如何使用java（android studio）读取文本文件？ 我对android开发非常陌生，我一直在跟随斯坦福CS193A的讲座学习一些东西。在尝试创建字典时（不使用stand ford library），我觉得我做的大部分事情都是对的，但我无法在手机上启动应用程序。这里是我的java代码。请帮帮我。 package com.hfad.dictionarytwo； 导入android.os.Bundle； 导入android.view.view； 导入android.widget.AdapterView； 导入android.widget.ArrayAdapter； 导入android.widget.ListView； 导入android.widget.TextView； 导入android.widget.Toast； 导入androidx.appcompat.app.appcompat活动； 导入java.util.ArrayList； 导入java.util.Collections； 导入java.util.HashMap； 导入java.util.Scanner； 公共类MainActivity扩展了AppCompatActivity{ 私有HashMap字典； 私有数组列表； 专用阵列适配器； 私人ArrayList fiveDefns； @凌驾 受保护的void onCreate（Bundle savedInstanceState）{super.onCreate（savedInstanceState）； setContentView（R.layout.activity_main）； dictionary=newhashmap（）； 列表=新的ArrayList（）； fiveDefns=新的ArrayList（）； readWordsFromFile（）； 挑选单词（）； } 私有void readWordsFromFile（）{ Scanner scan=new Scanner（getResources（）.openRawResource（R.raw.grewords））； //以下去麻器用于在制表符处拆分 while（scan.hasNextLine（））{ String line=scan.nextLine（）； String[]parts=line.split（“\t”）； 如果（零件长度>=2）{ 字符串字=部分[0]； 字符串defn=零件[1]； 列表。添加（word）； 字典.put（单词，defn）； } } } 私有无效字（）{ //下面的代码洗牌所有单词，并取前三个单词 ArrayList threeWords=新的ArrayList（）； 集合。洗牌（列表）； 对于（int i=0；i=1）{ 字符串字=部分[0]； 字符串defn=零件[1]； 列表。添加（word）； 字典.put（单词，defn）； } } } 挑选单词（）； } 私有无效字（）{ //下面的代码洗牌所有单词，并取前三个单词 ArrayList threeWords=新的ArrayList（）； 收藏 abcd kolkata valsad 123 auto vapi 789 neha palghar klj ma ghfgh mnk fgdgdf papa public class MainActivity extends AppCompatActivity { private HashMap<String, String> dictionary; private ArrayList<String> list; private ArrayAdapter<String> adapter; private ArrayList<String> fiveDefns; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); dictionary = new HashMap<String,String>(); list = new ArrayList<String>(); fiveDefns = new ArrayList<String>(); readWordsFromFile(); } private void readWordsFromFile(){ Scanner scan = new Scanner(getResources().openRawResource(R.raw.grewords)); //following delimator is for spliting at tab while (scan.hasNextLine()){ String line = scan.nextLine(); if(line.contains(" ")) { String[] parts = line.split(" "); if (parts.length >= 1) { String word = parts[0]; String defn = parts[1]; list.add(word); dictionary.put(word, defn); } } } pickRandomWords(); } private void pickRandomWords() { //folowing code shuffles all the words and takes the first three words ArrayList<String> threeWords = new ArrayList<String>(); Collections.shuffle(list); for (int i = 0; i < 3; i++) { threeWords.add(list.get(i)); } //display the first word, after shuffling ofcourse final String theWord = threeWords.get(0); TextView theWordView = findViewById(R.id.the_word); theWordView.setText(theWord); fiveDefns.clear(); for (String word : threeWords) { fiveDefns.add(dictionary.get(word)); } //shuffle it again Collections.shuffle(fiveDefns); //make adapter to show three definitions on screen if (adapter == null) { adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, fiveDefns); } else { adapter.notifyDataSetChanged(); } ListView listView = findViewById(R.id.word_list); listView.setAdapter(adapter); listView.setOnItemClickListener(new AdapterView.OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { //get the posiiton of definition user clicked from threeDefn arraylist String defnClicked = (String) fiveDefns.get(position); //want to know if it is right definition String rightAnswer = dictionary.get(theWord); if (defnClicked.equals(rightAnswer)) { //note that just 'this' will not work b/c we want to refer to over all activity //not this little activity, which is small activity inside overall activity Toast.makeText(MainActivity.this, "You are awesome", Toast.LENGTH_SHORT).show(); } else { Toast.makeText(MainActivity.this, "You Suck", Toast.LENGTH_SHORT).show(); } pickRandomWords(); } }); } }

