Question

我正在开发和Android应用程序，其中我不想读取本地json文件来填充ListView，问题是我无法读取本地json文件，这里我如何继续。

首先我创建了一个对象类，因为我想使用 ObjectMapper 。

已经创建了基类（Theme，CouchesTheme和ClassesEvenement）。

这是子类 LireTheme ：

package com.myapp.theme;

public class LireTheme {

private Theme theme;
private CouchesTheme couchesTheme;
private ClassesEvenement classesEvenement;

private String message;
private boolean ok;

public LireTheme() {
    super();
    // TODO Auto-generated constructor stub
}
public LireTheme(Theme theme, CouchesTheme couchesTheme,
        ClassesEvenement classesEvenement, String message, boolean ok) {
    super();
    this.theme = theme;
    this.couchesTheme = couchesTheme;
    this.classesEvenement = classesEvenement;
    this.message = message;
    this.ok = ok;
}
public Theme getTheme() {
    return theme;
}
public void setTheme(Theme theme) {
    this.theme = theme;
}
public CouchesTheme getCouchesTheme() {
    return couchesTheme;
}
public void setCouchesTheme(CouchesTheme couchesTheme) {
    this.couchesTheme = couchesTheme;
}
public ClassesEvenement getClassesEvenement() {
    return classesEvenement;
}
public void setClassesEvenement(ClassesEvenement classesEvenement) {
    this.classesEvenement = classesEvenement;
}
public String getMessage() {
    return message;
}
public void setMessage(String message) {
    this.message = message;
}
public boolean isOk() {
    return ok;
}
public void setOk(boolean ok) {
    this.ok = ok;
}

}

第二我创建了一个主题列表的对应HashMap类。

package com.myapp.recensement;

import java.util.ArrayList;
import java.util.HashMap;

import com.myapp.theme.LireTheme;

public class LireThemes extends HashMap<String, ArrayList<LireTheme>> {
   private static final long serialVersionUID = 1L;
}

然后像这样使用它。

package com.myapp.recensement;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;

import org.codehaus.jackson.JsonFactory;
import org.codehaus.jackson.JsonParseException;
import org.codehaus.jackson.JsonParser;
import org.codehaus.jackson.map.ObjectMapper;

import android.os.Environment;
import android.util.Log;

import com.myapp.theme.LireTheme;

public class LireThemesController {
private ObjectMapper objectMapper = null;
private JsonFactory jsonFactory = null;
private JsonParser jp = null;
private ArrayList<LireTheme> themeList = null;
private LireThemes lirethemes = null;
private File jsonFile;

boolean availble=false;

public LireThemesController() {
    objectMapper = new ObjectMapper();
    jsonFactory = new JsonFactory();
}

public void init() {
    availble=isExternalStorageReadble();
    if(availble){
        Log.w("myApp", "file available");
    }else{
        Log.w("myApp", "file not available");
    }

    jsonFile = new File("c:\\lireThemes.json");
    try{
        jp = jsonFactory.createJsonParser(jsonFile);
        lirethemes = objectMapper.readValue(jp, LireThemes.class);
        themeList = lirethemes.get("themes");
    } catch(JsonParseException e) {
        e.printStackTrace();
    } catch(IOException e) {
        e.printStackTrace();
    }
}

public ArrayList<LireTheme> findAll() {
    return themeList;
}
public LireTheme findById(int id) {
    return themeList.get(id);
}

public boolean isExternalStorageReadble() {
    String state = Environment.getExternalStorageState();
    if (Environment.MEDIA_MOUNTED.equals(state)) {
        return true;
    }
    return false;
}
}

并且还已在AndroidManifest中添加了权限。

    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

当我跑步时我得到这个错误：

12-29 04:16:04.287: W/System.err(2060): java.io.FileNotFoundException: /c:\lireThemes.json: open failed: ENOENT (No such file or directory).

请问这个问题的任何解决方案吗？

Answer 1

您无法从c：\读取Android设备上的文件，这是一个Windows文件系统路径。

您必须在Assets文件夹中复制JSON文件，然后使用

加载它

public String loadJSONFromAsset() {

String json = null;
try {

    InputStream is = getAssets().open("yourfilename.json");

    int size = is.available();

    byte[] buffer = new byte[size];

    is.read(buffer);

    is.close();

    json = new String(buffer, "UTF-8");


} catch (IOException ex) {
    ex.printStackTrace();
    return null;
}
return json;

}

Answer 2

问题是jsonFile = new File("c:\\lireThemes.json"); 你的Android设备上没有c：\ lireThemes.json文件。

如果您将文件添加到资产目录（在项目中），您可以通过getAssets().open("lireThemes.json")访问，这将返回输入流或者您可以将它放在res / raw文件夹中并通过getActivity().getResources().openRawResource(R.raw.lireThemes)访问它，这也将返回一个输入流

无法读取本地json文件：打开失败：ENOENT（没有这样的文件或目录）

2 个答案: