android studio中ListView与SQLite的结合使用

灰太狼 2022-03-29 15:18 218阅读 0赞

Da.java

public class Db extends SQLiteOpenHelper {
        public Db(Context context) {
            super(context, "db", null, 1);
        }
    
        @Override
        public void onCreate(SQLiteDatabase db) {
            db.execSQL("CREATE TABLE user2(" +
                    "_id INT DEFAULT 0," +
                    "name TEXT DEFAULT \"\"," +
                    "sex TEXT DEFAULT \"\")");
        }
    
        @Override
        public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
    
        }
    }

MainActivity.java

public class MainActivity extends AppCompatActivity {
        private SimpleCursorAdapter mAdapter;
        private ListView listView;
    
        private Button btn_add;
        private Button btn_delete;
    
        private Button btn_back;
        private EditText et_id;
        private EditText et_name;
        private EditText et_sex;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
    
            btn_add = (Button) findViewById(R.id.btn_add);
            btn_delete = (Button) findViewById(R.id.btn_delete);
            listView = (ListView) findViewById(R.id.list);
    
            btn_add.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    addData();
                    refleshListView();
                }
            });
    
            btn_delete.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    deleteData();
                    refleshListView();
                }
            });
    
            listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
                @Override
                public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
    //                Toast.makeText(MainActivity.this,""+position,Toast.LENGTH_SHORT).show();
                    int positions = position + 1;
                    Db db = new Db(MainActivity.this);
                    SQLiteDatabase dbWrite = db.getWritableDatabase();
                    dbWrite.delete("user2","_id=?",new String[]{""+positions});
                    dbWrite.close();
                    refleshListView();
                }
            });
        }
    
        public void addData() {
            btn_back = (Button) findViewById(R.id.btn_back);
            et_id = (EditText) findViewById(R.id.et_id);
            et_name = (EditText) findViewById(R.id.et_name);
            et_sex = (EditText) findViewById(R.id.et_sex);
    
            btn_add = (Button) findViewById(R.id.btn_add);
            btn_delete = (Button) findViewById(R.id.btn_delete);
            listView = (ListView) findViewById(R.id.list);
    
            btn_add.setVisibility(View.GONE);
            btn_delete.setVisibility(View.GONE);
            listView.setVisibility(View.GONE);
    
            btn_back.setVisibility(View.VISIBLE);
            et_id.setVisibility(View.VISIBLE);
            et_name.setVisibility(View.VISIBLE);
            et_sex.setVisibility(View.VISIBLE);
    
            btn_back.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    btn_add.setVisibility(View.VISIBLE);
                    btn_delete.setVisibility(View.VISIBLE);
                    listView.setVisibility(View.VISIBLE);
    
                    btn_back.setVisibility(View.GONE);
                    et_id.setVisibility(View.GONE);
                    et_name.setVisibility(View.GONE);
                    et_sex.setVisibility(View.GONE);
    
                    String id = et_id.getText().toString(),
                            name =et_name.getText().toString(),
                            sex = et_sex.getText().toString();
    
    
                    Db db = new Db(MainActivity.this);
                    SQLiteDatabase dbWrite = db.getWritableDatabase();
    
                    ContentValues cv = new ContentValues();
                    cv.put("_id", id);
                    cv.put("name", name);
                    cv.put("sex", sex);
                    dbWrite.insert("user2", null, cv);
    
                    dbWrite.close();
    
                    refleshListView();
                }
            });
    
    //        String id = et_id.getText().toString(),
    //               name =et_name.getText().toString(),
    //               sex = et_sex.getText().toString();
    //
    //
    //        Db db = new Db(MainActivity.this);
    //        SQLiteDatabase dbWrite = db.getWritableDatabase();
    //
    //        ContentValues cv = new ContentValues();
    //        cv.put("_id",id);
    //        cv.put("name", name);
    //        cv.put("sex", sex);
    //        dbWrite.insert("user2", null, cv);
    //
    //        dbWrite.close();
        }
    
        public void deleteData() {
            Db db = new Db(MainActivity.this);
            SQLiteDatabase dbWrite = db.getWritableDatabase();
            dbWrite.delete("user2",null,new String[]{});
            dbWrite.close();
        }
    
        public void refleshListView() {
            Db db = new Db(MainActivity.this);
            SQLiteDatabase dbRead = db.getReadableDatabase();
            Cursor c = dbRead.query("user2", null, null, null, null, null, null);
    
            mAdapter = new SimpleCursorAdapter(MainActivity.this, R.layout.user_info, c,
                    new String[]{"_id","name","sex"}, new int[]{R.id._id,R.id._name,R.id._sex});
    
            listView.setAdapter(mAdapter);
    
            dbRead.close();
        }
    
    }

user_info.xml

activity_main.xml