我试图在PlanetFragment类的onCreateView方法的onPageFinished方法中使用handler。但我得到looper.prepare（）错误。请帮忙。还请告诉我们是否有更好的方法来使用进度条。
public class MainActivity extends Activity {
private DrawerLayout mDrawerLayout;
private ListView mDrawerList;
private ActionBarDrawerToggle mDrawerToggle;
private CharSequence mDrawerTitle;
private CharSequence mTitle;
private String[] mPlanetTitles;
static Handler progressBarHandler;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTitle = mDrawerTitle = getTitle();
mPlanetTitles = getResources().getStringArray(R.array.planets_array);
mDrawerLayout = (DrawerLayout) findViewById(R.id.drawer_layout);
mDrawerList = (ListView) findViewById(R.id.left_drawer);
// set a custom shadow that overlays the main content when the drawer
// opens
mDrawerLayout.setDrawerShadow(R.drawable.drawer_shadow,
GravityCompat.START);
// set up the drawer's list view with items and click listener
mDrawerList.setAdapter(new ArrayAdapter<String>(this,
R.layout.drawer_list_item, mPlanetTitles));
mDrawerList.setOnItemClickListener(new DrawerItemClickListener());
// enable ActionBar app icon to behave as action to toggle nav drawer
getActionBar().setDisplayHomeAsUpEnabled(true);
getActionBar().setHomeButtonEnabled(true);
// ActionBarDrawerToggle ties together the the proper interactions
// between the sliding drawer and the action bar app icon
mDrawerToggle = new ActionBarDrawerToggle(this, /* host Activity */
mDrawerLayout, /* DrawerLayout object */
R.drawable.ic_drawer, /* nav drawer image to replace 'Up' caret */
R.string.drawer_open, /* "open drawer" description for accessibility */
R.string.drawer_close /* "close drawer" description for accessibility */
) {
public void onDrawerClosed(View view) {
getActionBar().setTitle(mTitle);
invalidateOptionsMenu(); // creates call to
// onPrepareOptionsMenu()
}
public void onDrawerOpened(View drawerView) {
getActionBar().setTitle(mDrawerTitle);
invalidateOptionsMenu(); // creates call to
// onPrepareOptionsMenu()
}
};
mDrawerLayout.setDrawerListener(mDrawerToggle);
if (savedInstanceState == null) {
selectItem(0);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.main, menu);
return super.onCreateOptionsMenu(menu);
}
/* Called whenever we call invalidateOptionsMenu() */
@Override
public boolean onPrepareOptionsMenu(Menu menu) {
// If the nav drawer is open, hide action items related to the content
// view
boolean drawerOpen = mDrawerLayout.isDrawerOpen(mDrawerList);
menu.findItem(R.id.action_websearch).setVisible(!drawerOpen);
return super.onPrepareOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// The action bar home/up action should open or close the drawer.
// ActionBarDrawerToggle will take care of this.
if (mDrawerToggle.onOptionsItemSelected(item)) {
return true;
}
// Handle action buttons
switch (item.getItemId()) {
case R.id.action_websearch:
// create intent to perform web search for this planet
Intent intent = new Intent(Intent.ACTION_WEB_SEARCH);
intent.putExtra(SearchManager.QUERY, getActionBar().getTitle());
// catch event that there's no activity to handle intent
if (intent.resolveActivity(getPackageManager()) != null) {
startActivity(intent);
} else {
Toast.makeText(this, R.string.app_not_available,
Toast.LENGTH_LONG).show();
}
return true;
default:
return super.onOptionsItemSelected(item);
}
}
/* The click listner for ListView in the navigation drawer */
private class DrawerItemClickListener implements
ListView.OnItemClickListener {
@Override
public void onItemClick(AdapterView<?> parent, View view, int position,
long id) {
selectItem(position);
}
}
private void selectItem(int position) {
// update the main content by replacing fragments
Fragment fragment = new PlanetFragment();
Bundle args = new Bundle();
args.putInt(PlanetFragment.ARG_PLANET_NUMBER, position);
fragment.setArguments(args);
FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.content_frame, fragment).commit();
// update selected item and title, then close the drawer
mDrawerList.setItemChecked(position, true);
setTitle(mPlanetTitles[position]);
mDrawerLayout.closeDrawer(mDrawerList);
}
@Override
public void setTitle(CharSequence title) {
mTitle = title;
getActionBar().setTitle(mTitle);
}
/**
* When using the ActionBarDrawerToggle, you must call it during
* onPostCreate() and onConfigurationChanged()...
