介绍一个android开源文件选择对话框：android-file-dialog

链接见此：http://code.google.com/p/android-file-dialog/

源码在这里：http://code.google.com/p/android-file-dialog/source/browse/#svn%2Ftrunk%2FFileExplorer%2Fsrc%2Fcom%2Flamerman

谢谢作者的无私贡献，虽然功能简单，但能节省些许开发时间。同时还能应付一些常见的文件选择功能需求，大家可根据自己的项目需求在上面作相应更改。

使用说明：

Usage principles

The dialog is created like this:

Intent intent = new Intent(getBaseContext(), FileDialog.class);
                intent.putExtra(FileDialog.START_PATH, "/sdcard");
                
                //can user select directories or not
                intent.putExtra(FileDialog.CAN_SELECT_DIR, true);
                
                //alternatively you can set file filter
                //intent.putExtra(FileDialog.FORMAT_FILTER, new String[] { "png" });
                
                startActivityForResult(intent, REQUEST_SAVE);

Here "/sdcard" is the start path where the file dialog will open. REQUEST_SAVE is your integer constant, it will then be transmitted to onActivityResult;

CAN_SELECT_DIR - possibility to select directories FORMAT_FILTER - files filter. If file name ends with one of filters the file will be displayed.

When user selects a file or just goes back not selected anything, the activity closes, calling the standard onActivityResult method:

        public synchronized void onActivityResult(final int requestCode,
                int resultCode, final Intent data) {

                if (resultCode == Activity.RESULT_OK) {

                        if (requestCode == REQUEST_SAVE) {
                                System.out.println("Saving...");
                        } else if (requestCode == REQUEST_LOAD) {
                                System.out.println("Loading...");
                        }
                        
                        String filePath = data.getStringExtra(FileDialog.RESULT_PATH);

                } else if (resultCode == Activity.RESULT_CANCELED) {
                        Logger.getLogger(AccelerationChartRun.class.getName()).log(
                                        Level.WARNING, "file not selected");
                }

        }

The result code will be Activity.RESULT_OK if user has selected something and Activity.RESULT_CANCELED if he just pressed the BACK button not selecting anything. You can retrieve the filepath from the intent:

        data.getStringExtra(FileDialog.RESULT_PATH);

If for some reason the words startActivityForResult and onActivityResult are not familiar to you, just read documentation about them. In short, an activity is created and when it exits a handler is called. In this handler you can get the filepath.

You can add one more parameter to the Intent: SelectionMode.MODE_OPEN or SelectionMode.MODE_CREATE

intent.putExtra(FileDialog.SELECTION_MODE, SelectionMode.MODE_OPEN);

SelectionMode.MODE_OPEN will make the NEW button disabled. So user can only select existing files