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package tw.com.flag.ch15_hellosqlite;
 
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
 
import android.widget.TextView;
 
public class MainActivity extends AppCompatActivity {
 
    static final String db_name = "testDB";  //資料庫名稱
    static final String tb_name = "test";    //資料表名稱
    SQLiteDatabase db;  //資料庫物件
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
 
        //開啟或建立資料庫
        db = openOrCreateDatabase(db_name, Context.MODE_PRIVATE, null);
 
        String create = "CREATE TABLE IF NOT EXISTS" +
                            tb_name +   //資料表名稱
                            "(name VARCHAR(32)," +  //姓名欄位
                            "phone VARCHAR(16)," +  //電話欄位
                            "email VARCHAR(64))";   //email欄位
 
        db.execSQL(create);   //建立資料表
 
        Cursor c = db.rawQuery("SELECT * FROM " + tb_name, null);//查詢tb_name資料表中的所有資料
 
        if (c.getCount() == 0) { //若無資料,則立即新增2筆資料
            addData("Flag Publishing Co.", "02-23962357", "service@flag.com.tw");
 
            addData("PCDIY Magazine", "02-23214335", "service@pcdiy.com.tw");
 
            c = db.rawQuery("SELECT * FROM" + tb_name, null);//重新查詢
        }
 
        if (c.moveToFirst()) { //移到第1筆資料(若有資料才繼續)
 
            String str = "總共有" + c.getCount() + "筆資料\n";
            str += "----\n";
 
 
            do { //逐筆讀出資料, 並串接成訊息字串
                str += "name:" + c.getString(0) + "\n";
                str += "phone:" + c.getString(1) + "\n";
                str += "email:" + c.getString(2) + "\n";
                str += "----\n";
            } while (c.moveToNext());//有下一筆資料迴圈就繼續
 
            TextView txv = (TextView) findViewById(R.id.txv);
            txv.setText(str);//顯示訊息字串
        }
 
        db.close();
    }
 
    private void addData(String name, String phone, String email) {
 
        ContentValues cv = new ContentValues(3);//建立含3個資料項目的物件
        cv.put("name", name);
        cv.put("phone", phone);
        cv.put("email",email);
 
        db.insert(tb_name, null, cv);//把資料加到資料表
    }
 
}
 

Main.java:12: error: class MainActivity is public, should be declared in a file named MainActivity.java
public class MainActivity extends AppCompatActivity {
       ^
Main.java:3: error: package android.content does not exist
import android.content.ContentValues;
                      ^
Main.java:4: error: package android.content does not exist
import android.content.Context;
                      ^
Main.java:5: error: package android.database does not exist
import android.database.Cursor;
                       ^
Main.java:6: error: package android.database.sqlite does not exist
import android.database.sqlite.SQLiteDatabase;
                              ^
Main.java:7: error: package android.os does not exist
import android.os.Bundle;
                 ^
Main.java:8: error: package android.support.v7.app does not exist
import android.support.v7.app.AppCompatActivity;
                             ^
Main.java:10: error: package android.widget does not exist
import android.widget.TextView;
                     ^
Main.java:12: error: cannot find symbol
public class MainActivity extends AppCompatActivity {
                                  ^
  symbol: class AppCompatActivity
Main.java:16: error: cannot find symbol
    SQLiteDatabase db;  //?????
    ^
  symbol:   class SQLiteDatabase
  location: class MainActivity
Main.java:19: error: cannot find symbol
    protected void onCreate(Bundle savedInstanceState) {
                            ^
  symbol:   class Bundle
  location: class MainActivity
Main.java:18: error: method does not override or implement a method from a supertype
    @Override
    ^
Main.java:20: error: cannot find symbol
        super.onCreate(savedInstanceState);
        ^
  symbol:   variable super
  location: class MainActivity
Main.java:21: error: package R does not exist
        setContentView(R.layout.activity_main);
                        ^
Main.java:25: error: cannot find symbol
        db = openOrCreateDatabase(db_name, Context.MODE_PRIVATE, null);
                                           ^
  symbol:   variable Context
  location: class MainActivity
Main.java:35: error: cannot find symbol
        Cursor c = db.rawQuery("SELECT * FROM " + tb_name, null);//??tb_name?????????
        ^
  symbol:   class Cursor
  location: class MainActivity
Main.java:58: error: cannot find symbol
            TextView txv = (TextView) findViewById(R.id.txv);
            ^
  symbol:   class TextView
  location: class MainActivity
Main.java:58: error: cannot find symbol
            TextView txv = (TextView) findViewById(R.id.txv);
                            ^
  symbol:   class TextView
  location: class MainActivity
Main.java:58: error: package R does not exist
            TextView txv = (TextView) findViewById(R.id.txv);
                                                    ^
Main.java:67: error: cannot find symbol
        ContentValues cv = new ContentValues(3);//???3????????
        ^
  symbol:   class ContentValues
  location: class MainActivity
Main.java:67: error: cannot find symbol
        ContentValues cv = new ContentValues(3);//???3????????
                               ^
  symbol:   class ContentValues
  location: class MainActivity
21 errors

Standard output is empty