*/
@Override
protected void onPostCreate(Bundle savedInstanceState) {
super.onPostCreate(savedInstanceState);
// Sync the toggle state after onRestoreInstanceState has occurred.
mDrawerToggle.syncState();
}
@Override
public void onConfigurationChanged(Configuration newConfig) {
super.onConfigurationChanged(newConfig);
// Pass any configuration change to the drawer toggls
mDrawerToggle.onConfigurationChanged(newConfig);
}
/**
* Fragment that appears in the "content_frame", shows a planet
*/
public static class PlanetFragment extends Fragment {
public static final String ARG_PLANET_NUMBER = "planet_number";
public PlanetFragment() {
// Empty constructor required for fragment subclasses
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_planet,
container, false);
int i = getArguments().getInt(ARG_PLANET_NUMBER);
String planet = getResources()
.getStringArray(R.array.planets_array)[i];
int imageId = getResources().getIdentifier(
planet.toLowerCase(Locale.getDefault()), "drawable",
getActivity().getPackageName());
final WebView webview = ((WebView) rootView
.findViewById(R.id.image));
final ProgressBar progressbar = ((ProgressBar) rootView
.findViewById(R.id.progressbar));
webview.getSettings().setJavaScriptEnabled(true);
final PlanetFragment activity = this;
webview.setWebViewClient(new WebViewClient() {
@Override
public void onPageStarted(WebView view, String url,
Bitmap favicon) {
view.setVisibility(View.GONE);// hide the webview that will
// display your dialog
new Thread(new Runnable() {
private int progressBarStatus = 0;
private int fileSize;
public void run() {
progressBarHandler = new Handler();
while (progressBarStatus < 100) {
// process some tasks
progressBarStatus = doWork();
// your computer is too fast, sleep 1 second
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
// Update the progress bar
progressBarHandler.post(new Runnable() {
public void run() {
progressbar
.setProgress(progressBarStatus);
}
});
}
// ok, file is downloaded,
if (progressBarStatus >= 100) {
// sleep 2 seconds, so that you can see the 100%
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
private int doWork() {
while (fileSize <= 1000000) {
fileSize++;
if (fileSize == 100000) {
return 10;
} else if (fileSize == 200000) {
return 20;
} else if (fileSize == 300000) {
return 30;
} else if (fileSize == 200000) {
return 40;
} else if (fileSize == 300000) {
return 50;
} else if (fileSize == 200000) {
return 60;
} else if (fileSize == 300000) {
return 70;
} else if (fileSize == 200000) {
return 80;
} else if (fileSize == 300000) {
return 90;
}
}
return 100;
}
}).start();
}
@Override
public void onPageFinished(WebView view, String url) {
progressBarHandler = new Handler();
webview.loadUrl("javascript:document.getElementsByClassName('header')[0].style.display=\"none\";");
webview.loadUrl("javascript:document.getElementsByClassName('icon-anon')[0].style.display=\"none\";");
webview.loadUrl("javascript:document.getElementsByClassName('search')[0].style.display=\"none\";");
webview.loadUrl("javascript:document.getElementsByClassName('wh_ad')[0].style.display=\"none\";");
webview.loadUrl("javascript:document.getElementsByClassName('cse_x')[0].style.display=\"none\";");
webview.loadUrl("javascript:document.getElementsByClassName('wh_search')[0].style.display=\"none\";");
webview.loadUrl("javascript:document.getElementsByClassName('wh_ad')[0].style.display=\"none\";");
webview.loadUrl("javascript:document.getElementsByClassName('wh_ad')[0].style.display=\"none\";");
webview.loadUrl("javascript:document.getElementsByClassName('footer_random_button')[0].style.display=\"none\";");
webview.loadUrl("javascript:document.getElementsByClassName('mw-mf-page-left')[0].style.display=\"none\";");
webview.loadUrl("javascript:document.getElementsByClassName('mw-mf-viewport')[0].style.display=\"none\";");
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
// Code here will run in UI thread
}
},1000);
webview.getSettings().setJavaScriptEnabled(false);
view.setVisibility(View.VISIBLE);
// you might need this
view.bringToFront();
}
});
webview.loadUrl(planet);
getActivity().setTitle(planet);
return rootView;
}
}
}
答案 0 :(得分：0)
您必须在活动
中创建处理程序只需在 onCreate 活动方法中初始化处理程序
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
progressBarHandler = new Handler();
// rest of your code
并删除Fragment类中的初始化，因为它已在Activity中初始化。只需在Fragment Class中使用 progressBarHandler ，它就能正常工作。