我已根据此引用创建了一个项目https://www.youtube.com/watch?v=luxE7oEKiic,我正在尝试将其与此引用http://www.geeks.gallery/multiple-checkbox-values-in-listview-storing-retrieving-using-sharedpreferences/结合使用。但是,我遇到一个问题,复选框没有出现在我安装的应用程序列表旁边。我没有包含的文件之一是array.xml,在我的编码中有一行需要该文件。我对此做了以下更改。 ArrayAdapter adapter = new ArrayAdapter(this,android.R.layout.simple_list_item_multiple_choice); //我删除了getResources()。getStringArray(R.array.Mobile_OS)这就是我面临这个问题的原因吗?我该怎么做才能纠正这个问题?好心提醒。感谢。
public class MainActivity extends ListActivity{
private PackageManager packageManager = null;
private List<ApplicationInfo> applist = null;
private AppAdapter listadapter = null;
ListView myList;
Button getChoice, clearAll, selectAll;
SharedPreferences sharedpreferences;
public static final String MyPREFERENCES = "MyUserChoice" ;
ArrayList<String> selectedItems = new ArrayList<String>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
myList = (ListView)findViewById(android.R.id.list);
getChoice = (Button)findViewById(R.id.getchoice);
clearAll = (Button)findViewById(R.id.clearall);
selectAll = (Button)findViewById(R.id.selectall);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_multiple_choice);
myList.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);
myList.setAdapter(adapter);
sharedpreferences = getSharedPreferences(MyPREFERENCES, Context.MODE_PRIVATE);
if(sharedpreferences.contains(MyPREFERENCES)){
LoadSelections();
}
getChoice.setOnClickListener(new Button.OnClickListener() {
@Override
public void onClick(View v) {
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";
System.out.println("Checking list while adding:" + myList.getItemAtPosition(i).toString());
SaveSelections();
}
}
Toast.makeText(MainActivity.this, selected, Toast.LENGTH_LONG).show();
}
});
clearAll.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
ClearSelections();
}
});
selectAll.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
SelectAllSelections();
}
});
packageManager = getPackageManager();
new LoadApplications().execute();
}
private void SaveSelections() {
// save the selections in the shared preference in private mode for the user
SharedPreferences.Editor prefEditor = sharedpreferences.edit();
String savedItems = getSavedItems();
prefEditor.putString(MyPREFERENCES.toString(), savedItems);
prefEditor.commit();
}
private String getSavedItems() {
String savedItems = "";
int count = this.myList.getAdapter().getCount();
for (int i = 0; i < count; i++) {
if (this.myList.isItemChecked(i)) {
if (savedItems.length() > 0) {
savedItems += "," + this.myList.getItemAtPosition(i);
} else {
savedItems += this.myList.getItemAtPosition(i);
}
}
}
return savedItems;
}
private void LoadSelections() {
// if the selections were previously saved load them
if (sharedpreferences.contains(MyPREFERENCES.toString())) {
String savedItems = sharedpreferences.getString(MyPREFERENCES.toString(), "");
selectedItems.addAll(Arrays.asList(savedItems.split(",")));
int count = this.myList.getAdapter().getCount();
for (int i = 0; i < count; i++) {
String currentItem = (String) myList.getAdapter()
.getItem(i);
if (selectedItems.contains(currentItem)) {
myList.setItemChecked(i, true);
Toast.makeText(getApplicationContext(),
"Curren Item: " + currentItem,
Toast.LENGTH_LONG).show();
} else {
myList.setItemChecked(i, false);
}
}
}
}
private void ClearSelections() {
// user has clicked clear button so uncheck all the items
int count = this.myList.getAdapter().getCount();
for (int i = 0; i < count; i++) {
this.myList.setItemChecked(i, false);
}
// also clear the saved selections
SaveSelections();
}
private void SelectAllSelections() {
// user has clicked clear button so uncheck all the items
int count = this.myList.getAdapter().getCount();
for (int i = 0; i < count; i++) {
this.myList.setItemChecked(i, true);
}
// also clear the saved selections then uncomment the below line.
// SaveSelections();
}
protected void onListItemClick(ListView l, View v, int position, long id){
super.onListItemClick(l, v, position, id);
ApplicationInfo app = applist.get(position);
try{
Intent intent = packageManager.getLaunchIntentForPackage(app.packageName);
if(intent != null){
startActivity(intent);
}
}catch(ActivityNotFoundException e){
Toast.makeText(MainActivity.this,e.getMessage(), Toast.LENGTH_LONG).show();
}catch(Exception e){
Toast.makeText(MainActivity.this,e.getMessage(), Toast.LENGTH_LONG).show();
}
}
private List<ApplicationInfo> checkForLaunchIntent(List<ApplicationInfo> list){
ArrayList<ApplicationInfo> appList = new ArrayList<ApplicationInfo>();
for(ApplicationInfo info : list){
try{
if(packageManager.getLaunchIntentForPackage(info.packageName)!=null){
appList.add(info);
}
}catch(Exception e){
e.printStackTrace();
}
}
return appList;
}
private class LoadApplications extends AsyncTask<Void, Void, Void>{
private ProgressDialog progress = null;
protected Void doInBackground(Void... params){
applist = checkForLaunchIntent(packageManager.getInstalledApplications(PackageManager.GET_META_DATA));
listadapter = new AppAdapter(MainActivity.this, R.layout.activity_list_app, applist);
return null;
}
protected void onPostExecute(Void result){
setListAdapter(listadapter);
progress.dismiss();
super.onPostExecute(result);
}
protected void onPreExecute(){
progress = ProgressDialog.show(MainActivity.this, null, "Loading apps info...");
super.onPreExecute();
}
}
}
main.xml中
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<Button
android:id="@+id/getchoice"
android:layout_height="wrap_content"
android:layout_width="fill_parent"
android:text="Get Choice"/>
<Button
android:id="@+id/clearall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Clear All" />
<Button
android:id="@+id/selectall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Select All" />
<ListView
android:id="@android:id/list"
android:layout_height="wrap_content"
android:layout_width="fill_parent">
</ListView>
答案 0 :(得分:0)
不确定为什么你有2个listViews和2个列表适配器。
第一个适配器看起来没问题,因为它使用Android android.R.layout.simple_list_item_multiple_choice
内置的布局,但第二个适配器使用由您创建的R.layout.activity_list_app
。
尝试将R.layout.activity_list_app
替换为android.R.layout.simple_list_item_multiple_choice