如何将意图存储在android本地数据库中？

Question

我在将 intent.putExtra 存储在 android 本地数据库中时遇到问题。我正在为我的项目创建一个像 4Pics1Word 这样的游戏。它只有 25 个关卡，所以我创建了 25 个活动并将其随机化。解决特定活动后，它将被删除到类的 ArrayList，ArrayList<Class>。现在，我使用intent.putExtra("ACTIVITY_LIST", activityList); 来存储意图并将其传递给下一个活动。我的问题是我无法将其存储在本地数据库中。当我退出游戏时，进度没有保存，它从第一关重新开始。有什么建议么？谢谢！

这是我的 Main Activity 中的代码：

public class MainActivity extends AppCompatActivity implements View.OnClickListener{

Button btnStart;
Context context;
SharedPreferences mPrefs = getPreferences(MODE_PRIVATE);

@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;

            switch(number) {
                case 1:
                    activity = first.class;
                    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;
            }

            Intent intent = new Intent(getBaseContext(), activity);
            intent.putExtra("ACTIVITY_LIST", activityList);
    SharedPreferences.Editor prefsEditor = mPrefs.edit();
    Gson gson = new Gson();
    String json = gson.toJson(activityList); // myObject - instance of MyObject
    prefsEditor.putString("MyObject", json);
    prefsEditor.commit();
            startActivity(intent);
        }

}

这是我的 first 活动中的代码：

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?" +
                        "\n" +
                        "\n" +
                        "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

1. 每次来到 MainActivity 时，您都会新建一个 ArrayList 并添加所有活动，而不是从本地 SharedPreferences 获取缓存。
2. 当您在 Activity 中完成一场游戏时，您没有将进度保存在缓存中。

更新数组列表后，像这样保存你的数组列表：

SharedPreferences.Editor prefsEditor = mPrefs.edit();
Gson gson = new Gson();
String json = gson.toJson(activityList); // myObject - instance of MyObject
prefsEditor.putString("MyObject", json);
prefsEditor.commit();

当你想读取保存的arrayList时，这样做：

String arrayStr = mPrefs.getString("myObject","defValue");
Gson gson = new Gson();
List<Class> array = gson.fromGson(arrayStr,new TypeToken<List<Class>>(){}.getType());
if(array==null){
    array = new ArrayList<>();
    array.add(...);
}