Android獲取各種系統路徑的方法

通過Environment獲取的

• Environment.getDataDirectory().getPath() :                                      獲得根目錄/data 內部儲存路徑
• Environment.getDownloadCacheDirectory().getPath()  :               獲得快取目錄/cache
• Environment.getExternalStorageDirectory().getPath():                  獲得SD卡目錄/mnt/sdcard（獲取的是手機外接sd卡的路徑）
• Environment.getRootDirectory().getPath() :                                     獲得系統目錄/system

通過Context獲取的

• Context.getDatabasePath()                                返回通過Context.openOrCreateDatabase 建立的資料庫檔案

• Context.getCacheDir().getPath() :          用於獲取APP的cache目錄/data/data//cache目錄

• Context.getExternalCacheDir().getPath()  :                           用於獲取APP的在SD卡中的cache目錄/mnt/sdcard/

  android/data//cache

• Context.getFilesDir().getPath()  :          用於獲取APP的files目錄 /data/data//files

• Context.getObbDir().getPath():              用於獲取APPSDK中的obb目錄/mnt/sdcard/Android/obb/

• Context.getPackageName() :                                                  用於獲取APP的所在包目錄

• Context.getPackageCodePath()  :                                          來獲得當前應用程式對應的 apk 檔案的路徑
• Context.getPackageResourcePath() :                                   獲取該程式的安裝包路徑

完整 操作手機檔案 工具類:

    public void saveToPhone(View v) {
//        FileDir();
        SDCardTest();
    }

    private void FileDir() {
        boolean mExternalStorageAvailable = false;
        boolean mExternalStorageWriteable = false;
        String state = Environment.getExternalStorageState();
        if (Environment.MEDIA_MOUNTED.equals(state)) {
        // We can read and write the media
            mExternalStorageAvailable = mExternalStorageWriteable = true;
        } else if (Environment.MEDIA_MOUNTED_READ_ONLY.equals(state)) {
            // We can only read the media
            mExternalStorageAvailable = true;
            mExternalStorageWriteable = false;
        } else {
            // Something else is wrong. It may be one of many other states, but all we need
            //  to know is we can neither read nor write
            mExternalStorageAvailable = mExternalStorageWriteable = false;
        }


        Log.i("codecraeer", "getFilesDir = " + getFilesDir());
        Log.i("codecraeer", "getExternalFilesDir = " + getExternalFilesDir("exter_test").getAbsolutePath());
        Log.i("codecraeer", "getDownloadCacheDirectory = " + Environment.getDownloadCacheDirectory().getAbsolutePath());
        Log.i("codecraeer", "getDataDirectory = " + Environment.getDataDirectory().getAbsolutePath());
        Log.i("codecraeer", "getExternalStorageDirectory = " + Environment.getExternalStorageDirectory().getAbsolutePath());
        Log.i("codecraeer", "getExternalStoragePublicDirectory = " + Environment.getExternalStoragePublicDirectory("pub_test"));
    }

    /**
     * SDcard操作
     */
    public void SDCardTest(){
        try {
            //獲取擴充套件SD卡裝置狀態
            String sDStateString = Environment.getExternalStorageState();
            //擁有可讀可寫許可權
            if(sDStateString.equals(Environment.MEDIA_MOUNTED)){
                //獲取擴充套件儲存裝置的檔案目錄
                    File SDFile = Environment.getExternalStorageDirectory();
                String fileDirectoryPath=SDFile.getAbsolutePath()+File.separator+"測試資料夾";
                File fileDirectory=new File(fileDirectoryPath);
                //開啟檔案
                File myFile = new File(fileDirectoryPath+File.separator+"MyFile.txt");
                //判斷是否存在,不存在則建立
                if (!fileDirectory.exists()) {
                        //按照指定的路徑建立資料夾
                        fileDirectory.mkdirs();
                }
                if (!myFile.exists()) {
                    try {
                        //在指定的資料夾中建立檔案
                        myFile.createNewFile();
                    } catch (Exception e) {
                    }
                }
                //寫資料
                String szOutText="Hello, World!+姚佳偉";
                FileOutputStream outputStream=new FileOutputStream(myFile);
                outputStream.write(szOutText.getBytes());
                outputStream.close();
            }
            //擁有隻讀許可權
            else if(sDStateString.endsWith(Environment.MEDIA_MOUNTED_READ_ONLY)){
                //獲取擴充套件儲存裝置的檔案目錄
                File SDFile=android.os.Environment.getExternalStorageDirectory();
                //建立一個檔案
                File myFile=new File(SDFile.getAbsolutePath()+File.separator+"MyFile.txt");
                //判斷檔案是否存在
                if(myFile.exists()){
                    //讀資料
                    FileInputStream inputStream=new FileInputStream(myFile);
                    byte[]buffer=new byte[1024];
                    inputStream.read(buffer);
                    inputStream.close();
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
            Log.d("yjw","檢查許可權");
        }
    }

public class FileUtils {
    static String directoryPath = Environment.getExternalStorageDirectory().getAbsolutePath() + File.separator + "FileDemo" + File.separator;
    String fileName = directoryPath + getISO8601TimeFileName() + ".txt";

