Andriod常用Menu之一:ContextMenu

ContextMenu通过长摁某个View弹出的上下文菜单

1. 创建

android是通过长按某个视图元素来弹出上下文菜单的,通过setOnCreateContextMenuListener(this)来给一个控件设置上下文菜单事件,通常用于ListView和GrideView.
注意:给控件设置监听事件的时候传递this,并不需要像点击事件那样实现抽象方法,因为父类里本身就包含这个方法,只需要重写,进行自己的实现即可.

2.重写创建Contextmenu方法,实现加载自己的布局

 @Override    public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {getMenuInflater().inflate(R.menu.main_context_menu,menu); super.onCreateContextMenu(menu, v, menuInfo);}

getMenuInflater().inflate(R.menu.main_context_menu,menu)给创建的menu加载要显示的布局文件

下面来解释一下onCreateContextMenu的参数:

• ContextMenu menu:要生成的menu对象
• View v:被设置监听事件的对象,也就是触发创建menu的控件对象,比如listview
• ContextMenu.ContextMenuInfo menuInfo :记录了触发控件的位置,id信息.如果使用在listview上要使用id或者position信息必须强转
  int position = ((AdapterView.AdapterContextMenuInfo) menuInfo).position;

3.给menu每个item添加点击事件,通过item 的id区分

 @Override    public boolean onContextItemSelected(MenuItem item) {        ContextMenu.ContextMenuInfo menuInfo;        AdapterView.AdapterContextMenuInfo adapterContextMenuInfo;        switch (item.getItemId()){            case R.id.main_context_menu_delete:                menuInfo = item.getMenuInfo();                adapterContextMenuInfo = (AdapterView.AdapterContextMenuInfo) menuInfo;                mDatabase.delete("table_pwd","_id=?",new String[]{String.format("%d",adapterContextMenuInfo.id)});                refreshData();                break;            case R.id.main_context_menu_edit:                adapterContextMenuInfo = (AdapterView.AdapterContextMenuInfo) item.getMenuInfo();                long id = adapterContextMenuInfo.id;                Intent intent = new Intent(this, EditActivity.class);                intent.putExtra("id",id);                startActivity(intent);                break;            case R.id.main_context_menu_openWeb:                long webId = ((AdapterView.AdapterContextMenuInfo) item.getMenuInfo()).position;                View childAt = mListview.getChildAt((int) webId);  //Long 强转int                CharSequence text = ((TextView) ((GridLayout) childAt).getChildAt(4)).getText();  //从列表中获取网址                if (text != null&&!"".equals(text.toString())) {                    String web = text.toString();                    web="http:/"+web;//                    Toast.makeText(MainActivity.this, web, Toast.LENGTH_SHORT).show();                    Intent intent1 = new Intent();                    intent1.setAction(Intent.ACTION_VIEW);                    intent1.setData(Uri.parse(web));                    startActivity(intent1);                }else {                    Toast.makeText(MainActivity.this, "该条目不存在网址信息", Toast.LENGTH_SHORT).show();                }//                Toast.makeText(MainActivity.this, "id:"+webid, Toast.LENGTH_SHORT).show();                break;        }        return super.onContextItemSelected(item);    }