以下是一个launcher主函数, 请问(我是初学者)，从字面上看，主函数中的几个函数作用是什么?
请说具体一些，给高分，分还可以加. 

setContentView(R.layout.activity_main);   //调用布局文件
registerLauncherReceivers();            //注册广播接收者, 这有何具体作用?
initNotification();                     //这个函数功能?
initView();                             //初始化界面?
initData();         //初始化数据?

protected void onCreate(Bundle savedInstanceState) {

setContentView(R.layout.activity_main);
registerLauncherReceivers();

initNotification();
initView();
initData();
}

private void initNotification() {

mPowerManager = (PowerManager) getSystemService(Context.POWER_SERVICE);
mLoadingWakeLock = mPowerManager.newWakeLock(
PowerManager.ACQUIRE_CAUSES_WAKEUP
| PowerManager.SCREEN_BRIGHT_WAKE_LOCK,
“Lancher::Loading”);
mLoadingWakeLock.setReferenceCounted(false);
mNotification = new NotificationUIManager(this, mPowerManager,
mLoadingWakeLock);
}

private void initData() {
adapterBlue = BluetoothAdapter.getDefaultAdapter();
if (adapterBlue == null
|| adapterBlue.getAddress() == null
|| BluetoothAdapter.getDefaultAdapter().getState() == BluetoothAdapter.STATE_OFF) {
mQrcodeView.setImageResource(R.drawable.theme_error);
mQrcodeView.setVisibility(View.VISIBLE);
mClearbtn.setVisibility(View.INVISIBLE);
mQrcodeView.setImageResource(R.drawable.theme_error);

} else {
mQrcodeView.setImageBitmap(Utilities.createQRImage(adapterBlue
.getAddress()));
}

mHScrollLayout.setListener(new ScrollStateListener() {

@Override
public void stateChanged(int state) {

}

@Override
public void pageChanged(int currentPage) {
currPageH = currentPage;
Log.i(TAG, “——————>currPageH:” + currPageH);
}
});
mVScrollLayout.setListener(new ScrollStateListener() {

@Override
public void stateChanged(int state) {
if (state == 1) {
// mHScrollLayout.setScrollEnable(false);
}
}

@Override
public void pageChanged(int currentPage) {
currPageV = currentPage;
Log.i(TAG, “——————>currPageV:” + currPageV);
// setHScrollEnable(currentPage);
}
});

mNotification.setEmptyView(this.findViewById(R.id.empty));

homeLayout.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
if (clockEditMode)
return false;
enterEditMode();
return false;
}
});

mClearbtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
showExitNotiAlert();
}
});
}

private void initView() {

mFrameLayout = (FrameLayout) findViewById(R.id.launcher_bg);
mHScrollLayout = (HScrollLayout) findViewById(R.id.rootview);
mVScrollLayout = (VScrollLayout) findViewById(R.id.vscroll);

mQrcodeView = (ImageView) findViewById(R.id.qrcodeview);

mQrcodeView.setVisibility(View.VISIBLE);

topLayout = (LinearLayout) findViewById(R.id.quic_settings_layout);
bottomLayout = (LinearLayout) findViewById(R.id.music_settings_layout);

homeLayout = (RelativeLayout) findViewById(R.id.home_screen);

notificationLayout = (RelativeLayout) findViewById(R.id.notification);

mClearbtn = (ImageView) findViewById(R.id.clearbutton);
notificationLayout.addView(mNotification.getListView());
mHScrollLayout.setLeftView(mNotification.getListView());

mHScrollLayout.requestLayout();
mVScrollLayout.requestLayout();

}