Android——ListView相关作业

Posted 2020-07-10 柒寒

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：

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     xmlns:tools="http://schemas.android.com/tools"
 4     android:layout_width="match_parent"
 5     android:layout_height="match_parent"
 6     android:paddingBottom="@dimen/activity_vertical_margin"
 7     android:paddingLeft="@dimen/activity_horizontal_margin"
 8     android:paddingRight="@dimen/activity_horizontal_margin"
 9     android:paddingTop="@dimen/activity_vertical_margin"
10     tools:context="com.hanqi.testapp2.PractiseActivity7"
11     android:orientation="vertical">
12 
13     <GridView
14         android:layout_width="match_parent"
15         android:layout_height="wrap_content"
16         android:id="@+id/gv_1"
17         android:numColumns="4"
18         android:stretchMode="columnWidth"
19         android:gravity="center"
20         android:horizontalSpacing="30dp"></GridView>
21     <Button
22         android:layout_width="wrap_content"
23         android:layout_height="wrap_content"
24         android:text="点击添加"
25         android:onClick="bt_tj_onClick"/>
26 </LinearLayout>

 

activity_practise7_1的layout文件：

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     android:orientation="vertical"
 4     android:layout_width="match_parent"
 5     android:layout_height="match_parent">
 6 
 7     <EditText
 8         android:layout_width="match_parent"
 9         android:layout_height="wrap_content"
10         android:id="@+id/et_3"
11         android:gravity="center"
12         android:hint="从a，b，c，d里面选择图片"/>
13     <EditText
14         android:layout_width="match_parent"
15         android:layout_height="wrap_content"
16         android:id="@+id/et_4"
17         android:hint="给图片命名"
18         android:gravity="center"/>
19 </LinearLayout>

gridview_layout的layout文件：

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     android:orientation="vertical"
 4     android:layout_width="match_parent"
 5     android:layout_height="match_parent">
 6 
 7     <ImageView
 8         android:layout_width="110dp"
 9         android:layout_height="110dp"
10         android:id="@+id/iv_3"/>
11     <TextView
12         android:layout_width="wrap_content"
13         android:layout_height="wrap_content"
14         android:id="@+id/tv_3"/>
15 </LinearLayout>

