我想做一个游戏，如果我按下播放按钮，随机关卡（活动）将打开。我得到了这个代码。https:/stackoverflow.coma2957937313101103。这是可行的，但我想编辑一下，例如，所有的关卡都有两个不同的答案，答案1是失败，答案2是通过关卡，如果用户通过了第1关，而在第2关失败，则回到主活动，如果重新开始，则通过的关卡将不会再显示。
例如:有5个关卡，用户开始随机关卡，例如第3关，通过了，进入下一个随机关卡，例如第2关，通过了，进入下一个......第4关，失败了，回到主活动，用户再次开始，但是已经通过的关卡不会显示，只有未通过的......例如开始第3关......如果通过了，则进入第1关......。
我如何编辑这段代码？谁能给我一些提示？因为在这段代码中，如果我回到mainactivity并重新开始，那么它将从所有级别开始...... 我试着编辑，但我卡住了，无法工作......
另外，我想在用户离开应用时保存进度。在sharedpreferences中，我如何保存已通过的关卡（数组列表）......？
MainActivity:
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);
}
});
Level1AActivity: Level2, Level3..:
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......是一样的，只是id-s不同。
我建议使用 单人模式 来处理活动之间的数据传递。
你可以通过intent的 putExtra() 或以 SharedPreferences 但有 Singleton 类，它看起来更好，更容易操作你的数据，因为它们是 囊化. 所以在你想保存关卡状态的情况下（例如，当它们已经完成时）。
然而，如果你真的坚持使用 SharedPreferences 如果要保存列表，那么我建议将其转换为 Json 借用 Gson. (请看下面我的回答，如何实现这个功能)。
正如我所说，我会使用 Singleton 模式，以避免创建不必要的模板代码并封装关卡的状态。
LevelManager类 夫
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();
}
}
在MainActivity的onCreate里面
// 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();
}
});
在每个关卡活动的onCreate里面。
// 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();
}
});
如你所见，你可以简单地使用 finish() 方法，而你则使用下面的代码进入下一关。
// 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: 为了避免调用 finish() 当开始下一关时，你可以把它明确地放在 android:noHistory="true" 在你的manifest文件内的levels' activity标签中。
如何通过使用Gson将列表转换为Json来保存到SharedPreferences。
实际使用 Gson，你必须添加 implementation 'com.google.code.gson:gson:2.8.6' 在你的app gradle依赖里面。
另外，在 Gson 在解析 Class 对象 Json: 你需要创建自己的 序列器 和 反序列器 这些对象，并将其注册到您的 GsonBuilder.
类适配器类 (这是我们为Class对象创建自己的自定义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;
}
}
下面是一个将列表保存到的示例用法。SharedPreferences 由 Json 使用 Gson:
// 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();
并将列表找回。
// 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);
我希望你能得到解决这个问题的宝贵建议！和往常一样，祝你编码愉快