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Android-实现增加数据进入数据库

继续写简单增删改查，终于可以实现插入数据进入数据库了

主要代码差不多了，现在主要是需要解决一个显示数据的问题，这个问题之后接着写。

初步效果

 

 然后我们用可视化应用打开curd.db , 可以看见数据插进去了哈

部分代码

Student.java

 1 package com.example.myapplication;
 2 
 3 public class Student {
 4 
 5     public static final String TABLE= "Student1";
 6 
 7     public static final String KEY_KEYS = "keys";
 8     public static final String KEY_NAME="name";
 9     public static final String KEY_ID = "id";
10     public static final String KEY_GRADE = "grade";
11 
12     public int student_keys;
13     public String student_name;
14     public String student_id;
15     public String student_grade;
16 
17 }

MainActivty.java

 1 package com.example.myapplication;
 2 
 3 import androidx.appcompat.app.AppCompatActivity;
 4 import androidx.recyclerview.widget.ListAdapter;
 5 
 6 import android.app.ListActivity;
 7 import android.content.Intent;
 8 import android.os.Bundle;
 9 import android.view.View;
10 import android.widget.AdapterView;
11 import android.widget.Button;
12 import android.widget.ListView;
13 import android.widget.SimpleAdapter;
14 import android.widget.TextView;
15 import android.widget.Toast;
16 
17 import java.util.ArrayList;
18 import java.util.HashMap;
19 
20 public class MainActivity extends ListActivity implements View.OnClickListener {
21 
22     private Button btn_add,btn_get;
23     private TextView student_keys;
24 
25     public void onCreate(Bundle saveInstanceState) {
26         super.onCreate(saveInstanceState);
27         setContentView(R.layout.activity_main);
28 
29         btn_add = (Button) findViewById(R.id.btn_add);
30         btn_add.setOnClickListener(this);
31 
32         btn_get = (Button) findViewById(R.id.btn_get);
33         btn_get.setOnClickListener(this);
34     }
35     @Override
36     public void onClick(View v) {
37         if(v == findViewById(R.id.btn_add)){
38 
39             Intent intent = new Intent(this,StudentDetail.class);
40             intent.putExtra("student_keys",0);
41             startActivity(intent);
42 
43         }
44     }
45 }

