Select multiple items in ListView and select multiple items in listview

Select multiple items in ListView and select multiple items in listview
The ListView itself has a single-choice and multi-choice mode. You can set it through listview. setChoiceMode:

Listview. setChoiceMode (ListView. CHOICE_MODE_MULTIPLE); // enable multi-choice listview. setChoiceMode (ListView. CHOICE_MODE_SINGLE); // enables single-choice listview. setChoiceMode (ListView. CHOICE_MODE_NONE); // default mode listview. setChoiceMode (ListView. CHOICE_MODE_MULTIPLE_MODAL); // I have never used it. I don't know what it is.

Single choiceRequired: listview. setChoiceMode (ListView. CHOICE_MODE_SINGLE );
The ListView control also needs to specify a selector: android: listSelector = "@ drawable/checkable_item_selector"

<selector xmlns:android="http://schemas.android.com/apk/res/android">    <item android:drawable="@color/c1" android:state_pressed="true"/>    <item android:drawable="@color/c1" android:state_checked="true"/>    <item android:drawable="@color/c2"/></selector>

However, the selected color is the system-selected color instead of the specified c1. Why?
Implement multiple choiceSettings: listview. setChoiceMode (ListView. CHOICE_MODE_SINGLE );
You need to implement the Checkable interface for the view of each item. The following is the Checkable interface implemented by LinearLayout:

Public class extends LinearLayout implements Checkable {private boolean mChecked; public CheckableLinearLayout (Context context, AttributeSet attrs) {super (context, attrs) ;}@ Override public void setChecked (boolean checked) {mChecked = checked; setBackgroundDrawable (checked? New ColorDrawable (0xff1_a0): null); // blue when elected} @ Override public boolean isChecked () {return mChecked;} @ Override public void toggle () {setChecked (! MChecked );}}

Use:

<com.ljfbest.temp.CheckableLinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="wrap_content">    <TextView        android:id="@+id/tv"        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:gravity="center_vertical"        android:minHeight="?android:attr/listPreferredItemHeightSmall"        android:paddingEnd="?android:attr/listPreferredItemPaddingEnd"        android:paddingStart="?android:attr/listPreferredItemPaddingStart"        android:textAppearance="?android:attr/textAppearanceListItemSmall" /></com.ljfbest.temp.CheckableLinearLayout> 

The demo diagram is attached as follows:

The following are several APIs for obtaining/setting information about the selected entries: listview. getCheckedItemCount (); // get the selected number of rows: the value of CHOICE_MODE_NONE is invalid. listview. getCheckedItemPosition (); // gets the selected row. The value is valid only in single-choice mode and intlistview is returned. getCheckedItemIds (); // obtain the ids of the selected items, which is of the long [] type. Note that the hasStableIds () of the adapter returns true, and these ids are the getItemId (int position) of the adapter) returned. the demo shows the listview. setItemChecked (position, value); // you can specify the status of a row.


In addition, the following error may be reported when ListView is used:Java. lang. ClassCastException: android. widget. HeaderViewListAdapter cannot be cast to android. widget. SimpleAdapterListView has headerView/footerView, and its original Adapter will be encapsulated into HeaderViewListAdapter:

ListAdapter used when a ListView has header views. this ListAdapter wraps another one and also keeps track of the header views and their associated data objects. this is intended as a base class; you will probably not need to use this class directly in your own code.

You can obtain the original Adapter in the following ways: HeaderViewListAdapter hAdapter = (HeaderViewListAdapter) listview. getAdapter (); MyAdapter my = (MyAdapter) hAdapter. getWrappedAdapter ();
Therefore, when a header/footer is added, lv_data.getAdapter ()). getWrappedAdapter (). getCount () and (HeaderViewListAdapter) listview. getAdapter ()). getWrappedAdapter (). getCount () is 1 different
Demo address:Http://download.csdn.net/detail/ljfbest/8109731


How to restrict multiple selection of listview in C #? Only one record can be selected

If you must
Control cannot be selected multiple times
If I have not answered
If you only want to avoid this problem, you can select the first data item by default.
 
In android development, how does one add a single choice and a check box in listview?

You need to redefine a component by yourself. Baidu search custom components should be able to find what you want. If the code is deleted, it will not be rewritten.