java - 在保存 Activity 中打开另一个共享首选项会替换旧的共享首选项

Question

问题

1. 我创建了一个 SharedPreferenceAdapter.java，其中包含一些常用的连接。
2. 我在同一 Activity 中创建了两个SharedPreferenceAdapter对象，它们都访问不同的共享首选项文件。比方说，第一个是打开 ABC.xml 的 firstadb，第二个是打开 DEF.xml 的 secondadb。
3. firstadb 在我的 JSONObjectRequest 中使用，并在 Volley 响应时调用。而 secondadb 会立即被调用并执行其任务，并且不再使用。
4. 当响应到来并且 firstadb 以某种方式执行其任务时，当我附加调试器并查看文件名时，它正在访问 DEF.xml 而不是 ABC .xml.

SharedPreferenceAdapter.java

public class SharedPreferenceAdapter {

    static SharedPreferences main;
    static SharedPreferences.Editor edit;
    String KEY_FIRST_RUN = "first_run";
    String KEY_POSTED = "posted";
    String KEY_DEFAULT_FILENAME = "ABC";
    Context cont;
    Map<String, ?> shpf_contents;

    // I was earlier using PreferenceManager.getDefaultPreference but later changed to this code just for debugging. I use this constructor for firstadb.    
    public SharedPreferenceAdapter(Activity act){
        main = act.getSharedPreferences(KEY_DEFAULT_FILENAME, 0);
        this.cont = act;
    }

    // I use this one for secondadb
    public SharedPreferenceAdapter(Context cont, String AdapterName){
        this.cont = cont;
        main =  cont.getSharedPreferences(AdapterName, 0);
        this.shpf_contents = main.getAll();
    }

    public boolean onFirstRun(){
        edit = main.edit();
        edit.putBoolean(KEY_FIRST_RUN, false);
        return edit.commit();
    }

    public boolean onPost(String value){
        edit = main.edit();
        edit.putString(KEY_POSTED, value);
        return edit.commit();
    }

    public boolean onLoggedIn(String val){
        return saveData(Keys.usertable.USER_KEY_TOKEN, val);
    }

    public boolean isFirstRun(){
        return main.getBoolean(KEY_FIRST_RUN, true);
    }

    public String isPosted(){
        return main.getString(KEY_POSTED, null);
    }

    public String getData(String key){
        return main.getString(key, null);
    }

    public String isLoggedIn(){
        return main.getString(Keys.usertable.USER_KEY_TOKEN, null);
    }

    public boolean saveData(String key, String val){
        edit = main.edit();
        edit.putString(key, val);
        return edit.commit();
    }

    public boolean saveData(String key, int val){
        edit = main.edit();
        edit.putInt(key, val);
        return edit.commit();
    }

    public boolean saveData(String key, long val){
        edit = main.edit();
        edit.putLong(key, val);
        return edit.commit();
    }

    public boolean clearData(){
        edit = main.edit();
        edit.clear();
        return edit.commit();
    }

    public boolean clearPost(){
        edit = main.edit();
        edit.remove(KEY_POSTED);
        return edit.commit();
    }

    public void logout(){
        edit = main.edit();
        boolean success = edit.remove(Keys.usertable.USER_KEY_TOKEN).commit();
        boolean bf = main.contains(Keys.usertable.USER_KEY_TOKEN);
        this.shpf_contents = main.getAll();
        DatabaseAdapter dbadb = new DatabaseAdapter(cont);
        dbadb.open();
        dbadb.delAll(Keys.Property.PROPERTY_TABLE_NAME);
        dbadb.close();
    }
}

在我的 Activity 中

onStart(){
    getData();
}

onResume(){
    SharedPreferenceAdapter secondadb = new SharedPreferenceAdapter(ACTIVITY.this, "DEF");
    secondadb.clearData();
}

public void getData(){
    SharedPreferenceAdapter firstadb = new SharedPreferenceAdapter(ACTIVITY.this);
    // Check if net is working
    JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, URL, null, new Response.Listener<JSONObject>() {
            @Override
            public void onResponse(JSONObject response) {
                try {
                    verify_getUserObjects(response);
                } catch (JSONException ex){
                    //TODO Something with ex
                }
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {

                NetworkResponse response = error.networkResponse;

                if(response != null && response.data != null){
                    try{
                        JSONObject error_obj = new JSONObject(new String(response.data));
                        verify_getUserProperty(error_obj);
                    }catch (JSONException ex) {
                        // TODO Something with ex
                    }
                }
            }
        }) {

            @Override
            public Map<String, String> getHeaders() throws AuthFailureError {
                Map<String, String> headers = new HashMap<>();

                // SOMEHOW, when isLoggedIn is called, firstadb is accessing "DEF.xml" (XML file used by secondadb)
                headers.put(KEY_AUTHORIZATION, VALUE_AUTHORIZATION+firstadb.isLoggedIn());
                return headers;
            }
        };

        requestQueue.add(request);
}

目前找到的解决方法

如果我不创建 SharedPreferenceAdapter，而是直接将 SharedPreferences 用于 secondaryadb，firstadb 就可以正常工作。

Answer 1

产生问题的原因是您的 SharedPreferences 和 SharedPreferences.Editor 是静态的，因此，当您实例化新的 SharedPreferenceAdapter.java 时并更改编辑器或共享首选项对象，它将针对所有实例进行更改，并且始终具有由最后一次调用任何构造函数生成的值。

只需删除 static 关键字，一切就应该正常工作。