标签:SQLite 半期 name editText age db null 考试 String
半期考试 之 SQLite 操作2
要求:
- 两个输入框,要求输入姓名和年龄;
- 下方四个按钮,分别表示增加,删除,更新,回滚;
- 添加或者删除后,下方的listview数据动态改变;
xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<EditText
android:id="@+id/editText_name"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:ems="10"
android:hint="Input name?"
android:inputType="textPersonName"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<EditText
android:id="@+id/editText_age"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginTop="11dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:ems="10"
android:hint="Input age?"
android:inputType="number"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/editText_name" />
<Button
android:id="@+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="44dp"
android:layout_marginEnd="10dp"
android:layout_marginRight="10dp"
android:onClick="add"
android:text="Add"
app:layout_constraintEnd_toStartOf="@+id/button2"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="@+id/editText_age"
tools:ignore="OnClick" />
<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="6dp"
android:layout_marginRight="6dp"
android:onClick="delete"
android:text="Delete"
app:layout_constraintBottom_toTopOf="@+id/listView"
app:layout_constraintEnd_toStartOf="@+id/button3"
app:layout_constraintStart_toEndOf="@+id/button"
tools:ignore="OnClick" />
<Button
android:id="@+id/button3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="2dp"
android:layout_marginRight="2dp"
android:onClick="update"
android:text="Update"
app:layout_constraintBottom_toTopOf="@+id/listView"
app:layout_constraintEnd_toStartOf="@+id/button4"
app:layout_constraintStart_toEndOf="@+id/button2"
tools:ignore="OnClick" />
<Button
android:id="@+id/button4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="1dp"
android:layout_marginRight="1dp"
android:onClick="retrieve"
android:text="Retrieve"
app:layout_constraintBottom_toTopOf="@+id/listView"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toEndOf="@+id/button3"
tools:ignore="OnClick" />
<ListView
android:id="@+id/listView"
android:layout_width="0dp"
android:layout_height="0dp"
android:layout_marginStart="8dp"
android:layout_marginLeft="8dp"
android:layout_marginEnd="8dp"
android:layout_marginRight="8dp"
android:layout_marginBottom="8dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/button" />
</androidx.constraintlayout.widget.ConstraintLayout>
java
public class MainActivity extends AppCompatActivity {
MySqlHelper mySQLHelper;
SQLiteDatabase db;
EditText editText_name, editText_age;
ListView listView;
SimpleCursorAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
editText_name = findViewById(R.id.editText_name);
editText_age = findViewById(R.id.editText_age);
listView = findViewById(R.id.listView);
mySQLHelper = new MySqlHelper(this, "db", null, 1);
db = mySQLHelper.getWritableDatabase();
Cursor cursor = db.query(MySqlHelper.PersonTable, null, null, null, null, null, null, null);
adapter = new SimpleCursorAdapter(this, android.R.layout.simple_list_item_2, cursor, new String[]{"name", "age"}, new int[]{android.R.id.text1, android.R.id.text2}, CursorAdapter.FLAG_REGISTER_CONTENT_OBSERVER);
listView.setAdapter(adapter);
}
public void add(View view) {
String name = editText_name.getText().toString();
String age = editText_age.getText().toString();
// db.execSQL("insert into person(name,age) values('"+name+"','"+age+"')");
ContentValues contentValues = new ContentValues();
contentValues.put("name", name);
contentValues.put("age", age);
db.insert(MySqlHelper.PersonTable, null, contentValues);
reload();
}
public void delete(View view) {
String name = editText_name.getText().toString();
db.delete(MySqlHelper.PersonTable, "name=?", new String[]{name});
reload();
}
public void update(View view) {
String name = editText_name.getText().toString();
String age = editText_age.getText().toString();
ContentValues contentValues = new ContentValues();
contentValues.put("name", name);
contentValues.put("age", age);
db.update(MySqlHelper.PersonTable, contentValues, "name=?", new String[]{name});
reload();
}
public void retrieve(View view) {
String name = editText_name.getText().toString();
new MyAsyncTask().execute("%" + name + "%");
// Cursor cursor=db.query(MySQLHelper.PersonTable,null,"name like *",new String[]{name},null,null,null,null);
// adapter.swapCursor(cursor);
}
private void reload() {
Cursor cursor = db.query(MySqlHelper.PersonTable, null, null, null, null, null, null, null);
adapter.swapCursor(cursor);
}
class MyAsyncTask extends AsyncTask<String, Nullable, Cursor> {
@Override
protected Cursor doInBackground(String... strings) {
Cursor cursor = db.query(MySqlHelper.PersonTable, null, "name like ?", new String[]{"%" + strings[0] + "%"}, null, null, null, null);
return cursor;
}
@Override
protected void onPostExecute(Cursor cursor) {
super.onPostExecute(cursor);
adapter.swapCursor(cursor);
}
}
}
数据库操作类
public class MySqlHelper extends SQLiteOpenHelper {
public static final String PersonTable = "person";
public MySqlHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
super(context, name, factory, version);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("create table if not exists person(_id integer primary key autoincrement,name text,age integer)");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
标签:SQLite,半期,name,editText,age,db,null,考试,String 来源: https://blog.csdn.net/twenty_four_7/article/details/122043127
本站声明: 1. iCode9 技术分享网(下文简称本站)提供的所有内容,仅供技术学习、探讨和分享; 2. 关于本站的所有留言、评论、转载及引用,纯属内容发起人的个人观点,与本站观点和立场无关; 3. 关于本站的所有言论和文字,纯属内容发起人的个人观点,与本站观点和立场无关; 4. 本站文章均是网友提供,不完全保证技术分享内容的完整性、准确性、时效性、风险性和版权归属;如您发现该文章侵犯了您的权益,可联系我们第一时间进行删除; 5. 本站为非盈利性的个人网站,所有内容不会用来进行牟利,也不会利用任何形式的广告来间接获益,纯粹是为了广大技术爱好者提供技术内容和技术思想的分享性交流网站。