java类： 

  1 package com.hanqi.testapp2;
  2 
  3 import android.app.AlertDialog;
  4 import android.content.DialogInterface;
  5 import android.os.Bundle;
  6 import android.support.v7.app.AppCompatActivity;
  7 import android.view.LayoutInflater;
  8 import android.view.View;
  9 import android.view.ViewGroup;
 10 import android.widget.AdapterView;
 11 import android.widget.BaseAdapter;
 12 import android.widget.EditText;
 13 import android.widget.GridView;
 14 import android.widget.ImageView;
 15 import android.widget.TextView;
 16 import android.widget.Toast;
 17 
 18 import java.util.ArrayList;
 19 import java.util.List;
 20 
 21 public class PractiseActivity7 extends AppCompatActivity {
 22 
 23     GridView gv_1;
 24     List<MyClass> liv;
 25     TextView tv_3;
 26     ImageView iv_3;
 27     final ImageAdapter imageAdapter = new ImageAdapter();
 28 
 29     @Override
 30     protected void onCreate(Bundle savedInstanceState) {
 31         super.onCreate(savedInstanceState);
 32         setContentView(R.layout.activity_practise7);
 33         gv_1 = (GridView)findViewById(R.id.gv_1);
 34         tv_3 = (TextView)findViewById(R.id.tv_3);
 35         iv_3 = (ImageView)findViewById(R.id.iv_3);
 36 
 37         //1、数据 图片的id
 38         liv = new ArrayList<>();
 39         final MyClass myClass = new MyClass(R.drawable.f1,"美食1的介绍");
 40         liv.add(myClass);
 41         liv.add(new MyClass(R.drawable.f2,"美食2的介绍"));
 42         liv.add(new MyClass(R.drawable.f3,"美食3的介绍"));
 43         liv.add(new MyClass(R.drawable.f4,"美食4的介绍"));
 44         liv.add(new MyClass(R.drawable.f5,"美食5的介绍"));
 45         liv.add(new MyClass(R.drawable.f6,"美食6的介绍"));
 46         liv.add(new MyClass(R.drawable.f7,"美食7的介绍"));
 47         liv.add(new MyClass(R.drawable.f8,"美食8的介绍"));
 48 
 49         gv_1.setAdapter(imageAdapter);
 50 
 51         gv_1.setOnItemClickListener(new AdapterView.OnItemClickListener() {
 52             @Override
 53             public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
 54                 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
 55                 LayoutInflater layoutInflater = getLayoutInflater();
 56                 final View view1 = layoutInflater.inflate(R.layout.activity_practise7_1, null);
 57                 new AlertDialog.Builder(PractiseActivity7.this)
 58                         .setTitle("修改内容")
 59                         .setPositiveButton("确定", new DialogInterface.OnClickListener() {
 60                             @Override
 61                             public void onClick(DialogInterface dialog, int which) {
 62                                 EditText et_3=(EditText)view1.findViewById(R.id.et_3);
 63                                 String string1=et_3.getText().toString();
 64                                 EditText et_4 = (EditText)view1.findViewById(R.id.et_4);
 65                                 String string2 = et_4.getText().toString();
 66                                 String a="a",b="b",c="c",d="d";
 67                                 if (string1.equals(a))
 68                                 {
 69                                     if (string2.length() ==0)
 70                                     {
 71                                         myClass.setImg(R.drawable.anniu01);
 72                                     }
 73                                     else
 74                                     {
 75                                         myClass.setImg(R.drawable.anniu01);
 76                                         myClass.setContent(string2);
 77                                     }
 78                                 }
 79                                 else if (string1.equals(b))
 80                                 {
 81                                     if (string2.length() ==0)
 82                                     {
 83                                         myClass.setImg(R.drawable.anniu02);
 84                                     }
 85                                     else
 86                                     {
 87                                         myClass.setImg(R.drawable.anniu02);
 88                                         myClass.setContent(string2);
 89                                     }
 90                                 }
 91                                 else if (string1.equals(c))
 92                                 {
 93                                     if (string2.length() ==0)
 94                                     {
 95                                         myClass.setImg(R.drawable.anniu04);
 96                                     }
 97                                     else
 98                                     {
 99                                         myClass.setImg(R.drawable.anniu04);
100                                         myClass.setContent(string2);
101                                     }
102                                 }
103                                 else if (string1.equals(d))
104                                 {
105                                     if (string2.length() ==0)
106                                     {
107                                         myClass.setImg(R.drawable.anniu05);
108                                     }
109                                     else
110                                     {
111                                         myClass.setImg(R.drawable.anniu05);
112                                         myClass.setContent(string2);
113                                     }
114                                 }
115                                 else
116                                 {
117                                     Toast.makeText(PractiseActivity7.this, "请做出至少一项修改", Toast.LENGTH_SHORT).show();
118                                 }
119                                 imageAdapter.notifyDataSetChanged();
120                             }
121                         })
122                         .setView(view1)
123                         .show();
124             }
125         });
126 
127         gv_1.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
128             @Override
129             public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
130 
131                 //1.删除数据
132                 //从集合里删除长按的数据
133                 liv.remove(position);
134                 //2.刷新视图，看到效果
135                 //通知适配器，数据源改变
136                 imageAdapter.notifyDataSetChanged();
137                 Toast.makeText(PractiseActivity7.this, "删除了记录索引 = " + position, Toast.LENGTH_SHORT).show();
138                 return true;//事件已经被消费，不要再处理了
139             }
140         });
141     }
142     public void bt_tj_onClick(View v)
143     {
144         final View view=View.inflate(PractiseActivity7.this, R.layout.activity_practise7_1, null);
145         new AlertDialog.Builder(PractiseActivity7.this)
146                 .setTitle("添加的内容")
147                 .setPositiveButton("确定", new DialogInterface.OnClickListener() {
148                     @Override
149                     public void onClick(DialogInterface dialog, int which) {
150                         EditText et_3=(EditText)view.findViewById(R.id.et_3);
151                         String string1=et_3.getText().toString();
152                         EditText et_4 = (EditText)view.findViewById(R.id.et_4);
153                         String string2 = et_4.getText().toString();
154                         String a="a",b="b",c="c",d="d";
155                         if (string1.equals(a))
156                         {
157                             liv.add(new MyClass(R.drawable.anniu01,string2));
158                         }
159                         else if (string1.equals(b))
160                         {
161                             liv.add(new MyClass(R.drawable.anniu02,string2));
162                         }
163                         else if (string1.equals(c))
164                         {
165                             liv.add(new MyClass(R.drawable.anniu04,string2));
166                         }
167                         else if (string1.equals(d))
168                         {
169                             liv.add(new MyClass(R.drawable.anniu05,string2));
170                         }
171                         else
172                         {
173                             Toast.makeText(PractiseActivity7.this, "请从a,b,c,d中选择",
174                                     Toast.LENGTH_SHORT).show();
175                         }
176                         imageAdapter.notifyDataSetChanged();
177                     }
178                 })
179                 .setView(view)
180                 .show();
181     }
182     class MyClass
183     {
184         private int img;
185         private String content;
186 
187         public int getImg() {
188             return img;
189         }
190 
191         public void setImg(int img) {
192             this.img = img;
193         }
194 
195         public String getContent() {
196             return content;
197         }
198 
199         public void setContent(String content) {
200             this.content = content;
201         }
202         public MyClass(int img,String content)
203         {
204             this.img = img;
205             this.content = content;
206         }
207     }
208     //适配器
209     class ImageAdapter extends BaseAdapter
210     {
211         @Override
212         public int getCount() {
213             return liv.size();
214         }
215 
216         @Override
217         public Object getItem(int position) {
218             return liv.get(position);
219         }
220 
221         @Override
222         public long getItemId(int position) {
223             return 0;
224         }
225 
226         @Override
227         public View getView(int position, View convertView, ViewGroup parent) {
228             //1.得到数据 图片的id
229             MyClass myClass = liv.get(position);
230             //2.准备View
231             if (convertView ==null) {
232                 convertView = View.inflate(PractiseActivity7.this, R.layout.gridview_layout, null);
233             }
234             //3.适配
235             //转换
236             ImageView imageView = (ImageView)convertView.findViewById(R.id.iv_3);
237             imageView.setImageResource(myClass.getImg());
238 
239             TextView textView = (TextView)convertView.findViewById(R.id.tv_3);
240             textView.setText(myClass.getContent());
241             return convertView;
242         }
243     }
244 
245 }