我正在开发一个概念验证应用程序，以便我可以在我正在制作的更大的应用程序中实现该功能。我对Java和Android Dev有点新意，但希望这不应该是一个简单或复杂的问题。
基本上，我正在尝试从CSV文件中读取字符串列表，并使其可用于在应用程序的主要活动上显示列表。
我正在使用外部类来读取CSV文件。这是类代码：
CSVFile.java
package com.yourtechwhiz.listdisplay;
import android.util.Log;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
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);
Log.d("VariableTag", row[0].toString());
}
}
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;
}
}
这是我的主要活动代码：
MainActivity.java
package com.yourtechwhiz.listdisplay;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
// Array of strings that's used to display on screen
String[] mobileArray = {"Android","IPhone","WindowsMobile","Blackberry",
"WebOS","Ubuntu","Windows7","Max OS X"};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
prepArray();
//Display List on Activity
ArrayAdapter adapter = new ArrayAdapter<String>(this,
R.layout.activity_listview, mobileArray);
ListView listView = (ListView) findViewById(R.id.mobile_list);
listView.setAdapter(adapter);
}
//Get list of strings from CSV ready to use
private void prepArray() {
InputStream inputStream = getResources().openRawResource(R.raw.strings);
CSVFile csvFile = new CSVFile(inputStream);
List myList = csvFile.read();
//This is where it has an error
//Set first array in myList to this new array myArray
String[] myArray = myList.get(0);
}
}
我实际上还没有设置mobileArray数组。现在我只是想从List对象myList中“提取”信息......
有人可以向我解释这是怎么做到的吗？也许我只是不完全理解List类型。看起来当在CSVFile读取方法中返回resultList时，它将作为由String数组对象组成的List对象返回。但我似乎无法让它像那样工作。
感谢任何帮助！
最终编辑（工作代码）
private void prepArray() {
try{
CSVReader reader = new CSVReader(new InputStreamReader(getResources().openRawResource(R.raw.strings)));//Specify asset file name
String [] nextLine;
while ((nextLine = reader.readNext()) != null) {
// nextLine[] is an array of values from the line
System.out.println(nextLine[0] + nextLine[1] + "etc...");
Log.d("VariableTag", nextLine[0]);
}
}catch(Exception e){
e.printStackTrace();
Toast.makeText(this, "The specified file was not found", Toast.LENGTH_SHORT).show();
}
}
修改
现在我的prepArray功能如下所示：
private void prepArray() {
try{
String csvfileString = this.getApplicationInfo().dataDir + File.separatorChar + "strings.csv"
File csvfile = new File(csvfileString);
CSVReader reader = new CSVReader(new FileReader("csvfile.getAbsolutePath()"));
String [] nextLine;
while ((nextLine = reader.readNext()) != null) {
// nextLine[] is an array of values from the line
System.out.println(nextLine[0] + nextLine[1] + "etc...");
}
}catch(FileNotFoundException e){
e.printStackTrace();
Toast.makeText(this, "The specified file was not found", Toast.LENGTH_SHORT).show();
}
}
仍然产生FileNotFoundException。
编辑2/3
这是我在实际手机上运行应用程序时生成的日志，其中strings.csv位于字符串的子文件夹（src \ main \ assets \ strings \ strings.csv）中，并且您对代码请求了更改：< / p>
03/27 17:44:01: Launching app
$ adb push C:\Users\Roy\AndroidStudioProjects\ListDisplay\app\build\outputs\apk\app-debug.apk /data/local/tmp/com.yourtechwhiz.listdisplay
$ adb shell pm install -r "/data/local/tmp/com.yourtechwhiz.listdisplay"
pkg: /data/local/tmp/com.yourtechwhiz.listdisplay
Success
$ adb shell am start -n "com.yourtechwhiz.listdisplay/com.yourtechwhiz.listdisplay.MainActivity" -a android.intent.action.MAIN -c android.intent.category.LAUNCHER -D
Connecting to com.yourtechwhiz.listdisplay
D/HyLog: I : /data/font/config/sfconfig.dat, No such file or directory (2)
D/HyLog: I : /data/font/config/dfactpre.dat, No such file or directory (2)
D/HyLog: I : /data/font/config/sfconfig.dat, No such file or directory (2)
W/ActivityThread: Application com.yourtechwhiz.listdisplay is waiting for the debugger on port 8100...
I/System.out: Sending WAIT chunk
I/dalvikvm: Debugger is active
I/System.out: Debugger has connected
I/System.out: waiting for debugger to settle...
Connected to the target VM, address: 'localhost:8609', transport: 'socket'
I/System.out: waiting for debugger to settle...
I/System.out: waiting for debugger to settle...
I/System.out: waiting for debugger to settle...
I/System.out: waiting for debugger to settle...
I/System.out: waiting for debugger to settle...
I/System.out: waiting for debugger to settle...
I/System.out: waiting for debugger to settle...
I/System.out: debugger has settled (1498)
I/dalvikvm: Could not find method android.view.Window$Callback.onProvideKeyboardShortcuts, referenced from method android.support.v7.view.WindowCallbackWrapper.onProvideKeyboardShortcuts
W/dalvikvm: VFY: unable to resolve interface method 16152: Landroid/view/Window$Callback;.onProvideKeyboardShortcuts (Ljava/util/List;Landroid/view/Menu;I)V
D/dalvikvm: VFY: replacing opcode 0x72 at 0x0002
W/dalvikvm: VFY: unable to find class referenced in signature (Landroid/view/SearchEvent;)
I/dalvikvm: Could not find method android.view.Window$Callback.onSearchRequested, referenced from method android.support.v7.view.WindowCallbackWrapper.onSearchRequested
W/dalvikvm: VFY: unable to resolve interface method 16154: Landroid/view/Window$Callback;.onSearchRequested (Landroid/view/SearchEvent;)Z
D/dalvikvm: VFY: replacing opcode 0x72 at 0x0002
I/dalvikvm: Could not find method android.view.Window$Callback.onWindowStartingActionMode, referenced from method android.support.v7.view.WindowCallbackWrapper.onWindowStartingActionMode
W/dalvikvm: VFY: unable to resolve interface method 16158: Landroid/view/Window$Callback;.onWindowStartingActionMode (Landroid/view/ActionMode$Callback;I)Landroid/view/ActionMode;
D/dalvikvm: VFY: replacing opcode 0x72 at 0x0002
I/dalvikvm: Could not find method android.content.res.TypedArray.getChangingConfigurations, referenced from method android.support.v7.widget.TintTypedArray.getChangingConfigurations
W/dalvikvm: VFY: unable to resolve virtual method 455: Landroid/content/res/TypedArray;.getChangingConfigurations ()I
D/dalvikvm: VFY: replacing opcode 0x6e at 0x0002
I/dalvikvm: Could not find method android.content.res.TypedArray.getType, referenced from method android.support.v7.widget.TintTypedArray.getType
W/dalvikvm: VFY: unable to resolve virtual method 477: Landroid/content/res/TypedArray;.getType (I)I
D/dalvikvm: VFY: replacing opcode 0x6e at 0x0008
I/dalvikvm: Could not find method android.widget.FrameLayout.startActionModeForChild, referenced from method android.support.v7.widget.ActionBarContainer.startActionModeForChild
W/dalvikvm: VFY: unable to resolve virtual method 16589: Landroid/widget/FrameLayout;.startActionModeForChild (Landroid/view/View;Landroid/view/ActionMode$Callback;I)Landroid/view/ActionMode;
D/dalvikvm: VFY: replacing opcode 0x6f at 0x0002
I/dalvikvm: Could not find method android.content.Context.getColorStateList, referenced from method android.support.v7.content.res.AppCompatResources.getColorStateList
W/dalvikvm: VFY: unable to resolve virtual method 269: Landroid/content/Context;.getColorStateList (I)Landroid/content/res/ColorStateList;
D/dalvikvm: VFY: replacing opcode 0x6e at 0x0006
I/dalvikvm: Could not find method android.content.res.Resources.getDrawable, referenced from method android.support.v7.widget.ResourcesWrapper.getDrawable
W/dalvikvm: VFY: unable to resolve virtual method 418: Landroid/content/res/Resources;.getDrawable (ILandroid/content/res/Resources$Theme;)Landroid/graphics/drawable/Drawable;
D/dalvikvm: VFY: replacing opcode 0x6e at 0x0002
I/dalvikvm: Could not find method android.content.res.Resources.getDrawableForDensity, referenced from method android.support.v7.widget.ResourcesWrapper.getDrawableForDensity
W/dalvikvm: VFY: unable to resolve virtual method 420: Landroid/content/res/Resources;.getDrawableForDensity (IILandroid/content/res/Resources$Theme;)Landroid/graphics/drawable/Drawable;
D/dalvikvm: VFY: replacing opcode 0x6e at 0x0002
E/dalvikvm: Could not find class 'android.graphics.drawable.RippleDrawable', referenced from method android.support.v7.widget.AppCompatImageHelper.hasOverlappingRendering
