Android ListView用法

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     xmlns:tools="http://schemas.android.com/tools"
 4     android:layout_width="match_parent"
 5     android:layout_height="match_parent"
 6     android:orientation="vertical">
 7 
 8     <TextView
 9         android:layout_width="wrap_content"
10         android:layout_height="wrap_content"
11         android:id="@+id/wordTextView"
12         android:text="word"
13         android:textSize="26dp"
14         android:layout_gravity="center"/>
15     <ListView
16         android:layout_width="match_parent"
17         android:layout_height="match_parent"
18         android:id="@+id/definitions_ListView">
19 
20     </ListView>
21 
22 </LinearLayout>

 1 package com.chenye.dictionarychange;
 2 
 3 import android.support.v7.app.AppCompatActivity;
 4 import android.os.Bundle;
 5 import android.view.View;
 6 import android.widget.AdapterView;
 7 import android.widget.ArrayAdapter;
 8 import android.widget.ListView;
 9 import android.widget.TextView;
10 import android.widget.Toast;
11 
12 import org.w3c.dom.Text;
13 
14 import java.util.ArrayList;
15 import java.util.Collection;
16 import java.util.Collections;
17 import java.util.HashMap;
18 import java.util.Scanner;
19 
20 public class MainActivity extends AppCompatActivity {
21 
22     private HashMap<String, String> dictionary;  // 存放单词-单词含义的字典
23     private ArrayList<String> chosenWords; // 将所有单词存放到chosenwords
24     private String word;   //单词
25     private ArrayList<String> definations; // 含义列表
26     private ArrayAdapter<String> adapter;
27 
28     @Override
29     protected void onCreate(Bundle savedInstanceState) {
30         super.onCreate(savedInstanceState);
31         setContentView(R.layout.activity_main);
32         readAllDefination();
33         this.chosenWords = new ArrayList<>(this.dictionary.keySet());  // 获取到所有单词并存在在ArrayList中
34         this.definations = new ArrayList<>();
35         this.adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, this.definations);  // 初始化ArrayAdapter
36         // 随机选择5个单词含义
37         pick4Definations();
38         // 将列表添加到adapter中
39         ListView defnListView = findViewById(R.id.definitions_ListView);
40         defnListView.setAdapter(this.adapter);
41         // 监听这个列表， 用到了匿名内部类
42         defnListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
43             @Override
44             public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
45                 ListView defnListView = findViewById(R.id.definitions_ListView);
46                 String chooseDefnText = defnListView.getItemAtPosition(i).toString();  // 获取点击位置的字符串， i是list的位置, 大部分情况下i和l（list的第几行）是一样的
47                 String correctDefn = MainActivity.this.dictionary.get(word);   // 获取对应单词的解释
48                 // 如果选择和正确结果一致，则：
49                 if(correctDefn.equals(chooseDefnText)){
50                     Toast.makeText(MainActivity.this, "Correct", Toast.LENGTH_SHORT).show();
51                 }else{
52                     Toast.makeText(MainActivity.this, "Wrong", Toast.LENGTH_SHORT).show();
53                 }
54                 // 选择之后在重新刷新一次列表,即再次挑选一个单词和5个单词的含义
55                 pick4Definations();
56 
57             }
58         });
59     }
60     public void pick4Definations(){
61 
62         Collections.shuffle(this.chosenWords);  // 打乱单词的存放位置
63         this.word = this.chosenWords.get(0);  // 获取存放单词的list中的第一个单词
64         TextView wordText = findViewById(R.id.wordTextView);
65         wordText.setText(this.word);  // 显示单词
66         this.definations.clear();  // 防止结果有脏数据，清空一下单词含义的list
67         for(int i = 0; i < 4; i++){
68             String defn = this.dictionary.get(this.chosenWords.get(i));  // 获取到单词对应的意思
69             this.definations.add(defn);
70         }
71         Collections.shuffle(this.definations);  // 打乱结果
72         this.adapter.notifyDataSetChanged();  // 通知adpter改变
73     }
74     // 将所有单词及其含义放在dictionary这个字典中
75     private void readAllDefination(){
76         Scanner scanner = new Scanner(getResources().openRawResource(R.raw.gre_words));
77         if(this.dictionary == null){
78             this.dictionary = new HashMap<>();
79         }
80         while (scanner.hasNext()){
81             String line = scanner.nextLine();
82             String[] spiece = line.split("\t");
83             this.dictionary.put(spiece[0], spiece[1]);
84         }
85     }
86 }