ListView 实现多选/无线电

ListView本身与无线电、多选模式。由listview.setChoiceMode设置：

listview.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);//开启多选模式

listview.setChoiceMode(ListView.CHOICE_MODE_SINGLE);//开启单选模式

listview.setChoiceMode(ListView.CHOICE_MODE_NONE);//默认模式

listview.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE_MODAL);//没用过，不知道用来干嘛的

实现单选

    须要设置：listview.setChoiceMode(ListView.CHOICE_MODE_SINGLE); 

    ListView控件还须要指定一个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>

可是单选选中时的颜色还是系统选中的颜色。而不是自己设定的c1。不知道为什么？

实现多选

    设置：listview.setChoiceMode(ListView.CHOICE_MODE_SINGLE); 

    须要对每一个item的view实现Checkable接口。下面是LinearLayout实现Checkable接口：

public class CheckableLinearLayout 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(0xff0000a0) : null);//当选中时呈现蓝色
    }
    @Override
    public boolean isChecked() {
        return mChecked;
    }
    @Override
    public void toggle() {
        setChecked(!mChecked);
    }
}

例如以下使用：

<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>

下面附上demo图:

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下面是几个获取/设置 选中条目信息的API:

listview.getCheckedItemCount();//获取选中行数:对CHOICE_MODE_NONE无效

listview.getCheckedItemPosition();//获取选中的某行,仅仅针对单选模式有效，返回int

listview.getCheckedItemIds();//获取选中条目的ids,是long[]类型，注意须要adapter的hasStableIds()返回true,而且这些id是adapter的getItemId(int position)返回的.demo中有演示

listview.setItemChecked(position, value);//设置某行的状态  

另外，使用ListView时可能会报下面错误：

    java.lang.ClassCastException: android.widget.HeaderViewListAdapter cannot be cast to android.widget.SimpleAdapter

ListView有headerView/footerView时，它的原来的Adapter会被封装一下成为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.

可通过下面方式获取原来的Adapter:

    HeaderViewListAdapter hAdapter = (HeaderViewListAdapter) listview.getAdapter();

    MyAdapter my = ( MyAdapter) hAdapter.getWrappedAdapter();

所以，当添加一条header/footer时lv_data.getAdapter()).getWrappedAdapter().getCount()与((HeaderViewListAdapter)listview.getAdapter()).getWrappedAdapter().getCount()是相差1的

Demo地址：

  http://download.csdn.net/detail/ljfbest/8109731

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