Java 创建并加载活动后如何发送广播

我正在创建一个音乐应用程序。我想从主要活动中发送广播。接受者也在主要活动中。此广播访问创建并显示为片段的Arraylist。每个片段都在寻呼机的视图中。查看寻呼机处于主要活动中

现在的问题是我正在发送广播以访问arraylist，Receiver接收（从主类的oncreate方法发送广播），但arraylist仍然没有创建，因此没有数据存在，因此显示错误。 在生成arraylist并创建片段之后，是否有任何方法可以发送广播

public class MainActivity extends AppCompatActivity implements           SeekBar.OnSeekBarChangeListener{

private static int songEnded = 0;
View view;
Intent intent;
int a = 0, b = 0;
int x=0;
String[] path = Kaibee.getInstance().path;
ArrayList<collection> collections;
ArrayList<collection> songlist = Kaibee.getInstance().collections;
ArrayList<collection> fav = fav_collection.getInstance().fav;
TextView bsongname,starttime,endtime;
collectionAdapter collectionadapter=new favorite().mAdapter;
ImageView bsongimage;
int seekProgress;
ImageButton greenplay,favourite;
RelativeLayout songinfo, rl;
LinearLayout bottomll;
View bottomSheet;
FloatingActionButton fb;
MediaPlayer mediaPlayer;
ImageView bnext,bprev,playlist;
favlistdb mydb;
bottomsheetdb bdb;
playerservice ps;
favorite f=new favorite();
private BottomSheetBehavior mBottomSheetBehavior;
private SeekBar seekBar;
private int seekMax;
private Toolbar toolbar;
ActionBarDrawerToggle actionBarDrawerToggle;
DrawerLayout drawerLayout;

private BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent serviceIntent) {
        updateUI(serviceIntent);
    }
};
private IntentFilter bfilter = new IntentFilter("songclick");
private IntentFilter filter = new IntentFilter("songc");
//   private IntentFilter pfilter = new IntentFilter("bottomsheetbutton");
@Override
protected void onRestart() {
    super.onRestart();
}
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_main);
    LocalBroadcastManager.getInstance(getApplicationContext()).registerReceiver(bBroadcastReceiver, bfilter);
    LocalBroadcastManager.getInstance(getApplicationContext()).registerReceiver(broadcastReceiver, filter);
    ps= new playerservice();

    bdb = new bottomsheetdb(this);
 Cursor result=bdb.getdata();
    if (result != null) {
        int pos=0;
        String listname = null;
        if (result.moveToFirst() ) {

            do{
            listname =  result.getString(result.getColumnIndex(bottomsheetdb.COL_2)) ;
                pos =(result.getInt(result.getColumnIndex(String.valueOf(bottomsheetdb.COL_3))));
                System.out.println("bottomsheet data "+listname+" "+pos);
                Intent minten = new Intent("songclick");
                minten.addFlags(Intent.FLAG_INCLUDE_STOPPED_PACKAGES);
                minten.putExtra("position",pos);
                minten.putExtra("pause","play");
                minten.putExtra("collect",listname);
                LocalBroadcastManager.getInstance(getApplicationContext()).sendBroadcast(minten);
                ps.setupHandler();

            }while(result.moveToNext());

        }
    }
    else{bottomSheet.setVisibility(View.GONE);}




    // Create an adapter that knows which fragment should be shown on each page
    category_adapter adapter = new category_adapter(this, getSupportFragmentManager());

    // Set the adapter onto the view pager
    viewPager.setAdapter(adapter);
    TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);

    // Connect the tab layout with the view pager. This will
    //   1. Update the tab layout when the view pager is swiped
    //   2. Update the view pager when a tab is selected
    //   3. Set the tab layout's tab names with the view pager's adapter's titles
    //      by calling onPageTitle()
    tabLayout.setupWithViewPager(viewPager);

    //setting data inside bottom sheet
    try {
        Intent serviceIntent = new Intent(this, playerservice.class);

        // --- set up seekbar intent for broadcasting new position to service ---
        intent = new Intent("seek_update");
        seekBar.setOnSeekBarChangeListener(this);
    }
    catch (Exception e) {
        e.printStackTrace();
        Toast.makeText(getApplicationContext(),
                e.getClass().getName() + " " + e.getMessage(),
                Toast.LENGTH_LONG).show();
    }

