广播接收器（BroadcastReceiver）的使用

import android.content.BroadcastReceiver;import android.content.Context;import android.content.Intent;import java.util.ArrayList;import android.content.IntentFilter;import android.net.Uri;import android.os.storage.StorageVolume;public class MountReceiver extends BroadcastReceiver {    private static final String TAG="MountReceiver";    private final MountPointManager mMountPointManager;    private final ArrayList<MountListener>mMountListenerList=new ArrayList<MountListener>();    private static final String INTENT_SD_SWAP="com.mediatek.SD_SWAP";    public interface MountListener{        /**         * This method will be called to do things before MountPoint init.         */        //void prepareForMount(String mountPoint);        /**         * This method will be called when receive a mounted intent.         */        void onMounted(String mountPoint);        /**         * This method will be implemented by its class who implements this interface,         * and called when receive a unMounted intent.         */        void onUnMounted(StorageVolume volume);        /**         * This method cancel the current action on the SD card which will be unmounted         */        void onEjected(String unMountPoint);        /**         * This method re-load volume info when sd swap on/off         */        void onSdSwap();    }    /**     * This method gets MountPointManager's instance     */    public MountReceiver(){        mMountPointManager=MountPointManager.getInstance();    }    /**     * This method adds listener for activities     *     * @param listener listener of certain activity to respond mounted and unMounted intent     */    public void registerMountListener(MountListener listener){        mMountListenerList.add(listener);    }    public void unregisterMountListener(MountListener listener){        mMountListenerList.remove(listener);    }    @Override    public void onReceive(Context context, Intent intent) {        String action = intent.getAction();        String mountPoint = null;        StorageVolume volume = null;        Uri mountPointUri = intent.getData();        if (mountPointUri != null) {            mountPoint = mountPointUri.getPath();        }        LogUtils.d(TAG, "onReceive,handle SD_SWAP");        if(INTENT_SD_SWAP.equals(action)){            synchronized (this){                for(MountListener listener:mMountListenerList){                    LogUtils.d(TAG,"onReceive,handle SD_SWAP");                    listener.onSdSwap();                }            }        }        if(mountPoint==null || mountPointUri==null){            return;        }        if(Intent.ACTION_MEDIA_MOUNTED.equals(action)){            //cancel the current operation before MountPointManager init            //to avoid concurrently access to mountpoint arraylist.            for(MountListener listener:mMountListenerList){                listener.onMounted(mountPoint);            }        }else if(Intent.ACTION_MEDIA_UNMOUNTED.equals(action)){            volume=(StorageVolume)intent.getExtras(StorageVolume.EXTRAZ_STORAGE_VOLUME);            mMountPointManager.changeMountState(mountPoint,false);            for(MountListener listener:mMountListenerList){                listener.onUnMounted(volume);            }        }else if(Intent.ACTION_MEDIA_EJECT.equals(action)){            for(MountListener listener:mMountListenerList){                listener.onEjected(mountPoint);            }        }    }    /**     * Register a MountReceiver for context.See     * {@link Intent.ACTION_MEDIA_MOUNTED}{@link Intent.ACTION_MEDIA_UNMOUNTED}     *     * @param context Context to use     * @return A mountReceiver     */    public static MountReceiver registerMountReceiver(Context context){        MountReceiver receiver=new MountReceiver();        IntentFilter intentFilter=new IntentFilter();        intentFilter.addAction(Intent.ACTION_MEDIA_MOUNTED);        intentFilter.addAction(Intent.ACTION_MEDIA_UNMOUNTED);        intentFilter.addAction(Intent.ACTION_MEDIA_EJECT);        intentFilter.addDataScheme("file");        context.registerReceiver(receiver,intentFilter);        if(OptionsUtils.isMtkSDSwapSurpported()){            IntentFilter intentFilterSDSwap=new IntentFilter();            intentFilterSDSwap.addAction(INTENT_SD_SWAP);            context.registerReceiver(receiver,intentFilterSDSwap);        }        return receiver;    }}