Android——ListView相关作业（修改版）

给GridView提供点击按钮添加新数据，单击项目修改，长按删除功能

activity_practise7的layout文件：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.hanqi.testapp2.PractiseActivity7"
    android:orientation="vertical">

    <GridView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/gv_1"
        android:numColumns="4"
        android:stretchMode="columnWidth"
        android:gravity="center"
        android:horizontalSpacing="30dp"></GridView>
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="点击添加"
        android:onClick="bt_tj_onClick"/>
</LinearLayout>

activity_practise7_1的layout文件：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/et_3"
        android:gravity="center"
        android:hint="从a，b，c，d里面选择图片"/>
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/et_4"
        android:hint="给图片命名"
        android:gravity="center"/>
</LinearLayout>

gridview_layout的layout文件：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <ImageView
        android:layout_width="110dp"
        android:layout_height="110dp"
        android:id="@+id/iv_3"/>
    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/tv_3"/>
</LinearLayout>

java类： 

package com.hanqi.testapp2;

import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.EditText;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

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

public class PractiseActivity7 extends AppCompatActivity {

    GridView gv_1;
    List<MyClass> liv;
    TextView tv_3;
    ImageView iv_3;
    final ImageAdapter imageAdapter = new ImageAdapter();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_practise7);
        gv_1 = (GridView)findViewById(R.id.gv_1);
        tv_3 = (TextView)findViewById(R.id.tv_3);
        iv_3 = (ImageView)findViewById(R.id.iv_3);

        //1、数据 图片的id
        liv = new ArrayList<>();
        final MyClass myClass = new MyClass(R.drawable.f1,"美食1的介绍");
        liv.add(myClass);
        liv.add(new MyClass(R.drawable.f2,"美食2的介绍"));
        liv.add(new MyClass(R.drawable.f3,"美食3的介绍"));
        liv.add(new MyClass(R.drawable.f4,"美食4的介绍"));
        liv.add(new MyClass(R.drawable.f5,"美食5的介绍"));
        liv.add(new MyClass(R.drawable.f6,"美食6的介绍"));
        liv.add(new MyClass(R.drawable.f7,"美食7的介绍"));
        liv.add(new MyClass(R.drawable.f8,"美食8的介绍"));

        gv_1.setAdapter(imageAdapter);

        gv_1.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                final MyClass myClass = liv.get(position);  //这一步非常重要，要不然不知道修改的哪部分
                LayoutInflater layoutInflater = getLayoutInflater();
                final View view1 = layoutInflater.inflate(R.layout.activity_practise7_1, null);
                new AlertDialog.Builder(PractiseActivity7.this)
                        .setTitle("修改内容")
                        .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                EditText et_3=(EditText)view1.findViewById(R.id.et_3);
                                String string1=et_3.getText().toString();
                                EditText et_4 = (EditText)view1.findViewById(R.id.et_4);
                                String string2 = et_4.getText().toString();
                                String a="a",b="b",c="c",d="d";
                                if (string1.equals(a))
                                {
                                    if (string2.length() ==0)
                                    {
                                        myClass.setImg(R.drawable.anniu01);
                                    }
                                    else
                                    {
                                        myClass.setImg(R.drawable.anniu01);
                                        myClass.setContent(string2);
                                    }
                                }
                                else if (string1.equals(b))
                                {
                                    if (string2.length() ==0)
                                    {
                                        myClass.setImg(R.drawable.anniu02);
                                    }
                                    else
                                    {
                                        myClass.setImg(R.drawable.anniu02);
                                        myClass.setContent(string2);
                                    }
                                }
                                else if (string1.equals(c))
                                {
                                    if (string2.length() ==0)
                                    {
                                        myClass.setImg(R.drawable.anniu04);
                                    }
                                    else
                                    {
                                        myClass.setImg(R.drawable.anniu04);
                                        myClass.setContent(string2);
                                    }
                                }
                                else if (string1.equals(d))
                                {
                                    if (string2.length() ==0)
                                    {
                                        myClass.setImg(R.drawable.anniu05);
                                    }
                                    else
                                    {
                                        myClass.setImg(R.drawable.anniu05);
                                        myClass.setContent(string2);
                                    }
                                }
                                else
                                {
                                    Toast.makeText(PractiseActivity7.this, "请做出至少一项修改", Toast.LENGTH_SHORT).show();
                                }
                                imageAdapter.notifyDataSetChanged();
                            }
                        })
                        .setView(view1)
                        .show();
            }
        });

        gv_1.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
            @Override
            public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {

                //1.删除数据
                //从集合里删除长按的数据
                liv.remove(position);
                //2.刷新视图，看到效果
                //通知适配器，数据源改变
                imageAdapter.notifyDataSetChanged();
                Toast.makeText(PractiseActivity7.this, "删除了记录索引 = " + position, Toast.LENGTH_SHORT).show();
                return true;//事件已经被消费，不要再处理了
            }
        });
    }
    public void bt_tj_onClick(View v)
    {
        final View view=View.inflate(PractiseActivity7.this, R.layout.activity_practise7_1, null);
        new AlertDialog.Builder(PractiseActivity7.this)
                .setTitle("添加的内容")
                .setPositiveButton("确定", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        EditText et_3=(EditText)view.findViewById(R.id.et_3);
                        String string1=et_3.getText().toString();
                        EditText et_4 = (EditText)view.findViewById(R.id.et_4);
                        String string2 = et_4.getText().toString();
                        String a="a",b="b",c="c",d="d";
                        if (string1.equals(a))
                        {
                            liv.add(new MyClass(R.drawable.anniu01,string2));
                        }
                        else if (string1.equals(b))
                        {
                            liv.add(new MyClass(R.drawable.anniu02,string2));
                        }
                        else if (string1.equals(c))
                        {
                            liv.add(new MyClass(R.drawable.anniu04,string2));
                        }
                        else if (string1.equals(d))
                        {
                            liv.add(new MyClass(R.drawable.anniu05,string2));
                        }
                        else
                        {
                            Toast.makeText(PractiseActivity7.this, "请从a,b,c,d中选择",
                                    Toast.LENGTH_SHORT).show();
                        }
                        imageAdapter.notifyDataSetChanged();
                    }
                })
                .setView(view)
                .show();
    }
    class MyClass
    {
        private int img;
        private String content;

        public int getImg() {
            return img;
        }

        public void setImg(int img) {
            this.img = img;
        }

        public String getContent() {
            return content;
        }

        public void setContent(String content) {
            this.content = content;
        }
        public MyClass(int img,String content)
        {
            this.img = img;
            this.content = content;
        }
    }
    //适配器
    class ImageAdapter extends BaseAdapter
    {
        @Override
        public int getCount() {
            return liv.size();
        }

        @Override
        public Object getItem(int position) {
            return liv.get(position);
        }

        @Override
        public long getItemId(int position) {
            return 0;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            //1.得到数据 图片的id
            MyClass myClass = liv.get(position);
            //2.准备View
            if (convertView ==null) {
                convertView = View.inflate(PractiseActivity7.this, R.layout.gridview_layout, null);
            }
            //3.适配
            //转换
            ImageView imageView = (ImageView)convertView.findViewById(R.id.iv_3);
            imageView.setImageResource(myClass.getImg());

            TextView textView = (TextView)convertView.findViewById(R.id.tv_3);
            textView.setText(myClass.getContent());
            return convertView;
        }
    }

}