java - 如何在 SharedPreferences 中存储 ArrayList 来存储游戏进度？

Question

我是 Android 开发新手，我正在为我的项目创建一个类似于“4 Pics 1 Word”的 Android 应用程序。我在将 ArrayList 存储在 SharedPreferences 或 Android 手机的内部存储中时遇到困难。原因是因为我使用随机生成器和 ArrayList 随机化下一个 Activity 。有什么建议或想法对我的案子有帮助吗？先感谢您!我已经被困在这里几个小时了。

这是我的主要 Activity

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

Button btnStart;
Context context;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    Button btnStart = (Button) findViewById(R.id.btnStart);
    btnStart.setOnClickListener(this);
}

@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(first.class);
            activityList.add(second.class);
            activityList.add(third.class);
            activityList.add(fourth.class);
            activityList.add(fifth.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 = first.class;
                    // We are adding the number of the activity to the list
                    activityList.remove(first.class);
                    break;
                case 2:
                    activity = second.class;
                    activityList.remove(second.class);
                    break;
                case 3:
                    activity = third.class;
                    activityList.remove(third.class);
                    break;
                case 4:
                    activity = fourth.class;
                    activityList.remove(fourth.class);
                    break;
                default:
                    activity = fifth.class;
                    activityList.remove(fifth.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);
        }
    }

这是我的第一个 Activity :

public class first extends AppCompatActivity implements View.OnClickListener{
EditText etAnswer;
Button btnGo;
Context context;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_first);
    etAnswer = (EditText) findViewById(R.id.etAnswer);
    btnGo = (Button) findViewById(R.id.btnGo);
    btnGo.setOnClickListener(this);
}

@Override
public void onClick(View v) {
    switch(v.getId()){
        case R.id.btnGo:
            String answer = etAnswer.getText().toString();
            if(answer.equals("Jose Rizal") ||  answer.equals("jose rizal") || answer.equals("Rizal") || answer.equals("rizal") ){
                AlertDialog.Builder dlgAlert  = new AlertDialog.Builder(this);
                dlgAlert.setMessage("The famous Rizal monument in Luneta was not the work of a Filipino but a Swiss sculptor named Richard Kissling?" +
                        "Source: http://www.joserizal.ph/ta01.html");
                dlgAlert.setTitle("Did you know that ...");
                dlgAlert.setPositiveButton("Next",
                        new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog, int which) {
                                ArrayList<Class> activityList = new ArrayList<>();
                                Bundle extras = getIntent().getExtras();
                                activityList = (ArrayList<Class>) extras.get("ACTIVITY_LIST");

                                if(activityList.size() == 0) {
                                    Context context = getApplicationContext();
                                    CharSequence last = "Congratulations! You just finished the game! Please wait for the next update!";
                                    int durationFinal = Toast.LENGTH_LONG;

                                    Toast toast = Toast.makeText(context, last, durationFinal);
                                    toast.show();
                                } 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);
                                    intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
                                    startActivity(intent);
                                }
                            }
                        });
                dlgAlert.setCancelable(true);
                dlgAlert.create().show();

            }else{
                Context context = getApplicationContext();
                CharSequence text = "Wrong! Try Again.";
                int duration = Toast.LENGTH_SHORT;

                Toast toast = Toast.makeText(context, text, duration);
                toast.show();
            }
            break;
    }
}

}

Answer 1

好吧，这是一个可怕的黑客行为，我不以任何方式认可它，但由于您即将完成您的应用程序，我建议一个解决方法:

而不是存储ArrayList<Class>在你的SharedPreferences (这是不可能的)，存储 HashSet<String>通过 putStringSet() 包含类的完全限定名称 .

为了得到String您需要调用的类的完全限定名称的表示 getName() ，例如first.class.getName() .

然后，您可以获得Set<String>来自SharedPreferences使用getStringSet()并创建一个 Class每个 String 的实例在该集合中通过 Class.forName() .