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ActionMode是3.0之后，官方推荐的一种上下文菜单的实现方式，在之前一直用的是Context Menu，今天这篇文章简单介绍一下ActionMode，并实现多选删除功能。
如果要在ListView这类控件中实现多选，我们可以通过设置setChoiceMode(ListView.CHOICE_MODE_MULTIPLE_MODAL)来实现，，然后通过设置setMultiChoiceModeListener之后，就可以开启ActionMode。ActionMode并不是一个View，只是一个操作模式，所以我们用的时候不能按照View的用法来使用。
下面是实现的效果图
这个和GMail的删除是不是很像？
因为ActionMode没有多少知识点要说，咱们就简单介绍下，然后上代码，这个功能主要其实主要是逻辑麻烦点，也很简单。
设置完多选模式监听器之后，我们需要实现下面的方法
mListView.setMultiChoiceModeListener(new MultiChoiceModeListener(){@Overridepublic boolean onCreateActionMode(ActionMode mode, Menu menu) {// TODO Auto-generated method stubreturn false;}@Overridepublic boolean onPrepareActionMode(ActionMode mode, Menu menu) {// TODO Auto-generated method stubreturn false;}@Overridepublic boolean onActionItemClicked(ActionMode mode, MenuItem item) {// TODO Auto-generated method stubreturn false;}@Overridepublic void onDestroyActionMode(ActionMode mode) {// TODO Auto-generated method stub}@Overridepublic void onItemCheckedStateChanged(ActionMode mode,int position, long id, boolean checked) {// TODO Auto-generated method stub}}); 就5个方法，看名字也很好理解。
在onCreateActionMode()中，一般实现ActionMode下右侧的MenuItem配置，和标题设置，比如像下面这样
@Overridepublic boolean onCreateActionMode(ActionMode mode, Menu menu) {// 在进入ActionMode的时候调用MenuInflater inflater = mode.getMenuInflater();inflater.inflate(R.menu.menu_delete, menu);mode.setTitle("Delete");isInActionMode = true;isInDeleteMode = false;return true;} onActionItemClicked则是在我们设置的MenuItem点击之后调用，和ActionBar里面的MenuItem一样，所以我们可以像下面这样@Overridepublic boolean onActionItemClicked(ActionMode mode, MenuItem item) {// 当listview中的item被点击的时候调用if (item.getItemId() == R.id.action_delete) {mAnimateDismissAdapter.animateDismiss(mCheckedPositions);isInDeleteMode = true;mode.finish();return true;}return false;} onItemCheckedStateChanged则是我们的listview的item点击的时候调用，我们可以根据position和checked进行逻辑操作。
基本这几个方法就基本满足我们的功能了，下面是完整的示例代码
package com.imooc.multychoice;import java.util.ArrayList;import java.util.Iterator;import android.app.Activity;import android.os.Bundle;import android.view.ActionMode;import android.view.Menu;import android.view.MenuInflater;import android.view.MenuItem;import android.view.View;import android.view.ViewGroup;import android.widget.AbsListView;import android.widget.AbsListView.MultiChoiceModeListener;import android.widget.BaseAdapter;import android.widget.CheckBox;import android.widget.ListView;import android.widget.TextView;import com.haarman.listviewanimations.itemmanipulation.AnimateDismissAdapter;import com.haarman.listviewanimations.itemmanipulation.OnDismissCallback;import com.imooc.multychoice.R;public class MainActivity extends Activity {protected static final String TAG = "TAG";private ListView mListView;private MultyAdapter mAdapter;// 是否处于ActionMode模式private boolean isInActionMode;private boolean isInDeleteMode = false;private AnimateDismissAdapter<Model> mAnimateDismissAdapter;private ArrayList<Integer> mCheckedPositions;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);mListView = (ListView) findViewById(R.id.lv);mAdapter = new MultyAdapter();mCheckedPositions = new ArrayList<Integer>();mAnimateDismissAdapter = new AnimateDismissAdapter<MainActivity.Model>(mAdapter, new MyDismissCallBack());mAnimateDismissAdapter.setAbsListView(mListView);mListView.setAdapter(mAnimateDismissAdapter);mListView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE_MODAL);mListView.setMultiChoiceModeListener(new