我正在构建一个应用程序来显示Dropbox帐户中的文件，如果她选择的话，也允许用户在本地下载文件。 Dropbox的内容将显示在一个标签片段中！
它成功链接到保管箱帐户，但没有显示文件，也冻结了，因为我正在UI类中执行网络操作。
我有两个问题.. 1.如何在代码中使用AsyncTask 2.如何在单个选项卡片段中显示文件并为用户提供在本地下载文件的选项？
我是Android开发的新手，任何其他提示将不胜感激。 提前谢谢。
MainActivity code ..
public class MainActivity extends ActionBarActivity {
final static private String APP_KEY = "key_here";
final static private String APP_SECRET = "secret_here";
final static private AccessType ACCESS_TYPE = AccessType.DROPBOX;
private static final boolean USE_OAUTH1 = false;
// You don't need to change these, leave them alone.
final static private String ACCOUNT_PREFS_NAME = "prefs";
final static private String ACCESS_KEY_NAME = "ACCESS_KEY";
final static private String ACCESS_SECRET_NAME = "ACCESS_SECRET";
// In the class declaration section;
protected DropboxAPI<AndroidAuthSession> mDBApi;
static String[] fnames;
@Override
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
// Notice that setContentView() is not used, because we use the root
// android.R.id.content as the container for each fragment
// setup action bar for tabs
ActionBar actionBar = getSupportActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
actionBar.setDisplayShowTitleEnabled(true);
final String info = "Info";
final String db = "Dropbox";
Tab tab = actionBar.newTab()
.setText(info)
.setTabListener(new TabListener<InfoFragment>(
this,"info", InfoFragment.class));
actionBar.addTab(tab);
tab = actionBar.newTab()
.setText(db)
.setTabListener(new TabListener<DbFragment>(
this, "dropbox", DbFragment.class));
actionBar.addTab(tab);
// And later in some initialization function:
AndroidAuthSession session = buildSession();
mDBApi = new DropboxAPI<AndroidAuthSession>(session);
if (USE_OAUTH1){
mDBApi.getSession().startAuthentication(MainActivity.this);
} else{
mDBApi.getSession().startOAuth2Authentication(MainActivity.this);
}
int i = 0;
fnames = null;
Entry entries;
ArrayList<Entry> files = new ArrayList<Entry>();
ArrayList<String> dir = new ArrayList<String>();
try {
entries = mDBApi.metadata("/", 100, null, true, null);
for (Entry e: entries.contents){
if (!e.isDeleted){
files.add(e);
dir.add(new String(files.get(i++).path));
}
}
} catch (DropboxException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
fnames = dir.toArray(new String[dir.size()]);
}
public static class TabListener<T extends Fragment> implements ActionBar.TabListener {
private Fragment mFragment;
private final Activity mActivity;
private final String mTag;
private final Class<T> mClass;
/** Constructor used each time a new tab is created.
* @param activity The host Activity, used to instantiate the fragment
* @param tag The identifier tag for the fragment
* @param clz The fragment's Class, used to instantiate the fragment
*/
public TabListener(Activity activity, String tag, Class<T> clz) {
mActivity = activity;
mTag = tag;
mClass = clz;
}
/* The following are each of the ActionBar.TabListener callbacks */
public void onTabSelected(Tab tab, FragmentTransaction ft) {
// Check if the fragment is already initialized
if (mFragment == null) {
// If not, instantiate and add it to the activity
mFragment = Fragment.instantiate(mActivity, mClass.getName());
ft.add(android.R.id.content, mFragment, mTag);
} else {
// If it exists, simply attach it in order to show it
ft.attach(mFragment);
}
}
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
if (mFragment != null) {
// Detach the fragment, because another one is being attached
ft.detach(mFragment);
}
}
public void onTabReselected(Tab tab, FragmentTransaction ft) {
// User selected the already selected tab. Usually do nothing.
