手把手教你写《雷神》游戏（四）

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <ListView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/rankList" >
    </ListView>

</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="40dp"
    android:orientation="horizontal" >

    <TextView
        android:id="@+id/txtUser"
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="match_parent"
        android:textSize="20sp"
        android:singleLine="true"
        android:gravity="right|center" />

    <TextView
        android:id="@+id/txtScore"
        android:layout_width="0dp"
        android:layout_weight="1"
        android:layout_height="match_parent"
        android:textSize="20sp"
        android:singleLine="true"
        android:gravity="left|center" />

</LinearLayout>

package com.example.gamedemo;

import java.util.ArrayList;
import java.util.List;

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;


import db.Ranking;
import db.User;

public class RankListActivity extends Activity {
    private ArrayList<User> userList = new ArrayList<User>();
    private ListView rankList;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.ranklist);

        //从数据库中读取数据
        Ranking r = new Ranking(this);
        userList = r.getData();

        rankList = (ListView) findViewById(R.id.rankList);
        ArrayAdapterDemo adapter = new ArrayAdapterDemo(RankListActivity.this,
                0, 0, userList);
        rankList.setAdapter(adapter);
    }

    /**
     * 重写返回键
     * (non-Javadoc)
     * @see android.app.Activity#onKeyDown(int, android.view.KeyEvent)
     */
    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if (keyCode == KeyEvent.KEYCODE_BACK) {  
            setResult(RESULT_OK);
            finish();
            return true;  
        } else  
            return super.onKeyDown(keyCode, event);  
    }

    /**
     * 自定义adapter。需要用到listview的优化
     */
    public class ArrayAdapterDemo extends ArrayAdapter<User> {
        private Wrapper wrapper;

        public ArrayAdapterDemo(Context context, int resource,
                int textViewResourceId, List<User> objects) {
            super(context, 0, 0, objects);
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            if (convertView == null) {
                convertView = getLayoutInflater().inflate(R.layout.rankitem,
                        null);
                wrapper = new Wrapper();
                wrapper.tvName = (TextView) convertView
                        .findViewById(R.id.txtUser);
                wrapper.tvScore = (TextView) convertView
                        .findViewById(R.id.txtScore);
                convertView.setTag(wrapper);
            } else {
                wrapper = (Wrapper) convertView.getTag();
            }
            wrapper.tvName.setText(userList.get(position).getUserName());
            wrapper.tvScore
                    .setText("得分" + userList.get(position).getUserScore());
            return convertView;
        }
    }

    class Wrapper { // 持有者模式
        private TextView tvName, tvScore;
    }
}

package db;

public class User {
    private String userName;
    private int userScore;

    public User(String userName, int userScore) {
        this.userName = userName;
        this.userScore = userScore;
    }
    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName;
    }
    public int getUserScore() {
        return userScore;
    }
    public void setUserScore(int userScore) {
        this.userScore = userScore;
    }
}

package db;

import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;

//创建数据库、数据表
public class DBOpenHelper extends SQLiteOpenHelper {
    private static final int VERSION = 1;
    private static final String DBNAME = "game.db";

    public DBOpenHelper(Context context) {
        super(context, DBNAME, null, VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("create table ranking( username varchar(50), userscore integer)");
    }

    @Override
    // 以便数据库版本更新
    public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {
    }
}

package db;

import java.util.ArrayList;

import android.content.Context;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;

public class Ranking {
    private DBOpenHelper helper;
    private SQLiteDatabase db;

    public Ranking(Context context) {
        helper = new DBOpenHelper(context);
        db = helper.getWritableDatabase();
    }

    public ArrayList<User> getData() {
        ArrayList<User> list = new ArrayList<User>();
        Cursor cursor = db.rawQuery("select * from ranking", null);
        while (cursor.moveToNext()) {
            list.add(new User(cursor.getString(cursor
                    .getColumnIndex("username")), cursor.getInt(cursor
                    .getColumnIndex("userscore"))));
        }
        return list;
    }

    public void insert(User user) {
        db.execSQL("insert into ranking (username, userscore) values (?,?)",
                new Object[] { user.getUserName(), user.getUserScore() });
    }
}