ListView中獲取checkbox選中事件

這段時間在些項目時發現一個小技術點還是挺有意思的，特來總結一下，就是如何在ListView的item中自己寫了一個checkbox，那麼如何獲取到這個item的checkbox的選中事件，進而怎樣操作，比方說點擊全選、取消後如何讓checkbox被選擇或者是取消，我們來一起學習一下。
先上代碼

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="25dp"
android:layout_centerVertical="true">
<ImageView
    android:id="@+id/iv_app_icon"
    android:src="@mipmap/ic_launcher"
    android:layout_width="48dp"
    android:layout_height="48dp"
    android:layout_centerVertical="true"/>
    <TextView
    android:id="@+id/tv_app_name"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_toRightOf="@id/iv_app_icon"
    android:layout_centerVertical="true"
    android:text="微信"
    android:paddingLeft="18dp"
    android:textSize="15dp"/>
    <CheckBox
    android:id="@+id/cb_app_uninstall"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentRight="true"
    android:layout_centerVertical="true"
    android:focusable="false"
    android:clickable="false"/>
</RelativeLayout>

大家可以看到我將checkbox命名爲cb_app_uninstall，其實主要是一個與卸載相關的選中鍵，然後我將adapter與holder提取出來單獨封裝爲一個類

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;

import java.util.ArrayList;

//這個是自定義的adpter的基類
public class MyBaseAdapter<T> extends BaseAdapter {

private ArrayList<T> dataList;
private Context mContext;
LayoutInflater inflater;

public MyBaseAdapter(Context context,ArrayList<T> dataList){
    this.mContext = context;
    this.dataList = dataList;
    inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
@Override
public int getCount() {
    return dataList.size();
}

@Override
public Object getItem(int position) {
    return dataList.get(position);
}
@Override
public long getItemId(int position) {
    return position;
}

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    return null;
    }
}

下面是我單獨提取出來的AppManagerAdapter

import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CheckBox;
import android.widget.ImageView;
import android.widget.TextView;

import com.qingcheng.mobilemanager.R;
import com.qingcheng.mobilemanager.bean.AppInfo;
import com.qingcheng.mobilemanager.holder.AppViewholder;

import java.util.ArrayList;
import java.util.List;

public class AppManagerAdapter extends MyBaseAdapter<AppInfo> {

private Context mContext;
private ArrayList<AppInfo> mDatas;
public List<Boolean> mChecked;

public AppManagerAdapter(Context context, ArrayList<AppInfo> dataList) {
    super(context, dataList);
    this.mContext = context;
    this.mDatas = dataList;

    mChecked = new ArrayList<Boolean>();
    for (int i = 0; i < dataList.size(); i++){
        mChecked.add(false);
    }
}

@Override
public AppInfo getItem(int position) {
    return mDatas.get(position);
}

@Override
public View getView(final int position, View convertView, ViewGroup parent) {
    AppViewholder holder ;
    if (convertView == null){
        convertView = View.inflate(mContext,R.layout.list_item_app_manager,null);
        holder = new AppViewholder();
        holder.ivAppIcon = (ImageView)convertView.findViewById(R.id.iv_app_icon);
        holder.tvAppName = (TextView) convertView.findViewById(R.id.tv_app_name);
        holder.cbAppUninstall = (CheckBox) convertView.findViewById(R.id.cb_app_uninstall);
        convertView.setTag(holder);
    }else{
        holder = (AppViewholder) convertView.getTag();
    }
    AppInfo info = getItem(position);
    holder.ivAppIcon.setImageDrawable(info.appIcon);
    holder.tvAppName.setText(info.appName);
    holder.cbAppUninstall.setChecked(mChecked.get(position));
    return convertView;
    }
}

BaseHolder是holder的基類

import android.view.View;

public  abstract class BaseHolder<T> {
public View convertView;
public T mData;

public BaseHolder(){
    convertView = initView();
    convertView.setTag(this);
}

public abstract View initView();

public void setData(T data){
    mData = data;
    }
}

這個是我抽取出來的AppViewholder

import android.view.View;
import android.widget.CheckBox;
import android.widget.ImageView;
import android.widget.TextView;

import com.qingcheng.mobilemanager.R;
import com.qingcheng.mobilemanager.bean.AppInfo;
import com.qingcheng.mobilemanager.utils.UiUtils;

public class AppViewholder extends BaseHolder<AppInfo> {

public ImageView ivAppIcon;
public TextView tvAppName;
public CheckBox cbAppUninstall;

@Override
public View initView() {
    View view = UiUtils.inflate(R.layout.list_item_app_manager);
    ivAppIcon = (ImageView) view.findViewById(R.id.iv_app_icon);
    tvAppName = (TextView) view.findViewById(R.id.tv_app_name);
    cbAppUninstall = (CheckBox) view.findViewById(R.id.cb_app_uninstall);

    return view;
}

@Override
public void setData(AppInfo data) {
    super.setData(data);
    tvAppName.setText(mData.appName);
    }
}

好了，現在來說說我們的正事，如何獲取listview中checkbox的選中事件

首先不知道大家有沒有注意到我在AppManagerAdapter中設置了一個

public List<Boolean> mChecked;

mChecked集合 就是一切的關鍵

//先在AppManagerAdapter中定義mChecked的長度並賦值
mChecked = new ArrayList<Boolean>();
    for (int i = 0; i < dataList.size(); i++){
        mChecked.add(false);
    }

然後在getView中set

holder.cbAppUninstall.setChecked(mChecked.get(position));

再在Activity中對listView的item獲取點擊事件,先要對listView設置監聽，並對checkbox的點擊事件設置爲

    android:focusable="false"
    android:clickable="false"

如果不這麼設置會讓listView的item得不到點擊事件

    /**
     * 每個item被點擊監聽
     */
     lvAppDisplay.setOnItemClickListener(new AdapterView.OnItemClickListener() {
        @Override
        public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
            if (mAdapter.mChecked.get(position)){
                mAdapter.mChecked.set(position,false);
            }else if (!mAdapter.mChecked.get(position)){
                mAdapter.mChecked.set(position,true);
            }
            mAdapter.notifyDataSetChanged();
        }
    });

這樣就可以及時獲取checkbox的點擊事件並及時更新控制他們的mChecked的狀態

當想要點擊一個類似全選的按鈕達到全選的效果時可以這樣做

private boolean checkedAll = false;

    /**
     * 全選事件
     */
     tvCheckAll.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            if (!checkedAll){
                for (int i = 0; i < mDatas.size(); i++){
                  mAdapter.mChecked.set(i,true);
                }
                checkedAll = true;
                mAdapter.notifyDataSetChanged();
            }else{
                for (int i = 0; i < mDatas.size(); i++){
                    mAdapter.mChecked.set(i,false);
                }
                checkedAll = false;
                mAdapter.notifyDataSetChanged();
            }
            }
    });

這樣就完美實現了在全選和全部取消之間的切換，從而我們就可以另一個方法中獲取被選中item的position

    for (int i = 0;i< mAdapter.mChecked.size();i++){
            if (mAdapter.mChecked.get(i)){
                //listItemID爲被選中item的position
                listItemID.add(i);

            }
        }