如何在 Android Studio 中将 CSV 文件解析为数组

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【中文标题】如何在 Android Studio 中将 CSV 文件解析为数组【英文标题】:How to parse CSV file into an array in Android Studio 【发布时间】:2016-11-19 19:39:36 【问题描述】:

我想知道如何解析 CSV 文件并将内容存储到数组中。我的 csv 文件看起来像这样:

1,bulbasaur,1,7,69,64,1,1
2,ivysaur,2,10,130,142,2,1

我只想要名字,所以第二个字段。我想将 csv 中的所有这些项目存储到字符串的数组或数组列表中。

任何想法如何做到这一点?

任何帮助将不胜感激!

【问题讨论】:

【参考方案1】:

将 CSV 文件放在 Android 中的什么位置 在“res”文件夹中创建一个名为“raw”的文件夹,并将 CSV 文件放入其中。

如何读取 CSV 文件, 自从它的android以来没有什么特别的。我们将使用我们的标准 Java 代码。最好使用我们自己的代码而不是使用 API。下面的类是一个读取 CSV 文件的实用程序,它可以在 Android 应用程序中使用。 我们将在哪个数组中存储 csv 文件的项目 在这些示例中,它是 scorelist arraylist 。

public class CSVFile 
    InputStream inputStream;

    public CSVFile(InputStream inputStream)
        this.inputStream = inputStream;
    

    public List read()
        List resultList = new ArrayList();
        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
        try 
            String csvLine;
            while ((csvLine = reader.readLine()) != null) 
                String[] row = csvLine.split(",");
                resultList.add(row);
            
        
        catch (IOException ex) 
            throw new RuntimeException("Error in reading CSV file: "+ex);
        
        finally 
            try 
                inputStream.close();
            
            catch (IOException e) 
                throw new RuntimeException("Error while closing input stream: "+e);
            
        
        return resultList;
    

那么如何从“raw”文件夹中加载 CSV 文件并使用上述工具读取呢?

InputStream inputStream = getResources().openRawResource(R.raw.stats);
CSVFile csvFile = new CSVFile(inputStream);
List scoreList = csvFile.read();

MainActivity.java

public class MainActivity extends Activity 
    private ListView listView;
    private ItemArrayAdapter itemArrayAdapter;

    @Override
    public void onCreate(Bundle savedInstanceState) 
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listView = (ListView) findViewById(R.id.listView);
        itemArrayAdapter = new ItemArrayAdapter(getApplicationContext(), R.layout.item_layout);

        Parcelable state = listView.onSaveInstanceState();
        listView.setAdapter(itemArrayAdapter);
        listView.onRestoreInstanceState(state);

        InputStream inputStream = getResources().openRawResource(R.raw.stats);
        CSVFile csvFile = new CSVFile(inputStream);
        List scoreList = csvFile.read();

        for(String[] scoreData:scoreList ) 
            itemArrayAdapter.add(scoreData);
        
    

ItemArrayAdapter.java

public class ItemArrayAdapter extends ArrayAdapter 
    private List scoreList = new ArrayList();

    static class ItemViewHolder 
        TextView name;
        TextView score;
    

    public ItemArrayAdapter(Context context, int textViewResourceId) 
        super(context, textViewResourceId);
    

    @Override
    public void add(String[] object) 
        scoreList.add(object);
        super.add(object);
    

    @Override
    public int getCount() 
        return this.scoreList.size();
    

    @Override
    public String[] getItem(int index) 
        return this.scoreList.get(index);
    

    @Override
    public View getView(int position, View convertView, ViewGroup parent) 
        View row = convertView;
        ItemViewHolder viewHolder;
        if (row == null) 
            LayoutInflater inflater = (LayoutInflater) this.getContext().
                    getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            row = inflater.inflate(R.layout.item_layout, parent, false);
            viewHolder = new ItemViewHolder();
            viewHolder.name = (TextView) row.findViewById(R.id.name);
            viewHolder.score = (TextView) row.findViewById(R.id.score);
            row.setTag(viewHolder);
         else 
            viewHolder = (ItemViewHolder)row.getTag();
        
        String[] stat = getItem(position);
        viewHolder.name.setText(stat[0]);
        viewHolder.score.setText(stat[1]);
        return row;
    

activity_mail.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_
    android:layout_
    tools:context="com.javapapers.android.csvfileread.app.MainActivity">
    <ListView
        android:layout_
        android:layout_
        android:id="@+id/listView"
        android:layout_alignParentTop="true"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="10dp" />
</RelativeLayout>

item_layout.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_
    android:layout_>
    <TextView
        android:layout_
        android:layout_
        android:id="@+id/name"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_marginLeft="20dp" />
    <TextView
        android:layout_
        android:layout_
        android:id="@+id/score"
        android:layout_alignParentTop="true"
        android:layout_alignParentRight="true"
        android:layout_marginRight="20dp" />
</RelativeLayout>

完整的源代码可以参考这些链接javapapers.com/wp-content/uploads/2014/07/CSVFileRead.zip

我认为这会有所帮助

【讨论】:

如果 ',' 嵌套在嵌套引号中,这会避免拆分字符串吗? 公共类 CSVFile 放在哪里?在 mainactivity.java 中? 我的 csv 文件非常大,在“scoreData”中只有 10-12 个第一行项目。 csv 文件没有新的行或内容,只是 ',' 分隔项目【参考方案2】:

