java - Android:无法在文件中保存超过 195 的数字

Question

对于我的游戏，我将用户玩过的游戏数量存储在内部存储上的文件中。这完全有效，直到存储了数字 195，之后无论玩了多少场游戏，它都不会增加。

public void saveNumGames(){
    Log.d("saveNumGames", "Called");
    int numGames;
    File numGamesFile = new File(mainActivity.getFilesDir(), "numGames");
    try {

        BufferedInputStream BIS = new BufferedInputStream(new FileInputStream(numGamesFile));
        numGames = BIS.read();
    }catch (Exception e) {
        e.printStackTrace();
        numGames = 0;
    }
    try{
        numGames++;
        Log.d("numGames", Integer.toString(numGames));
        FileOutputStream fos = new FileOutputStream(numGamesFile);
        PrintWriter PW = new PrintWriter(new OutputStreamWriter(fos));
        PW.write(numGames);
        PW.flush();
        PW.close();
        if(numGames==12){
            Games.Achievements.unlock(MainActivity.apiClient, "CgkIlcXhyp4YEAIQDA");
        } else if(numGames==50){
            Games.Achievements.unlock(MainActivity.apiClient, "CgkIlcXhyp4YEAIQDQ");
        }
    }catch (Exception e){
        e.printStackTrace();
    }
}

我的思考过程是，这是由于数字 195 是字节(或位？)中可存储的最大值引起的。如果是这样，我应该采取什么措施来防止出现此数量上限。

Answer 1

首先你使用了两个错误的方法。第一个是 numGames = BIS.read(); read() 方法专为只读一个字节而设计。另一个方法 PW.write(numGames) 方法 write 其参数是 int 指定要写入的字符。它应该有效:

  public static void saveNumGames() {
    Log.d("saveNumGames", "Called");
    int numGames;
    File numGamesFile = new File(mainActivity.getFilesDir(), "numGames");
    try {
        numGames = new Integer(new String(Files.readAllBytes(Paths.get(mainActivity.getFilesDir() + "numGames"))));
    } catch (Exception e) {
        e.printStackTrace();
        numGames = 0;
    }

    try (FileOutputStream fos = new FileOutputStream(numGamesFile)) {
        numGames++;
        Log.d("numGames", Integer.toString(numGames));
        PrintWriter PW = new PrintWriter(fos);
        PW.write(String.valueOf(numGames));
        PW.flush();
        PW.close();
        if (numGames == 12) {
            Games.Achievements.unlock(MainActivity.apiClient, "CgkIlcXhyp4YEAIQDA");
        } else if (numGames == 50) {
            Games.Achievements.unlock(MainActivity.apiClient, "CgkIlcXhyp4YEAIQDQ");
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
}