android-7 _Android

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增删改查

< ?xml version="1.0" encoding="utf-8"?> < LinearLayout android:padding="16dp" android:orientation="vertical" android:background="@drawable/bg" android:layout_height="match_parent" android:layout_width="match_parent" xmlns:android="http://schemas.android.com/apk/res/android"> < LinearLayout android:layout_height="wrap_content" android:layout_width="match_parent" android:layout_marginTop="130dp"> < TextView android:layout_height="wrap_content" android:layout_width="wrap_content" android:textSize="18sp" android:text="姓名："/> < EditText android:layout_height="wrap_content" android:layout_width="match_parent" android:textSize="16sp" android:hint="请输入姓名" android:id="@+id/et_name"/> < /LinearLayout> -< LinearLayout android:layout_height="wrap_content" android:layout_width="match_parent" android:layout_marginBottom="10dp"> < TextView android:layout_height="wrap_content" android:layout_width="wrap_content" android:textSize="18sp" android:text="年龄："/> < EditText android:layout_height="wrap_content" android:layout_width="match_parent" android:textSize="16sp" android:hint="输入年龄" android:id="@+id/et_age"/> < /LinearLayout> -< LinearLayout android:layout_height="wrap_content" android:layout_width="match_parent"> < Button android:background="#B9B9FF" android:layout_height="wrap_content" android:layout_width="0dp" android:textSize="18sp" android:text="添加" android:id="@+id/btn_add" android:onClick="add" android:layout_weight="1" android:layout_marginRight="2dp"/> < Button android:background="#DCB5FF" android:layout_height="wrap_content" android:layout_width="0dp" android:textSize="18sp" android:text="查询" android:id="@+id/btn_query" android:onClick="search" android:layout_weight="1" android:layout_marginRight="2dp"/> < Button android:background="#E6CAFF" android:layout_height="wrap_content" android:layout_width="0dp" android:textSize="18sp" android:text="修改" android:id="@+id/btn_update" android:onClick="update" android:layout_weight="1" android:layout_marginRight="2dp"/> < Button android:background="#ACD6FF" android:layout_height="wrap_content" android:layout_width="0dp" android:textSize="18sp" android:text="删除" android:id="@+id/btn_delete" android:onClick="delete" android:layout_weight="1"/> < /LinearLayout> -< ScrollView android:layout_height="wrap_content" android:layout_width="match_parent"> < TextView android:layout_height="wrap_content" android:layout_width="match_parent" android:layout_marginTop="25dp" android:textSize="20sp" android:id="@+id/tv_show"/> < /ScrollView> < /LinearLayout>

package com.example.android; import android.annotation.SuppressLint; import android.os.Bundle; import android.app.Activity; import android.content.ContentValues; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.view.Menu; import android.view.View; import android.widget.EditText; import android.widget.TextView; import android.widget.Toast; public class MainActivity extends Activity {@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); }@SuppressLint("WrongConstant") public void add(View v) { StuOpenHelper helper = new StuOpenHelper(this); SQLiteDatabase db = helper.getWritableDatabase(); String name = ((EditText) findViewById(R.id.et_name)).getText() .toString(); int age = Integer.parseInt(((EditText) findViewById(R.id.et_age)) .getText().toString()); // 原生sql操作, // db.execSQL("insert into stuinfo (name,age) values(‘lisi‘,22)"); // db.execSQL("insert into stuinfo (name,age) values(?,?)",new // Object[]{"kitty",30}); db.execSQL("insert into stuinfo (name,age) values(?,?)", new Object[] { name, age }); Toast.makeText(this, "ok", 0).show(); }public void delete(View view) { StuOpenHelper helper = new StuOpenHelper(this); SQLiteDatabase db = helper.getWritableDatabase(); db.execSQL("delete from stuinfo where _id=?", new Object[] { 2 }); Toast.makeText(this, "删除成功", 0).show(); }@SuppressLint("WrongConstant") public void update(View view) { StuOpenHelper helper = new StuOpenHelper(this); SQLiteDatabase db = helper.getWritableDatabase(); db.execSQL("update stuinfo set name=? where _id=?", new Object[] { "micky", 3 }); Toast.makeText(this, "修改成功", 0).show(); }public void search(View view) { StuOpenHelper helper = new StuOpenHelper(this); SQLiteDatabase db = helper.getWritableDatabase(); String s = ""; Cursor cursor = db.rawQuery("select * from stuinfo", null); if (cursor.getCount() != 0) {while (cursor.moveToNext()) { s += cursor.getInt(0) + "" + cursor.getString(1) + "" + cursor.getInt(2) + " "; } }// Toast.makeText(this, s, 0).show(); ((TextView) (findViewById(R.id.tv_show))).setText(s); }}

package com.example.android; import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteDatabase.CursorFactory; import android.database.sqlite.SQLiteOpenHelper; public class StuOpenHelper extends SQLiteOpenHelper {public StuOpenHelper(Context context) { super(context, "stu.db", null, 1); // TODO Auto-generated constructor stub }@Override public void onCreate(SQLiteDatabase db) { // TODO Auto-generated method stub db.execSQL("create table stuinfo(_id integer primary key autoincrement,name varchar(20),age integer)"); }@Override public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) { // TODO Auto-generated method stub}}