Android----弹出框选择文件夹目录 以及启用新的Task打开文件

首先看效果图

 

第一个Activity很简单就是一个按钮Button 加一个 TextView

见main.xml

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout
   xmlns:android="http://schemas.android.com/apk/res/android"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent"
   android:orientation="vertical"
   android:background="@drawable/white"
 >
 <Button
     android:id="@+id/button"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:text="选择文件"
     />
 <TextView
     android:id="@+id/fileText"
     android:gravity="center"
     android:textSize="20px"
     android:textColor="#219ac6"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent"
     />
 </LinearLayout>

Button弹出显示文件夹选择框

TextView就是用来显示当前选择的文件夹路径

 public class MainAcivity extends Activity{

     public static final int FILE_RESULT_CODE = 1;

     private TextView textView;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main);
         Button button = (Button)findViewById(R.id.button);
         textView = (TextView)findViewById(R.id.fileText);
         button.setOnClickListener(new OnClickListener() {

             public void onClick(View v) {
                 Intent intent = new Intent(MainAcivity.this,MyFileManager.class);
                 startActivityForResult(intent, FILE_RESULT_CODE);
             }
         });
     }

     @Override
     protected void onActivityResult(int requestCode, int resultCode, Intent data) {
         if(FILE_RESULT_CODE == requestCode){
             Bundle bundle = null;
             if(data!=null&&(bundle=data.getExtras())!=null){
                 textView.setText("选择文件夹为："+bundle.getString("file"));
             }
         }
     }
 }

这里通过startActivityForResult()弹出的Activity  所以要重写onActivityResult方法

在目标Activity调用方法finish()的时候会回调

这里需要注意在按返回键时也会调用该方法 所以这里还需要判空

然后再 MyFileManager 这个Activity中通过ListView来显示文件列表

布局文件 fileselect.xml

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout
   xmlns:android="http://schemas.android.com/apk/res/android"
   android:layout_width="250px"
   android:layout_height="400px"
   android:orientation="vertical"
   android:background="@drawable/white"
 >
   <TextView
     android:id="@+id/mPath"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:padding="5px"
     android:textSize="18sp"
     android:textColor="@drawable/blue"
   >
   </TextView>
   <ListView
     android:id="@android:id/list"
     android:layout_width="fill_parent"
     android:layout_height="330px"
   >
   </ListView>
   <LinearLayout
     android:gravity="center"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:orientation="horizontal"
     android:background="@drawable/white"
     >
     <Button
     android:id="@+id/buttonConfirm"
     android:layout_width="125px"
     android:layout_height="fill_parent"
     android:text="确定"
     />
     <Button
     android:id="@+id/buttonCancle"
     android:layout_width="125px"
     android:layout_height="fill_parent"
     android:text="取消"
     />

   </LinearLayout>
 </LinearLayout>

列表显示Item 通过布局文件 file_row.xml

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout
   xmlns:android="http://schemas.android.com/apk/res/android"
   android:orientation="horizontal"
   android:layout_width="fill_parent"
   android:layout_height="fill_parent"
   android:background="#ffffff"
 >
 <LinearLayout
         android:orientation="horizontal"
         android:layout_width="fill_parent"
         android:layout_height="fill_parent"
         android:background="@drawable/listview_selected"
         android:padding="6px"
     >
   <ImageView android:id="@+id/icon"
     android:layout_width="30dip"
     android:layout_height="30dip"
   >
   </ImageView>
   <TextView android:id="@+id/text"
     android:layout_gravity="center_horizontal"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:textColor="@drawable/black"
   >
   </TextView>
   </LinearLayout>
 </LinearLayout>

