I'm developing an Android app which uses a webview to display a webpage. Most of my code is related to the webview. My main activity contains a webview which displays an specific web site.
I'm trying to prevent an error when my webview.db is corrupted. I know that is not a common situation but I would like to make sure that my app will not crash.
Attempting to access the webview database when it has been
corrupted will result in a crash.
I added the method setUncaughtExceptionHandler to handle the exception. I can catch the exeption but when I tried to restart my app the webview never finishes loading.
I tried the follow code to "restart" my app:
Intent i = new Intent(context, Error.class);
i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
context.startActivity(i);
My last try was unsuccessfully then I added some code which displays an error message, removes the webview databases and closes the app.
AlertDialog alertDialog = new AlertDialog.Builder(
DiscoverMobile.this).create();
alertDialog.setTitle("Error");
alertDialog.setMessage("Application files have been deleted or corrupted. The app will close to fix this issue. You can restart the app later");
alertDialog.setButton("OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog,
int which) {
webview.getContext().deleteDatabase(
"webview.db");
webview.getContext().deleteDatabase(
"webviewCache.db");
WebViewDatabase webViewDB = WebViewDatabase
.getInstance(getBaseContext());
System.exit(0);
}
});
alertDialog.show();
Could this be a good solution?
Override
public void onPageFinished(WebView view, String url) {
super.onPageFinished(view, url);
view.clearCache(true);
}
Maybe you tried this, but maybe also set the WebView Cache size to something small. I'm not sure if 0 will work, so maybe 1:
webview.getSettings().setAppCacheMaxSize(1);
Related
if there is no internet means I'm not able to load web resources. For this reason I'm giving the toast like "Check internet connectivity". After this toast, user may enable the internet option at notification bar and comes back. When he comes back, i want to reload the activity. For this requirement, i tried
onWindowFocusChanged and onActivityReenter
override methods but these are not working properly
MyCode
public void onWindowFocusChanged(boolean hasFocus) {
super.onWindowFocusChanged(hasFocus);
if(hasFocus){
Intent intent = new Intent(CommonActivity.this, OtherActivity.class);
startActivity(intent);
}
}
When I'm using above code, my activity reloading again and again
There is a solution which i know is not perfect but it will work.
Define a activity level veriable like this
Boolean isAlreadyFocused = false;
Then in your onFocusChanged method do like this.
public void onWindowFocusChanged(boolean hasFocus) {
super.onWindowFocusChanged(hasFocus);
if(hasFocus && !isAlreadyFocused ){
isAlreadyFocused = true;
Intent intent = new Intent(CommonActivity.this,OtherActivity.class);
startActivity(intent);
}else{
isAlreadyFocused = false;
}
}
Check this and tell me if this does not work.
By fallowing another way (i got this idea when i saw the flipkart app) i solved this internet checking
I'm checking for the internet connection, if there is no internet means i'm redirecting to NoInternetActivity that's design looks like
When user clicks on Retry button means i'm again checking for internet. If internet was accessible means i'm allowing user to home page of my app otherwise i'm redirecting to the NoInternetActivity again
New to Android... I understand Dialogs are asynchronous. But I really can't get my head around the flow for confirming an action. Can someone please explain the flow?
I want to save a file on the sdcard. The Activity prompts the used for the filename. Then it checks to see if the file exists. If it exists, it needs to prompt the user to confirm if they want to overwrite it. Then it proceeds to erase and write the file.
I know you can't hold execution waiting for the response. How then would this common flow work in Android?
Thanks
I am not 100% it is what you are looking for, but here is a link to the Android documentation explaining how we should display Confirmation and Acknowledgement popups using the "Android standard way":
http://developer.android.com/design/patterns/confirming-acknowledging.html
I do not know the exact flow, I suppose it would depend on how the application was written. I would check for the file if it existed call the dialog windows then if the Ok/Yes/Confirm is pressed overwrite the file.
Dialogs | Android Developers - Has an excellent code example
public class FireMissilesDialogFragment extends DialogFragment {
#Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
// Use the Builder class for convenient dialog construction
AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
builder.setMessage(R.string.dialog_fire_missiles)
.setPositiveButton(R.string.fire, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
// FIRE ZE MISSILES! AKA Overwrite your file.
}
})
.setNegativeButton(R.string.cancel, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
// User cancelled the dialog AKA do nothing
}
});
// Create the AlertDialog object and return it
return builder.create();
}
}
I know it's slightly silly example but basically check for the file (if exist) > Call Dialog (if yes)> Overwrite.
