在多选列表视图中保存复选框的选中状态

Question

我是这个多选列表视图的新手。我想在列表视图中保存复选框的选中状态，以便如果用户关闭应用程序然后再次打开，选中的复选框仍保持选中状态。有没有办法做到这一点。我搜索了它，发现它可以使用 SharedPreference 来完成，但我没有获得有关如何使用它的更多信息。谢谢

public class MainActivity extends AppCompatActivity {

    ListView myList;
    Button getChoice;

    String[] listContent = {

            "January",
            "February",
            "March",
            "April",
            "May",
            "June",
            "July",
            "August",
            "September",
            "October",
            "November",
            "December"

    };

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

        myList = (ListView)findViewById(R.id.list);
        getChoice = (Button)findViewById(R.id.getchoice);

        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_multiple_choice, listContent);
        myList.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);

        myList.setAdapter(adapter);

        getChoice.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String selected = "";
                int cntChoice = myList.getCount();

                SparseBooleanArray sparseBooleanArray = myList.getCheckedItemPositions();
                for(int i = 0; i < cntChoice; i++){
                    if(sparseBooleanArray.get(i)) {
                        selected += myList.getItemAtPosition(i).toString() + "\n";

                    }

                }

                Toast.makeText(MainActivity.this, selected, Toast.LENGTH_LONG).show();

            }
        });



    }
}

Answer 1

您可以保存状态，例如，在 SharedPreferences 中。

所以您的 onCreate 和 onDestroy 方法将如下所示：

SharedPreferences sharedPreferences = getSharedPreferences("MySharedPrefs", MODE_PRIVATE);

@Override
protected void onCreate(final Bundle savedInstanceState) {
    ...
    Set<String> checkedItemsSource = sharedPreferences.getStringSet("checked_items", new HashSet<String>());
    SparseBooleanArray checkedItems = convertToCheckedItems(checkedItemsSource);
    for (int i = 0; i < checkedItems.size(); i++) {
        int checkedPosition = checkedItems.keyAt(i);
        listView.setItemChecked(checkedPosition, true);
    }
}

@Override
protected void onDestroy() {
    super.onDestroy();
    SparseBooleanArray checkedItems = listView.getCheckedItemPositions();
    Set<String> stringSet = convertToStringSet(checkedItems);
    sharedPreferences.edit()
            .putStringSet("checked_items", stringSet)
            .apply();
}

private SparseBooleanArray convertToCheckedItems(Set<String> checkedItems) {
    SparseBooleanArray array = new SparseBooleanArray();
    for(String itemPositionStr : checkedItems) {
        int position = Integer.parseInt(itemPositionStr);
        array.put(position, true);
    }

    return array;
}

private Set<String> convertToStringSet(SparseBooleanArray checkedItems) {
    Set<String> result = new HashSet<>();
    for (int i = 0; i < checkedItems.size(); i++) {
        result.add(String.valueOf(checkedItems.keyAt(i)));
    }

    return result;
}

Answer 2

在列表项上设置您的复选框，如下所示

listView.setOnItemClickListener(new OnItemClickListener()
        {
            public void onItemClick(AdapterView<?> parent, View view, int position, long id)
            {
                AppListOfAllApps hideSelectedApps = (AppListOfAllApps) parent.getItemAtPosition(position);
                if (view != null)
                {
                    CheckBox checkBox = (CheckBox) view.findViewById(R.id.checkBox1);
                    hideSelectedApps = (AppListOfAllApps) checkBox.getTag();
                    hideSelectedApps.setSelected(!checkBox.isChecked());
                    checkBox.setChecked(!checkBox.isChecked());
                }
            }
        });

将所选项目存储在 sharedprefrence 中，然后点击按钮，对列表中的所有当前项目和存储在共享 prefrence 中的项目进行比较，如下所示

boolean chkbox = false;
        String selecteditem = SharedPreferences.getSharedPref(getApplicationContext()).selecteditem();

那就这样做吧

if (allitems.contains(selecteditem ))
                {
                    chkbox = true;
                }
                else
                {
                    chkbox = false;
                }

现在将它传递给适配器构造函数 这将保存复选框状态并检索它

Answer 3

为此，您需要维护模型中的状态。在每个 onBindView 调用中，只需根据模型重置状态。 有关详细信息，您可以向 -

寻求帮助

https://stackoverflow.com/a/38182528/1741586

希望对你有帮助:)

Answer 4

首先你需要为选定的值维护布尔数组，然后你可以将它存储在 sharedpreference 中，你还需要自定义适配器，也请检查Multiple Checkbox values in listview storing & retrieving using sharedpreferences

活动

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



    String[] listArray = new String[] { //Add String values };
    SharedPreferences sharedPreferences = getSharedPreferences("status", MODE_PRIVATE);

    Boolean[] checkedStatus = new Boolean[listArray.length];
    for ( int index = 0; index < checkedStatus.length; index++)
        checkedStatus[index] = sharedPreferences.getBoolean(Integer.toString(index), false);

    ListView listView = (ListView) findViewById(R.id.listview);
    CustomAdapter adapter = new CustomAdapter(this, R.layout.row_layout, listArray, checkedStatus);
    listView.setAdapter(adapter);
}

试试这个方法

public class CustomAdapter extends ArrayAdapter<String> implements CompoundButton.OnCheckedChangeListener{

String[] values;
Boolean[] checkedStatus;

public CustomAdapter(Context context, int resource, String[] values, Boolean[] checkedStatus) {
    super(context, resource, values);

    this.values = values;
    this.checkedStatus = checkedStatus;
}

@Override
public int getCount() {
    return values.length;
}

@Override
public String getItem(int position) {
    return values[position];
}

@Override
public long getItemId(int position) {
    return 0;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    View view = convertView;
    if(view == null){
        LayoutInflater inflater = (LayoutInflater) getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        view = inflater.inflate(R.layout.row_layout, null);
    }

    TextView textView = (TextView) view.findViewById(R.id.title);
    textView.setText(values[position]);

    CheckBox box = (CheckBox) view.findViewById(R.id.chk);
    box.setTag(position);
    box.setOnCheckedChangeListener(this);
    box.setChecked(checkedStatus[position]);

    return view;
}

@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
    Integer index = (Integer) buttonView.getTag();
    checkedStatus[index] = isChecked;
    String key = index.toString();

    SharedPreferences sharedPreferences=getContext().getSharedPreferences("status", Context.MODE_PRIVATE);
    SharedPreferences.Editor editor=sharedPreferences.edit();
    editor.putBoolean(key,isChecked);
    editor.apply();
}