Android中讀取中文字符的文件與文件讀取相關

一、如何顯示assets/license.txt（中文）的內容？

(1)方法1：InputStream.available()得到字節數，然後一次讀取完。

private String readUserAgreementFromAsset(String assetName) {

         String content ="";

         try {

                   InputStream is= getAssets().open(assetName);

                   if (is != null){

                            DataInputStream dIs = newDataInputStream(is);

                            intlength = dIs.available();

                            byte[] buffer = new byte[length];

                            dIs.read(buffer);

                            content= EncodingUtils.getString(buffer, "UTF-8");

                            is.close();

                   }

         } catch (IOException e) {

                   e.printStackTrace();

         }

         return content;

}

(2)方法2：用BufferedReader.readLine()行讀取再加換行符，最後用StringBuilder.append()連接成字符串。

A.以下是先行讀取再轉碼UTF8：

private String readUserAgreementFromAsset(String assetName) {

         StringBuilder sb = newStringBuilder("");

         String content ="";

         try {

                   InputStream is= getAssets().open(assetName);

                   if (is != null){

                            BufferedReader d = newBufferedReader(new InputStreamReader(is));

                            while (d.ready()) {

                                      sb.append(d.readLine() +"\n");

                            }

                            content =EncodingUtils.getString(sb.toString().getBytes(), "UTF-8");

                            is.close();

                  }

         } catch (IOException e) {

                  e.printStackTrace();

         }

         return content;

}

B.以下是InputStreamReader先指定以UTF8讀取文件，再進行讀取讀取操作：

private String readUserAgreementFromAsset(String assetName) {

         StringBuilder sb = newStringBuilder("");

         String content ="";

         try {

                   InputStream is= getAssets().open(assetName);

                   if (is != null){

                            BufferedReaderd = new BufferedReader(new InputStreamReader(is, "UTF-8"));

                            while(d.ready()) {

                                     sb.append(d.readLine() +"\n");

                            }

                            content= sb.toString();

                            is.close();

                   }

         } catch (IOException e) {

                  e.printStackTrace();

         }

         return content;

}

另外，UTF8轉碼也可以用new String(buffer, “utf-8”)。

(3)替代方法3：將license.txt內容作為string.xml的string，如：

<stringname="license_content">用戶協議

\n \n一、服務條款的確認和接納

\n…

</string>

需要注意的是：string裡需要加\n作為換行符，原來txt裡的換行符在取得string後無效。

不可取方法4：每次讀取4096字節，以UTF8轉碼，最後連接字符串。因為漢字可能被截斷，導致4096的倍數附近的中文可能出現亂碼。

private String readUserAgreementFromAsset(String assetName) {

         StringBuilder sb = newStringBuilder("");

         String content ="";

         try {

                   InputStream is= getAssets().open(assetName);

                   if (is != null){

                            DataInputStream dIs = new DataInputStream(is);

                            byte[] buffer = new byte[1024*4];

                            int length = 0;

                            while ((length = dIs.read(buffer)) >0) {

                                      content =EncodingUtils.getString(buffer, 0, length, "UTF-8");

                                     sb.append(content);

                            }

                    is.close();

                   }

         } catch (IOException e) {

                   e.printStackTrace();

         }

         return sb.toString();

}

 

二、Android中讀寫文件

(1) 從resource中的raw文件夾中獲取文件並讀取數據（資源文件只能讀不能寫，\res\raw\test.txt）

String res = "";

try{

InputStream in = getResources().openRawResource(R.raw.test);

int length = in.available();

byte [] buffer = newbyte[length];

in.read(buffer);

res = EncodingUtils.getString(buffer,"UTF-8");//選擇合適的編碼，如果不調整會亂碼

in.close();

}catch(Exception e){

e.printStackTrace();

}

(2) 從asset中獲取文件並讀取數據（資源文件只能讀不能寫，\assets\test.txt）

與raw文件夾類似，只是：

InputStream is = getAssets().open(“test.txt”);

(3) 私有文件夾下的文件存取（/data/data/包名/files/test.txt）

使用openFileOutput寫文件：

public void writeFileData(String fileName,String message){

        try{

             FileOutputStream fout =openFileOutput(fileName,MODE_PRIVATE);

        byte [] bytes =message.getBytes();

        fout.write(bytes);

        fout.close();

        }

    catch(Exception e){

        e.printStackTrace();

    }

}

使用openFileInput讀文件：

public String readFileData(String fileName){

    String str = “”;

        try{

             FileInputStream fin =openFileInput(fileName);

        int length = in.available();

        byte [] bytes = newbyte[length];

        fin.read(bytes);

        str = EncodingUtils.getString(bytes,"UTF-8");

        fin.close();

        }

    catch(Exception e){

        e.printStackTrace();

}

return str;

}

(4) sdcard目錄下的文件存取（/mnt/sdcard/）

使用FileOutputStream寫文件：

public void writeFile2Sdcard(String fileName,String message){

    try{

             FileOutputStream fout = new FileOutputStream(fileName);

        byte [] bytes =message.getBytes();

        fout.write(bytes);

        fout.close();

        }

    catch(Exception e){

        e.printStackTrace();

    }

}

使用FileInputStream讀文件：

public String readFileFromSdcard(String fileName){

    String res="";

    try{

        FileInputStream fin = newFileInputStream(fileName);

        int length =fin.available();

        byte [] buffer = newbyte[length];

        fin.read(buffer);

        res =EncodingUtils.getString(buffer, "UTF-8");

        fin.close();

    }

    catch(Exception e){

         e.printStackTrace();

    }

    return res;

}