如您所见，我有这个 PlayLesson_01 活动，它同时显示图像和音频。此活动有两个处理程序，一个用于控制图像和音频，而另一个将完成课程并返回上一个活动（课程菜单）。
目标：单击硬后退按钮返回上一个活动并停止播放图像和音频。
问题：当我单击硬“返回”时，我能够返回到上一个活动，但音频仍在播放。我无法停止或终止在活动中启动的处理程序。
问题：我怎样才能完全杀死或停止这些处理程序？
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.media.MediaPlayer;
import android.media.MediaPlayer.OnCompletionListener;
import android.os.Bundle;
import android.os.Handler;
import android.os.Looper;
import android.view.View;
import android.view.ViewGroup;
import android.view.Window;
import android.view.animation.AnimationUtils;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.RelativeLayout.LayoutParams;
import android.widget.ViewSwitcher.ViewFactory;
public class PlayLesson_01 extends Activity implements OnItemSelectedListener,
ViewFactory, Runnable {
// Setting up images
// Keeping all Images in array references to our images
public Integer[] mThumbIds = { R.drawable.nouraniyah,
R.drawable.back_angle, R.drawable.back_fox, R.drawable.back_apple,
R.drawable.back_twitter, R.drawable.back_thunderbird };
// setting up music
int[] myMusic = { R.raw.button_3, R.raw.button_3, R.raw.button_3,
R.raw.button_3, R.raw.button_3, R.raw.button_3 };
int mNext;
private ImageSwitcher mSwitcher;
MediaPlayer mp;
Handler mHandlerWholeLesson = new Handler();
Runnable mRunnableWholelesson = new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
startActivity(new Intent("com.example.AmazingGame.LESSONONE"));
}
};
Handler mHandlerNextfile = new Handler();
Runnable mRunnableNextFile = new Runnable() {
@Override
public void run() {
// TODO Auto-generated method stub
mp.setOnCompletionListener(mListener);
mp.start();
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.image_switcher); // it could be lesson one
// layout.
mSwitcher = (ImageSwitcher) findViewById(R.id.imgswitcher);
mSwitcher.setFactory(this);
mSwitcher.setInAnimation(AnimationUtils.loadAnimation(this,
android.R.anim.fade_in));
mSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this,
android.R.anim.fade_out));
Gallery g = (Gallery) findViewById(R.id.gallery);
g.setAdapter(new ImageAdapter(this));
g.setOnItemSelectedListener(this);
// usual onCreate stuff here, then...
// either here or whenever you want to start the sequence
mNext = 0;
startNextFile();
// Is this good !! Yes it is. count the time for all audio.
mHandlerWholeLesson.postDelayed(mRunnableWholelesson, 25000);
}
@Override
public void onBackPressed() {
super.onBackPressed();
startActivity(new Intent("com.example.AmazingGame.LESSONONE"));
System.exit(0);
mHandlerNextfile
.removeCallbacks(mRunnableNextFile, PlayLesson_01.class);
mHandlerWholeLesson.removeCallbacks(mRunnableWholelesson,
PlayLesson_01.class);
PlayLesson_01.this.finish();
}
@Override
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
// mHandlerNextFile.removeCallbacksAndMesssages(PlayLesson_01.class);
}
public void onItemSelected(AdapterView<?> parent, View v,
final int position, long id) {
}
@Override
public void onNothingSelected(AdapterView<?> arg0) {
// TODO Auto-generated method stub
}
@Override
public View makeView() {
ImageView i = new ImageView(this);
i.setBackgroundColor(0xFF000000);
i.setScaleType(ImageView.ScaleType.FIT_CENTER);
i.setLayoutParams(new ImageSwitcher.LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
return i;
}
public class ImageAdapter extends BaseAdapter {
public ImageAdapter(Context c) {
mContext = c;
}
public int getCount() {
return mThumbIds.length;
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ImageView i = new ImageView(mContext);
i.setImageResource(mThumbIds[position]);
i.setAdjustViewBounds(true);
i.setLayoutParams(new Gallery.LayoutParams(
LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
i.setBackgroundResource(R.drawable.picture_frame);
return i;
}
private Context mContext;
}
OnCompletionListener mListener = new OnCompletionListener() {
@Override
public void onCompletion(MediaPlayer mp) {
mp.release();
startNextFile();
}
};
@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
this.finish();
}
public void startNextFile() {
if (mNext < myMusic.length) {
mp = MediaPlayer.create(this, myMusic[mNext]);
mSwitcher.setImageResource(mThumbIds[mNext++]);
mHandlerNextfile.postDelayed(mRunnableNextFile, 3000);
}
}
@Override
public void run() {
// TODO Auto-generated method stub
}
}