我有一个片段，其中包含我的应用程序的所有配置文件的列表。此列表使用自定义 BaseAdapter。这是此适配器的规格：
- 用户一次只能启用一个配置文件。
- 如果用户尝试禁用所有配置文件，则会警告用户并且最后启用的配置文件将设置回启用。
- 如果用户尝试启用未配置的配置文件，用户将收到警告，最后启用的配置文件将设置回启用。
- 用户可以配置每个配置文件。
一切正常，除了第一次创建列表时我当前的实现存在一个问题：
- 如果用户在第一次创建列表时启用（用户选中 Switch）列表中的第一个配置文件，然后尝试启用另一个配置文件，则第一个配置文件仍会被选中（仍选中 Switch）。另请注意，即使检查了第一个配置文件，实际启用的配置文件也将是稍后检查的配置文件。
- 如果选择了其他配置文件，则不会发生这种情况。每当启用其他配置文件时，所有其他配置文件都会被禁用。
- 但是，在活动暂停并恢复后，一切都按预期进行。这意味着仍然检查第一个开关的问题将消失。
这是此问题的图形表示：
这是承载 BaseAdapter (AdapterProfiles) 的该片段的代码。PreferenceData 是一个处理与共享首选项相关的所有内容的类。：
public class Profiles extends Fragment implements OnCustomClickListener {
private View view_profiles;
private ListView lv_profiles;
private PreferenceData dataPreferenceObj;
private AdapterProfiles adapter;
private ArrayList<String> profileList = new ArrayList<String>();
private final ArrayList<HashMap<String, String>> profilesList = new ArrayList<HashMap<String, String>>();
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// ...
lv_profiles = (ListView) view_profiles.findViewById(R.id.lv_profiles);
// ...
}
@Override
public void onResume() {
createProfileList();
// Registers broadcast receiver
super.onResume();
}
private void createProfileList() {
if (profilesList.isEmpty() == true) {
profileList = new ProfileList().getProfileList();
for (int i = 0; i < profileList.size(); i++) {
HashMap<String, String> map = new HashMap<String, String>();
map.put(Keys.KEY_PROFILE.toString(), profileList.get(i));
profilesList.add(map);
}
}
adapter = new AdapterProfiles(getActivity(), profilesList, this);
lv_profiles.setAdapter(adapter);
}
/*
* This is a custom onclick listener that gets handle from of list from
* LazyAdapterProfiles
*/
@Override
public void OnCustomClick(View view, int position) {
switch (view.getId()) {
case R.id.iv_profiles_settings:
// Opens setting for settings of profile clicked on
break;
case R.id.sw_profiles:
Switch sw_profiles = (Switch) view.findViewById(R.id.sw_profiles);
// Stops user from enabling profile that is not configured.
if (dataPreferenceObj.getTemporaryRingtoneUri().equals("") == true
|| dataPreferenceObj.getTemporaryLocation().equals("") == true) {
sw_profiles.setChecked(false);
showWarningDialog(
"Profile Disabled",
"Profile location and ringtone must be selected in order to enable this profile.");
} else if (dataPreferenceObj.getTemporaryRingtoneUri().equals("") != true
&& dataPreferenceObj.getTemporaryLocation().equals("") != true) {
if (sw_profiles.isChecked() == true) {
unselectProfileState(position);
} else if (sw_profiles.isChecked() == false) {
// Stops user from disabling profile as atleast one profile
// must be enabled
showWarningDialog("Profile Cannot Disable",
"Atleast one profile must be enabled");
sw_profiles.setChecked(true);
}
// Rest of the code that writes the preference and broadcast it
}
break;
}
}
// Gets switch map of all profiles and uncheck profile other than one that
// is selected.
private void unselectProfileState(int position) {
for (int i = 0; i < profileList.size(); i++) {
if (position != i) {
AdapterProfiles.getMapHolder().get(i).sw_profiles
.setChecked(false);
}
}
}
}
我有一个自定义 BaseAdapter，它的每一行都包含 TextView、ImageView 和 Switch，如下所示：
这是我在列表中创建行的 BaseAdapter 的实现：
public class AdapterProfiles extends BaseAdapter {
private ArrayList<HashMap<String, String>> data;
private static LayoutInflater inflater = null;
private String profile_name;
private String retrived_profile_name;
private ViewHolder holder;
private Activity activity;
private OnCustomClickListener callback;
private static SparseArray<ViewHolder> mapHolder = new SparseArray<ViewHolder>();
public AdapterProfiles(Activity activity,
ArrayList<HashMap<String, String>> data,
OnCustomClickListener callback) {
this.activity = activity;
this.data = data;
this.callback = callback;
inflater = (LayoutInflater) activity
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public AdapterProfiles(Activity activity,
ArrayList<HashMap<String, String>> data) {
this.data = data;
inflater = (LayoutInflater) activity
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
convertView = inflater.inflate(R.layout.ui_profiles_row, null);
holder = new ViewHolder();
holder.tv_profiles_name = (TextView) convertView
.findViewById(R.id.tv_profiles_name);
holder.tv_profiles_location_name = (TextView) convertView
.findViewById(R.id.tv_profiles_location_name);
holder.iv_profiles_settings = (ImageView) convertView
.findViewById(R.id.iv_profiles_settings);
holder.sw_profiles = (Switch) convertView
.findViewById(R.id.sw_profiles);
holder.iv_profiles_settings
.setOnClickListener(new CustomOnClickListener(callback,
position));
holder.sw_profiles.setOnClickListener(new CustomOnClickListener(
callback, position));
convertView.setTag(holder);
mapHolder.put(position, holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
getPrefs(position);
setUIData();
return convertView;
}
private void getPrefs(int position) {
HashMap<String, String> word = new HashMap<String, String>();
word = data.get(position);
profile_name = word.get(Keys.KEY_PROFILE.toString());
SharedPreferences settings = activity.getSharedPreferences(
Keys.PREFS_APP.toString(), 0);
// This allows us to retrive unique data based on the profile names
String PROFILE_LOCATION = Keys.KEY_LOCATION.toString() + "_"
+ profile_name;
retrived_profile_name = settings.getString(Keys.KEY_PROFILE.toString(),
"");
}
// Sets UI data of item in the list
private void setUIData() {
if (profile_name.equals(retrived_profile_name) == true) {
holder.sw_profiles.setChecked(true);
} else if (profile_name.equals(retrived_profile_name) == false) {
holder.sw_profiles.setChecked(false);
}
}
public static class ViewHolder {
public ImageView iv_profiles_settings;
public TextView tv_profiles_location_name;
public TextView tv_profiles_name;
public Switch sw_profiles;
}
public static SparseArray<ViewHolder> getMapHolder() {
return mapHolder;
}
}
最后是 CustomOnClickListener 类，如果有人想知道它是什么。该类的实现是将回调映射到列表中的特定组件。这个类最初是由某人创建的（我没有在我的书签中找到它来感谢作者），我使用他/她的示例来适应我自己的实现。这是代码：
public class CustomOnClickListener implements OnClickListener {
private int position;
private OnCustomClickListener callback;
public CustomOnClickListener(OnCustomClickListener callback, int position) {
this.position = position;
this.callback = callback;
}
@Override
public void onClick(View v) {
callback.OnCustomClick(v, position);
}
}
public interface OnCustomClickListener {
public void OnCustomClick(View view, int position);
}