按下按鈕時的隨機活動

Question

我想做一個游戲，如果我按下播放按鈕，隨機關卡（活動）將打開。 我得到了這個代碼： https://stackoverflow.com/a/29579373/13101103這是有效的，但我想編輯，例如，所有級別都有2個不同的答案，answer1是失敗，answer2是通過級別，如果用戶通過 level1，在 level2 失敗，然后 go 回到 mainactivity，如果重新啟動，則通過的級別將不會再次顯示。

示例：有5個級別，用戶啟動隨機級別，例如級別3，它通過了，go到下一個隨機級別，例如級別2，它通過，go到下一個...級別4，它失敗了，Z34D1F91FB2E,514B857BZ返回到主活動但是已經通過的級別將不會顯示，只有未通過...示例開始級別 3...如果通過然后 go 到級別 1...。

如何為我的解決方案編輯此代碼？ 有人可以給我一些提示嗎？ 因為在此，如果我 go 回到 mainactivity 並重新開始，那么它會從所有級別開始......我試圖編輯，但我被卡住了，無法工作......

另外，我想在用戶離開應用程序時保存進度。 在 sharedpreferences 中，我如何保存傳遞的級別（arraylist）......？

主要活動：

enter code here

Button level1Button = findViewById(R.id.level1Button);
    level1Button.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            // We are creating a list, which will store the activities that haven't been opened yet
            ArrayList<Class> activityList = new ArrayList<>();
            activityList.add(Level1Activity.class);
            activityList.add(Level2Activity.class);
            activityList.add(Level3Activity.class);
            activityList.add(Level4Activity.class);
            activityList.add(Level5Activity.class);

            Random generator = new Random();
            int number = generator.nextInt(5) + 1;

            Class activity = null;

            // Here, we are checking to see what the output of the random was
            switch(number) {
                case 1:
                    activity = Level1Activity.class;
                    // We are adding the number of the activity to the list
                    activityList.remove(Level1Activity.class);
                    break;
                case 2:
                    activity = Level2Activity.class;
                    activityList.remove(Level2Activity.class);
                    break;
                case 3:
                    activity = Level3Activity.class;
                    activityList.remove(Level3Activity.class);
                    break;
                case 4:
                    activity = Level4Activity.class;
                    activityList.remove(Level4Activity.class);
                    break;
                default:
                    activity = Level5Activity.class;
                    activityList.remove(Level5Activity.class);
                    break;
            }
            // We use intents to start activities
            Intent intent = new Intent(getBaseContext(), activity);
            // `intent.putExtra(...)` is used to pass on extra information to the next activity
            intent.putExtra("ACTIVITY_LIST", activityList);
            startActivity(intent);
        }
    });

一級活動：

enter code here
failbutton1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v){
            ArrayList<Class> activityList = new ArrayList<>();
            activityList.add(Level1Activity.class);
            Bundle extras = getIntent().getExtras();
            activityList = (ArrayList<Class>) extras.get("ACTIVITY_LIST");


            //Class activity = null;


            Intent intent = new Intent(Level1Activity.this, Main2Activity.class);
            intent.putExtra("ACTIVITY_LIST", activityList);
            startActivity(intent);
        }
    });

    buttonlevel1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            ArrayList<Class> activityList = new ArrayList<>();
            Bundle extras = getIntent().getExtras();
            activityList = (ArrayList<Class>) extras.get("ACTIVITY_LIST");

            if(activityList.size() == 0) {
                // Do something when after all activities have been opened
                //startActivity(new Intent(Level1Activity.this, Main2Activity.class));

                //Intent intent = new Intent(Level1Activity.this, Main2Activity.class);
                //intent.putExtra("ACTIVITY_LIST", activityList);
                //startActivity(intent);
            } else {
                // Now, the random number is generated between 1 and however many
                // activities we have remaining
                Random generator = new Random();
                int number = generator.nextInt(activityList.size()) + 1;

                Class activity = null;

                // Here, we are checking to see what the output of the random was
                switch(number) {
                    case 1:
                        // We will open the first remaining activity of the list
                        activity = activityList.get(0);
                        // We will now remove that activity from the list
                        activityList.remove(0);
                        break;
                    case 2:
                        // We will open the second remaining activity of the list
                        activity = activityList.get(1);
                        activityList.remove(1);
                        break;
                    case 3:
                        // We will open the third remaining activity of the list
                        activity = activityList.get(2);
                        activityList.remove(2);
                        break;
                    case 4:
                        // We will open the fourth remaining activity of the list
                        activity = activityList.get(3);
                        activityList.remove(3);
                        break;
                    default:
                        // We will open the fifth remaining activity of the list
                        activity = activityList.get(4);
                        activityList.remove(4);
                        break;
                }

                // Note: in the above, we might not have 3 remaining activities, for example,
                // but it doesn't matter because that case wouldn't be called anyway,
                // as we have already decided that the number would be between 1 and the number of
                // activities left.


                // Starting the activity, and passing on the remaining number of activities
                // to the next one that is opened
                Intent intent = new Intent(getBaseContext(), activity);
                intent.putExtra("ACTIVITY_LIST", activityList);
                startActivity(intent);
            }
        }
    });

level2, level3.... 相同，只是 id-s 不同

Answer 1

我建議使用Singleton 模式來處理活動之間的數據傳遞。

您可以通過意圖的putExtra()或SharedPreferences傳遞列表，但使用Singleton class，看起來更好更容易操作您的數據，因為它們是封裝的。 在您想要保存關卡狀態的情況下（例如，當它們已經完成時）非常重要。

但是，如果您真的堅持使用SharedPreferences來保存列表，那么我建議您使用Gson Json （在我的回答下面查看如何實現這一點。）

正如我所說，我會使用Singleton模式來避免創建不必要的樣板代碼並封裝關卡的狀態。

LevelManager class （單例）

final class LevelManager {

    // constants
    private static final String LEVELS_SHARED_PREFERENCES_NAME = "app_name.LEVELS";

    // variables
    private static LevelManager instance;
    private List<Class> levels;
    private SharedPreferences sharedPreferences;

    private LevelManager(Context context) {
        sharedPreferences =
                context.getSharedPreferences(LEVELS_SHARED_PREFERENCES_NAME, Context.MODE_PRIVATE);
        levels = new ArrayList<>();
        initializeList();
    }

    private void initializeList() {
        // Initialize levels, ie. add levels that are not yet completed/passed
        // Check in SharedPreferences if level has already been completed
        boolean alreadyPassed;

        alreadyPassed = sharedPreferences.getBoolean(Level1Activity.class.getSimpleName(), false);
        if (!alreadyPassed) levels.add(Level1Activity.class);

        alreadyPassed = sharedPreferences.getBoolean(Level2Activity.class.getSimpleName(), false);
        if (!alreadyPassed) levels.add(Level2Activity.class);

        alreadyPassed = sharedPreferences.getBoolean(Level3Activity.class.getSimpleName(), false);
        if (!alreadyPassed) levels.add(Level3Activity.class);

        alreadyPassed = sharedPreferences.getBoolean(Level4Activity.class.getSimpleName(), false);
        if (!alreadyPassed) levels.add(Level4Activity.class);

        alreadyPassed = sharedPreferences.getBoolean(Level5Activity.class.getSimpleName(), false);
        if (!alreadyPassed) levels.add(Level5Activity.class);
    }

    static LevelManager getInstance(Context context) {
        if (instance == null) {
            instance = new LevelManager(context);
        }
        return instance;
    }

    Class getRandomLevel() {
        if (levels.isEmpty()) {
            return null; // Return null if all levels are already completed
        }
        Collections.shuffle(levels);
        return levels.get(0);
    }

    void saveLevelState(Class levelClass, boolean passed) {
        sharedPreferences.edit().putBoolean(levelClass.getSimpleName(), passed).apply();
        if (passed) {
            // Remove level from list if user passed it so that it won't
            // be included in next levels
            levels.remove(levelClass);
        }
    }

    void reset() {
        // Clears all entries in SharedPreferences and re-initialize list
        sharedPreferences.edit().clear().apply();
        initializeList();
    }

}

MainActivity 中的 onCreate 內部

// Get LevelManager singleton instance
final LevelManager levelManager = LevelManager.getInstance(this);

Button startButton = findViewById(R.id.startButton);
startButton.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        // Get next random level
        Class levelToStart = levelManager.getRandomLevel();

        // If all levels are already completed
        if (levelToStart == null) {
            Toast.makeText(MainActivity.this, "All levels are completed!",
                    Toast.LENGTH_LONG).show();
            return;
        }

        Intent intent = new Intent(MainActivity.this, levelToStart);
        startActivity(intent);
    }
});

// I added a new button to reset all levels
Button resetButton = findViewById(R.id.resetButton);
resetButton.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        // Use the method reset() from LevelManager to restart everything
        levelManager.reset();
        Toast.makeText(MainActivity.this, "All levels have been reset!",
                Toast.LENGTH_LONG).show();
    }
});

每個 Level Activity 的 onCreate 內部

// Get LevelManager
final LevelManager levelManager = LevelManager.getInstance(this);

// I created two buttons to simulate pass and fail
Button pass = findViewById(R.id.passButton);
Button fail = findViewById(R.id.failButton);

pass.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        // Save state (Don't forget to change 'N' below)
        levelManager.saveLevelState(LevelNActivity.class, true);

        // Get next level
        Class levelToStart = levelManager.getRandomLevel();

        // Check if all are levels already completed
        if (levelToStart == null) {
            Toast.makeText(LevelNActivity.this, "Completed all levels",
                    Toast.LENGTH_LONG).show();
            finish(); // Must implement to avoid going back to previous level (ie. Activity)
            return;
        }

        Intent intent = new Intent(LevelNActivity.this, levelToStart);
        startActivity(intent);
        finish();
    }
});

fail.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        finish();
    }
});

如您所見，如果用戶未通過該級別，您可以簡單地使用finish()方法，而您使用下面的代碼進入下一個級別：

// Get LevelManager
LevelManager levelManager = LevelManager.getInstance(this);

// Set that the user passed this level (Change 'N' to the current level we are in)
levelManager.saveLevelState(LevelNActivity.class, true);

// Get next level
Class nextLevel = levelManager.getRandomLevel();

// If all levels are completed then 'nextLevel' will be null
if (nextLevel == null) {
    // ...
}

// Start next level and finish current
Intent intent = new Intent(this, nextLevel);
startActivity(intent);
finish();

注意：為避免在開始下一個關卡時顯式調用finish() ，您可以將android:noHistory="true"放在清單文件中關卡的活動標簽中。

---

如何通過使用 Gson 將列表轉換為 Json 來將列表保存到 SharedPreferences

To actually use Gson , you'll have to add implementation 'com.google.code.gson:gson:2.8.6' inside your app gradle dependencies.

此外，在將Class對象解析為Json Gson時，Gson 存在問題：您需要為這些對象創建自己的序列化器和反序列化器並將其注冊到您的GsonBuilder 。

ClassAdapter class （這是我們為 Class 對象創建自己的自定義序列化器和反序列化器的地方）

public class ClassAdapter implements JsonSerializer<Class>, JsonDeserializer<Class> {

    @Override
    public JsonElement serialize(Class src, Type typeOfSrc, JsonSerializationContext context) {
        // Get our class 'src' name
        return new JsonPrimitive(src.getName());
    }

    @Override
    public Class deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException {
        try {
            // Get class
            return Class.forName(json.getAsString());
        } catch (ClassNotFoundException e) {
            // If class could not be found or did not exists, handle error here...
            e.printStackTrace();
        }
        return null;
    }

}

這是Json使用Gson將列表保存到SharedPreferences的示例用法：

// Create new GsonBuilder and register our adapter for Class objects
GsonBuilder gsonBuilder = new GsonBuilder();
gsonBuilder.registerTypeAdapter(Class.class, new ClassAdapter());

// Initialize our list of levels (ie. classes)
List<Class> classes = new ArrayList<>();
classes.add(Level1Activity.class);
classes.add(Level2Activity.class);
classes.add(Level3Activity.class);
classes.add(Level4Activity.class);
classes.add(Level5Activity.class);

// Create Gson from GsonBuilder and convert list to json
Gson gson = gsonBuilder.create();
String json = gson.toJson(classes);

// Save json to SharedPreferences
SharedPreferences sharedPreferences = getSharedPreferences("app_name", MODE_PRIVATE);
sharedPreferences.edit().putString("levels", json).apply();

並檢索列表：

// Retrieve json from SharedPreferences
SharedPreferences sharedPreferences = getSharedPreferences("app_name", MODE_PRIVATE);
String json = sharedPreferences.getString("levels", null);

// Handle here if json doesn't exist yet
if (json == null) {
    // ...
}

// Create new GsonBuilder and register our adapter for Class objects
GsonBuilder gsonBuilder = new GsonBuilder();
gsonBuilder.registerTypeAdapter(Class.class, new ClassAdapter());

// Create Gson from GsonBuilder and specify type of list
Gson gson = gsonBuilder.create();
Type type = new TypeToken<ArrayList<Class>>(){}.getType();

// Convert json to list
List<Class> classes = gson.fromJson(json, type);

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我希望你獲得了解決這個問題的寶貴技巧，並且一如既往地快樂編碼！