SD card read/write功能

SD card read/write功能
功能：讀寫SD card

AndroidManifest.xml
    加入權限"android.permission.WRITE_EXTERNAL_STORAGE"

 Xxx.java
    // Write
    private writeToSdCard() {
        File vSDCard= null;
        try {
            // 獲得外部外接裝置位置
            vSDCard= Environment.getExternalStorageDirectory();
 
            // vSDCard.getParent() - "/" ; vSDCard.getName() - "sdcard"
            FileWriter vFile = new FileWriter(vSDCard.getParent() + vSDCard.getName() + "/Log.txt", true);
            // 使用這種方式有可能會得到錯誤的路徑，所以改用下面的方式
            // vSDCard.getAbsolutePath() - 擷取目前位置路徑
            FileWriter vFile = new FileWriter(vSDCard.getAbsolutePath() + "/Log.txt", true);
    
            // write the data to file
            vFile.append("," + status + "," + level + "," + "\n");
            vFile.close();
        }
        catch (Exception e) {
        }
    }

    // Read
    private void readFromSdCard() {
        File vSDCard= null;
        try {
            // 獲得外部外接裝置位置
            vSDCard= Environment.getExternalStorageDirectory();
 
            // read data form sd card file
            FileReader vFile = new FileReader( vSDCard.getAbsolutePath() + "/sd_test.txt" );
            StringBuffer sb = new StringBuffer();
            int c;
            // if value = "-1", it mean the end of the file
            while ((c = vFile.read()) != -1) {
                sb.append((char) c);
            }
            vFile.close();
        }
        catch (Exception e) {
        }
    }