我正在开发一款应用，允许用户从外部存储中选择一个文件并使用Android Beam发送。
这是FileBrowser Activity，用于从目录中选择文件并将文件名和目录路径返回给主活动：
public class FileBrowser extends Activity {
private String root;
private String currentPath;
private ArrayList<String> targets;
private ArrayList<String> paths;
private File targetFile;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_file_browser);
getActionBar().setDisplayHomeAsUpEnabled(true);
root = "/";
currentPath = root;
targets = null;
paths = null;
targetFile = null;
showDir(currentPath);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_file_browser, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
NavUtils.navigateUpFromSameTask(this);
return true;
}
return super.onOptionsItemSelected(item);
}
public void selectDirectory(View view) {
File f = new File(currentPath);
targetFile = f;
//Return target File to activity
returnTarget();
}
public void setCurrentPathText(String message)
{
TextView fileTransferStatusText = (TextView) findViewById(R.id.current_path);
fileTransferStatusText.setText(message);
}
private void showDir(String targetDirectory){
setCurrentPathText("Current Directory: " + currentPath);
targets = new ArrayList<String>();
paths = new ArrayList<String>();
File f = new File(targetDirectory);
File[] directoryContents = f.listFiles();
if (!targetDirectory.equals(root))
{
targets.add(root);
paths.add(root);
targets.add("../");
paths.add(f.getParent());
}
for(File target: directoryContents)
{
paths.add(target.getPath());
if(target.isDirectory())
{
targets.add(target.getName() + "/");
}
else
{
targets.add(target.getName());
}
}
ListView fileBrowserListView = (ListView) findViewById(R.id.file_browser_listview);
ArrayAdapter<String> directoryData = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, targets);
fileBrowserListView.setAdapter(directoryData);
fileBrowserListView.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> arg0, View view, int pos,long id) {
File f = new File(paths.get(pos));
if(f.isFile())
{
targetFile = f;
returnTarget();
//Return target File to activity
}
else
{
//f must be a dir
if(f.canRead())
{
currentPath = paths.get(pos);
showDir(paths.get(pos));
}
}
}
});
}
public void returnTarget()
{
Intent returnIntent = new Intent();
returnIntent.putExtra("file", targetFile);
returnIntent.putExtra("path", currentPath);
setResult(RESULT_OK, returnIntent);
finish();
}
}
以下是MainActivity的代码，其中FileBrowser Activity返回的文件是使用android beam发送的：
public class MainActivity extends Activity {
private NfcAdapter nfcAdapter;
public final int fileRequestID = 98;
String name;
String[] extension={".png",".docx",".jpeg",".pdf",".doc"};
ArrayList <String>supportedExtension=new ArrayList<String>(Arrays.asList(extension));
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
PackageManager pm = this.getPackageManager();
// Check whether NFC is available on device
if (!pm.hasSystemFeature(PackageManager.FEATURE_NFC)) {
// NFC is not available on the device.
Toast.makeText(this, "The device does not has NFC hardware.",
Toast.LENGTH_SHORT).show();
}
// Check whether device is running Android 4.1 or higher
else if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {
// Android Beam feature is not supported.
Toast.makeText(this, "Android Beam is not supported.",
Toast.LENGTH_SHORT).show();
}
else {
// NFC and Android Beam file transfer is supported.
Toast.makeText(this, "Android Beam is supported on your device.",
Toast.LENGTH_SHORT).show();
}
}
public void browseForFile(View view) {
Intent clientStartIntent = new Intent(this, FileBrowser.class);
startActivityForResult(clientStartIntent, fileRequestID);
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
//fileToSend
boolean filePathProvided;
File fileToSend;
if (resultCode == Activity.RESULT_OK && requestCode == fileRequestID) {
//Fetch result
File targetDir = (File) data.getExtras().get("file");
String path = (String)data.getExtras().get("path");
Log.i("Path=",path);
if(targetDir.isFile())
{
if(targetDir.canRead()) {
try{
String ext=targetDir.getName().substring(targetDir.getName().lastIndexOf("."));
if (supportedExtension.contains(ext)) {
fileToSend = targetDir;
filePathProvided = true;
setTargetFileStatus(targetDir.getName() + " selected for file transfer");
Button btn = (Button) findViewById(R.id.send);
btn.setVisibility(View.VISIBLE);
name = targetDir.getName();
}
else{
Toast.makeText(getApplicationContext(), "File with this extension cannot be printed",
Toast.LENGTH_LONG).show();
}
}catch (Exception e){e.printStackTrace();}
}
else
{
filePathProvided = false;
setTargetFileStatus("You do not have permission to read the file " + targetDir.getName());
}
}
else
{
filePathProvided = false;
setTargetFileStatus("You may not transfer a directory, please select a single file");
}
}
}
public void setTargetFileStatus(String message)
{
TextView targetFileStatus = (TextView) findViewById(R.id.selected_filename);
targetFileStatus.setText(message);
}
public void sendFile(View view) {
nfcAdapter = NfcAdapter.getDefaultAdapter(this);
// Check whether NFC is enabled on device
if(!nfcAdapter.isEnabled()){
Toast.makeText(this, "Please enable NFC.", Toast.LENGTH_SHORT).show();
startActivity(new Intent(Settings.ACTION_NFC_SETTINGS));
}
else if(!nfcAdapter.isNdefPushEnabled()) {
Toast.makeText(this, "Please enable Android Beam.",
Toast.LENGTH_SHORT).show();
startActivity(new Intent(Settings.ACTION_NFCSHARING_SETTINGS));
}
else {
Uri[] mFileUris = new Uri[1];
String fileName=name;
// Retrieve the path to the user's public pictures directory
File fileDirectory = Environment
.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
File fileToTransfer;
fileToTransfer = new File(fileDirectory, fileName);
fileToTransfer.setReadable(true, false);
mFileUris[0] = Uri.fromFile(fileToTransfer);
nfcAdapter.setBeamPushUris(mFileUris, this);
}
}
}
现在，正如您在我的MainActivity中所看到的，我将目录设置为图片。
File fileDirectory = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
我的问题是如何根据从FileBrowser Activity获得的实际目录值每次动态更改我的目录？
我已经浏览了How to send files using Android Beam的android文档，但是没有发现它对我的问题有用。我也浏览了Environment的android文档，但是听不懂。
对此有任何帮助将非常感激。提前谢谢！
答案 0 :(得分：0)
您已在OnActivityResult方法中选择了该文件。只需改变
mFileUris[0] = Uri.fromFile(fileToTransfer);
到
mFileUris[0] = Uri.fromFile(targetDir);