【Android】菜单功能的实现：上下文菜单

1.在主面板里面添加一个列表视图，如下：

<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"
tools:context=".MainActivity" >

<ListView
android:id="@+id/listView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true" >
</ListView>

</RelativeLayout>

2.要实现的功能就是在List上长按，然后弹出菜单，菜单代码布局如下：

<menu xmlns:android="http://schemas.android.com/apk/res/android" >

<item
android:id="@+id/edit"
android:orderInCategory="100"
android:showAsAction="never"
android:title="Edit"/>
<item
android:id="@+id/share"
android:orderInCategory="101"
android:showAsAction="never"
android:title="Share"/>
<item
android:id="@+id/delete"
android:orderInCategory="102"
android:showAsAction="never"
android:title="Delete"/>

</menu>

3.为ListView注册上下文菜单：

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
listView = (ListView) this.findViewById(R.id.listView1);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, getData());
listView.setAdapter(adapter);
// 给listView注册上下文菜单
registerForContextMenu(listView);
}

public List<String> getData() {
List<String> list = new ArrayList<String>();
for (int i = 1; i <= 7; i++) {
list.add("jack" + i);
}
return list;
}

4.此时可以看到列表，但还无法弹出菜单。加载菜单代码如下：

// 上下文菜单
@Override
public void onCreateContextMenu(ContextMenu menu, View v,
ContextMenuInfo menuInfo) {
// TODO Auto-generated method stub

// 加载XML中的上下文菜单
super.onCreateContextMenu(menu, v, menuInfo);
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.main, menu);
}

此时可以弹出菜单。

5.定义选项的动作。

// 相应上下文菜单的操作
@Override
public boolean onContextItemSelected(MenuItem item) {
// TODO Auto-generated method stub
switch (item.getItemId()) {
case R.id.delete:
Toast.makeText(this, "delete", Toast.LENGTH_SHORT).show();
break;
case R.id.share:
Toast.makeText(this, "share", Toast.LENGTH_SHORT).show();
break;
case R.id.edit:
Toast.makeText(this, "edit", Toast.LENGTH_SHORT).show();
break;
default:
break;
}

return super.onContextItemSelected(item);
}