Android ListView长按多选模式
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本文示例实现ListView长按条目进入Action Mode，然后可以进行多选，并将选择的条目提前。功能和例子很简单，为的是更好的说明如何实现。
先看一下我们的Activity布局，activity_main.xml
然后是item的布局item_with_check_box.xml，也很简单
CheckBox默认不可见，后面我们会看到，只有进入Action Mode时才会显示，我们关注的重点在于CheckBox的clickable和focusable属性都是false，这样可以避免界面响应CheckBox的点击事件，这就避免了我们手动点击CheckBox导致的勾选，大家或许有疑问，这样不对吗？在正常情况下使用，的确是对的，但是由于ListView会重复利用ItemView，所以我们如果靠我们自己记录ItemView中的CheckBox的状态就会出现问题，我们无法知道我们自己维护的CheckBox是否已经重复使用。如果想测试，大家可以自己做个试验，做一个ListView，每个条目中有一个CheckBox，不要置clickable和focusable属性为false，条目多一些，保证一个屏幕放置不下，这时候你先滚动到最底下，然后手动点击CheckBox，然后来回滚动ListView，你会发现，之前勾选的会消失。
当然，如果你乐意，可以维护CheeckBox的勾选状态，但是这样实在是太费劲了，反正我是不乐意。
接下来，还有两个xml文件，一个是我们进入到Action Mode时的Action Bar布局action_mode_bar.xml，如下所示
下面是我们的MainActivity
package com.yjp.listviewmultiplechoicemodaldemo;
import android.annotation.SuppressLint;
import android.content.Context;
import android.support.annotation.LayoutRes;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.ActionMode;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AbsListView;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.CheckBox;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private CheckListViewAdapter mAdapter;
private List mItems = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ListView listView = (ListView) findViewById(R.id.list_view);
mAdapter = new CheckListViewAdapter(this,
R.layout.item_with_check_box,
mItems);
listView.setAdapter(mAdapter);
listView.setMultiChoiceModeListener(new MultiChoiceModeListener(listView));
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView parent, View view, int position, long id) {
Toast.makeText(MainActivity.this, "点击条目", Toast.LENGTH_SHORT).show();
}
});
}
@Override
protected void onStart() {
super.onStart();
mItems.addAll(getItems());
mAdapter.notifyDataSetChanged();
}
@Override
protected void onStop() {
super.onStop();
mItems.clear();
}
private List getItems() {
List items = new ArrayList<>();
for (int i = 0; i < 20; i++) {
items.add(i);
}
return items;
}
private class MultiChoiceModeListener implements AbsListView.MultiChoiceModeListener {
private ListView mListView;
private TextView mTitleTextView;
private List mSelectedItems = new ArrayList<>();
private MultiChoiceModeListener(ListView listView) {
mListView = listView;
}
@Override
public void onItemCheckedStateChanged(ActionMode mode, int position, long id, boolean checked) {
mSelectedItems.add(mAdapter.getItem(position));
mTitleTextView.setText("已选择 " + mListView.getCheckedItemCount() + " 项");
mAdapter.notifyDataSetChanged();
}
@Override
public boolean onCreateActionMode(ActionMode mode, Menu menu) {
mode.getMenuInflater().inflate(R.menu.check_task_priority, menu);
@SuppressLint("InflateParams")
View multiSelectActionBarView = LayoutInflater.from(MainActivity.this)
.inflate(R.layout.action_mode_bar, null);
mode.setCustomView(multiSelectActionBarView);
mTitleTextView = (TextView)multiSelectActionBarView.findViewById(R.id.title);
mTitleTextView.setText("已选择 0 项");
mAdapter.setCheckable(true);
mAdapter.notifyDataSetChanged();
return true;
}
@Override
public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
return false;
}
@Override
public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
switch (item.getItemId()) {
case R.id.cancel:
break;
case R.id.up:
Collections.sort(mSelectedItems);
for (Integer selectedItem : mSelectedItems) {
mItems.remove(selectedItem);
}
mItems.addAll(0, mSelectedItems);
break;
default:
break;
}
mode.finish();
return true;
}
@Override
public void onDestroyActionMode(ActionMode mode) {
mSelectedItems.clear();
mAdapter.setCheckable(false);
mAdapter.notifyDataSetChanged();
}
}
private class CheckListViewAdapter extends ArrayAdapter {
private boolean mCheckable;
private CheckListViewAdapter(@NonNull Context context,
@LayoutRes int resource,
@NonNull List objects) {
super(context, resource, objects);
}
@NonNull
@Override
public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) {
ViewHolder holder;
if (null == convertView) {
convertView = LayoutInflater.from(getContext())
.inflate(R.layout.item_with_check_box, parent, false);
holder = new ViewHolder();
holder.textView = (TextView) convertView.findViewById(R.id.text_view);
holder.checkBox = (CheckBox) convertView.findViewById(R.id.selected_check_box);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
Integer item = getItem(position);
if (item != null) {
holder.textView.setText(item.toString());
}
//可见性和选中状态
if (mCheckable) {
holder.checkBox.setVisibility(View.VISIBLE);
} else {
holder.checkBox.setVisibility(View.INVISIBLE);
}
holder.checkBox.setChecked(((ListView) parent).isItemChecked(position));
return convertView;
}
//用来设置是否CheckBox可见
private void setCheckable(boolean checkable) {
mCheckable = checkable;
}
private class ViewHolder {
private TextView textView;
private CheckBox checkBox;
}
}
}
