ListView Item layout optimization skills in Android

This article describes the ListView Item layout optimization techniques in Android. Share it for your reference, as follows:

I have never known that ListView has multiple layout optimization methods, which can only be achieved through hiding. I also know that the efficiency is definitely very low, but I don’t know what methods are there. I checked some information these days and then knew that Google has already thought of an optimization solution for us.

Suppose your ListView Item has three possible layout styles: for example, it is very simple to display a line of characters, which should be left, centered, and right.

At this time, we can rewrite two methods in BaseAdapter:

private static final int TYPE_LEFT = 0; 
private static final int TYPE_CENTER = 1; 
private static final int TYPE_RIGHT = 2; 
@Override 
public int getViewTypeCount() { 
 return 3; 
} 
//If our data list is a list, the bean inside has a property (type) indicating which layout the item should use.@Override 
public int getItemViewType(int position) { 
 return (position).type; 
} 
// Then in our getView method, it's OK@Override 
public View getView(int position, View convertView, ViewGroup parent) { 
 int type = getItemViewType(position); 
 ViewHoldLeft holdLeft; 
 ViewHoldCenter holdCenter; 
 ViewHoldRight holdRight; 
 if (convertView == null) { 
  switch(type) { 
   case TYPE_LEFT: 
    holdLeft = new ViewHoldLeft(); 
    convertView = xxxxxx//Like ordinary     = xxxxxx//Like ordinary    ("holdLeft"); 
    (holdLeft); 
    break; 
   case TYPE_CENTER: 
    holdCenter = new ViewHoldCenter(); 
    convertView = xxxxxx//Like ordinary     = xxxxxx//Like ordinary    ("holdCenter"); 
    (holdCenter); 
    break; 
   case TYPE_RIGHT: 
    holdRight = new ViewHoldRight(); 
    convertView = xxxxxx//Like ordinary     = xxxxxx//Like ordinary    ("holdRight"); 
    (holdRight); 
    break; 
   default: 
    break; 
  } 
 } else { 
  switch(type) { 
   case TYPE_LEFT: 
    holdLeft = (ViewHoldLeft)(); 
    ("holdLeft"); 
    break; 
   case TYPE_CENTER: 
    holdCenter = (ViewHoldCenter)(); 
    ("holdCenter"); 
    break; 
   case TYPE_RIGHT: 
    holdRight = (ViewHoldRight)(); 
    ("holdRight"); 
    break; 
   default: 
    break; 
  } 
 } 
 return convertView; 
} 
private static class ViewHoldLeft { 
 private TextView textView; 
} 
private static class ViewHoldCenter { 
 private TextView textView; 
} 
private static class ViewHoldRight { 
 private TextView textView; 
}

Google is still very human.

I hope this article will be helpful to everyone's Android programming design.