android

ListView默认选中某一项

给选中的Item添加效果（For API 11+）:

  1. Set list view to single choice:
    <ListView android:choiceMode="singleChoice" />

  2. Set the background of the root element of your item layout to your selector:
    <LinearLayout android:background="@drawable/selector">

  3. Change android:state_selected to android:state_activated:

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    <selector xmlns:android="http://schemas.android.com/apk/res/android">
        <item android:drawable="@color/list_item_selected_color"
            android:state_activated="true"/>
        <item android:drawable="@color/list_item_default_color"/>
    </selector>

  4. Highlight item using listView.setItemChecked(index, true);

Note: To make it clear regarding view’s states, specially state_activated you can check this post; it is interesting.

下面是给GridView默认第二项选中的例子：

Activity.java：

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

    long cuttStamp = System.currentTimeMillis();
    dateList = new ArrayList<Map<String, Object>>();
    for (int i = 0; i < 4; i++) {
        Map<String, Object> item = new HashMap<String, Object>();
        item.put("date", DateUtils.getMonDay(cuttStamp));
        item.put("week", DateUtils.getWeek(cuttStamp));
        dateList.add(item);
        cuttStamp += 24 * 3600 * 1000;
    }

    simple = new SimpleAdapter(this, dateList, R.layout.item_grid_date,
            new String[]{"date", "week"}, new int[]{R.id.tv_date, R.id.tv_week});
    gridView.setAdapter(simple);
    gridView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int postion, long id) {
            gridView.getChildAt(postion).setSelected(true);
        }
    });
    gridView.post(new Runnable() {
        @Override
        public void run() {
            gridView.performItemClick(gridView.getChildAt(1), 1, gridView.getItemIdAtPosition(1));
        }

    });
}

item_grid_date.xml

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<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="@drawable/list_item_color_bg"
    android:orientation="vertical">

    <TextView
        android:id="@+id/tv_week"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:gravity="center"
        android:text="abc" />

    <TextView
        android:id="@+id/tv_date"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginBottom="8dp"
        android:gravity="center"
        android:text="abc" />
</LinearLayout>

list_item_color_bg.xml

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<?xml version="1.0" encoding="utf-8"?>
<selector
    xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_activated="true" android:drawable="@color/blue"></item>
    <item android:drawable="@color/white"></item>
</selector>