在您的活动中，在readWordsFromFile（）中更改条件，并从readWordsFromFile（）调用pickRandomWords（）。 请参阅下面的代码

确保您的文件包含以下内容：

I am very new to android development and I was following Stanford CS193A lectures to learn something. While trying to create dictionary(without using stand-ford library), i feel like I did most of the things right but I am not able to launch app on phone. Here my java code. Please help me.



    package com.hfad.dictionarytwo;

    import android.os.Bundle;
    import android.view.View;
    import android.widget.AdapterView;
    import android.widget.ArrayAdapter;
    import android.widget.ListView;
    import android.widget.TextView;
    import android.widget.Toast;

    import androidx.appcompat.app.AppCompatActivity;

    import java.util.ArrayList;
    import java.util.Collections;
    import java.util.HashMap;
    import java.util.Scanner;

    public class MainActivity extends AppCompatActivity {

        private HashMap<String, String> dictionary;
        private ArrayList<String> list;
        private ArrayAdapter<String> adapter;
        private ArrayList<String> fiveDefns;

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

            dictionary = new HashMap<String,String>();
            list = new ArrayList<String>();
            fiveDefns = new ArrayList<String>();
            readWordsFromFile();

            pickRandomWords();
        }

        private void readWordsFromFile(){
            Scanner scan = new Scanner(getResources().openRawResource(R.raw.grewords));
            //following delimator is for spliting at tab
            while (scan.hasNextLine()){
                String line = scan.nextLine();
                String[] parts = line.split("\t");
                if (parts.length >= 2){
                String word = parts[0];
                String defn = parts[1];
                list.add(word);
                dictionary.put(word,defn);
                }

            }
        }

        private void pickRandomWords() {
            //folowing code shuffles all the words and takes the first three words
            ArrayList<String> threeWords = new ArrayList<String>();
            Collections.shuffle(list);
            for (int i = 0; i < 5; i++) {
                threeWords.add(list.get(i));
            }
            //display the first word, after shuffling ofcourse
            final String theWord = threeWords.get(0);
            TextView theWordView = findViewById(R.id.the_word);
            theWordView.setText(theWord);

            fiveDefns.clear();
            for (String word : threeWords) {
                fiveDefns.add(dictionary.get(word));
            }

            //shuffle it again
            Collections.shuffle(fiveDefns);
            //make adapter to show three definitions on screen
            if (adapter == null) {
                adapter = new ArrayAdapter<>(this,
                        android.R.layout.simple_list_item_1, fiveDefns);
            } else {
                adapter.notifyDataSetChanged();

            }


            ListView listView = findViewById(R.id.word_list);
            listView.setAdapter(adapter);
            listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {

                @Override
                public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                    //get the posiiton of definition user clicked from threeDefn arraylist
                    String defnClicked = (String) fiveDefns.get(position);
                    //want to know if it is right definition
                    String rightAnswer = dictionary.get(theWord);
                    if (defnClicked.equals(rightAnswer)) {
                        //note that just 'this' will not work b/c we want to refer to over all activity
                        //not this little activity, which is small activity inside overall activity
                        Toast.makeText(MainActivity.this, "You are awesome", Toast.LENGTH_SHORT).show();
                    } else {
                        Toast.makeText(MainActivity.this, "You Suck", Toast.LENGTH_SHORT).show();
                    }