}



public BroadcastReceiver bBroadcastReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context c, Intent i) {
        x=0;
        String ss=i.getExtras().getString("collect");
        if(ss.equals("song_list_fragment")){collections=Kaibee.getInstance().collections;}
        else if(ss.equals("album")){collections=song_album_fetch.getInstance().albumsong;}
        else if(ss.equals("artist")){collections=artist_songs_fetch.getInstance().artistsong;}
        else if(ss.equals("genres")){collections=genres_songs_fetch.getInstance().genresong;
        }
        else{collections=fav_collection.getInstance().fav;}
        a = i.getExtras().getInt("position");
        collectionadapter=new collectionAdapter(getApplicationContext(),fav);
    //    collectionadapter=f.mAdapter;
        String s = i.getExtras().getString("pause");
        String play = "play", pause = "pause";
        if (s.equals(play)) {
            greenplay.setImageResource(R.drawable.ic_play_circle_filled);
            fb.setImageResource(R.drawable.ic_play_arrow);
        } else {
            greenplay.setImageResource(R.drawable.ic_pause_circle_outline);
            fb.setImageResource(R.drawable.ic_pause);
        }

        bottomSheet.setVisibility(View.VISIBLE);

    }
};






/**
 * Dispatch onResume() to fragments.  Note that for better inter-operation
 * with older versions of the platform, at the point of this call the
 * fragments attached to the activity are <em>not</em> resumed.  This means
 * that in some cases the previous state may still be saved, not allowing
 * fragment transactions that modify the state.  To correctly interact
 * with fragments in their proper state, you should instead override
 * {@link #onResumeFragments()}.
 */
@Override
protected void onResume() {
    super.onResume();

}

@Override
protected void onDestroy() {
    super.onDestroy();
    LocalBroadcastManager.getInstance(getApplicationContext()).unregisterReceiver(bBroadcastReceiver);
    LocalBroadcastManager.getInstance(getApplicationContext()).unregisterReceiver(broadcastReceiver);
}

public类MainActivity扩展AppCompatActivity实现SeekBar.OnSeekBarChangeListener{
私有静态int=0；
视图；
意图；
int a=0，b=0；
int x=0；
String[]path=Kaibee.getInstance（）.path；
阵列列表集合；
ArrayList songlist=Kaibee.getInstance（）.collections；
ArrayList fav=fav_collection.getInstance（）.fav；
TextView bsongname、starttime、endtime；
collectionAdapter collectionAdapter=新收藏夹（）.mAdapter；
图像视图；
国际搜索进程；
图像按钮绿色游戏，最爱；
RelativeLayout songinfo，rl；
线性布局底部；
查看底板；
浮动操作按钮fb；
媒体播放器；
ImageView bnext、bprev、播放列表；
favlistdb mydb；
下表DB bdb；
playerservice-ps；
favorite f=新收藏夹（）；
私人银行行为mBottomSheetBehavior；
私人SeekBar SeekBar；
私有int-seekMax；
专用工具栏；
ActionBarDrawerToggle ActionBarDrawerToggle；
抽屉布局抽屉布局；
private BroadcastReceiver BroadcastReceiver=新的BroadcastReceiver（）{
@凌驾
公共void onReceive（上下文上下文、意图serviceIntent）{
更新（服务意图）；
}
};
私有IntentFilter bfilter=新IntentFilter（“歌曲点击”）；
私有IntentFilter筛选器=新IntentFilter（“songc”）；
//私有IntentFilter pfilter=新IntentFilter（“底部挡板按钮”）；
@凌驾
受保护的void onRestart（）{
super.onRestart（）；
}
@凌驾
创建时受保护的void（Bundle savedInstanceState）{
super.onCreate（savedInstanceState）；
setContentView（R.layout.activity_main）；
LocalBroadcastManager.getInstance（getApplicationContext（））.registerReceiver（bBroadcastReceiver，bfilter）；
LocalBroadcastManager.getInstance（getApplicationContext（））.registerReceiver（broadcastReceiver，filter）；
ps=新的playerservice（）；
bdb=新的底部挡板DB（本）；
游标结果=bdb.getdata（）；
如果（结果！=null）{
int pos=0；
字符串listname=null；
if（result.moveToFirst（））{
做{
listname=result.getString（result.getColumnIndex（bottomsheetdb.COL_2））；
pos=（result.getInt（result.getColumnIndex（String.valueOf（bottomsheetdb.COL_3）））；
System.out.println（“底页数据”+listname+“”+pos）；
Intent minten=新的Intent（“歌曲点击”）；
minten.addFlags（Intent.FLAG包含停止的包）；
minten.putExtra（“位置”，位置）；
minten.putExtra（“暂停”、“播放”）；
minten.putExtra（“collect”，列表名）；
LocalBroadcastManager.getInstance（getApplicationContext（））.sendBroadcast（minten）；
ps.setupHandler（）；
}while（result.moveToNext（））；
}
}
else{bottomSheet.setVisibility（View.GONE）；}
//创建一个适配器，它知道应该在每个页面上显示哪个片段
category_adapter adapter=新的category_适配器（这个，getSupportFragmentManager（））；
//将适配器设置到视图寻呼机上
viewPager.setAdapter（适配器）；
TabLayout TabLayout=（TabLayout）findViewById（R.id.tabs）；
//将选项卡布局与视图寻呼机连接。这将
//1.在浏览寻呼机时更新选项卡布局
//2.选择选项卡时更新视图寻呼机
//3.使用视图寻呼机适配器的标题设置选项卡布局的选项卡名称
//通过调用onPageTitle（）实现
tabLayout.setupWithViewPager（viewPager）；
//在底部工作表中设置数据
试一试{
意向服务意向=新意向（此，playerservice.class）；
//---设置seekbar意图，以便向服务广播新位置---
意向=新意向（“寻求更新”）；
seekBar.setonseekbarchaneglistener（这个）；
}
捕获（例外e）{
e、 printStackTrace（）；
Toast.makeText（getApplicationContext（），
e、 getClass（）.getName（）+“”+e.getMessage（），
Toast.LENGTH_LONG）.show（）；
}
}
公共广播接收器bBroadcastReceiver=新广播接收器（）{
@凌驾
接收时公共无效（上下文c，意图i）{
x=0；
String ss=i.getExtras（）.getString（“collect”）；
if（ss.equals（“歌曲列表片段”）{collections=Kaibee.getInstance（）.collections；}
else if（ss.equals（“album”）{collections=song\u album\u fetch.getInstance（）.albumsong；}
else if（ss.equals（“artist”）{collections=artist\u songs\u fetch.getInstance（）.artistsong；}
else如果（ss.equals（“genres”）{collections=genres\u songs\u fetch.getInstance（）.genresong；
}
else{collections=fav_collection.getInstance（）.fav；}
a=i.getExtras（）.getInt（“位置”）；
collectionadapter=新的collectionadapter（getApplicationContext（），fav）；
//collectionadapter=f.mAdapter；
字符串s=i.getExtras（）.getString（“暂停”）；
字符串play=“play”，pause=“pause”；
如果（s.equals（play））{
greenplay.setImageResource（R.drawable.ic_play_circle_filled）；
fb.setImageResource（R.drawable.ic\u play\u箭头）；
}否则{
greenplay.setImageResource（R.drawable.ic\u pause\u circle\u outline）；
fb.setImageResource（R.drawable.ic_pause）；
}
bottomSheet.setVisibility（View.VISIBLE）；
}
};
/**
*将onResume（）分派给片段。请注意，为了更好地进行交互操作
*使用旧版本
private MyReceiver mMyReceiver;

private class mMyReceiver extends BroadcastReceiver {
    Context mContext;
    public mMyReceiver(Context context){
        mContext = context;
    }

    @Override
    public void onReceive(Context context, Intent intent) {
        if (intent.getAction().equals(YOUR_ACTION)) {
            // get data from intent
        }
    }
}

private void registerReceiver() {
    if (mMyReceiver== null) {
        mMyReceiver= new MyReceiver(this);
    }

    IntentFilter intentFilter = new IntentFilter(YOUR_ACTION);
    registerReceiver(mMyReceiver, intentFilter);
}

@Override
protected void onCreate(Bundle savedInstanceState) {
    // others
    registerReceiver();
}

@Override
protected void onDestroy() {
   if(mMyReceiver != null){
        unregisterReceiver(mMyReceiver );
    }
    super.onDestroy();
}

 registerReceiver(myReceiver, new IntentFilter("INTENT_NAME"));



 private BroadcastReceiver myReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {

    }
};

Intent intent = new Intent("INTENT_NAME");
sendBroadcast(intent);