从第一个活动到第三个活动的传递列表

Question

我有一个启动屏幕活动（ACTIVITY A），它在加载完成时打开ACTIVITY B

活动 B ** 包含一个打开 **活动 C 的按钮

ACTIVITY A使用异步任务加载列表

我希望这个加载的列表在打开时显示在ACTIVITY C中

我已经阅读了很多关于如何将值从第一个活动传递到第三个活动的帖子，并尝试实现所有这些但没有任何帮助

甚至尝试通过 ACTIVITY A > ACTÌVITY B > ACTIVITY C 的意图传递列表对象，但没有成功

最后，我使用“jacksons library”将加载的列表转换为jsonstring，然后将其放入ACTIVITY A中的sharedpreferences中，然后从sharedpreferences中检索jsonstring，将其转换回**中的列表对象活动 C** 并显示列表

但是列表没有显示出来

怎么办，有没有更好的流程

飞溅活动（活动 A）

public class SplashActivity extends Activity{

    List<ParseObject> ob;
    List<CodeList> codelist = null;
    ObjectMapper mapper;
    SearchPreferences searchpref;

    @Override
    public void onCreate(Bundle savedInstanceState){
        // TODO: Implement this method
        super.onCreate(savedInstanceState);
        setContentView(R.layout.splash);

        mapper = new ObjectMapper();
        searchpref = new SearchPreferences();

        new DataTask().execute();
    }

    public class DataTask extends AsyncTask<Void, Void, List<CodeList>>{
        @Override
        protected List<CodeList> doInBackground(Void[] p1){    
            codelist = new ArrayList<CodeList>();
            try {
                ParseQuery<ParseObject> query = new ParseQuery<ParseObject>("InterActivity");

                query.orderByAscending("_created_at");

                ob = query.find();
                for (ParseObject inter : ob) {
                    CodeList map = new CodeList();
                    map.setIntroduction((String) inter.get("intro"));
                    codelist.add(map);
                }
                return codelist;
            } 
            catch (ParseException e) {
                Log.e("Error", e.getMessage());
                e.printStackTrace();
            }
            return null;
        }

        @Override
        protected void onPostExecute(List<CodeList> result){
            try{
                String jsonsearchlist = mapper.writeValueAsString(result);
                Intent i = new Intent(SplashActivity.this, MainActivity.class);

                searchpref.save(SplashActivity.this, jsonsearchlist);

                startActivity(i);
            }
            catch (JsonProcessingException e){}
        }
    }
}

活动 C

public class SearchActivity extends Activity{

    protected  EditText searchedittext;
    ImageButton searchButton;
    List<ParseObject> ob;
    List<CodeList> splashcodes;
    FinalAdapter fnladapter;

    SearchPreferences searchpref;
    ObjectMapper mapper;

    @Override
    public void onCreate(Bundle savedInstanceState){

        super.onCreate(savedInstanceState);
        setContentView(R.layout.search_layout);

        searchpref = new SearchPreferences();
        mapper = new ObjectMapper();

        String jsonsearchobj = searchpref.getValue(SearchActivity.this);

        try{
             splashcodes = (List<CodeList>) mapper.readValue(jsonsearchobj, CodeList.class);

            final ListView searchedlist = (ListView) findViewById(R.id.searchlist);
            fnladapter = new FinalAdapter(SearchActivity.this, splashcodes);
            searchedlist.setAdapter(fnladapter);
        }
        catch (IOException e){}
    }
}

Answer 1

创建一个全局类并将该列表放入该类中。填写完列表后，在活动 C 中访问列表数据。

Answer 2

您走在正确的道路上：通过第二个活动循环您的信息。请注意，CodeList 必须是可序列化的。

public class SplashActivity extends Activity{
 ...
 protected void onPostExecute(ArrayList<CodeList> result){
   Intent intent = new Intent(SplashActivity.this, SoCalledBActivity.class);
   intent.putExtra("YOUR_UNIQUE_KEY",result);
   this.startActivity(intent);
 }
}

public class SoCalledBActivity extends Activity{
 ...
 Button trigger = (Button) findViewById(R.id.trigger);
    trigger.setOnClickListener(new Button.OnClickListener() {
        public void onClick(View v) {
          //get result list
          ArrayList<CodeList> result = (ArrayList<CodeList>) this.getIntent().getExtras().get("YOUR_UNIQUE_KEY");
          Intent intent = new Intent(SoCalledBActivity.this, SearchActivity .class);
          //add list for C activity
          intent.putExtra("YOUR_UNIQUE_KEY",result);
          this.startActivity(intent);
        }
    });

public class SearchActivity extends Activity{
  ...
  public void onCreate(Bundle savedInstanceState){
   //extract list
   ArrayList<CodeList> result = (ArrayList<CodeList>) this.getIntent().getExtras().get("YOUR_UNIQUE_KEY");
   //do whatever you want with your list...
  }
...
}