这里简单实现点击变换底色的效果 通过两层LinearLayout 的方式实现 创建一个select可以自定义点击效果 就不赘述了

文件选择代码

 package com.debby;
 import java.io.File;
 import java.util.ArrayList;
 import java.util.List;
 import android.app.ListActivity;
 import android.content.Intent;
 import android.net.Uri;
 import android.os.Bundle;
 import android.util.Log;
 import android.view.View;
 import android.view.View.OnClickListener;
 import android.view.Window;
 import android.widget.Button;
 import android.widget.ListView;
 import android.widget.TextView;
 public class MyFileManager extends ListActivity {
     private List<String> items = null;
     private List<String> paths = null;
     private String rootPath = "/";
     private String curPath = "/";
     private TextView mPath;
     private final static String TAG = "bb";
     @Override
     protected void onCreate(Bundle icicle) {
         super.onCreate(icicle);
         requestWindowFeature(Window.FEATURE_NO_TITLE);
         setContentView(R.layout.fileselect);
         mPath = (TextView) findViewById(R.id.mPath);
         Button buttonConfirm = (Button) findViewById(R.id.buttonConfirm);
         buttonConfirm.setOnClickListener(new OnClickListener() {
             public void onClick(View v) {
                 Intent data = new Intent(MyFileManager.this, MainAcivity.class);
                 Bundle bundle = new Bundle();
                 bundle.putString("file", curPath);
                 data.putExtras(bundle);
                 setResult(2, data);
                 finish();
             }
         });
         Button buttonCancle = (Button) findViewById(R.id.buttonCancle);
         buttonCancle.setOnClickListener(new OnClickListener() {
             public void onClick(View v) {
                 finish();
             }
         });
         getFileDir(rootPath);
     }
     private void getFileDir(String filePath) {
         mPath.setText(filePath);
         items = new ArrayList<String>();
         paths = new ArrayList<String>();
         File f = new File(filePath);
         File[] files = f.listFiles();
         if (!filePath.equals(rootPath)) {
             items.add("b1");
             paths.add(rootPath);
             items.add("b2");
             paths.add(f.getParent());
         }
         for (int i = 0; i < files.length; i++) {
             File file = files[i];
             items.add(file.getName());
             paths.add(file.getPath());
         }
         setListAdapter(new MyAdapter(this, items, paths));
     }
     @Override
     protected void onListItemClick(ListView l, View v, int position, long id) {
         File file = new File(paths.get(position));
         if (file.isDirectory()) {
             curPath = paths.get(position);
             getFileDir(paths.get(position));
         } else {
             //可以打开文件
         }
     }
 }

 

 import java.io.File;
 import java.util.List;
 import com.debby.R;
 import android.content.Context;
 import android.graphics.Bitmap;
 import android.graphics.BitmapFactory;
 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 MyAdapter extends BaseAdapter
 {
   private LayoutInflater mInflater;
   private Bitmap mIcon1;
   private Bitmap mIcon2;
   private Bitmap mIcon3;
   private Bitmap mIcon4;
   private List<String> items;
   private List<String> paths;
   public MyAdapter(Context context,List<String> it,List<String> pa)
   {
     mInflater = LayoutInflater.from(context);
     items = it;
     paths = pa;
     mIcon1 = BitmapFactory.decodeResource(context.getResources(),R.drawable.back01);
     mIcon2 = BitmapFactory.decodeResource(context.getResources(),R.drawable.back02);
     mIcon3 = BitmapFactory.decodeResource(context.getResources(),R.drawable.folder);
     mIcon4 = BitmapFactory.decodeResource(context.getResources(),R.drawable.doc);
   }

   @Override
   public int getCount()
   {
     return items.size();
   }
   @Override
   public Object getItem(int position)
   {
     return items.get(position);
   }

   @Override
   public long getItemId(int position)
   {
     return position;
   }

   @Override
   public View getView(int position,View convertView,ViewGroup parent)
   {
     ViewHolder holder;

     if(convertView == null)
     {
       convertView = mInflater.inflate(R.layout.file_row, null);
       holder = new ViewHolder();
       holder.text = (TextView) convertView.findViewById(R.id.text);
       holder.icon = (ImageView) convertView.findViewById(R.id.icon);

       convertView.setTag(holder);
     }
     else
     {
       holder = (ViewHolder) convertView.getTag();
     }
     File f=new File(paths.get(position).toString());
     if(items.get(position).toString().equals("b1"))
     {
       holder.text.setText("返回根目录..");
       holder.icon.setImageBitmap(mIcon1);
     }
     else if(items.get(position).toString().equals("b2"))
     {
       holder.text.setText("返回上一层..");
       holder.icon.setImageBitmap(mIcon2);
     }
     else
     {
       holder.text.setText(f.getName());
       if(f.isDirectory())
       {
         holder.icon.setImageBitmap(mIcon3);
       }
       else
       {
         holder.icon.setImageBitmap(mIcon4);
       }
     }
     return convertView;
   }
   private class ViewHolder
   {
     TextView text;
     ImageView icon;
   }
 }

在 onListItemClick 事件中改变ListView的Adapter实现打开文件夹

这里点击文件夹时可以打开目录，如果选择文件可以根据类型来启用不同工具来打开

方法如下

 private void openFile(File f) {
         Intent intent = new Intent();
         intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
         intent.setAction(android.content.Intent.ACTION_VIEW);
         String type = getMIMEType(f);
         intent.setDataAndType(Uri.fromFile(f), type);
         startActivity(intent);
     }
     private String getMIMEType(File f) {
         String type = "";
         String fName = f.getName();
         String end = fName
                 .substring(fName.lastIndexOf(".") + 1, fName.length())
                 .toLowerCase();
         if (end.equals("m4a") || end.equals("mp3") || end.equals("mid")
                 || end.equals("xmf") || end.equals("ogg") || end.equals("wav")) {
             type = "audio";
         } else if (end.equals("3gp") || end.equals("mp4")) {
             type = "video";
         } else if (end.equals("jpg") || end.equals("gif") || end.equals("png")
                 || end.equals("jpeg") || end.equals("bmp")) {
             type = "image";
         } else {
             type = "*";
         }
         type += "/*";
         return type;
     }

根据文件的后缀名来确定type 然后打开文件，打开方式通过setDataAndType方法设置