更好的 CSV 解析器处理引用字段

    import android.content.Context;
    import android.widget.Toast;
    import java.io.BufferedReader;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.InputStream;
    import java.io.InputStreamReader;
    import java.util.ArrayList;
    import java.util.List;

    public class CSVReader 
        private class StringDArray 
            private String[] data=new String[0];
            private int used=0;
            public void add(String str) 
                if (used >= data.length)
                    int new_size= used+1;
                    String[] new_data=new String[new_size];
                    java.lang.System.arraycopy( data,0,new_data,0,used);
                    data=new_data;
                
                data[used++] = str;
            
            public int length()
                return  used;
            
            public String[] get_araay()
                return data;
            
        
        private  Context context;
        public CSVReader(Context context)
            this.context=context;
        
        public List read(File file)
            List resultList = new ArrayList();
            try
                InputStream inputStream= new FileInputStream(file);
                BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
                String csvLine;
                final char Separator = ',';
                final char Delimiter = '"';
                final char LF = '\n';
                final char CR = '\r';
                boolean quote_open = false;
                while ((csvLine = reader.readLine()) != null) 
                    //String[] row = csvLine.split(",");// simple way
                    StringDArray a=new StringDArray();
                    String token="";
                        csvLine+=Separator;
                    for(char c:csvLine.toCharArray())
                        switch (c)
                            case LF: case CR:// not required as we are already read line
                                quote_open=false;
                                a.add(token);
                                token="";
                            break;
                            case Delimiter:
                                quote_open=!quote_open;
                            break;
                            case Separator:
                                if(quote_open==false)
                                    a.add(token);
                                    token="";
                                else
                                    token+=c;
                                
                            break;
                            default:
                                token+=c;
                            break;
                        
                    
                    if(a.length()>0 ) 
                        if(resultList.size()>0)
                            String[] header_row =(String[]) resultList.get(0);
                            if(a.length()>=header_row.length) 
                                String[] row = a.get_araay();
                                resultList.add(row);
                            
                        else
                            String[] row = a.get_araay();
                            resultList.add(row);//header row
                        
                    
                
                inputStream.close();
            catch (Exception e)
                Toast.makeText(context,"Error : " + e.getMessage(), Toast.LENGTH_LONG).show();
            
            return resultList;
        
    

用法

    File file=new File(path);
    CSVReader csvReader=new CSVReader(activity.this);
    List csv=csvReader.read(file);
    if(csv.size()>0)
        String[] header_row =(String[]) csv.get(0);
        if(header_row.length>1)
            String col1=header_row[0];
            String col2=header_row[1];
        
    

    Toast.makeText(activity.this,csv.size() + " rows", Toast.LENGTH_LONG).show();

使用的样本数据 身份证、姓名 1、测试项目1 "2","测试项目 2" "3","测试,第 3 项" 4、测试项目4

【讨论】:

【参考方案3】:

免责声明:我从未使用过 Android,但我知道 Java,所以希望一切都一样。

话虽如此,你可以试试这样的。

Scanner scanner = new Scanner(new File("file.csv"));
ArrayList<String> pokemon = new ArrayList<>();
while(scanner.hasNextLine()) 
    pokemon.add(scanner.nextLine().split(",")[1]);

scanner.close();

【讨论】:

【参考方案4】:

Android 默认不创建 raw 文件夹。在项目的 res/raw 下创建 raw 文件夹。在其中复制您的 CSV 文件。将 CSV 文件的名称保持小写,并在询问时转换为文本格式。我的 CSV 文件名为 welldata.scv WellData - 它是带有 getter 和 setter 的模型类。 wellDataList 是存储数据的ArrayList。

private void readData() 
InputStream is = getResources().openRawResource(R.raw.welldata);
BufferedReader reader = new BufferedReader(
        new InputStreamReader(is, Charset.forName("UTF-8")));
String line = "";
try 
    while ((line = reader.readLine()) != null) 
       //set splitter
        String[] tokens = line.split(",");

        //read the data
        WellData wellData = new WellData();
        wellData.setOwner(tokens[0]);
        wellData.setApi(tokens[1]);
        wellData.setLongitude(tokens[2]);
        wellData.setLatitude(tokens[3]);
        wellData.setProperty(tokens[4]);
        wellData.setWellName(tokens[5]);
        wellDataList.add(wellData);

        Log.d("MainActivity" ,"Just Created " +wellData);

    
 catch (IOException e1) 
    Log.e("MainActivity", "Error" + line, e1);
    e1.printStackTrace();

【讨论】:

【参考方案5】:

我扩展了 Sharma 的答案,使核心类在 CSV 文件的各种条件下更加灵活。我更喜欢构建器设计模式来配置如何读取 CSV 文件。

public class CSVFile 
    private static final Charset UTF8 = Charset.forName("UTF-8");
    private final static String DEFAULT_DELIMITER = ",";

    private InputStream inputStream;
    private Charset charset;
    private String delimiter;
    private boolean ignoreHead;

    public CSVFile(InputStream inputStream) 
        this.inputStream = inputStream;
        this.charset = UTF8;
        this.delimiter = DEFAULT_DELIMITER;
        this.ignoreHead = false;
    

    public CSVFile setCharset(Charset charset) 
        this.charset = charset;
        return this;
    

    public CSVFile setDelimiter(String delimiter) 
        this.delimiter = delimiter;
        return this;
    

    public CSVFile ignoreHead() 
        ignoreHead = true;
        return this;
    

    public List<String[]> read() 
        boolean firstRow = true;
        List<String[]> resultList = new ArrayList<>();
        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream, charset));
        try 
            String csvLine;
            while ((csvLine = reader.readLine()) != null) 
                if (firstRow) 
                    firstRow = false;

                    if (ignoreHead) 
                        continue;
                    
                

                String[] row = csvLine.split(delimiter);
                resultList.add(row);
            
         catch (IOException ex) 
            throw new RuntimeException("Error in reading CSV file: " + ex);
         finally 
            try 
                inputStream.close();
             catch (IOException e) 
                throw new RuntimeException("Error while closing input stream: " + e);
            
        
        return resultList;
    

【讨论】:

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