我正在构建一个应用程序，以在dropbox帐户中显示文件，如果用户愿意，还可以在本地下载文件。dropbox的内容将显示在单个选项卡片段中！
它成功链接到dropbox帐户，但没有显示文件，而且它冻结了，因为我在UI类中执行网络操作。
我有两个问题。。1.如何在代码中使用AsyncTask2.我如何显示文件，并让用户选择在本地下载，所有这些都在一个选项卡片段中？
我是android开发的新手，任何其他提示都将不胜感激。提前谢谢。
主活动代码。。
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碎片代码
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片段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>
如果您想在列表视图中显示下拉框的文件和文件夹，那么只需在项目中使用此代码，它就能解决您的问题。
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);
}