DBHelper.java

 1 package com.example.myapplication;
 2 
 3 import android.content.Context;
 4 import android.database.sqlite.SQLiteDatabase;
 5 import android.database.sqlite.SQLiteOpenHelper;
 6 
 7 import androidx.annotation.Nullable;
 8 
 9 public class DBHelper extends SQLiteOpenHelper {
10 
11     private static final int DATABASE_VERSION=4;
12 
13     private static final String DATABASE_NAME="crud.db";
14 
15     public DBHelper(Context context) {
16         super(context,DATABASE_NAME,null,DATABASE_VERSION);
17     }
18 
19     @Override
20     public void onCreate(SQLiteDatabase db) {
21         String CREATE_TABLE_STUDENT="CREATE TABLE "+ Student.TABLE+"("
22                 +Student.KEY_KEYS+" INTEGER PRIMARY KEY AUTOINCREMENT ,"
23                 +Student.KEY_NAME+" TEXT ,"
24                 +Student.KEY_ID+" TEXT ,"
25                 +Student.KEY_GRADE+" TEXT)";
26         db.execSQL(CREATE_TABLE_STUDENT);
27 
28     }
29 
30     @Override
31     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
32 
33         db.execSQL("DROP TABLE IF EXISTS "+ Student.TABLE);
34 
35         onCreate(db);
36     }
37 }
StudentDetail.java
 1 package com.example.myapplication;
 2 
 3 import android.app.Activity;
 4 import android.content.Intent;
 5 import android.os.Bundle;
 6 import android.view.Menu;
 7 import android.view.View;
 8 import android.widget.Button;
 9 import android.widget.EditText;
10 import android.widget.Toast;
11 import android.widget.Toolbar;
12 
13 import androidx.appcompat.app.ActionBar;
14 
15 
16 public class StudentDetail extends Activity implements View.OnClickListener {
17 
18     private Button btn_save,btn_delete;
19     private Button btn_close;
20 
21     private EditText et_name;
22     private EditText et_id;
23     private EditText et_grade;
24     private int _student_keys = 0;
25 
26     protected void onCreate(Bundle saveInstanceState) {
27         super.onCreate(saveInstanceState);
28         setContentView(R.layout.activity_student);
29 
30         btn_save = (Button) findViewById(R.id.btn_save);
31         btn_delete = (Button) findViewById(R.id.btn_delete);
32         btn_close = (Button) findViewById(R.id.btn_close);
33 
34         et_name = (EditText) findViewById(R.id.et_name);
35         et_id = (EditText) findViewById(R.id.et_id);
36         et_grade =(EditText) findViewById(R.id.et_grade);
37 
38         btn_save.setOnClickListener(this);
39         btn_delete.setOnClickListener(this);
40         btn_close.setOnClickListener(this);
41 
42         _student_keys = 0;
43         Intent intent = getIntent();
44         _student_keys = intent.getIntExtra("student_keys",0);
45         StudentRepo repo = new StudentRepo(this);
46         Student student = new Student();
47         student = repo.getStudentByKeys(_student_keys);
48 
49         et_name.setText(student.student_name);
50         et_id.setText(student.student_id);
51         et_grade.setText(student.student_grade);
52 
53     }
54 
55     public void onClick(View v){
56         if(v== findViewById(R.id.btn_save)){
57             StudentRepo repo = new StudentRepo(this);
58             Student student = new Student();
59             student.student_name = et_name.getText().toString();
60             student.student_id = et_name.getText().toString();
61             student.student_grade = et_grade.getText().toString();
62             student.student_keys = _student_keys;
63 
64             if(_student_keys==0){
65                 _student_keys= repo.insert(student);
66                 Toast.makeText(this,"插入成功",Toast.LENGTH_SHORT).show();
67             }70 71         }   else if (v == findViewById(R.id.btn_close)) {
72             finish();
73         }
74     }
75 
76 }
StudentRepo.java
  1 package com.example.myapplication;
  2 
  3 import android.annotation.SuppressLint;
  4 import android.content.ContentValues;
  5 import android.content.Context;
  6 import android.database.Cursor;
  7 import android.database.sqlite.SQLiteDatabase;
  8 
  9 import java.util.ArrayList;
 10 import java.util.HashMap;
 11 
 12 public class StudentRepo {
 13 
 14     private DBHelper dbHelper;
 15 
 16     public StudentRepo(Context context){
 17         dbHelper = new DBHelper(context);
 18     }
 19 
 20     public int insert(Student student){
 21 
 22         SQLiteDatabase db = dbHelper.getWritableDatabase();
 23         ContentValues values = new ContentValues();
 24 
 25         values.put(Student.KEY_NAME,student.student_name);
 26         values.put(Student.KEY_ID,student.student_id);
 27         values.put(Student.KEY_GRADE,student.student_grade);
 28 
 29         long student_keys = db.insert(Student.TABLE,null,values);
 30         db.close();
 31         return (int)student_keys;
 32     }
 33     public void delete(int student_keys){
 34 
 35         SQLiteDatabase db = dbHelper.getWritableDatabase();
 36         db.delete(Student.TABLE,Student.KEY_KEYS+"=?",new String[]{String.valueOf(student_keys)});
 37         db.close();
 38     }
 39     public void update(Student student){
 40         SQLiteDatabase db = dbHelper.getWritableDatabase();
 41         ContentValues values = new ContentValues();
 42 
 43         values.put(Student.KEY_NAME,student.student_name);
 44         values.put(Student.KEY_ID,student.student_id);
 45         values.put(Student.KEY_GRADE,student.student_grade);
 46 
 47         db.update(Student.TABLE,values,Student.KEY_KEYS+"=?",new String[]{String.valueOf(student.student_keys)});
 48         db.close();
 49     }
 50     @SuppressLint("Range")
 51     public ArrayList<HashMap<String,String>> getStudentList(){
 52         SQLiteDatabase db = dbHelper.getReadableDatabase();
 53         String selectQuery = "SELECT "+
 54                 Student.KEY_KEYS+","+
 55                 Student.KEY_NAME+","+
 56                 Student.KEY_ID+","+
 57                 Student.KEY_GRADE+" FROM "+Student.TABLE;
 58         ArrayList<HashMap<String,String>> studentList = new ArrayList<HashMap<String,String>>();
 59         Cursor cursor = db.rawQuery(selectQuery,null);
 60 
 61         if (cursor.moveToFirst()){
 62             do{
 63                 HashMap<String,String> student = new HashMap<String,String>();
 64                 student.put("name",cursor.getString(cursor.getColumnIndex(Student.KEY_NAME)));
 65                 student.put("id",cursor.getString(cursor.getColumnIndex(Student.KEY_ID)));
 66                 student.put("grade",cursor.getString(cursor.getColumnIndex(Student.KEY_GRADE)));
 67                 studentList.add(student);
 68             }while (cursor.moveToNext());
 69         }
 70         cursor.close();
 71         db.close();
 72         return studentList;
 73     }
 74     @SuppressLint("Range")
 75     public Student getStudentByKeys(int keys){
 76         SQLiteDatabase db = dbHelper.getReadableDatabase();
 77         String selectQuery = "SELECT "+
 78                 Student.KEY_KEYS +","+
 79                 Student.KEY_NAME +","+
 80                 Student.KEY_ID + ","+
 81                 Student.KEY_GRADE+
 82                 " FROM " + Student.TABLE
 83                 +" WHERE " +
 84                 Student.KEY_KEYS + "=?";
 85         int count = 0;
 86         Student student = new Student();
 87         Cursor cursor = db.rawQuery(selectQuery,new String[]{String.valueOf(keys)});
 88         if (cursor.moveToFirst()){
 89             do {
 90                 student.student_keys = cursor.getInt(cursor.getColumnIndex(Student.KEY_KEYS));
 91                 student.student_name = cursor.getString(cursor.getColumnIndex(Student.KEY_NAME));
 92                 student.student_id = cursor.getString(cursor.getColumnIndex(Student.KEY_ID));
 93                 student.student_grade = cursor.getString(cursor.getColumnIndex(Student.KEY_GRADE));
 94             }while (cursor.moveToNext());
 95         }
 96         cursor.close();
 97         db.close();
 98         return student;
 99     }
100 }

 

posted @ 2023-02-25 18:23  冰稀饭Aurora  阅读(72)  评论(0)  编辑  收藏  举报