    //建立資料夾及檔案
    public void CreateText() throws IOException {
        File file = new File(directoryPath);
        if (!file.exists()) {
            try {
                //按照指定的路徑建立資料夾
                file.mkdirs();
            } catch (Exception e) {
                // TODO: handle exception
            }
        }
        File dir = new File(fileName);
        if (!dir.exists()) {
            try {
                //在指定的資料夾中建立檔案
                dir.createNewFile();
            } catch (Exception e) {
            }
        }
    }

    //向已建立的檔案中寫入資料
    public void print(String str) {
        FileWriter fw = null;
        BufferedWriter bw = null;
        String datetime = "";
        try {
            CreateText();
            SimpleDateFormat tempDate = new SimpleDateFormat("yyyy-MM-dd" + " " + "hh:mm:ss");
            datetime = tempDate.format(new java.util.Date()).toString();
            fw = new FileWriter(fileName, true);//
            // 建立FileWriter物件，用來寫入字元流
            /**
             * 如果想要每次寫入,清除之前的內容,使用FileOutputStream流
             */
            bw = new BufferedWriter(fw); // 將緩衝對檔案的輸出
            String myreadline = datetime + "[]" + str;

            bw.write(myreadline + "\n"); // 寫入檔案
            bw.newLine();
            bw.flush(); // 重新整理該流的緩衝
            bw.close();
            fw.close();
        } catch (IOException e) {
            e.printStackTrace();
            try {
                bw.close();
                fw.close();
            } catch (IOException e1) {
            }
        }
    }

    /**
     * 此方法為android程式寫入sd檔案檔案，用到了android-annotation的支援庫@
     *
     * @param buffer   寫入檔案的內容
     * @param folder   儲存檔案的資料夾名稱,如log；可為null，預設儲存在sd卡根目錄
     * @param fileName 檔名稱，預設app_log.txt
     * @param append   是否追加寫入，true為追加寫入，false為重寫檔案
     * @param autoLine 針對追加模式，true為增加時換行，false為增加時不換行
     */
    public synchronized static void writeFiledToSDCard(@NonNull final byte[] buffer, @Nullable final String folder, @Nullable final String fileName, final boolean append, final boolean autoLine) {
        new Thread(new Runnable() {
            @Override
            public void run() {
                boolean sdCardExist = Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED);
                String folderPath = "";
                if (sdCardExist) {
                    //TextUtils為android自帶的幫助類
                    if (TextUtils.isEmpty(folder)) {
                        //如果folder為空，則直接儲存在sd卡的根目錄
//                        folderPath = Environment.getExternalStorageDirectory() + File.separator;
                        folderPath = directoryPath;
                    } else {
                        folderPath = Environment.getExternalStorageDirectory() + File.separator + folder + File.separator;
                    }
                } else {
                    return;
                }

                File fileDir = new File(folderPath);
                if (!fileDir.exists()) {
                    if (!fileDir.mkdirs()) {
                        return;
                    }
                }
                File file;
                //判斷檔名是否為空
                if (TextUtils.isEmpty(fileName)) {
                    file = new File(folderPath + getISO8601TimeFileName() + ".txt");
                } else {
                    file = new File(folderPath + fileName);
                }
                RandomAccessFile raf = null;
                FileOutputStream out = null;
                try {
                    if (append) {
                        //如果為追加則在原來的基礎上繼續寫檔案
                        raf = new RandomAccessFile(file, "rw");
                        raf.seek(file.length());
                        raf.write(buffer);
                        if (autoLine) {
                            raf.write("\n".getBytes());
                        }
                    } else {
                        //重寫檔案，覆蓋掉原來的資料
                        out = new FileOutputStream(file);
                        out.write(buffer);
                        out.flush();
                    }
                    Log.d("yjw", "writeFiledToSDCard===" + "檔案存入成功");
                } catch (IOException e) {
                    e.printStackTrace();
                } finally {
                    try {
                        if (raf != null) {
                            raf.close();
                        }
                        if (out != null) {
                            out.close();
                        }
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        }).start();
    }

    public static String getISO8601TimeFileName() {
        TimeZone tz = TimeZone.getTimeZone("Asia/Shanghai");
        DateFormat df = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSS'Z'");
        df.setTimeZone(tz);
        String nowAsISO = df.format(new Date());
        return nowAsISO;
    }
}