Android 简单数据库操作(Java部分)

我会带着你远行 2022-05-09 15:54 214阅读 0赞

**Android中操作SQLite数据库，Demo已经上传，只列出了MainActivity部分，导入时注意id**

import android.content.ContentValues;
    import android.database.Cursor;
    import android.database.sqlite.SQLiteDatabase;
    import android.support.v7.app.AppCompatActivity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    import android.widget.EditText;
    import android.widget.TextView;
    import android.widget.Toast;
    
    public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    
        public MyHelper myHelper;
        private EditText mEtName, mEtPhone;
        private TextView mTvShow;
        private Button btnAdd, btnQuery, btnUpdate, btnDelete;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            myHelper = new MyHelper(this);
            init();
        }
    
        private void init() {
            mEtName = (EditText) findViewById(R.id.et_name);
            mEtPhone = (EditText) findViewById(R.id.et_pass);
            mTvShow = (TextView) findViewById(R.id.tv_show);
            btnAdd = (Button) findViewById(R.id.btn_add);
            btnDelete = (Button) findViewById(R.id.btn_delete);
            btnQuery = (Button) findViewById(R.id.btn_query);
            btnUpdate = (Button) findViewById(R.id.btn_update);
            btnAdd.setOnClickListener(this);
            btnUpdate.setOnClickListener(this);
            btnQuery.setOnClickListener(this);
            btnDelete.setOnClickListener(this);
        }
    
        @Override
        public void onClick(View v) {
            String name, phone;
            SQLiteDatabase db;
            ContentValues values;
            switch (v.getId()) {
                case R.id.btn_add:
                    name = mEtName.getText().toString();
                    phone = mEtPhone.getText().toString();
                    db = myHelper.getReadableDatabase();//获取可读写的SQLiteDatabase对象
    
                    values = new ContentValues();
                    values.put("name", name);
                    values.put("phone", phone);
                    db.insert("information", null, values);
                    Toast.makeText(this, "信息添加成功", Toast.LENGTH_SHORT).show();
                    db.close();
                    break;
                case R.id.btn_query:
                    db = myHelper.getReadableDatabase();
                    Cursor cursor = db.query("information", null, null, null, null, null, null);
                    if (cursor.getCount() == 0) {
                        mTvShow.setText(" ");
                        Toast.makeText(this, "没有数据", Toast.LENGTH_SHORT).show();
                    } else {
                        cursor.moveToFirst();
                        mTvShow.setText("Name :" + cursor.getString(1) + "; Tel :" + cursor.getString(2));
                    }
                    while (cursor.moveToNext()) {
                        mTvShow.append("\n" + "Name:" + cursor.getString(1) + "; Tel:" + cursor.getString(2));
                    }
                    cursor.close();
                    db.close();
                    break;
                case R.id.btn_update:
                    db = myHelper.getReadableDatabase();
                    values = new ContentValues();
                    values.put("phone", phone = mEtPhone.getText().toString());
                    db.update("information", values, "name?", new String[]{mEtName.getText().toString()});
                    Toast.makeText(this, "信息已修改", Toast.LENGTH_SHORT).show();
                    db.close();
                    break;
                case R.id.btn_delete:
                    db = myHelper.getReadableDatabase();
                    db.delete("information", null, null);
                    Toast.makeText(this, "信息已删除", Toast.LENGTH_SHORT).show();
                    mTvShow.setText(" ");
                    db.close();
                    break;
            }
        }
    }