MultiChoiceModeListener() {@Overridepublic boolean onPrepareActionMode(ActionMode mode, Menu menu) {return false;}@Overridepublic void onDestroyActionMode(ActionMode mode) {// 在退出ActionMode的时候调用，如果处于删除状态，就删除选中的数据，// 否则，重置所有选中的状态if (!isInDeleteMode) {for (Model model : mAdapter.models) {model.setChecked(false);}mCheckedPositions.clear();}isInActionMode = false;}@Overridepublic boolean onCreateActionMode(ActionMode mode, Menu menu) {// 在进入ActionMode的时候调用MenuInflater inflater = mode.getMenuInflater();inflater.inflate(R.menu.menu_delete, menu);mode.setTitle("Delete");isInActionMode = true;isInDeleteMode = false;return true;}@Overridepublic boolean onActionItemClicked(ActionMode mode, MenuItem item) {// 当listview中的item被点击的时候调用if (item.getItemId() == R.id.action_delete) {mAnimateDismissAdapter.animateDismiss(mCheckedPositions);isInDeleteMode = true;mode.finish();return true;}return false;}@Overridepublic void onItemCheckedStateChanged(ActionMode mode,int position, long id, boolean checked) {// 当item的选中状态被选中的时候调用mAdapter.models.get(position).setChecked(checked);mAdapter.notifyDataSetChanged();mode.setSubtitle(mListView.getCheckedItemCount()+ " item selected");if (mCheckedPositions.contains(position) && !checked) {mCheckedPositions.remove(Integer.valueOf(position));} else {mCheckedPositions.add(position);}}});}private class MultyAdapter extends BaseAdapter {private ArrayList<Model> models;public MultyAdapter() {models = new ArrayList<Model>();for (int i = 0; i < 20; i++) {models.add(new Model("I’m " + i));}}@Overridepublic int getCount() {return models.size();}@Overridepublic Model getItem(int position) {return models.get(position);}@Overridepublic long getItemId(int position) {return 0;}@Overridepublic View getView(int position, View convertView, ViewGroup parent) {ViewHolder viewHolder;Model model = mAdapter.models.get(position);if (convertView == null) {convertView = getLayoutInflater().inflate(R.layout.item_multy_choice, parent, false);viewHolder = new ViewHolder();viewHolder.tv = (TextView) convertView.findViewById(R.id.tv);viewHolder.chb = (CheckBox) convertView.findViewById(R.id.chb);convertView.setTag(viewHolder);} else {viewHolder = (ViewHolder) convertView.getTag();}viewHolder.tv.setText(model.getTitle());viewHolder.chb.setChecked(model.isChecked());viewHolder.chb.setVisibility(isInActionMode ? View.VISIBLE: View.GONE);return convertView;}}private static class ViewHolder {TextView tv;CheckBox chb;}/** * 测试Model * * @author zhaokaiqiang * */private class Model {private String title;private boolean isChecked;public Model(String title) {this.title = title;isChecked = false;}public String getTitle() {return title;}public boolean isChecked() {return isChecked;}public void setChecked(boolean isChecked) {this.isChecked = isChecked;}}private class MyDismissCallBack implements OnDismissCallback {@Overridepublic void onDismiss(AbsListView arg0, int[] arg1) {mCheckedPositions.clear();Iterator<Model> iterator = mAdapter.models.iterator();while (iterator.hasNext()) {if (iterator.next().isChecked()) {// 删除选中的元素iterator.remove();}}mAdapter.notifyDataSetChanged();}}} 在上面的代码中，为了实现动画效果，我使用了开源项目ListViewAnimation中的AnimationDismissAdapter，具体用法很简单，直接看代码就可以啦~
下载地址：https://github.com/ZhaoKaiQiang/MultyChoiceDemo
最好的节约是珍惜时间，最大的浪费是虚度年华。
