Java Android Basic 游戏 - 使用共享首选项保存高分 - 初学者

Question

我是 Java Android 编程的初学者。我正在使用 Eclipse 创建一个基本的 android 游戏，我想保存高分。我被告知要使用共享首选项，所以当我退出游戏并再次打开时，高分会被保存。我已经在我的“主菜单”页面上保存了高分，但对将共享首选项代码放在哪里感到很困惑？它应该在我的 OnCreate 中吗？请查看我的代码并尝试帮助我。我知道这可能很简单，但我已经研究了一段时间。

代码如下:

package cct.mad.lab;

import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.SharedPreferences;
import android.content.SharedPreferences.Editor;
import android.graphics.Bitmap;
import android.graphics.drawable.BitmapDrawable;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import cct.mad.lab.GameView;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.media.SoundPool;
import android.net.Uri;

public class MainMenu extends Activity {

    //MediaPlayer backgroundmusic;////////////////////

    private static final int SCORE_REQUEST_CODE = 1;// The request code for the intent

    private static final int PREFERENCE_MODE_PRIVATE = 0;

    TextView tvHighScore;
    TextView tvLastScore;
    //TextView tvScore
    String score;
    Intent gameIntent;
    int HighNum = 0;
    SoundPool sp;
    MediaPlayer mp;
    int hit = 0;
    ImageView crash;
    ImageView image;
    //int highscore = 0;



    protected void onCreate(Bundle savedInstanceState) 
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.game_start);
        tvHighScore = (TextView) findViewById(R.id.tvGuessGame);
        tvLastScore = (TextView) findViewById(R.id.LastGameNumb);


    }

    public void startGame(View v)

    {
        gameIntent = new Intent(this,GameActivity.class);
        startActivityForResult(gameIntent, SCORE_REQUEST_CODE );  

        mp = MediaPlayer.create(this, R.raw.bgmusic); // Assigns the media player to the bgmusic in the raw flder
        mp.setLooping(true); // loops the media player so it continues to play
        mp.start(); // starts the media player when the start game button is called
    } 


    /* Create Options Menu */
    public boolean onCreateOptionsMenu(Menu menu) 
    {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main_menu, menu);
        return true;
    }


    // Respond to item selected on OPTIONS MENU
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle item selection
        switch (item.getItemId()) {
        //put data in Intent
        case R.id.easy:
            Toast.makeText(this, "Easy chosen", Toast.LENGTH_SHORT).show();
            return true;
        case R.id.medium:
            Toast.makeText(this, "Medium chosen", Toast.LENGTH_SHORT).show();
            return true;
        case R.id.hard:
            Toast.makeText(this, "Hard chosen", Toast.LENGTH_SHORT).show();
            return true;
        case R.id.other:
            Toast.makeText(this, "Other chosen", Toast.LENGTH_SHORT).show();
            return true;
        default:
            return super.onOptionsItemSelected(item);
        }
    }


    protected void onActivityResult(int requestCode, int resultCode, Intent retIntent) {

    mp.pause(); // Pauses the Mediaplayer when the game is stopped and returned to the main menu.

        // Check which request we're responding to
        if (requestCode == SCORE_REQUEST_CODE) {
            // Make sure the request was successful
            if (resultCode == RESULT_OK) {
                if (retIntent.hasExtra("GAME_SCORE")) 
                {
                    int scoreFromGame = retIntent.getExtras().getInt("GAME_SCORE");

                    if (scoreFromGame > HighNum) 
                    {
                    tvHighScore.setText(Integer.toString(scoreFromGame));   
                    tvLastScore.setText(Integer.toString(scoreFromGame));   
                    HighNum = scoreFromGame;
                    }   

                    else if (scoreFromGame > HighNum) 
                    {
                        tvHighScore.setText(Integer.toString(scoreFromGame));   
                        tvLastScore.setText(Integer.toString(scoreFromGame));   
                    }   

                    else if (scoreFromGame < HighNum) 
                    {
                        tvLastScore.setText(Integer.toString(scoreFromGame));   
                    }
                }
            }   
        }

    }


    @Override
    protected void onDestroy() {
        // TODO Auto-generated method stub
        super.onDestroy();
        mp.stop(); // Stops the mediaplayer when the game/emulator is exited.
        mp.release(); // Stops the mediaplayer when the game/emulator is exited.
    } 







    /*
    @Override
    public void onSaveInstanceState(Bundle savedInstanceState){ // When activity stops, system calls onSaveInstancState to save info.
        //Save the user's current game state
        savedInstanceState.putInt("GAME_SCORE", HighNum);
         super.onSaveInstanceState(savedInstanceState); //Calls superclass to view the hierachy state
    }

    @Override
    public void onRestoreInstanceState(Bundle savedInstanceState){
        super.onCreate(savedInstanceState); // Calls the superclass first

        if (savedInstanceState != null) {
            HighNum = savedInstanceState.getInt("GAME_SCORE");
        } else {



        }

        super.onRestoreInstanceState(savedInstanceState);
    }



    */




}

Answer 1

你应该查看 Android Activity lifecycle如果您不完全了解 Activity 的生命周期。该图像演示了您的 Activity 可能处于的状态，以及您调用的用于在这些状态之间切换的函数。

您应该能够在 onPause 中保存您的首选项，并在您的 Activity 类的 onResume 函数中加载首选项。这意味着每次关闭/打开 Activity 时都会保存/加载您的首选项。