Question

我在Android Studio的资源文件目录中有wifi2.txt文件。但是，当我尝试访问它时，我不断收到NULLPointException。我的代码如下:(非常感谢提前）

             //CSV FILE READING
    File file = null;



    try {



        FileInputStream is = new FileInputStream(file);

        try {
            BufferedReader reader = new BufferedReader(new InputStreamReader(getAssets().open("wifi2.txt")));
            String line;
            Log.e("Reader Stuff",reader.readLine());
            while ((line = reader.readLine()) != null) {
                Log.e("code",line);
                String[] RowData = line.split(",");
                LatLng centerXY = new LatLng(Double.valueOf(RowData[1]), Double.valueOf(RowData[2]));
                if (RowData.length == 4) {
                    mMap.addMarker(new MarkerOptions().position(centerXY).title(String.valueOf(RowData[0]) + String.valueOf(RowData[3])).icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN)));
                }

            }

        } catch (IOException ex) {
           ex.printStackTrace();
        } finally {
            try {
                is.close();
            } catch (IOException e) {
               e.printStackTrace();
            }
        }
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }


   //Done with CSV File Reading

Answer 1

从资产中读取文件的方法：

    public static String readFile(AssetManager mgr, String path) {
        String contents = "";
        InputStream is = null;
        BufferedReader reader = null;
        try {
            is = mgr.open(path);
            reader = new BufferedReader(new InputStreamReader(is));
            contents = reader.readLine();
            String line = null;
            while ((line = reader.readLine()) != null) {
                contents += '\n' + line;
            }
        } catch (final Exception e) {
            e.printStackTrace();
        } finally {
            if (is != null) {
                try {
                    is.close();
                } catch (IOException ignored) {
                }
            }
            if (reader != null) {
                try {
                    reader.close();
                } catch (IOException ignored) {
                }
            }
        }
        return contents;
    }

Answer 2

File file = null;
try {
    FileInputStream is = new FileInputStream(file);

实际上你并没有在任何地方使用FileInputStream。只需使用这段代码

  try {
        BufferedReader reader = new BufferedReader(new InputStreamReader(getAssets().open("wifi2.txt")));
        String line;
        Log.e("Reader Stuff",reader.readLine());
        while ((line = reader.readLine()) != null) {
            Log.e("code",line);
            String[] RowData = line.split(",");
            LatLng centerXY = new LatLng(Double.valueOf(RowData[1]), Double.valueOf(RowData[2]));
            if (RowData.length == 4) {
                mMap.addMarker(new MarkerOptions().position(centerXY).title(String.valueOf(RowData[0]) + String.valueOf(RowData[3])).icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN)));
            }

        }

    } catch (IOException ex) {
       ex.printStackTrace();
    }

Answer 3

在Kotlin中，我们可以实现这一目标：-

val string = requireContext().assets.open("wifi2.txt").bufferedReader().use {
                it.readText()
            }

Answer 4

用法： String yourData = LoadData("wifi2.txt");

假设 wifi2.txt 位于assets

 public String LoadData(String inFile) {
        String tContents = "";

    try {
        InputStream stream = getAssets().open(inFile);

        int size = stream.available();
        byte[] buffer = new byte[size];
        stream.read(buffer);
        stream.close();
        tContents = new String(buffer);
    } catch (IOException e) {
        // Handle exceptions here
    }

    return tContents;

 }

Reference

如何从Android Studio中的资源中读取文本文件？

4 个答案: