android应用如何有效获取管理存储

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谷歌原生没有提供有效的获取内部存储、SD卡、OTG设备文件区分，那么，怎样有效获取？

一般情况：

1.   通过反射调用：

StorageManager.getVolumeList();

2. 通过调用得到StorageVolume 列表，但是我们不能有效的区分哪一个是sd,otg,内部存储，怎么办？

一般内部存储的文件path以"/storage/emulated"开头，通过该标志可判断内部存储

关于sd卡和otg怎么判断？

根据前面获取到的列表数据： 

DiskInfo di= mStorageManager.findVolumeByUuid(sv.getUuid()).getDisk();

di对象有isSd()、isUsb()方法，至此可以区分开来。

具体可参考如下：

package com.fileexplorer.service;

import android.app.Service;
import android.content.Intent;
import android.os.Environment;
import android.os.IBinder;
import android.os.storage.StorageManager;
import android.os.storage.StorageEventListener;
import android.os.storage.StorageVolume;
import android.os.storage.DiskInfo;

import android.util.Log;

import com.fileexplorer.service.FileManageService;

import java.io.File;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;


/**
 * Created by Xuehao.Jiang on 2017/6/27.
 */

public class FileManageService extends Service {

    private static final String TAG = FileManageService.class.getSimpleName();
    private StorageManager mStorageManager;
    private StorageVolume[]  storageVolumes = null;
    private static List storageVolumeAll = new ArrayList();
    private List sListeners = new ArrayList();

    private static  final int PHONE_ROOT = 0;
    private static  final int SD_ROOT = 1;
    private static  final int OTG_ROOT = 2;
    private static  final int NONE_ROOT = -1;


    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onCreate() {
        super.onCreate();
        Log.d(TAG,"  onCreate .... ");
        mStorageManager = (StorageManager) getSystemService(STORAGE_SERVICE);
        mStorageManager.registerListener(mStorageListener);
        init();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        mStorageManager.unregisterListener(mStorageListener);
        Log.d(TAG,"  onDestroy .... ");
    }

    private final StorageEventListener mStorageListener = new StorageEventListener() {

        @Override
        public void onStorageStateChanged(String path, String oldState, String newState) {
            refresh();
            notifyStorageChanged(path,oldState,newState);
        }
    };

    public  void init(){
        Log.d(TAG,"  init .... ");
        refresh();
    }

    private void refresh(){

        storageVolumeAll.clear();
        storageVolumes = mStorageManager.getVolumeList();
        if(storageVolumes != null && storageVolumes.length>0){
            for(int i=0; i< storageVolumes.length ; i++){
                StorageVolume sv = storageVolumes[i];
                Log.d(TAG,"   ....storageVolumes[ "+i+"] = "+sv +" mfsUuid="+ sv.getUuid()+"  path="+ sv.getPath() +" label="+ sv.getDescription(this));
                File f =sv.getPathFile();
                if( f.exists()&& f.isDirectory() && f.canWrite()){
                    if(Environment.MEDIA_MOUNTED.equals(sv.getState())){
                        storageVolumeAll.add(sv);
                    }
                }
            }
            Log.d(TAG,"  storageVolumeAll  size="+ storageVolumeAll.size());
        }
    }

    public static List getStorageVolumes(){
        return storageVolumeAll;
    }

    public static int getRootPath(String path){
        if(storageVolumeAll.size()>0){
            for(StorageVolume sv: storageVolumeAll){
                String mPath = sv.getPath();
                if(path!=null && path.equals(mPath)){
                    if(path.startsWith("/storage/emulated")){
                        return PHONE_ROOT;
                    }else {
                        DiskInfo di= mStorageManager.findVolumeByUuid(sv.getUuid()).getDisk();
                        if(di.isSd()){
                            return SD_ROOT;
                        }else if(di.isUsb()){
                            return OTG_ROOT;
                        }
                    }
                }
            }
        }
        return NONE_ROOT;
    }



    public interface CallBackListener{
        public void notifyStorageChanged(String path, String oldState, String newState);
    }

    private final Object sLock = new Object();
    public void addCallBackListener(CallBackListener scl) {
        synchronized (sLock) {
            sListeners.add(scl);
        }
    }

    public void removeCallBackListener(CallBackListener scl) {
        synchronized (sLock) {
            sListeners.remove(scl);
        }
    }
    public void notifyStorageChanged(String path, String oldState, String newState) {
        synchronized (sLock) {
            for (CallBackListener l : sListeners) {
                l.notifyStorageChanged(path, oldState, newState);
            }
        }
    }
}