex list_items.

The core idea is

Listen for sliding data loading and load data asynchronously.

The getView function must not be time-consuming. Time-consuming tasks must be loaded asynchronously.

The main methods:

1. First determine the current state of ListView. Only when ListView stops sliding will a new thread be started to load data. Other states are ignored.

2. Use the getFirstVisiblePosition and getLastVisiblePosition methods to display the item.

3. Time-consuming tasks must not be performed in the getView method, but should be performed asynchronously.

The specific code is as follows:

 //Judge listView status  
 AbsListView.OnScrollListener onScrollListener = new AbsListView.OnScrollListener() { // ListView  
 // Touch event   
  
 public   void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
 } 
  
 public   void onScrollStateChanged(AbsListView view, int scrollState) {
 switch (scrollState) {
 case AbsListView.OnScrollListener.SCROLL_STATE_FLING: // sliding state  
 threadFlag = false ;
 break ;
 case AbsListView.OnScrollListener.SCROLL_STATE_IDLE: // Stop  
 threadFlag = true ;
 startThread(); //Start a new thread and load data  
 break ;
 case AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL: // Touch listView  
 threadFlag = false ;
 break ;
 default :
 // Toast.makeText(contextt, "default",  
 // Toast.LENGTH_SHORT).show();  
 break ;
 }
 }
 };

I believe that if you do the above three points, you can use ListView with ease.