package xiaohang.zhimeng;import android.app.Activity;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.view.KeyEvent;
import android.widget.TextView;public class Activity01 extends Activity {private MIDIPlayer    mMIDPlayer = null;private boolean     mbMusic       = false;private TextView    mTextView  = null;@Overridepublic void onCreate(Bundle savedInstanceState){super.onCreate(savedInstanceState);setContentView(R.layout.main);mTextView = (TextView) this.findViewById(R.id.TextView01);mMIDPlayer = new MIDIPlayer(this);/*装载资源*///取得活动的preferences对象.//getPreferences方法返回单一的SharedPreferences实例 //getPreferences参数 为操作模式 分别有 //MODE_PRIVATE私有int值为0   MODE_WORLD_READABLE可读int值为1  MODE_WORLD_WRITEABLE可写int值为2SharedPreferences settings = getPreferences(Activity.MODE_PRIVATE);//取得值 如果mbMusic的值不存在 则直接把false赋给它mbMusic = settings.getBoolean("bmusic", false);if (mbMusic) {mTextView.setText("当音乐状态：开");mbMusic = true;mMIDPlayer.PlayMusic();}else {mTextView.setText("当前音乐状态：关");}}public boolean onKeyUp(int keyCode, KeyEvent event){switch (keyCode) {case KeyEvent.KEYCODE_DPAD_UP:mTextView.setText("当前音乐状态：开");mbMusic = true;mMIDPlayer.PlayMusic();break;case KeyEvent.KEYCODE_DPAD_DOWN:mTextView.setText("当前音乐状态：关");mbMusic = false;mMIDPlayer.FreeMusic();break;}return true;}public boolean onKeyDown(int keyCode, KeyEvent event){if (keyCode == KeyEvent.KEYCODE_BACK) {/*这里我们在退出应用程序时保存数据*///取得活动的preferences对象SharedPreferences uiState = getPreferences(0);//取得编辑对象SharedPreferences.Editor editor = uiState.edit();//添加值editor.putBoolean("bmusic", mbMusic);//提交保存  NOTE:如果不commit 保存无效
            editor.commit();if ( mbMusic ) {mMIDPlayer.FreeMusic();}this.finish();return true;}return super.onKeyDown(keyCode, event);}
}

package xiaohang.zhimeng;import java.io.IOException;import android.content.Context;
import android.media.MediaPlayer;public class MIDIPlayer {public     MediaPlayer playerMusic = null;private Context        mContext     = null;public MIDIPlayer(Context context){mContext = context;}//播放音乐public void PlayMusic(){//装载资源文件中的音乐playerMusic = MediaPlayer.create(mContext, R.raw.start);//设置是否循环playerMusic.setLooping(true);try {playerMusic.prepare();} catch (IllegalStateException e) {e.printStackTrace();}catch (IOException e) {e.printStackTrace();}playerMusic.start();}//停止播放音乐public void FreeMusic(){if (playerMusic != null) {playerMusic.stop();playerMusic.release();}}
}