I have some code that build a dialog box and makes a listener for it. The dialog box displays fine, but the code inside the listener doesn't seem to run, and I don't know why.
private void showBackgrounDialog() {
AlertDialog.Builder builder = new AlertDialog.Builder(MeacruxActivity.this);
builder.setTitle(R.string.background_dialog_title).setCancelable(true)
.setItems(R.array.background_options,
new DialogInterface.OnClickListener(){
#Override
public void onClick(DialogInterface dialog, int selection) {
Log.d(logID, "the selection is: " + selection);
if(backgrounds.length==selection){
notImplementedYet.show();
return;
}
setBckground(backgrounds[selection]);
}
});
currentDialog = builder.create();
currentDialog.show();
}
private void setBackground(String bgName) {
Log.d(logID, bgName);
}
The dialog shows up properly with all the options and everything, but when I click on one nothing come sup in the log.... Why is that?
Edit: I did some more testing and I can confirm that the code inside of the onClick function is being run, its just that the log isnt showing up...
I'm assuming you are looking in eclipse or studio
In DDMS view, make sure the device is selected.
In Logcat view, make sure there's not a filter applied.
On terminal, type adb logcat... does it show up there?
In my onCreate method Im creating an webView and then loading an HTML file thats saved in my assets folder. This is all working fine. When a button is pressed it sends a call using javascript to this method to open the qr code scanner.
webView.setWebViewClient(new WebViewClient()
{
/* On Android 1.1 shouldOverrideUrlLoading() will be called every time the user clicks a link,
* but on Android 1.5 it will be called for every page load, even if it was caused by calling loadUrl()! */
#Override
public boolean shouldOverrideUrlLoading(WebView view, String url)
{
System.out.println(url);
if (url.equals("fake://qr_scan"))
{
launchQRScanner(view);
}
return false;
}
});
Here is the method launchQRScanner()
public void launchQRScanner(View v) {
if (isCameraAvailable()) {
Intent intent = new Intent(this, ZBarScannerActivity.class);
intent.putExtra(ZBarConstants.SCAN_MODES, new int[]{Symbol.QRCODE});
startActivityForResult(intent, ZBAR_SCANNER_REQUEST);
} else {
Toast.makeText(this, "Rear Facing Camera Unavailable", Toast.LENGTH_SHORT).show();
}
}
So this works for the first time the button is pressed. The qr code reader open as an intent, it scans, disappears and returns the value correctly. But for every time after the method shouldOverrideUrlLoading() doesn't get called when the button is pressed. Possibly has something to do with leaving the app and coming back? Can't seem to figure it out.
BTW this is the project that I used to implement the qr code reader
https://github.com/DushyanthMaguluru/ZBarScanner
Fixed, Just had to reload the webView after the barcode is scanned. Simple fix.
I recently started developing a mobile app in Phonegap 1.8 + Jquerymobile 1.1.0 +jquery 1.7.1 for Android 2.3.3. My problem is:
I've tried overriding backbutton in Android in several ways, nothing works though. I've tried using
document.addEventListener("backbutton", handleBackButton, false);
function handleBackButton() {//do sth}
then I've just overrided it in Application.java code. And it works... almost.
My 1st page (index.html) is being just used to login after that there is main page (main.html) with links to other pages. I've overrided backbutton to goback on every other page than login and main. On those two pages it should exit the app after clicking "yes" in AlertDialog. Well, in MainPage it shows the AlertDialog and then goes straight back to login page without waiting even for my response. On login page it just shows the AlertDialog and waits for my reaction. Don't know why. Here is some of my code.
public void onBackPressed() {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("Are you sure you want to exit?")
.setCancelable(false)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
SampleApplication.this.finish();
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
dialog.cancel();
}
});
AlertDialog alert = builder.create();
String testUrl = appView.getUrl();
if(testUrl.equals("file:///android_asset/www/index.html"))
{
alert.show();
}
if (testUrl.equals("file:///android_asset/www/main.html"))
{
alert.show();
}
if ((!testUrl.equals("file:///android_asset/www/index.html")) && (!testUrl.equals("file:///android_asset/www/main.html")))
{
this.appView.goBack();
}
}
What you could do is use the regular back button on all pages that you want the regular back button behaviour but create a separate button for the pages where you need a different behaviour and just make it look like the normal back button:
In your header bar, just add an anchor where you add a custom data-rel (and hook it up to whatever function you want) e.g.
<a data-rel="custombackbtn">Back</a>
Then add in that data-rel to wherever your regular back button is styled (your theme's css or regular css) so, wherever there's a mention of a[data-rel='back'] add data-rel='custombackbtn' e.g.
a[data-rel='back'], .ui-header a[data-rel='back'] {
*/Styling*/
}
is changed to
a[data-rel='back'], .ui-header a[data-rel='back'], a[data-rel='backbtn'], .ui-header a[data-rel='backbtn'] {
*/Styling*/
}