Develop Reference

Android WebView canGoBack() returns false when URL is similar

I have an Android webview that I want it to go back with the Android back button. I have it working if the previous site is, for example https://www.aaa.com/index.php and https://www.aaa.com/index2.php, but canGoBack() returns false when the URLs are for example, https://www.aaa.com/index.php?page=page1 and https://www.aaa.com/index.php?page=page2. I think this is probably because the URLs are the same, it's just the variables at the end that change. This is my code:
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (event.getAction() == KeyEvent.ACTION_DOWN) {
switch (keyCode) {
case KeyEvent.KEYCODE_BACK:
if (view.canGoBack()) {
view.goBack();
} else {
finish();
}
return true;
}
}
return super.onKeyDown(keyCode, event);
}
How can I make it to go back even if the variable on the URL changes?

You are probably being hit by the bug in Chrome version 63. See: https://bugs.chromium.org/p/chromium/issues/detail?id=794020

Android: Stop Back Button From Exiting LockTask / Kiosk Mode

I want to implement a KioskMode, I'm targeting only Android L, since this is a very specific App.
I already went through the process of setting my App as DeviceAdmin, and
DevicePolicyManager.isLockTaskPermitted(this.getPackageName()) already returns true.
I then start a LockTask via startLockTask().
Everything is fine, but when I hold down the backbutton, the app still exits the kiosk mode.
I have overridden onKeyPress to show a custom Dialog for unlocking the app, but this does not hinder android to automatically exit my lock task if the user holds down back.
I don't really know what to do at the moment and would be thankful for every input.
I now have overridden
#Override
public boolean onKeyDown(int KeyCode, KeyEvent event)
{
if(KeyCode == KeyEvent.KEYCODE_BACK)
{
BackDownButtonPressed = true;
if(VolDownPressed)
showTaskLockDialog();
return true;
}
else if(KeyCode == KeyEvent.KEYCODE_VOLUME_DOWN)
{
VolDownPressed = true;
if(BackDownButtonPressed)
showTaskLockDialog();
return true;
}
return super.onKeyDown(KeyCode, event);
}
#Override
public boolean onKeyUp(int KeyCode, KeyEvent event) {
if(KeyCode == KeyEvent.KEYCODE_BACK)
{
BackDownButtonPressed = false;
return true;
}
else if(KeyCode == KeyEvent.KEYCODE_VOLUME_DOWN)
{
VolDownPressed = false;
return true;
}
return super.onKeyUp(KeyCode, event);
}
#Override
public void onBackPressed()
{
return;
}
#Override
public boolean onNavigateUp() {
return true;
}
#Override
public boolean dispatchKeyEvent (KeyEvent event)
{
if (event.getKeyCode() == KeyEvent.KEYCODE_BACK) {
return true;
}
return true;
}
#Override
public boolean onKeyLongPress(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
//do something or nothing in your case
return true;
}
return super.onKeyLongPress(keyCode, event);
}
For the record, I am using a Samsung SM-T700 Tablet with Cyanogenmod CM12.1

Just to close this topic..
I couldn't figure out a perfect solution to this day. My current workaround is receiving an event if the user leaves the kiosk mode and just entering the kiosk mode again.
Sadly this leaves the user with 2 toasts saying "screen unpinned" and "screen pinned", which is unfortunate. But this satisfies my current needs.

Perhaps you need to override onKeyLongPress
#Override
public boolean onKeyLongPress(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
//do something or nothing in your case
return true
}
return super.onKeyLongPress(keyCode, event);
}

Not sure if it's helpful at all, but I wrote a blog about setting Kiosk Mode here:
http://www.sureshjoshi.com/mobile/android-kiosk-mode-without-root/
And also wrote sample code for it here:
https://github.com/sureshjoshi/android-kiosk-example
Not sure if you see any major differences between your code and mine, but I just tried to do a long press on a Samsung Galaxy Tab 4 running Android 5.0, and it won't exit the app.
Could it be something with rooting with Cyanogen?
If you don't have this in your code, perhaps add it in and check out if you see any problems:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Remove title bar and notification bar
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
ComponentName deviceAdmin = new ComponentName(this, AdminReceiver.class);
mDpm = (DevicePolicyManager) getSystemService(Context.DEVICE_POLICY_SERVICE);
if (!mDpm.isAdminActive(deviceAdmin)) {
Toast.makeText(this, getString(R.string.not_device_admin), Toast.LENGTH_SHORT).show();
}
if (mDpm.isDeviceOwnerApp(getPackageName())) {
mDpm.setLockTaskPackages(deviceAdmin, new String[]{getPackageName()});
} else {
Toast.makeText(this, getString(R.string.not_device_owner), Toast.LENGTH_SHORT).show();
}
mDecorView = getWindow().getDecorView();
}
and
protected void enableKioskMode(boolean enabled) {
try {
if (enabled) {
if (mDpm.isLockTaskPermitted(this.getPackageName())) {
startLockTask();
mIsKioskEnabled = true;
} else {
Toast.makeText(this, getString(R.string.kiosk_not_permitted), Toast.LENGTH_SHORT).show();
}
} else {
stopLockTask();
mIsKioskEnabled = false;
}
} catch (Exception e) {
// TODO: Log and handle appropriately
}
}

