package helloworld.dongnaoedu.com.imoocsqlitedemo;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
import android.os.Environment;
import android.support.annotation.IdRes;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.RadioGroup;
import android.widget.SimpleCursorAdapter;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
private EditText nameEdt,ageEdt,idEdt;
private RadioGroup genderGp;
private String genderStr = "男";
private SQLiteDatabase db;
private ListView stuList;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//添加操作
//参数：环境上下文;数据库名称(如果只有一个数据库名称，那么这个数据库的位置会是在私有目录data中);
// 游标工厂，通过什么游标去操作数据，传null给我一个默认选择；版本号
//如果带SD卡路径，那么数据库位置则在指定的路径下
//~
String path = Environment.getExternalStorageDirectory() + "/stu.db";
SQLiteOpenHelper helper = new SQLiteOpenHelper(this,path,null,1) {
@Override
public void onCreate(SQLiteDatabase db) {
//创建
Toast.makeText(MainActivity.this,"数据库创建",Toast.LENGTH_SHORT).show();
//如果数据库不存在，则会调用onCreate方法，那么我们可以将表的创建工作放在这里完成
String sql = "create table info_db (_id integer primary key autoincrement," +
"name varchar(20)," +
"age integer," +
"gender varhcar(4))";
db.execSQL(sql);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
//升级
Toast.makeText(MainActivity.this,"数据库升级",Toast.LENGTH_SHORT).show();
}
};
//1、数据库存在则直接打开数据库；（所谓的打开指的是获得数据库对象）
//2、数据库不存在则创建再打开，
//3、数据库存在但版本号升高，则调用升级方法。
db = helper.getReadableDatabase();//用于获取数据库对象
nameEdt = (EditText) findViewById(R.id.name_edt);
ageEdt = (EditText) findViewById(R.id.age_edt);
idEdt = (EditText) findViewById(R.id.id_edt);
genderGp = (RadioGroup) findViewById(R.id.gender_gp);
genderGp.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(RadioGroup group, @IdRes int checkedId) {
if(checkedId == R.id.male) {genderStr = "男";}
else{ genderStr = "女";}
}
});
stuList = (ListView) findViewById(R.id.stu_list);
}
public void operate(View v){
String nameStr = nameEdt.getText().toString();
String ageStr = ageEdt.getText().toString();
String idStr = idEdt.getText().toString();
switch (v.getId()){
case R.id.insert_btn:
//db.rawQuery(); 查询 select * from 表名
//db.execSQL(); 添加，删除，修改，查找
//String sql = "insert into info_db(name,age,gender) values('张',12,'男')";
String sql = "insert into info_db (name,age,gender) values(?,?,?)";
db.execSQL(sql,new String[]{nameStr,ageStr,genderStr});
break;
case R.id.select_btn:
// db.rawQuery(sql)
//select * from 表名 where _id = ?
String sql2 = "select * from info_db";
if(!idStr.equals("")){
sql2 += " where _id=" + idStr;
}
//查询结果
Cursor c = db.rawQuery(sql2,null);
//SimpleCursorAdapter
//SimpleAdapter a = new SimpleAdapter
//参数3：数据源;4、表头，即键值对；5、要填充的位置;6、通知将变化的数据反映到页面上
//数据源要有下划线
SimpleCursorAdapter adapter = new SimpleCursorAdapter(this,R.layout.item,
c,new String[]{"_id","name","age","gender"},
new int[]{R.id.id_item,R.id.name_item,R.id.age_item,R.id.gender_item});
stuList.setAdapter(adapter);
break;
case R.id.delete_btn:
Log.d("MainActivity", "删除 ");
String sql3 = "delete from info_tb where _id="+idStr+"";
db.execSQL(sql3);
break;
case R.id.update_btn:
Log.d("MainActivity", "更新 ");
String sql4 = "update info_tb set name=?,age=?,gender=? where _id=?";
db.execSQL(sql4,new String[]{nameStr,ageStr,genderStr,idStr});
break;
}
}
}曾经的曾经去哪了
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