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;
         }
     }

 }