浅谈Android开发中ListView控件性能的一些优化方法

@Override

public View getView(intposition, View convertView, ViewGroup paramViewGroup) {

Object current_event = mObjects.get(position);

ViewHolder holder =null;if(convertView ==null) {

holder =newViewHolder();

convertView = inflater.inflate(R.layout.row_event,null);

holder.ThreeDimension = (ImageView) convertView.findViewById(R.id.ThreeDim);

holder.EventPoster = (ImageView) convertView.findViewById(R.id.EventPoster);

convertView.setTag(holder);

}else{

holder = (ViewHolder) convertView.getTag();

}

//在这里进行逻辑判断，这是有问题的

if(doesSomeComplexChecking()) {

holder.ThreeDimention.setVisibility(View.VISIBLE);

}else{

holder.ThreeDimention.setVisibility(View.GONE);

}

// 这是设置image的参数，每次getView方法执行时都会执行这段代码，这显然是有问题的

RelativeLayout.LayoutParams imageParams =newRelativeLayout.LayoutParams(measuredwidth, rowHeight);

holder.EventPoster.setLayoutParams(imageParams);

returnconvertView;

}

@Override

public View  getView(intposition, View convertView, ViewGroup paramViewGroup) {

Object object = mObjects.get(position);

ViewHolder holder =null;if(convertView ==null) {

holder =newViewHolder();

convertView = inflater.inflate(R.layout.row_event,null);

holder.ThreeDimension = (ImageView) convertView.findViewById(R.id.ThreeDim);

holder.EventPoster = (ImageView) convertView.findViewById(R.id.EventPoster);

//设置参数提到这里，只有第一次的时候会执行，之后会复用

RelativeLayout.LayoutParams imageParams =newRelativeLayout.LayoutParams(measuredwidth, rowHeight);

holder.EventPoster.setLayoutParams(imageParams);

convertView.setTag(holder);

}else{

holder = (ViewHolder) convertView.getTag();

}// 我们直接通过对象的getter方法代替刚才那些逻辑判断，那些逻辑判断放到别的地方去执行了holder.ThreeDimension.setVisibility(object.getVisibility());returnconvertView;

}

listView.setOnScrollListener(newOnScrollListener() {

@Override

public void onScrollStateChanged(AbsListView listView,intscrollState) {

//停止加载图片

if(scrollState == AbsListView.OnScrollListener.SCROLL_STATE_FLING) {

imageLoader.stopProcessingQueue();

}else{

//开始加载图片

imageLoader.startProcessingQueue();

}

}

@Override

public void onScroll(AbsListView view,intfirstVisibleItem,intvisibleItemCount,inttotalItemCount) {

// TODO Auto-generated method stub}

});

<android:id="@android:id/list"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:cacheColorHint="#00000000"

android:divider="@color/list_background_color"

android:dividerHeight="0dp"

android:listSelector="#00000000"

android:smoothScrollbar="true"

android:visibility="gone"/>

<android:id="@android:id/list"

android:layout_width="match_parent"

android:layout_height="wrap_content"

android:divider="@color/list_background_color"

android:dividerHeight="0dp"

android:listSelector="#00000000"

android:scrollingCache="false"

android:animationCache="false"

android:smoothScrollbar="true"

android:visibility="gone"/>