Question

通过图像按钮单击反转完整listView项目的任何可能方法我有一个ListView，它按顺序1-2-3-4-5-6-7-8-9-10显示一个列表。我想要的是，当点击ImageButton时，列表应以10-9-8-7-6-5-4-3-2-1的形式显示其对象。
示例 -

伦敦
纽约
波士顿新泽西州

In 的形式
新泽西州的波士顿
纽约市的士郎

MainActivity.java

        db = new MyDatabase(this);
        employees = db.getEmployees(); 
        final ListAdapter adapter = new SimpleCursorAdapter(this,
                android.R.layout.simple_list_item_1,
                employees,
                new String[] {"Name"},
                new int[] {android.R.id.text1});    
        final ListView listView = (ListView) findViewById(R.id.listV2);
        listView.setAdapter(adapter);

MyDatabase.java

public class MyDatabase extends SQLiteAssetHelper {

    private static final String DATABASE_NAME = "plethora.db";
    private static final int DATABASE_VERSION = 1;

    public MyDatabase(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }
    public Cursor getEmployees() {

        SQLiteDatabase db = getReadableDatabase();
        SQLiteQueryBuilder qb = new SQLiteQueryBuilder();

        String [] sqlSelect = {"2 _id", "Name"};
        String sqlTables = "DelhiBus";

        qb.setTables(sqlTables);
        Cursor c = qb.query(db, sqlSelect, null, null,
                null, null, null);

        c.moveToFirst();
        return c;

    }

}

Answer 1

您可以使用length并通知您的Collections.reverse(mArrayList);，以便将其撤销。

Answer 2

您所要做的就是撤消使用

填充列表视图的arraylist

// *-----------------------*
// |  MAIN-APP COMPONENT   |
// *-----------------------*

import React, { Component } from "react";
import { Col, Well, Panel } from "react-bootstrap";
import { Route, Switch } from "react-router-dom";

import SideNavComponent from "./SideNavComponent";

const HomeComponent = () => <div>Home</div>;
const GraphComponent = () => <div>Graph</div>;
const DeviceComponent = () => <div>Device</div>;
const TransformationComponent = () => <div>Transformation</div>;

class App extends Component {
  render() {
    return (
      <div>
        <div className="header" />
        <div className="body">
          <Col md={3}>
            <Well>
              <SideNavComponent />
            </Well>
          </Col>
          <Col md={9}>
            <Panel>
              <Switch>
                <Route path="/device" component={DeviceComponent} />
                <Route path="/transform" component={TransformationComponent} />
                <Route path="/graph" component={GraphComponent} />
                <Route exact path="/" component={HomeComponent} />
              </Switch>
            </Panel>
          </Col>
        </div>
        <div className="footer" />
      </div>
    );
  }
}

export default App;

// *-----------------------*
// | SIDENAV-COMPONENT     |
// *-----------------------*

import React, { Component } from "react";
import { Nav, NavItem } from "react-bootstrap";
import { Link } from "react-router-dom";

class SideNavComponent extends Component {
  render() {
    return (
      <div style={{ flexDirection: "column" }}>
        <Link to="/">Home</Link>
        <Link to="/graph">Graphs</Link>
      </div>
    );
  }
}

export default SideNavComponent;

// *-----------------------*
// | MAIN.JS (ENTRY POINT) |
// *-----------------------*

import React from 'react'
import { render } from 'react-dom'
import App from './components/App';
import { BrowserRouter } from 'react-router-dom';

render((
  <BrowserRouter>
    <App />
  </BrowserRouter>
), document.getElementById('root'));

然后调用适配器的Collections.reverse(aList);方法。

在listView中反转整个列表

2 个答案: