Android 编程之入门开发文件夹管理器开发详细讲解-1

在我们的手持设备中，一般都会自带设备公司自己开发的文件管理系统、拍照系统之类的东东，今天我给大伙说说入门级开发的文件夹管理器，代码贼少

总共就6个类吧，没有夹杂其他外部应用，就是一个纯文件夹管理器

APP主要功能设计：文件复制、文件夹复制、批量文件/文件夹复制、删除文件、删除文件夹、批量删除文件/文件夹、文件分类、文件搜索暂时没有写，

有兴趣的可以自己写写

APP主要应用：DrawerLayout 、ListView、Fragment、IO、序列化、文件过滤、文件排序、ActionBar、Adapter、v4包、一些事件等

下面开始讲开发吧，首先我们要给APP读写权限，在清单文件配置如下权限：

    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

主界面活动代码：

package com.example.maozhuafile;/** * 文件管理主界面 * @author Engineer-Jsp * @date 2014.10.27 * */import java.io.File; import java.util.ArrayList;import java.util.HashMap;  import java.util.List;import java.util.Map; import com.example.maozhuafile.MainActivity.FragmentA.FragmentB;import com.example.maozhuafile.MainActivity.FragmentA.FragmentC;import com.example.maozhuafile.MainActivity.FragmentA.FragmentD;import com.example.util.CustomFileFilter;import com.example.util.FileOpreationUitl;import com.example.util.FileSort;import com.example.util.FragmentAdapter;import android.net.Uri;import android.os.AsyncTask;import android.os.Bundle;import android.os.Environment;import android.provider.MediaStore;import android.app.ActionBar;import android.app.Activity;import android.app.AlertDialog;import android.app.Fragment;import android.content.Context;import android.content.DialogInterface;import android.content.DialogInterface.OnClickListener;import android.content.Intent;import android.database.Cursor;import android.support.v4.app.ActionBarDrawerToggle;import android.support.v4.widget.DrawerLayout;import android.util.Log;import android.util.SparseBooleanArray;import android.view.ActionMode;import android.view.Gravity;import android.view.KeyEvent;import android.view.LayoutInflater;import android.view.Menu;import android.view.MenuItem;import android.view.View;import android.view.ViewGroup;import android.widget.AbsListView.MultiChoiceModeListener;import android.widget.AdapterView;import android.widget.AdapterView.OnItemClickListener;import android.widget.EditText;import android.widget.ListView;import android.widget.SimpleAdapter;import android.widget.TextView;import android.widget.Toast;public class MainActivity extends Activity implements OnItemClickListener {private ActionBar actionbar;private ActionBarDrawerToggle drawertoggle;private DrawerLayout drawerLayout;private ListView drawerlistview;private String[] drawerdata;private SimpleAdapter adapter;private List<Map<String, Object>> draweralllist = new ArrayList<Map<String, Object>>();private FragmentA fragmentA;private FragmentB fragmentB;private FragmentC fragmentC;  private FragmentD fragmentD;private int[] list_image = { R.drawable.cunchu, R.drawable.music,R.drawable.movies, R.drawable.photos };private static int index = -1;private static File currentpath;private static File SDpath;//private static File[] mfileData;private static Context mContext;public  static boolean exit;private static boolean copy;private static MenuItem paste;int i=0;private static EditText newFile;private static FileOpreationUitl opreaFile=new FileOpreationUitl();protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);mContext = MainActivity.this;initDrawerLayout();//initDrawerContent();//if (null == savedInstanceState) {// 如果为空代表第一次执行fragmentA = new FragmentA();fragmentB = new FragmentB();fragmentC = new FragmentC();fragmentD = new FragmentD();// 动态添加android.app.FragmentManager fg = getFragmentManager();fg.beginTransaction().add(R.id.drawer_frame_a, fragmentA).commit();}}private void initDrawerContent() {drawerdata = getResources().getStringArray(R.array.array);drawerlistview = (ListView) findViewById(R.id.drawer_list);for (int i = 0; i < drawerdata.length; i++) {Map<String, Object> drawer_list_date = new HashMap<String, Object>();drawer_list_date.put("image", list_image[i]);drawer_list_date.put("text", drawerdata[i]);draweralllist.add(drawer_list_date);}adapter = new SimpleAdapter(this, draweralllist, R.layout.drawer_item,new String[] { "image", "text" }, new int[] {R.id.drawer_imageView, R.id.drawer_textView });drawerlistview.setAdapter(adapter);drawerlistview.setChoiceMode(ListView.CHOICE_MODE_SINGLE);// 单选模式drawerlistview.setItemChecked(0, true);// 默认选中第一项drawerlistview.setOnItemClickListener(this);}private void initDrawerLayout() {drawerLayout = (DrawerLayout) findViewById(R.id.chouti);actionbar = getActionBar();actionbar.setDisplayHomeAsUpEnabled(true);drawertoggle = new ActionBarDrawerToggle(this,// 活动drawerLayout,// 布局R.drawable.ic_drawer,// 图片资源R.string.drawer_open,// 打开显示文字R.string.app_name) {// 关闭显示文字public void onDrawerOpened(View drawerView) {actionbar.setTitle(R.string.drawer_open);if (index != -1) {actionbar.setTitle(drawerdata[index]);} else {actionbar.setTitle(R.string.app_name);}invalidateOptionsMenu();// 选项菜单重绘改变super.onDrawerOpened(drawerView);}public void onDrawerClosed(View drawerView) {if (index != -1) {actionbar.setTitle(drawerdata[index]);} else {actionbar.setTitle(R.string.app_name);}invalidateOptionsMenu();// 选项菜单重绘改变super.onDrawerClosed(drawerView);}};drawerLayout.setDrawerShadow(R.drawable.drawer_shadow, Gravity.START);drawerLayout.setDrawerListener(drawertoggle);}// 替换抽屉开关上的图片（向上箭头三道杠）protected void onPostCreate(Bundle savedInstanceState) {super.onPostCreate(savedInstanceState);drawertoggle.syncState();}public boolean onCreateOptionsMenu(Menu menu) {getMenuInflater().inflate(R.menu.main, menu);paste=menu.findItem(R.id.paste);return true;}// 选项菜单的预处理方法重写public boolean onPrepareOptionsMenu(Menu menu) {// 如果抽屉被打开if (drawerLayout.isDrawerOpen(Gravity.START)) {// 找到这个AcionBarMenu(操作欄菜單)Item把可见性显示为false（即显示为不可见）menu.findItem(R.id.action_menu_new).setVisible(false);}return super.onPrepareOptionsMenu(menu);}public boolean onOptionsItemSelected(MenuItem item) {// 抽屉开关控制Open,Offif (drawertoggle.onOptionsItemSelected(item)) {return true;}switch(item.getItemId()){case R.id.paste:copy=false;fragmentA.Paste();for(;i<fragmentA.filelist.size();i++){//if(fragmentA.filelist.get(i).exists()){//new AlertDialog.Builder(this)//.setTitle("复制提示")//.setMessage("已存在文件"+fragmentA.filelist.get(i).getName())//.setPositiveButton("覆盖", new OnClickListener() {//public void onClick(DialogInterface dialog, int which) {//}//})//.setNegativeButton("取消", null)  //                .show();opreaFile.copyDirectory(fragmentA.filelist.get(i), currentpath);//}}fragmentA.filelist.clear();fragmentA.openFile(currentpath);Log.d("Paete-XXXXXXXXXXX", "xxxxxxxxxxxx");fragmentA.showMessage("执行粘贴");break;case R.id.action_menu_new:View view=LayoutInflater.from(this).inflate(R.layout.list_item, null);newFile=(EditText)view.findViewById(R.id.newFile);new AlertDialog.Builder(this).setTitle("新建文件").setView(view).setPositiveButton("确定", new OnClickListener() {public void onClick(DialogInterface dialog, int which) {String newfile="/"+fragmentA.showpath.getText().toString()+"/"+newFile.getText().toString()+"/";File newfile2=new File(newfile);Log.d("***********", newfile);if(!newfile2.exists()){  newfile2.mkdirs();}fragmentA.filelist.clear();fragmentA.openFile(currentpath);fragmentA.showMessage("执行新建");} }).setNegativeButton("取消", null)              .show();break;case R.id.action_menu_search:break;}return super.onOptionsItemSelected(item);}public void onItemClick(AdapterView<?> parent, View view, int position,long id) {drawerLayout.closeDrawer(Gravity.START);//更新ActionBar(操作栏)的标题actionbar.setTitle(drawerdata[position]);index=position;//抽屉列表按钮switch (position) {case 0:getFragmentManager().beginTransaction().replace(R.id.drawer_frame_a, fragmentA).commit();break;        case 1:getFragmentManager().beginTransaction().replace(R.id.drawer_frame_a, fragmentB).commit();break;        case 2:        getFragmentManager().beginTransaction().replace(R.id.drawer_frame_a, fragmentC).commit();        break;        case 3:        getFragmentManager().beginTransaction().replace(R.id.drawer_frame_a, fragmentD).commit();        break;default:break;}}@Overridepublic boolean onKeyDown(int keyCode, KeyEvent event) {if(keyCode==KeyEvent.KEYCODE_BACK){if(currentpath.equals(SDpath)){if(!exit){//exit==falsefragmentA.showMessage("在点返回则退出程序！");exit=true;}else{finish();}}else{exit=false;  File path=currentpath.getParentFile();fragmentA.openFile(path);fragmentA.showpath.setText(String.valueOf(path));fragmentA.adapter.notifyDataSetChanged();}return true;  }return super.onKeyDown(keyCode, event);}public static class FragmentA extends Fragment implementsMultiChoiceModeListener, OnItemClickListener {public static TextView showpath;private ListView listview;private FragmentAdapter adapter;//private File[] files;private File[] mfileData;int n;private List<File> filelist=new ArrayList<File>();//下段注释代码表示往Map里面添加文件数据，如果filename为文件夹，则设置为图标icon[1]，否则设置icon[0]//private int[] icon = { R.drawable.wenjian, R.drawable.wenjianjia };//Map<String,Object> map=new HaspMap<String,Object>();//map.put("keyname",filename.isDirectory?icon[1]:icon[0]);public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {Log.d("onCreateView.........", "onCreateView.........");View view  = inflater.inflate(R.layout.fragment_a, container, false);showpath=(TextView)view.findViewById(R.id.showpath);listview = (ListView) view.findViewById(R.id.listView);////if (mfileData == null) {//SDpath = Environment.getExternalStorageDirectory();//showpath.setText(String.valueOf(SDpath));// mfileData = SDpath.listFiles(new CustomFileFilter()); // 过滤.文件// mfileData = FileSort.sortFile(mfileData);//排序// openFile(SDpath);//}//bindData();  return view;}// 绑定数据public void bindData() { if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) { // 判断sd卡是否正常if (mfileData == null) {SDpath = Environment.getExternalStorageDirectory();showpath.setText(String.valueOf(SDpath));getFileData();}//判断文件夹数据组是否取到了数据for (int i = 0; i < mfileData.length; i++) {Log.i("float1", "111111" + mfileData[i] + "");}} else {showMessage("SD卡出现异常");}}private File[] getFileData() {    mfileData = SDpath.listFiles(new CustomFileFilter()); // 过滤.文件mfileData = FileSort.sortFile(mfileData);//排序openFile(SDpath);return mfileData;}public void Paste() {if (copy) {paste.setVisible(true);paste.setShowAsAction(MenuItem.SHOW_AS_ACTION_ALWAYS);} else {paste.setVisible(false);paste.setShowAsAction(MenuItem.SHOW_AS_ACTION_NEVER);}}public boolean onActionItemClicked(ActionMode mode, MenuItem item) {SparseBooleanArray array = listview.getCheckedItemPositions();switch (item.getItemId()) {//case R.id.newfile:// qshowMessage(""+"新建");//break;//case R.id.search://showMessage(""+"搜索");//break;case R.id.remove://这处理下面这个稀疏数组时尽量不要使用静方法态调用和静态变量//静态不能再次调用静态，否则报异常for (int i = 0; i < array.size(); i++) {Log.d("del-4XXXXXXXXXXX", mfileData[array.keyAt(i)].getName().toString());if(array.valueAt(i)==true){ n= array.keyAt(i);opreaFile.deleteFile(mfileData[n]);}Log.d("del-XXXXXXXXXXX", currentpath.listFiles().toString());Log.d("del-XXXXXXXXXXX", currentpath.getName().toString());Log.d("del-XXXXXXXXXXX", showpath.getText().toString());}  openFile(currentpath);showMessage("删除成功");//showMessage("删除"+mfileData[array.keyAt(n)].isFile()?"删除文件成功！":"删除文件夹成功！");mode.finish();case R.id.copy:copy=true;Paste();//屏蔽复制按钮//mode.getMenu().findItem(R.id.copy).setVisible(false);////显示粘贴按钮//mode.getMenu().findItem(R.id.paste).setVisible(true);for(int i=0;i<array.size();i++){if(array.valueAt(i)==true){int x=array.keyAt(i);filelist.add(mfileData[x]);}}Log.d("Copy-XXXXXXXXXXX", "xxxxxxxxxxxx");mode.finish();//showMessage(""+"复制");break;//case R.id.paste://copy=false;//Paste();//for(int i=0;i<filelist.size();i++){//opreaFile.copyDirectory(filelist.get(i), currentpath);//}//filelist.clear();//openFile(currentpath);//Log.d("Paete-XXXXXXXXXXX", "xxxxxxxxxxxx");//showMessage("执行粘贴");//mode.finish();////showMessage(""+"粘贴");//break;default:break;}return true;}public boolean onCreateActionMode(ActionMode mode, Menu menu) {getActivity().getMenuInflater().inflate(R.menu.action_menu, menu);//mode.setTitle("你選擇了");return true;}public void onDestroyActionMode(ActionMode arg0) {}public boolean onPrepareActionMode(ActionMode arg0, Menu arg1) {return false; }public void onItemCheckedStateChanged(ActionMode mode, int position,long id, boolean checked) {int count = listview.getCheckedItemCount();mode.setTitle(count + "项");}  public void onItemClick(AdapterView<?> parent, View view, int position,long id) {File file = mfileData[position];showpath.setText(String.valueOf(file)); Log.d("onItem-xxxxxxxxxxxxxx", showpath.getText().toString());if(file.isDirectory()){openFile(file);adapter.notifyDataSetChanged();}else{//打開文件Uri uri = Uri.fromFile(file);Log.d("aaaaaaaaaaaaaa", uri.toString());String[] projection = { MediaStore.Files.FileColumns.MIME_TYPE };Cursor cursor = getActivity().getContentResolver().query(MediaStore.Files.getContentUri("external"), projection,MediaStore.Files.FileColumns.DATA + "=?",new String[] { file.getAbsoluteFile().toString() },null);cursor.moveToNext();String mime = cursor.getString(0);Log.d("bbbbbbbbbbbbbb", mime);// MimeTypeMap.getSingleton().getMimeTypeFromExtension(extension);Intent intent = new Intent(Intent.ACTION_VIEW);intent.setDataAndType(uri, mime);getActivity().startActivity(intent);} }public void openFile(File path) {currentpath=path;mfileData = path.listFiles(new CustomFileFilter()); // 过滤.文件mfileData= FileSort.sortFile(mfileData); // 排序adapter = new FragmentAdapter(mfileData,getActivity());listview.setAdapter(adapter);for (int i = 0; i < mfileData.length; i++) {Log.i("XXXXXXXXXXXX", "111111111111" + mfileData[i] + "");}//showMessage("当前文件夹有"+mfileData.length+"个对象");listview.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE_MODAL); listview.setMultiChoiceModeListener(FragmentA.this);listview.setOnItemClickListener(this);}public void showMessage(String info) {Toast.makeText(mContext, info, 1000).show();  }public static class FragmentB extends Fragment {private ListView mp3list;private SimpleAdapter mp3adapter;public View onCreateView(LayoutInflater inflater,ViewGroup container,Bundle savedInstanceState) {View view = inflater.inflate(R.layout.fragment_b, container, false);mp3list=(ListView)view.findViewById(R.id.mp3listView);opreaFile.getReciver(SDpath);mp3adapter=new SimpleAdapter(getActivity(),opreaFile.mp3_data,R.layout.mp3_fragment_b,new String[]{opreaFile.mp3_listitem},new int[]{R.id.mp3textView});mp3list.setAdapter(mp3adapter);return view;}  }public static class FragmentC extends Fragment {private ListView video_list;private SimpleAdapter video_adapter;public View onCreateView(LayoutInflater inflater,ViewGroup container,Bundle savedInstanceState) {View view = inflater.inflate(R.layout.fragment_c, container, false);video_list=(ListView)view.findViewById(R.id.video_listView);Log.d("2_XXXXXXXXXX", SDpath.getName().toString());opreaFile.getVideo(SDpath);video_adapter=new SimpleAdapter(getActivity(),opreaFile.video_data,R.layout.video_fragment_b,new String[]{opreaFile.video_listitem},new int[]{R.id.video_textView});video_list.setAdapter(video_adapter);return view;}}public static class FragmentD extends Fragment {private ListView picture_list;private SimpleAdapter picture_adapter; public View onCreateView(LayoutInflater inflater,ViewGroup container,Bundle savedInstanceState) {View view = inflater.inflate  (R.layout.fragment_d, container, false);picture_list=(ListView)view.findViewById(R.id.picture_listView);opreaFile.getPicture(SDpath);picture_adapter=new SimpleAdapter(getActivity(),opreaFile.picture_data,R.layout.picture_fragment_b,new String[]{opreaFile.picture_listitem}, new int[]{R.id.picture_textView});picture_list.setAdapter(picture_adapter);  return view;  }}  }/*public static class AsyncTaskTest extends AsyncTask<String, Integer, Integer>{@Overrideprotected Result doInBackground(Params... arg0) {return null;}}*/}

主布局：

<android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:id="@+id/chouti"    android:layout_width="match_parent"    android:layout_height="match_parent"    tools:context=".MainActivity" >    <FrameLayout         android:id="@+id/drawer_frame_a"        android:layout_width="match_parent"        android:layout_height="match_parent"        />    <FrameLayout         android:id="@+id/drawer_frame_b"        android:layout_width="match_parent"        android:layout_height="match_parent"        />    <ListView         android:id="@+id/drawer_list"        android:layout_width="240dp"        android:layout_height="match_parent"        android:layout_gravity="start"        android:background="#eee"        /></android.support.v4.widget.DrawerLayout>

文件列表 Item 布局文件：

<?xml version="1.0" encoding="utf-8"?><RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="fill_parent"    android:layout_height="fill_parent"    android:background="@drawable/drawer_bg"    >    <ImageView        android:id="@+id/filelist_imageview"        android:layout_width="24dp"        android:layout_height="24dp"        android:layout_alignParentLeft="true"        android:layout_alignParentTop="true"        android:layout_marginLeft="18dp"        android:layout_marginTop="10dp"        android:src="@drawable/photos"        />    <TextView        android:id="@+id/filelist_textview"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:layout_alignParentTop="true"        android:layout_marginLeft="17dp"        android:layout_toRightOf="@+id/filelist_imageview"        android:gravity="center_vertical"        android:text="showfiletext" />    <TextView        android:id="@+id/filelist_timeText"        android:layout_width="fill_parent"        android:layout_height="wrap_content"        android:layout_alignLeft="@+id/filelist_textview"        android:layout_alignParentRight="true"        android:layout_below="@+id/filelist_textview"        android:text="time" /></RelativeLayout>

自定义Adapter，控制文件与应用图片配对，队号入座，ViewHolder 节约内存资源：

package com.example.util;/** * 自定义容器Adapter * @author Engineer-Jsp * @date 2014.10.27 * */import java.io.File;import java.util.Date;import com.example.maozhuafile.R;import android.content.Context;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.ImageView;import android.widget.TextView;public class FragmentAdapter extends BaseAdapter {    private Context mContext ;     private File[] mfileData ;private LayoutInflater mlayoutinflater;public FragmentAdapter( File[]files ,Context pContext) {mContext = pContext ;mfileData = files ;mlayoutinflater = LayoutInflater.from(mContext);}public  void updata(File[] pfile){mfileData = pfile ;}public int getCount() {  return mfileData ==null? 0: mfileData.length;}public Object getItem(int position) {return mfileData[position];}public long getItemId(int position) {return position;}public static  class ViewHolder{public ImageView mFileImage ;public TextView mFileName ;public TextView mFileTime;}public View getView(int position, View convertView, ViewGroup parent) {ViewHolder mViewHolder ;View _view = convertView ;if(_view ==null){mViewHolder = new ViewHolder() ;_view = mlayoutinflater.inflate(R.layout.file_listview, null) ;mViewHolder.mFileImage =(ImageView) _view.findViewById(R.id.filelist_imageview) ;mViewHolder.mFileName = (TextView) _view.findViewById(R.id.filelist_textview) ;mViewHolder.mFileTime = (TextView) _view.findViewById(R.id.filelist_timeText);_view.setTag(mViewHolder) ;}else{mViewHolder = (ViewHolder) _view.getTag() ;}//目录的显示特点if(mfileData[position].isDirectory() && mfileData[position].canRead()){  //文件夹分为空与非空if(mfileData[position].listFiles().length == 0 && mfileData[position].listFiles()== null  ){mViewHolder.mFileImage.setImageResource(R.drawable.wenjian) ;mViewHolder.mFileName.setText(mfileData[position].getName()) ;mViewHolder.mFileTime.setText(new Date(System.currentTimeMillis()).toLocaleString());}else{mViewHolder.mFileImage.setImageResource(R.drawable.wenjianjia) ;mViewHolder.mFileName.setText(mfileData[position].getName()) ;mViewHolder.mFileTime.setText(new Date(System.currentTimeMillis()).toLocaleString());} }else{   //文件的处理  String _FileName = mfileData[position].getName().toLowerCase() ;  if(_FileName.endsWith(".txt")){  //文本显示t                  mViewHolder.mFileImage.setImageResource(R.drawable.wenjian) ;  mViewHolder.mFileName.setText(_FileName) ;   mViewHolder.mFileTime.setText(new Date(System.currentTimeMillis()).toLocaleString());   }else if(_FileName.endsWith(".png") || _FileName.endsWith(".jpg") ||_FileName.endsWith(".jpeg") || _FileName.endsWith(".gif")){ mViewHolder.mFileImage.setTag(mfileData[position].getAbsolutePath()) ; mViewHolder.mFileImage.setImageResource(R.drawable.ic_action_picture); mViewHolder.mFileName.setText(_FileName) ;   mViewHolder.mFileTime.setText(new Date(System.currentTimeMillis()).toLocaleString());  }else if(_FileName.endsWith(".mp4")|| _FileName.endsWith(".avi")|| _FileName.endsWith(".3gp") || _FileName.endsWith(".rmvb")){  mViewHolder.mFileImage.setImageResource(R.drawable.ic_action_video) ;  mViewHolder.mFileName.setText(_FileName) ;   mViewHolder.mFileTime.setText(new Date(System.currentTimeMillis()).toLocaleString());   }else if(_FileName.endsWith("mp3")){  mViewHolder.mFileImage.setImageResource(R.drawable.mp3) ;  mViewHolder.mFileName.setText(mfileData[position].getName()) ;   mViewHolder.mFileTime.setText(new Date(System.currentTimeMillis()).toLocaleString()); }else if(_FileName.endsWith("doc")){ mViewHolder.mFileImage.setImageResource(R.drawable.word) ; mViewHolder.mFileName.setText(mfileData[position].getName()) ;  mViewHolder.mFileTime.setText(new Date(System.currentTimeMillis()).toLocaleString()); } }/*View view = convertView ;view =mlayoutinflater.inflate(com.example.jsp.R.layout.list_item, null) ;TextView tv = (TextView)view.findViewById(com.example.jsp.R.id.tv_name1) ;tv.setText(mfileData[position].getName()+"") ;*/return _view;}//public static void main(String[] args) {//System.out.println(new Date(System.currentTimeMillis()).toString());//}}

至此主活动布局就完成了，主布局效果图：

注意：如果使用模拟器测试，请注意，如果模拟器没有开启 SD 内存iso，请自行开启测试，如果SD内存为空，请自行新建文件测试，谢谢~