ListView局部刷新

前言：

今天讲一个ListView优化的小技巧，很多时候，我们不需要刷新整个ListView,只是想刷新某一个Item，那么，这个技巧就派上用场了：

一：比如列表有收藏按钮，当前页面收藏

private List<Map<String, String>> mList = new ArrayList<>();
...
走收藏接口，在成功后
mList.get(position).put("favorites", "1");
notifyDataSetChanged();

二：比如列表有收藏按钮，下个页面进行收藏

这种情况下，收藏成功后，返回需要刷新上一个页面状态

DataAdapter

Intent intent = new Intent(activity, NextActivity.class);
intent.putExtra("userhead", doctorList.get(position) .getHeadImg());
intent.putExtra("username", doctorList.get(position) .getName());
intent.putExtra("userId", doctorList.get(position) .getUserinfo_djid());
intent.putExtra("position", position); startActivityForResult(intent,AppConfig.REQUEST_CODE_DIALOGUE);

NextActivity.class

收藏成功后，返回
Intent intent;
intent = new Intent();
Bundle bundle = new Bundle();
bundle.putInt("position", position);
intent.putExtras(bundle);
setResult(RESULT_OK, intent);
finish();

onActivityResult

public void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == AppConfig.REQUEST_CODE_DIALOGUE
&& resultCode == RESULT_OK) {
int position = data.getExtras().getInt("position");
Object object = dataAdapter.getItem(position);
if (object instanceof DoctorList) {
DoctorList doctorList = (DoctorList) object;
doctorList.setUnreadnum("0");
dataAdapter.notifyDataSetChanged();
}
}
super.onActivityResult(requestCode, resultCode, data);
}

DoctorList

class DialogueBean {
private String result;
private ArrayList<DoctorList> doctorList;
public class DoctorList implements Serializable {
private String userinfo_djid;
private String headImg;
private String name;
private String unreadnum;
private String infoContent;
private String sendDate;
private String ky_flag;
private String tobewritten;
}
}

三：以上只是未重新请求接口下刷新View，未真正局部刷新

ListView局部刷新

3、以上只是未重新请求接口下刷新View，未真正局部刷新

ListView局部刷新

private List<Map<String, Object>> mData;
private ListView mListView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mData = getData();
MyAdapter adapter = new MyAdapter(this);
mListView = (ListView) findViewById(R.id.listView);
mListView.setAdapter(adapter);
}

private List<Map<String, Object>> getData() {
List<Map<String, Object>> list = new ArrayList<>();
Map<String, Object> map;
for (int i = 0; i < 50; i++) {
map = new HashMap<>();
map.put("title", "G" + i);
list.add(map);
}
return list;
}

public class MyAdapter extends BaseAdapter {
private LayoutInflater mInflater;

public MyAdapter(Context context) {
this.mInflater = LayoutInflater.from(context);
}

@Override
public int getCount() {
return mData.size();
}

@Override
public Object getItem(int arg0) {
return mData.get(arg0);
}

@Override
public long getItemId(int arg0) {
return arg0;
}

@Override
public View getView(final int position, View convertView, ViewGroup parent) {
Log.d("wxl", "getView=" + position);
ViewHolder holder = null;
if (convertView == null) {
holder = new ViewHolder();
convertView = mInflater.inflate(R.layout.listview_item, null);
holder.textview = (TextView) convertView.findViewById(R.id.textview);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.textview.setText((String) mData.get(position).get("title"));
convertView.setOnClickListener(new View.OnClickListener() {

@Override
public void onClick(View v) {
updateItemView(position);//状态改变时，调用，这里是为了演示方便
}
});

return convertView;
}

public class ViewHolder {
public TextView textview;
}
}

public void updateItemView(int position) {
//得到第一个可显示控件的位置，
int visiblePosition = mListView.getFirstVisiblePosition();
//只有当要更新的view在可见的位置时才更新，不可见时，跳过不更新
int index = position - visiblePosition;
if (index >= 0) {
//得到要更新的item的view
View view = mListView.getChildAt(index);
//从view中取得holder
MyAdapter.ViewHolder holder = (MyAdapter.ViewHolder) view.getTag();
holder.textview.setText("测试数据");
mData.get(index).put("title", "测试数据");
}
}
}

listview_item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">

<TextView
android:id="@+id/textview"
android:layout_width="match_parent"
android:layout_height="60dp"
android:layout_gravity="center_vertical"
android:gravity="center_vertical" />
</LinearLayout>

RecyclerView局部刷新

RecyclerView已经替代了ListView，局部刷新很有必要知道

收藏成功后
mList.get(position).put("favorites", "0");
ViewHolder viewHolder = (ViewHolder) mRecyclerView.findViewHolderForAdapterPosition(position);
viewHolder.mCheck.setBackgroundResource(R.mipmap.collect_normal);