}
}
@Override
public void onResume(){
super.onResume();
if (mDBApi.getSession().authenticationSuccessful()){
try{
//Required to complete auth, sets the access token on the session
mDBApi.getSession().finishAuthentication();
String accessToken = mDBApi.getSession().getOAuth2AccessToken();
} catch (IllegalStateException e ){
Log.i("DBAuthLog", "Error authenticating",e );
}
}
}
private void loadAuth(AndroidAuthSession session) {
SharedPreferences prefs = getSharedPreferences(ACCOUNT_PREFS_NAME, 0);
String key = prefs.getString(ACCESS_KEY_NAME, null);
String secret = prefs.getString(ACCESS_SECRET_NAME, null);
if (key == null || secret == null || key.length() == 0 || secret.length() == 0) return;
if (key.equals("oauth2:")) {
// If the key is set to "oauth2:", then we can assume the token is for OAuth 2.
session.setOAuth2AccessToken(secret);
} else {
// Still support using old OAuth 1 tokens.
session.setAccessTokenPair(new AccessTokenPair(key, secret));
}
}
/**
* Shows keeping the access keys returned from Trusted Authenticator in a local
* store, rather than storing user name & password, and re-authenticating each
* time (which is not to be done, ever).
*/
private void storeAuth(AndroidAuthSession session) {
// Store the OAuth 2 access token, if there is one.
String oauth2AccessToken = session.getOAuth2AccessToken();
if (oauth2AccessToken != null) {
SharedPreferences prefs = getSharedPreferences(ACCOUNT_PREFS_NAME, 0);
Editor edit = prefs.edit();
edit.putString(ACCESS_KEY_NAME, "oauth2:");
edit.putString(ACCESS_SECRET_NAME, oauth2AccessToken);
edit.commit();
return;
}
// Store the OAuth 1 access token, if there is one. This is only necessary if
// you're still using OAuth 1.
AccessTokenPair oauth1AccessToken = session.getAccessTokenPair();
if (oauth1AccessToken != null) {
SharedPreferences prefs = getSharedPreferences(ACCOUNT_PREFS_NAME, 0);
Editor edit = prefs.edit();
edit.putString(ACCESS_KEY_NAME, oauth1AccessToken.key);
edit.putString(ACCESS_SECRET_NAME, oauth1AccessToken.secret);
edit.commit();
return;
}
}
private AndroidAuthSession buildSession() {
AppKeyPair appKeyPair = new AppKeyPair(MainActivity.APP_KEY, MainActivity.APP_SECRET);
AndroidAuthSession session = new AndroidAuthSession(appKeyPair);
loadAuth(session);
return session;
}
}
Dropbox Fragment Code
public class DbFragment extends ListFragment {
private ListView mListView;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
String[] xfnames = MainActivity.fnames;
ListView listView = new ListView(getActivity());
ArrayAdapter<String> array = new ArrayAdapter<String>(getActivity(),
android.R.layout.simple_list_item_1, xfnames);
for (String str: xfnames)
array.add(str);
setListAdapter(array);
return super.onCreateView(inflater, container, savedInstanceState);
}
}
主要活动XML
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/hello">
android:layout_marginTop="40dp"
android:textSize="40sp"/>
</TextView>
<ListView
android:id="@android:id/list"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
</ListView>
</LinearLayout>
Dropbox Fragment XML
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<ListView
android:id="@android:id/list"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
</ListView>
</RelativeLayout>
答案 0 :(得分：0)
如果要在列表视图中显示下拉框的文件和文件夹，只需在项目中使用此代码即可解决问题。
private void PopulateList()
{
List<String> filename = new ArrayList<String>();
String mPath = "/";
Entry dirent = null;
try
{
dirent = mApi.metadata(mPath, 1000, null, true, null);
} catch (DropboxException e)
{
System.out.println("Error : "+e.getMessage());
}
for (Entry ent: dirent.contents)
{
filename.add(ent.fileName());
//Putting all these FILES & FOLDER in LIST VIEW
ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(getBaseContext(),android.R.layout.simple_list_item_1, filename );
mListView.setAdapter(arrayAdapter);
}