W/dalvikvm: VFY: unable to resolve instanceof 140 (Landroid/graphics/drawable/RippleDrawable;) in Landroid/support/v7/widget/AppCompatImageHelper;
D/dalvikvm: VFY: replacing opcode 0x20 at 0x000c
W/System.err: java.io.FileNotFoundException: /csvfile.getAbsolutePath(): open failed: ENOENT (No such file or directory)
W/System.err: at libcore.io.IoBridge.open(IoBridge.java:462)
W/System.err: at java.io.FileInputStream.<init>(FileInputStream.java:78)
W/System.err: at java.io.FileInputStream.<init>(FileInputStream.java:105)
W/System.err: at java.io.FileReader.<init>(FileReader.java:66)
W/System.err: at com.yourtechwhiz.listdisplay.MainActivity.prepArray(MainActivity.java:43)
W/System.err: at com.yourtechwhiz.listdisplay.MainActivity.onCreate(MainActivity.java:26)
W/System.err: at android.app.Activity.performCreate(Activity.java:5287)
W/System.err: at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
W/System.err: at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2145)
W/System.err: at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2231)
W/System.err: at android.app.ActivityThread.access$700(ActivityThread.java:139)
W/System.err: at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1401)
W/System.err: at android.os.Handler.dispatchMessage(Handler.java:102)
W/System.err: at android.os.Looper.loop(Looper.java:137)
W/System.err: at android.app.ActivityThread.main(ActivityThread.java:5082)
W/System.err: at java.lang.reflect.Method.invokeNative(Native Method)
W/System.err: at java.lang.reflect.Method.invoke(Method.java:515)
W/System.err: at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:782)
W/System.err: at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:598)
W/System.err: at dalvik.system.NativeStart.main(Native Method)
W/System.err: Caused by: libcore.io.ErrnoException: open failed: ENOENT (No such file or directory)
W/System.err: at libcore.io.Posix.open(Native Method)
W/System.err: at libcore.io.BlockGuardOs.open(BlockGuardOs.java:110)
W/System.err: at libcore.io.IoBridge.open(IoBridge.java:446)
W/System.err: ... 19 more
I/Adreno-EGL: <qeglDrvAPI_eglInitialize:385>: EGL 1.4 QUALCOMM build: ()
OpenGL ES Shader Compiler Version: E031.24.00.01
Build Date: 12/27/13 Fri
Local Branch: qualcomm_only
Remote Branch:
Local Patches:
Reconstruct Branch:
D/OpenGLRenderer: Enabling debug mode 0
D/OpenGLRenderer: GL error from OpenGLRenderer: 0x502
E/OpenGLRenderer: GL_INVALID_OPERATION
答案 0 :(得分：20)
尝试OpenCSV - 它会让您的生活更轻松。
首先，将此包添加到您的gradle依赖项中，如下所示
compile 'com.opencsv:opencsv:3.9'
然后你可以做
import com.opencsv.CSVReader;
import java.io.IOException;
import java.io.FileReader;
...
try {
CSVReader reader = new CSVReader(new FileReader("yourfile.csv"));
String[] nextLine;
while ((nextLine = reader.readNext()) != null) {
// nextLine[] is an array of values from the line
System.out.println(nextLine[0] + nextLine[1] + "etc...");
}
} catch (IOException e) {
}
或
CSVReader reader = new CSVReader(new FileReader("yourfile.csv"));
List myEntries = reader.readAll();
try {
File csvfile = new File(Environment.getExternalStorageDirectory() + "/csvfile.csv");
CSVReader reader = new CSVReader(new FileReader("csvfile.getAbsolutePath()"));
String[] nextLine;
while ((nextLine = reader.readNext()) != null) {
// nextLine[] is an array of values from the line
System.out.println(nextLine[0] + nextLine[1] + "etc...");
}
} catch (Exception e) {
e.printStackTrace();
Toast.makeText(this, "The specified file was not found", Toast.LENGTH_SHORT).show();
}
如果要将.csv文件与应用程序打包并在安装应用程序时将其安装在内部存储上，请在项目assets文件夹中创建src/main文件夹（例如， ，c:\myapp\app\src\main\assets\），并将.csv文件放在那里，然后在您的活动中将其引用为：
String csvfileString = this.getApplicationInfo().dataDir + File.separatorChar + "csvfile.csv"
File csvfile = new File(csvfileString);
答案 1 :(得分：3)
以下代码段从raw资源文件夹中读取CSV文件（编译后将打包到您的.apk文件中）。
Android默认情况下不会创建raw文件夹。在项目中的res/raw下创建一个原始文件夹，然后将CSV文件复制到其中。将CSV文件的名称保留为小写，并在询问时将其转换为文本格式。我的CSV文件名为welldata.csv。
在代码段中，WellData是模型类（包含构造函数，getter和setter），wellDataList是用于存储数据的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) {
// Split the line into different tokens (using the comma as a separator).
