ListView的刷新

来源：互联网发布：梁朝伟张曼玉知乎编辑：程序博客网时间：2024/06/05 23:39

1.整体刷新

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

final ListView listView = (ListView) findViewById(R.id.list_view);

final List<Message> messageList = new ArrayList<>(100);
for (int i = 0; i < 100; i++) {
String time = Calendar.getInstance().getTime().toLocaleString();
messageList.add(new Message(
R.drawable.icon_contact,
"好友" + i,
"我是文本消息" + i,
time));
}

final BaseAdapter adapter = new MessageAdapter(this, messageList);
listView.setAdapter(adapter);

findViewById(R.id.add_message).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String time = Calendar.getInstance().getTime().toLocaleString();
messageList.add(0, new Message(
R.drawable.icon_contact,
"好友",
"我是文本消息",
time));
adapter.notifyDataSetChanged();
}
});

findViewById(R.id.remove_message).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (messageList.size() > 0) {
messageList.remove(0);
adapter.notifyDataSetChanged();
}
}
});
}
}

部分刷新，有些数据只是listview的某个item的数据发生了变化，这个时候并不需要整体刷新，只需要改变对应的item的数据：

public class MainActivity extends AppCompatActivity {    private ListView listView;    private List<Message> datas;    private EditText modifyPosition;    private View modifyButton;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        listView = (ListView) findViewById(R.id.list_view);        datas = new ArrayList<>(100);        for (int i = 0; i < 100; i++) {            String time = Calendar.getInstance().getTime().toLocaleString();            datas.add(new Message(                    R.drawable.icon_contact,                    "好友" + i,                    "我是文本消息" + i,                    time));        }        ListAdapter adapter = new MessageAdapter(this, datas);        listView.setAdapter(adapter);        modifyPosition = (EditText) findViewById(R.id.modify_position);        modifyButton = findViewById(R.id.modify_message);        modifyButton.setOnClickListener(new View.OnClickListener() {            public void onClick(View v) {                try {                    int position = Integer.parseInt(modifyPosition.getText().toString());                    Message message = datas.get(position);                    message.setContent("这是修改后的消息" + position);//这只是把数据设置好，但是并没有刷新显示界面！                    partialRefresh(listView, position);//刷新数据                } catch (NumberFormatException e) {                    e.printStackTrace();                    Toast.makeText(MainActivity.this, "输入不合法", Toast.LENGTH_SHORT).show();                }            }        });    }    private void partialRefresh(ListView listView, int position) {        if (position >= listView.getFirstVisiblePosition()                && position <= listView.getLastVisiblePosition()) {            int childIndex = position - listView.getFirstVisiblePosition();            Toast.makeText(getApplicationContext(),childIndex+"",Toast.LENGTH_LONG).show();            View child = listView.getChildAt(childIndex);            if (child.getTag() instanceof ViewHolder) {                //child.getTag() 是一个viewholder，在viewholder中有一个刷新方法，把传入的内容填充进对应的控件                ((ViewHolder) child.getTag()).refreshContent(datas.get(position).getContent());//                ((ViewHolder) child.getTag()).refreshContent(datas.get(position).getContent());            }        }    }}

viewholder

public class MessageAdapter extends BaseAdapter {    private List<Message> messageList;    private LayoutInflater layoutInflater;    public MessageAdapter(Context context, List<Message> messageList) {        this.layoutInflater = LayoutInflater.from(context);        this.messageList = messageList;    }    @Override    public int getCount() {        return messageList.size();    }    @Override    public Object getItem(int position) {        return messageList.get(position);    }    @Override    public long getItemId(int position) {        return position;    }    @Override    public View getView(int position, View convertView, ViewGroup parent) {        ViewHolder viewHolder;        if (convertView == null) {            convertView = layoutInflater.inflate(R.layout.text_message_item, parent, false);            TextView time = (TextView) convertView.findViewById(R.id.message_time);            TextView name = (TextView) convertView.findViewById(R.id.message_name);            ImageView head = (ImageView) convertView.findViewById(R.id.message_head);            TextView content = (TextView) convertView.findViewById(R.id.message_content);            viewHolder = new ViewHolder(time, name, head, content);            convertView.setTag(viewHolder);        } else {            viewHolder = (ViewHolder) convertView.getTag();        }        Message message = messageList.get(position);        viewHolder.getTime().setText(message.getTime());        viewHolder.getName().setText(message.getName());        viewHolder.getHead().setImageResource(message.getHeadImageResId());        viewHolder.getContent().setText(message.getContent());        return convertView;    }    public static class ViewHolder {        private TextView time;        private TextView name;        private ImageView head;        private TextView content;        public ViewHolder(                TextView time,                TextView name,                ImageView head,                TextView content) {            this.time = time;            this.name = name;            this.head = head;            this.content = content;        }        public TextView getTime() {            return time;        }        public TextView getName() {            return name;        }        public ImageView getHead() {            return head;        }        public TextView getContent() {            return content;        }        public void refreshContent(String content) {            this.content.setText(content);        }    }}

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