Android中GridView实现长按多选功能

前言：GridView可用于展示多行多列的统一格式数据，但本身没有多选操作。现通过一系列代码实现GridView的长按多选操作，可以先看一个示例图。

以下是实现该功能的主要代码：
MainActivity.java

package com.mygridview;import android.app.AlertDialog;import android.content.DialogInterface;import android.support.v7.app.ActionBar;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.KeyEvent;import android.view.View;import android.widget.AdapterView;import android.widget.Button;import android.widget.CheckBox;import android.widget.GridView;import android.widget.RelativeLayout;import android.widget.TextView;import android.widget.Toast;import java.util.ArrayList;import java.util.HashMap;public class MainActivity extends AppCompatActivity implements View.OnClickListener, AdapterView.OnItemClickListener, AdapterView.OnItemLongClickListener {    private ActionBar actionBar;    private Button btnCancel, btnDel, btnSelectAll, btnClear;    private RelativeLayout headerLayout;    private TextView numText;    private GridView gridView;    private ArrayList<HashMap<String, Object>> items; //每一个item    private ArrayList<Boolean> selectItems; //用于存储已选中项目的位置    private MyAdapter adapter;    private boolean isState;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        initView();    }    private void initView() {        actionBar = getSupportActionBar();        actionBar.setTitle("GridView");        numText = (TextView) findViewById(R.id.number);        btnCancel = (Button) findViewById(R.id.btn_cancel);        btnDel = (Button) findViewById(R.id.btn_del);        btnSelectAll = (Button) findViewById(R.id.btn_select_all);        btnClear = (Button) findViewById(R.id.btn_clear);        btnCancel.setOnClickListener(this);        btnDel.setOnClickListener(this);        btnSelectAll.setOnClickListener(this);        btnClear.setOnClickListener(this);        headerLayout = (RelativeLayout) findViewById(R.id.header);        gridView = (GridView) findViewById(R.id.grid_view);        items = new ArrayList<>();        selectItems = new ArrayList<>();        for (int i = 0; i < 20; i++) {            HashMap<String, Object> item = new HashMap<>();            item.put("image", R.drawable.image);            items.add(item);        }        adapter = new MyAdapter(this, items, R.layout.image, new String[]{"image"}, new int[]{R.id.my_image});        gridView.setAdapter(adapter);        gridView.setOnItemClickListener(this);        gridView.setOnItemLongClickListener(this);    }    public ArrayList<Boolean> getSelectItems() {        return selectItems;    }    @Override    public void onClick(View v) {        switch (v.getId()) {            case R.id.btn_cancel :                selectItems.clear();                numText.setText("已选择1项");                adapter.setIsState(false);                setState(false);                break;            case R.id.btn_clear :                setSelectAll(false);                break;            case R.id.btn_select_all:                setSelectAll(true);                break;            case R.id.btn_del:                delSelections();                break;        }    }    @Override    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {        if (isState) {            CheckBox checkBox = (CheckBox) view.findViewById(R.id.check_box);            if (checkBox.isChecked()) {                checkBox.setChecked(false);                selectItems.set(position, false);            } else {                checkBox.setChecked(true);                selectItems.set(position, true);            }            adapter.notifyDataSetChanged();            setSelectNum();        }    }    @Override    public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {        if (!isState) {            selectItems = new ArrayList<>();            for (int i = 0; i < items.size(); i++) {                selectItems.add(false);            }            CheckBox box = (CheckBox) view.findViewById(R.id.check_box);            box.setChecked(true);            selectItems.set(position, true);            setState(true);            adapter.setIsState(true);            setSelectNum();        }        return false;    }    //设置当前状态 是否在多选模式    private void setState(boolean b) {        isState = b;        if (b) {            headerLayout.setVisibility(View.VISIBLE);            btnDel.setVisibility(View.VISIBLE);            actionBar.hide();        } else {            headerLayout.setVisibility(View.GONE);            btnDel.setVisibility(View.GONE);            actionBar.show();        }    }    //显示已选项数目    private void setSelectNum() {        int num = 0;        for (Boolean b : selectItems) {            if (b)                num ++;        }        numText.setText("已选择" + num + "项");    }    //全选    private void setSelectAll(boolean b) {       for (int i = 0; i < selectItems.size(); i++) {           selectItems.set(i, b);           adapter.notifyDataSetChanged();           setSelectNum();       }        btnSelectAll.setVisibility(b? View.GONE : View.VISIBLE);        btnClear.setVisibility(b ? View.VISIBLE : View.GONE);    }    //删除    private void delSelections() {        AlertDialog.Builder builder = new AlertDialog.Builder(this);        if (!selectItems.contains(true)) {            builder.setTitle("提示").setMessage("当前未选中项目").setPositiveButton("确认", null).create().show();        } else {            builder.setTitle("提示");            builder.setMessage("确认删除所选项目？");            builder.setPositiveButton("确认", new DialogInterface.OnClickListener() {                @Override                public void onClick(DialogInterface dialog, int which) {                    for (int i = 0; i < items.size(); i++) {                        if (selectItems.get(i)) {                            items.set(i, null);                        }                    }                    while (items.contains(null)) {                        items.remove(null);                    }                    selectItems = new ArrayList<>();                    for (int i = 0; i < items.size(); i++) {                        selectItems.add(false);                    }                    adapter.setData(items);                    adapter.notifyDataSetChanged();                    if (items.size() == 0) {                        adapter.setIsState(false);                        setState(false);                        return;                    }                }            });            builder.setNegativeButton("取消", null);            builder.create().show();        }    }    private long mExitTime;    public boolean onKeyDown(int keyCode, KeyEvent event) {        if (keyCode == KeyEvent.KEYCODE_BACK) {            if (isState) {                selectItems.clear();                numText.setText("已选择1项");                adapter.setIsState(false);                setState(false);                return true;            } else {                if ((System.currentTimeMillis() - mExitTime) > 2000) {                    Toast.makeText(this, "再按一次退出程序", Toast.LENGTH_SHORT).show();                    mExitTime = System.currentTimeMillis();                }                else finish();                return true;            }        }        return super.onKeyDown(keyCode, event);    }}

