一、长按item时的响应

在长按item时，我希望能让CheckBox显示出来，并且呼出全选、反选、取消菜单，以及下载、删除、移动、复制操作菜单。

我在具体实现的时候发现处理item布局是一个很大的问题，因为不知道怎么在Fragment里面去改变每一个item的CheckBox状态。经过考虑，我打算把这些方法都写在ListViewAdapter里，并且在这个类里设置一个Map对象，记录每一个position对应的isCheck状态。当我点击每一个CheckBox或者从Fragment里面点击全选/反选时，改变这个Map的值，然后通过重写adapter里的getView方法来控制哪些CheckBox显示为已选，哪些为未选。

而另外的两个菜单，我在HomeFragment布局里面都把他们写了出来，然后初始化为不可见。当长按item触发OnItemLongClickedListener的时候将他们设置为可见，并且把他们覆盖了的组件设置为不可见（避免不可见但仍能响应Click事件的问题）

另外还有一个变量isSelecting我认为非常重要，它用来判断当前Fragment是否是处于选择阶段。

二、FileListAdapter

package com.example.vcloud_3_25.utils;import java.util.HashMap;import java.util.List;import java.util.Map;import android.annotation.SuppressLint;import android.content.Context;import android.view.View;import android.view.ViewGroup;import android.widget.CheckBox;import android.widget.CompoundButton;import android.widget.CompoundButton.OnCheckedChangeListener;import android.widget.SimpleAdapter;import com.example.vcloud_3_25.R;public class FileListAdapter extends SimpleAdapter {    private Map
     
       isSelected;    private boolean isSelecting;    private List
      
       
        > mResList;        @SuppressWarnings("unchecked")    public FileListAdapter(Context context,            List
        > data, int resource, String[] from,            int[] to) {        super(context, data, resource, from, to);        this.mResList = (List
        
         
          >)data;        init();    }    @Override    public View getView(final int position, View convertView, ViewGroup parent) {        View view = super.getView(position, convertView, parent);        CheckBox cb = (CheckBox) view.findViewById(R.id.file_checkbox);        if (!isSelecting) {            cb.setVisibility(View.INVISIBLE);        } else {            cb.setVisibility(View.VISIBLE);            cb.setChecked(isSelected.get(position));        }        cb.setOnCheckedChangeListener(new OnCheckedChangeListener() {                        @Override            public void onCheckedChanged(CompoundButton checkBox, boolean flag) {                    isSelected.put(position, flag);            }        });        return view;    }    @SuppressLint("UseSparseArrays")     public void init() {        isSelected = new HashMap
          
           (); for (int i = 0; i < mResList.size(); i++) { isSelected.put(i, false); } isSelecting = false; } public void setIsSelecting(boolean flag){ this.isSelecting = flag; } public void setSelected(int position,boolean flag){ isSelected.put(position, flag); } public Map
           
             getSelected(){ return isSelected; } public void selectAll(){ for (int i = 0; i < mResList.size(); i++) { isSelected.put(i, true); } } public void selectReverse(){ for (int i = 0; i < mResList.size(); i++) { isSelected.put(i, !isSelected.get(i)); } }}

三、HomeFragment里面的一些核心函数

mListView.setOnItemLongClickListener(new OnItemLongClickListener() {            @Override            public boolean onItemLongClick(AdapterView
      parent, View item,                    int position, long id) {                if (!isSelecting) {                    mFolderIndicator.setVisibility(View.INVISIBLE);                    mSelectBar.setVisibility(view.VISIBLE);                    mSelectActionBar.setVisibility(view.VISIBLE);                    isSelecting = true;                    adapter.init();                    adapter.setIsSelecting(isSelecting);                    adapter.setSelected(position, true);                    refreshListView();                }                return true;            }        });        mSelectCancelButton.setOnClickListener(new OnClickListener() {                        @Override            public void onClick(View arg0) {                backToNormal();            }        });                mSelectAllButton.setOnClickListener(new OnClickListener() {                        @Override            public void onClick(View arg0) {                adapter.selectAll();                refreshListView();            }        });        mSelectReverseButton.setOnClickListener(new OnClickListener() {                        @Override            public void onClick(View arg0) {                adapter.selectReverse();                refreshListView();            }        });        }    private void refreshListView() {        mResList.clear();        mResList.addAll(getResList(recentPid));        adapter.notifyDataSetChanged();    }    private void backToNormal() {        adapter.init();        isSelecting = false;        refreshListView();        mFolderIndicator.setVisibility(View.VISIBLE);        mSelectBar.setVisibility(View.INVISIBLE);        mSelectActionBar.setVisibility(View.INVISIBLE);    }

转载于:https://www.cnblogs.com/viaduct/p/6673557.html

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