I have the same problem: How to stop "holding the back button" from escaping "Lock Task mode" on Android 6+
The issue only occurs on my Android 7 tablet.
Running the app on my Android 6 tablet fixed the problem.
Could you add some code to illustrate your current work-around?

Executing simple code on android app before closing

Hello, I've been trying to integrate airpush in andriod but I've been having some issues.
#Override public boolean onKeyDown(int keyCode, KeyEvent event) {
if ((keyCode == KeyEvent.KEYCODE_BACK) && mWebView.canGoBack()) {
mWebView.goBack();
return true;
}
return super.onKeyDown(keyCode, event);
}
As you can see is the andriod go back code for webview via history.
The problem is that I want execute this code when it has no more history, meaning when the application is about to close.
airpush.startLandingPageAd();
Any help will be greatly appreciated guys :)..

You need to edit your code, like this:
#Override public boolean onKeyDown(int keyCode, KeyEvent event) {
if ((keyCode == KeyEvent.KEYCODE_BACK)) {
if(mWebView.canGoBack())
{
mWebView.goBack();
return true;
}
else
{
//Your webview doesn't have any history here and you can close your app here.
//You can also execute your Airpush code here.
airpush.startLandingPageAd();
return true;
}
}
return super.onKeyDown(keyCode, event);
}
I hope this helps.

Consider overriding onPause method of Activity for executing a piece of code before the activity hides.
#Override
protected void onPause() {
super.onPause();
airpush.startLandingPageAd();
}

Block the home button on android 4

I need to lock the home button in an app, because it will be used by older people and they will not know how to get back if they accidently touch on the home button. I already have that code below but that is not working on android 4.
What I really want is when somebody touches the home button, it does not do anything. Do you have any idea that can help me?
#Override
public void onAttachedToWindow() {
this.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);
super.onAttachedToWindow();
}
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (android.os.Build.VERSION.SDK_INT < android.os.Build.VERSION_CODES.ECLAIR
&& (keyCode == KeyEvent.KEYCODE_BACK || keyCode == KeyEvent.KEYCODE_HOME)
&& event.getRepeatCount() == 0)
{
onBackPressed();
}
return super.onKeyDown(keyCode, event);
}
#Override
public void onBackPressed() {
// Do nothing
return;
}

The only way to do this is to make your app the launcher app on that device, which may not be desirable to the vast majority of Android users, regardless of their age.

Android: How can I set a listener to the MenuButton?

I want to do a custom action when pressing on the Menu button on the phone.
Is it possible to set an onClickListener (or similar) on the button and if so, how?
onCreateOptionsMenu is only called the first time the button is pressed - I've already tried this.

Usually you shouldn't override MENU behavior as users expect menu to appear, however you can use something along these lines:
/* (non-Javadoc)
* #see android.app.Activity#onKeyDown(int, android.view.KeyEvent)
*/
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if ( keyCode == KeyEvent.KEYCODE_MENU ) {
Log.d(TAG, "MENU pressed");
return true;
}
return super.onKeyDown(keyCode, event);
}

But onPrepareOptionsMenu(..) is called each time. :)

Updated for AppCompat v.22.+
As mentioned in this forum, KeyDown is not called for KEYCODE_MENU button pressed.
The solution is to override dispatchKeyEvent to this way:
#Override
public boolean dispatchKeyEvent(KeyEvent event) {
int keyCode = event.getKeyCode();
int action = event.getAction();
boolean isDown = action == KeyEvent.ACTION_DOWN;
if (keyCode == KeyEvent.KEYCODE_MENU) {
return isDown ? this.onKeyDown(keyCode, event) : this.onKeyUp(keyCode, event);
}
return super.dispatchKeyEvent(event);
}
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if ( keyCode == KeyEvent.KEYCODE_MENU ) {
// do what you want to do here
return true;
}
return super.onKeyDown(keyCode, event);
}
It works until Google developers release a fix for this (or maybe it is not a bug and it works this way from now on).

You could probably hack something in using "OnMenuOpened" or some such, but I really wouldn't recommend it. The menu button is only supposed to be used to show menus, so there is consistency between applications.