设配器Adapter

package com.mygridview;import android.content.Context;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.CheckBox;import android.widget.SimpleAdapter;import java.util.ArrayList;import java.util.List;import java.util.Map;public class MyAdapter extends SimpleAdapter {    private List<? extends Map<String, ?>> data;    private int resourse;    private Context context;    private LayoutInflater inflater;    private boolean isState = false;    public MyAdapter(Context context, List<? extends Map<String, ?>> data, int resource, String[] from, int[] to) {        super(context, data, resource, from, to);        inflater = LayoutInflater.from(context);        this.resourse = resource;        this.data = data;        this.context = context;    }    public void setData(List<? extends Map<String, ?>> data) {        this.data = data;    }    public void setIsState(boolean isState) {        this.isState = isState;        notifyDataSetChanged();    }    @Override    public int getCount() {        return data.size();    }    @Override    public Object getItem(int position) {        return data.get(position);    }    @Override    public long getItemId(int position) {        return position;    }    @Override    public View getView(int position, View convertView, ViewGroup parent) {        ArrayList<Boolean> list = ((MainActivity) context).getSelectItems();        convertView = inflater.inflate(resourse ,null);        CheckBox checkBox = (CheckBox) convertView.findViewById(R.id.check_box);        checkBox.setVisibility(isState? View.VISIBLE : View.GONE);        if (list.size() != 0)            checkBox.setChecked(list.get(position));        return super.getView(position, convertView, parent);    }}

主页面布局 activity_main.xml

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.mygridview.MainActivity">    <RelativeLayout  android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentTop="true" android:id="@+id/header" android:visibility="gone" android:background="@color/colorPrimary" >        <Button  android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/btn_cancel" android:background="@android:color/transparent" android:text="取消" />        <TextView  android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="已选择1项" android:layout_centerVertical="true" android:layout_centerInParent="true" android:id="@+id/number" />        <Button  android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="全选" android:background="@android:color/transparent" android:id="@+id/btn_select_all" android:layout_alignParentEnd="true" />        <Button  android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="清除" android:background="@android:color/transparent" android:id="@+id/btn_clear" android:visibility="gone" android:layout_alignParentEnd="true" />    </RelativeLayout>    <GridView  android:layout_below="@+id/header" android:layout_width="match_parent" android:layout_height="wrap_content" android:numColumns="3" android:id="@+id/grid_view" android:verticalSpacing="10dp" android:horizontalSpacing="10dp" android:layout_above="@+id/btn_del" >    </GridView>    <Button  android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="删除" android:id="@+id/btn_del" android:visibility="gone" android:layout_alignParentBottom="true" android:layout_centerHorizontal="true" /></RelativeLayout>

每个item的布局 image.xml

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="wrap_content" android:layout_height="match_parent" android:descendantFocusability="blocksDescendants" >    <RelativeLayout  android:layout_width="wrap_content" android:layout_height="wrap_content">        <ImageView  android:layout_width="120dp" android:layout_height="150dp" android:src="@drawable/image" android:scaleType="centerCrop" android:id="@+id/my_image" />        <CheckBox  android:layout_width="wrap_content" android:layout_height="wrap_content" android:id="@+id/check_box" android:visibility="gone" android:layout_alignParentTop="true" android:layout_alignRight="@+id/my_image" android:layout_alignEnd="@+id/my_image" />    </RelativeLayout></LinearLayout>

问题总结：
1.当进入多选模式时点击图片CheckBox不会选中。
答：由于图片和多选框组成的view的点击事件与多选框的点击事件冲突，所以无法选中，可以在xml的根布局中加入android:descendantFocusability=”blocksDescendants”即可解决。

更多相关文章

随机推荐