用过UC浏览器的都熟悉如下功能：
长按图标会弹出删除的图标，点击删除会删除此项Item，下面研究一下如何实现类似效果。
1.配置布局main.xml文件：
<RelativeLayout 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" >
<GridView
android:id="@+id/gridView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:numColumns="4" >
</GridView>
</RelativeLayout> 2.配置GridView的填充组件布局 grid_item.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/ll_grid_item"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center"
android:orientation="vertical" >
<FrameLayout
android:id="@+id/starred_item_layout"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center" >
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginRight="4dip"
android:layout_marginTop="4dip"
android:gravity="center"
android:orientation="vertical" >
<ImageView
android:id="@+id/img"
android:layout_width="60dip"
android:layout_height="55dip" />
<TextView
android:id="@+id/name_tv"
android:layout_width="70dip"
android:layout_height="wrap_content"
android:layout_marginTop="10dip"
android:gravity="center"
android:textColor="@android:color/black"
android:textSize="15sp"
android:textStyle="bold" />
</LinearLayout>
<ImageView
android:id="@+id/delete_markView"
android:layout_width="20dip"
android:layout_height="20dip"
android:layout_gravity="right|top"
android:adjustViewBounds="true"
android:src="@drawable/delete"
android:visibility="gone" />
</FrameLayout>
</LinearLayout> 设置了id为delete_markView的ImageView的layout_gravity属性为right|top，说明该图片位于右上角，设置了其visibility为gone，说明该图片初始时是不显示的，后期可以控制该图片的显示。
3.adapter适配器文件：
package com.example.longdemo;
//省略导入包
public class GridViewAdapter extends BaseAdapter {
private ArrayList<HashMap<String, Object>> myList;
private Context mContext;
private TextView name_tv;
private ImageView img;
private View deleteView;
private boolean isShowDelete=false;// 根据这个变量来判断是否显示删除图标，true是显示，false是不显示
public GridViewAdapter(Context mContext,
ArrayList<HashMap<String, Object>> myList) {
this.mContext = mContext;
// this.names=names;
this.myList = myList;
}
public void setIsShowDelete(boolean isShowDelete) {
this.isShowDelete = isShowDelete;
notifyDataSetChanged();
}
@Override
public int getCount() {
return myList.size();
}
@Override
public Object getItem(int position) {
return myList.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
convertView = LayoutInflater.from(mContext).inflate(R.layout.grid_item,
null);
img = (ImageView) convertView.findViewById(R.id.img);
name_tv = (TextView) convertView.findViewById(R.id.name_tv);
deleteView = convertView.findViewById(R.id.delete_markView);
deleteView.setVisibility(isShowDelete ? View.VISIBLE : View.GONE);// 设置删除按钮是否显示
img.setBackgroundResource(myList.get(position).get("image").hashCode());
name_tv.setText(myList.get(position).get("name").toString());
return convertView;
}
}设置变量isShowDelete标识是否显示删除图标，默认是false 不显示，在getView方法中通过判断该标识，使用setVisibility方法控制删除图标的显示。同时定义了setIsShowDelete方法，供调用出调用以传入isShowDelete参数的值。
4.MainActivity.java:
package com.example.longdemo;
//省略导入包
public class MainActivity extends Activity implements OnItemLongClickListener {
private GridView mGridView;
private GridViewAdapter mAdapter;
private boolean isShowDelete = false;
private ArrayList<HashMap<String, Object>> myList;
final String[] name = new String[] { "test", "testa", "testb", "testc", "testd",
"testf", "testg" };
final int[] pic = new int[] { R.drawable.pic,
R.drawable.pic, R.drawable.pic,
R.drawable.pic, R.drawable.pic,
R.drawable.pic, R.drawable.pic };
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mGridView = (GridView) findViewById(R.id.gridView);
mGridView.setOnItemLongClickListener(this);//长按事件监听
myList = getMenuAdapter(pic, name);
mAdapter = new GridViewAdapter(MainActivity.this, myList);
mGridView.setAdapter(mAdapter);
}
@Override
public boolean onItemLongClick(AdapterView<?> parent, View view,
int position, long id) {
if (isShowDelete) {
isShowDelete = false;
} else {
isShowDelete = true;
mAdapter.setIsShowDelete(isShowDelete);
mGridView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
delete(position);//删除选中项
Log.i("------>", "进来了么");
mAdapter = new GridViewAdapter(MainActivity.this, myList);//重新绑定一次adapter
mGridView.setAdapter(mAdapter);
mAdapter.notifyDataSetChanged();//刷新gridview
}
});
}
Log.i("------>", "进来了没");
mAdapter.setIsShowDelete(isShowDelete);//setIsShowDelete()方法用于传递isShowDelete值
return true;
}
private void delete(int position) {//删除选中项方法
ArrayList<HashMap<String, Object>> newList = new ArrayList<HashMap<String, Object>>();
if (isShowDelete) {
myList.remove(position);
isShowDelete = false;
}
newList.addAll(myList);
myList.clear();
myList.addAll(newList);
}
private ArrayList<HashMap<String, Object>> getMenuAdapter(//将数据装入List
int[] menuImageArray, String[] menuNameArray) {
ArrayList<HashMap<String, Object>> data = new ArrayList<HashMap<String, Object>>();
for (int i = 0; i < menuImageArray.length; i++) {
HashMap<String, Object> map = new HashMap<String, Object>();
map.put("image", menuImageArray[i]);
map.put("name", menuNameArray[i]);
data.add(map);
}
return data;
}
} MainActivity实现了OnItemLongClickListener 接口，监听GridView的长按事件。同时设置了isShowDelete 变量用于记录删除图片的显示和隐藏，设置时调用setIsShowDelete()方法用于传递isShowDelete值到适配器类中。设置了Map集合存储image和string的值，可以参照注释进行理解。
5.运行实例如下：
效果已经实现，结合上一节的动态添加，可以实现动态添加和删除的功能。