String[] tokens = line.split(",");
// Read the data and store it in the WellData POJO.
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();
}
}
答案 2 :(得分：1)
Android Studio的新编码器。我一直在研究如何读取CSV文件，这最适合我的需求。 （s0，s1等。在程序的开头定义了字符串。）
File fileDirectory = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);
File fileToGet = new File(fileDirectory,"aFileName.csv");
try {
BufferedReader br = new BufferedReader(new FileReader(fileToGet));
String line;
while ((line = br.readLine()) !=null) {
String[] tokens = line.split(",");
s0=tokens[0].toString(); s1=tokens[1].toString(); s2=tokens[2].toString();
s3=tokens[3].toString(); s4=tokens[4].toString(); s5=tokens[5].toString();
}
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
答案 3 :(得分：1)
这在Kotlin为我工作。您需要将myfile.csv文件放置在res / raw文件夹中，如果不存在则创建它。
val inputStream: InputStream = resources.openRawResource(R.raw.myfile)
val reader = BufferedReader(InputStreamReader(inputStream, Charset.forName("UTF-8")))
reader.readLines().forEach {
//get a string array of all items in this line
val items = it.split(",")
//do what you want with each item
}
答案 4 :(得分：0)
这是一种简单的方法，对我有用。
<强> MainActivity.java
// Do not forget to call readWeatherData() in onCreate or wherever you need to :)
// Defining ordered collection as WeatherSample class
private List<WeatherSample> weatherSamples = new ArrayList<>();
private void readWeatherData() {
// Read the raw csv file
InputStream is = getResources().openRawResource(R.raw.data);
// Reads text from character-input stream, buffering characters for efficient reading
BufferedReader reader = new BufferedReader(
new InputStreamReader(is, Charset.forName("UTF-8"))
);
// Initialization
String line = "";
// Initialization
try {
// Step over headers
reader.readLine();
// If buffer is not empty
while ((line = reader.readLine()) != null) {
Log.d("MyActivity","Line: " + line);
// use comma as separator columns of CSV
String[] tokens = line.split(",");
// Read the data
WeatherSample sample = new WeatherSample();
// Setters
sample.setMonth(tokens[0]);
sample.setRainfall(Double.parseDouble(tokens[1]));
sample.setSumHours(Integer.parseInt(tokens[2]));
// Adding object to a class
weatherSamples.add(sample);
// Log the object
Log.d("My Activity", "Just created: " + sample);
}
} catch (IOException e) {
// Logs error with priority level
Log.wtf("MyActivity", "Error reading data file on line" + line, e);
// Prints throwable details
e.printStackTrace();
}
}
<强> WeatherSample.java
public class WeatherSample {
private String month;
private double rainfall;
private int sumHours;
public String getMonth() {
return month;
}
public void setMonth(String month) {
this.month = month;
}
public double getRainfall() {
return rainfall;
}
public void setRainfall(double rainfall) {
this.rainfall = rainfall;
}
public int getSumHours() {
return sumHours;
}
public void setSumHours(int sumHours) {
this.sumHours = sumHours;
}
@Override
public String toString() {
return "WeatherSample{" +
"month='" + month + '\'' +
", rainfall=" + rainfall +
", sumHours=" + sumHours +
'}';
}
}
对于源CSV文件，首先创建目录：
app - ＆gt; res（右键单击） - ＆gt;新 - ＆gt; Android资源目录 - ＆gt;资源类型（原始） - ＆gt;好的
然后将.csv文件复制并粘贴到新出现的目录中：
raw（右键单击） - ＆gt;在资源管理器中显示
这是我用于项目的源文件：
data.csv
如果您仍然有一些错误，这里是完整项目的链接：
Source Code
希望它有所帮助，玩得开心：）
答案 5 :(得分：0)
在 res / raw 文件夹中有一个名为 filename.csv 的文件：
private void gettingItemsFromCSV() {
BufferedInputStream bufferedInputStream = new BufferedInputStream(getResources().openRawResource(R.raw.filename));
BufferedReader bufferedReader = new BufferedReader(
new InputStreamReader(bufferedInputStream));
try {
String line;
while ((line = bufferedReader.readLine()) != null) {
Log.i("Test123", line);
}
} catch (Exception e) {
e.printStackTrace();
}
}