                    pickRandomWords();
                }
            });
        }

    }
注意：文本文件中的数据应采用上述格式。因为您使用空格（“\t”）拆分单词

public类MainActivity扩展了AppCompatActivity{
私有HashMap字典；
私有数组列表；
专用阵列适配器；
私人ArrayList fiveDefns；
@凌驾
受保护的void onCreate（Bundle savedInstanceState）{super.onCreate（savedInstanceState）；
setContentView（R.layout.activity_main）；
dictionary=newhashmap（）；
列表=新的ArrayList（）；
fiveDefns=新的ArrayList（）；
readWordsFromFile（）；
}
私有void readWordsFromFile（）{
Scanner scan=new Scanner（getResources（）.openRawResource（R.raw.grewords））；
//以下去麻器用于在制表符处拆分
while（scan.hasNextLine（））{
String line=scan.nextLine（）；
如果（第行包含（“”））{
String[]parts=line.split（“”）；
如果（零件长度>=1）{
字符串字=部分[0]；
字符串defn=零件[1]；
列表。添加（word）；
字典.put（单词，defn）；
}
}
}
挑选单词（）；
}
私有无效字（）{
//下面的代码洗牌所有单词，并取前三个单词
ArrayList threeWords=新的ArrayList（）；
收藏
abcd kolkata valsad
123 auto vapi
789 neha palghar
klj ma ghfgh
mnk fgdgdf papa

public class MainActivity extends AppCompatActivity {

        private HashMap<String, String> dictionary;
        private ArrayList<String> list;
        private ArrayAdapter<String> adapter;
        private ArrayList<String> fiveDefns;

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

            dictionary = new HashMap<String,String>();
            list = new ArrayList<String>();
            fiveDefns = new ArrayList<String>();
            readWordsFromFile();

        }

        private void readWordsFromFile(){
            Scanner scan = new Scanner(getResources().openRawResource(R.raw.grewords));
            //following delimator is for spliting at tab
            while (scan.hasNextLine()){
                String line = scan.nextLine();
                if(line.contains(" ")) {
                    String[] parts = line.split(" ");
                    if (parts.length >= 1) {
                        String word = parts[0];
                        String defn = parts[1];
                        list.add(word);
                        dictionary.put(word, defn);
                    }
                }

            }
            pickRandomWords();
        }

        private void pickRandomWords() {
            //folowing code shuffles all the words and takes the first three words
            ArrayList<String> threeWords = new ArrayList<String>();
            Collections.shuffle(list);
            for (int i = 0; i < 3; i++) {
                threeWords.add(list.get(i));
            }
            //display the first word, after shuffling ofcourse
            final String theWord = threeWords.get(0);
            TextView theWordView = findViewById(R.id.the_word);
            theWordView.setText(theWord);

            fiveDefns.clear();
            for (String word : threeWords) {
                fiveDefns.add(dictionary.get(word));
            }

            //shuffle it again
            Collections.shuffle(fiveDefns);
            //make adapter to show three definitions on screen
            if (adapter == null) {
                adapter = new ArrayAdapter<>(this,
                        android.R.layout.simple_list_item_1, fiveDefns);
            } else {
                adapter.notifyDataSetChanged();

            }


            ListView listView = findViewById(R.id.word_list);
            listView.setAdapter(adapter);
            listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {

                @Override
                public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                    //get the posiiton of definition user clicked from threeDefn arraylist
                    String defnClicked = (String) fiveDefns.get(position);
                    //want to know if it is right definition
                    String rightAnswer = dictionary.get(theWord);
                    if (defnClicked.equals(rightAnswer)) {
                        //note that just 'this' will not work b/c we want to refer to over all activity
                        //not this little activity, which is small activity inside overall activity
                        Toast.makeText(MainActivity.this, "You are awesome", Toast.LENGTH_SHORT).show();
                    } else {
                        Toast.makeText(MainActivity.this, "You Suck", Toast.LENGTH_SHORT).show();
                    }

                    pickRandomWords();
                }
            });
        }

}