将 SharePreference 字符串保存到 ListView [英] Save SharePreference string to a ListView

问题描述

我有两个活动.假设A"和B"，活动A"有一个名为Get"的按钮，它在每次点击后生成一个新字符串并一次显示一个.活动A"还有一个按钮发送"，它将生成的字符串发送到另一个活动B".当活动B"收到数据时，它必须将数据填充到 ListView 中.

I have two activities. Let's say "A" and "B", Activity "A" has a button called "Get" which generates a new string after each click and displays them one at a time. And the activity "A" also has a button "send" which will send the generated strings to another activity "B". When the activity "B" receives the data, it has to populate the data into a ListView.

以下是简单的机器步骤:

Here's the simple step by step machine steps:

In Activity "A"
1 - Generate 1 string by pressing the generate button
2 - text will be displayed in textView
3 - "send" button will send the text from textView to another activity "B" ( I'm using sharedPreference)

In Activity "B"
4 - receive the data sent by Activity "A" ( I'm using sharedPreference)
5 - populate string into a listview
6 - go to step 1 again.  

我的问题是，每当我单击发送按钮时，它都会将字符串发送到活动B"，但是当我再次执行相同的任务时，它只会填充最后生成的字符串.换句话说，我的代码只填充一个字符串.

My trouble is that whenever I click the send button, it will send the string to Activity "B" but when I do the same task again, it will only populate the last generated string. In other words, my code only populates one string.

到目前为止我已经尝试了以下代码，任何帮助将不胜感激.

I have tried following code so far, any help would be appreciated.

@Override
    public void onClick(View view) {


        switch(view.getId()) {
            case R.id.generateButton:
                generateString();
                break;

            case R.id.send:

                //displayText is a textView
                String text = displayText.getText().toString(); 

                // data sharing using sharedPref
                SharedPreferences.Editor editor = getApplicationContext().getSharedPreferences("lado", MODE_PRIVATE).edit();
                editor.putString("mug",text);
                editor.apply();
                break;


        }

---------

活动 B

ListView textList = (ListView) findViewById(R.id.list);

        SharedPreferences prefs = getSharedPreferences("lado", MODE_PRIVATE);
        final String text = prefs.getString("mug", "No name defined");

       String[] list = new String[]{name};


        // Create a List from String Array elements
        final List<String> fav_list = new ArrayList<>(Arrays.asList(list));



        ArrayAdapter<String> adapter = new ArrayAdapter<>(this,
                android.R.layout.simple_list_item_1, android.R.id.text1,list);

        // Assign adapter to ListView
        textList.setAdapter(adapter);

推荐答案

添加以下模型:

Dictionary.java

class Dictionary implements Serializable {
    private List<Words> wordsList = new ArrayList<>();


    List<Words> getWordsList() {
        return wordsList;
    }

    void setWordsList(List<Words> wordsList) {
        this.wordsList = wordsList;
    }
}

Words.java

public class Words implements Serializable {

    private String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

活动 A

@Override
    public void onClick(View view) {


        switch(view.getId()) {
            case R.id.generateButton:
                generateString();
                break;

            case R.id.send:

                //displayText is a textView
                String text = generateButton.getText().toString(); 

               SharedPreferences pref = this.getSharedPreferences("lado", Context.MODE_PRIVATE);



                Words words = new Words();
                words.setName(text);
                List<Words> wordsList = new ArrayList<>();

                Gson gson = new Gson();
                Dictionary dictionary = gson.fromJson(pref.getString("word", ""), Dictionary.class);
                if (dictionary != null && dictionary.getWordsList() != null) {
                    wordsList.addAll(dictionary.getWordsList());
                    dictionary.setWordsList(wordsList);
                    wordsList.add(words);
                } else {
                    dictionary = new Dictionary();
                    wordsList.add(words);
                    dictionary.setWordsList(wordsList);
                }
                SharedPreferences.Editor editor = pref.edit();
                editor.putString("word", new Gson().toJson(dictionary));
                editor.commit();

                break;


        }

活动 B

SharedPreferences pref = getSharedPreferences("lado", MODE_PRIVATE);

 List<String> list = new ArrayList<>();
Gson gson = new Gson();
Dictionary dictionary = gson.fromJson(pref.getString("word", ""), Dictionary.class);
if (dictionary != null)
    for (Words words : dictionary.getWordsList()) {
        list.add(words.getName());
    }
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
        android.R.layout.simple_list_item_1, android.R.id.text1, list);

// Assign adapter to ListView
textList.setAdapter(adapter);

//**Remove when click on item**
textList.setOnItemClickListener(new AdapterView.OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
        Gson gson = new Gson();
        Dictionary dictionary = gson.fromJson(pref.getString("word", ""), Dictionary.class);
        for (Words words :
                dictionary.getWordsList()) {
            if (words.getName().equalsIgnoreCase(list.get(i))) {
                dictionary.getWordsList().remove(words);
                list.remove(i);
                break;
            }
        }
        SharedPreferences.Editor editor = pref.edit();
        editor.putString("word", new Gson().toJson(dictionary));
        editor.commit();

        adapter.notifyDataSetChanged();
    }
});

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