I am able to detect when the back button is pressed by using:
#Override
public void onBackPressed() {
//Do my thing
}
But now I want to detect when the back button is released. How can I do that? I'm unable to find any method like onBackReleased() which I can override to do my thing.
There is no method that specifically detects the back button release, but you could use the onKeyDown() and onKeyUp() methods. Check to make sure the key is the back button, and do your stuff in the method. Here is something you could do:
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
// do your stuff for when the back button is initially pressed
return true;
} else {
return false;
}
}
#Override
public boolean onKeyUp(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
// do your stuff for when the back button is released
return true;
} else {
return false;
}
}
If you wanted to override the default back press, you could just use the onBackPressed() method, like so:
#Override
public void onBackPressed() {
// Prevents the user from clicking the back button and returning to the parent activity
}
These methods can be implemented directly in your class. Hope it helps!
Related
I am Using following method to disable HomeKey click event ,but after Clicking Home key My App will be closed. I want ,whenever user click home key my app will not be close.
#Override
protected void onUserLeaveHint() {
super.onUserLeaveHint();
moveTaskToBack(false);
}
Since Android 4 there is no effective method to deactivate the home
button. That is the reason why we need another little hack. In general
the idea is to detect when a new application is in foreground and
restart your activity immediately.
Check this workaround: http://www.andreas-schrade.de/2015/02/16/android-tutorial-how-to-create-a-kiosk-mode-in-android/
Override the below method in your Activity,
#Override
public void onAttachedToWindow() {
super.onAttachedToWindow();
this.getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);
}
And now handle the key event like this,
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if(keyCode == KeyEvent.KEYCODE_HOME)
{
Log.i("Home Button","Clicked");
}
if(keyCode==KeyEvent.KEYCODE_BACK)
{
finish();
}
return false;
}
Put his into your activity's code. It will intercept back button click
#Override
public void onBackPressed() {
}
u can ovverride home button pressed like this:
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if ((keyCode == KeyEvent.KEYCODE_HOME)) {
Toast.makeText(this, "You pressed the home button!", Toast.LENGTH_LONG).show();
return true;
}
return super.onKeyDown(keyCode, event);
}
i am trying to disable the back button in my device with the following code.
the code is working but i would like that the function that handle all the back button request in the fragments will derived from the Main Activity
this is the back button handler:
#Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
getView().setFocusableInTouchMode(true);
getView().requestFocus();
getView().setOnKeyListener(new View.OnKeyListener() {
#Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (event.getAction() == KeyEvent.ACTION_DOWN) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
Toast.makeText(getActivity(), "Please navigate via the menu", Toast.LENGTH_SHORT).show();
return true;
}
}
return false;
}
});
}
It's easier to override onBackPressed function:
private boolean disabled = true;
#Override
public void onBackPressed() {
if (!disabled) {
super.onBackPressed();
}
}
With this you can easy change disable flag and enable back button when needed.
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
// TODO Auto-generated method stub
if (keyCode == KeyEvent.KEYCODE_BACK) {
//leave it empty
}
return super.onKeyDown(keyCode, event);
}
It's generally not the best idea to disable the back button as the user expects that button to perform some sort of back navigation. Now that being said, if you have a specific reason you can disable the back button by overriding the onBackPressed at the activity level and not calling into super.
Put this code at your MainActivity:
#Override
public void onBackPressed() {
executeAtAndroidOnBackPressed();
}
#Override
public boolean onKeyDown(final int keyCode, final KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
executeAtAndroidOnBackPressed();
}
return false;
}
protected void executeAtAndroidOnBackPressed() {
// do nothing
}
How to disable back button pressed for webview in android ?
#Override
public boolean onKeyDown(int keyCode, KeyEvent event)
{
if (wv1 != null && (keyCode == KeyEvent.KEYCODE_BACK)
&& wv1.canGoBack() )
{
wv1.goBack();
}
return true;
}
If you want to disable back button action when the WebView Visible and enable back button action if the WebView in not Visible try the below code in your Activity
#Override
public void onBackPressed() {
if(webview.getVisibility()==View.VISIBLE){
// dont pass back button action
if(webview.canGoBack()){
webview.goBack();
}
return;
}else{
// pass back button action
super.onBackPressed();
}
}
Simply override the onBackPressed() method.
#Override
public void onBackPressed() { }
Please try this
#Override
public void onBackPressed() {
if(webview.canGoBack()){
webview.goBack();
}
else{
super.onBackPressed();
}
}
There are many ways to make it,
Solution 1, overriding dispatchKeyEvent()
dispatchKeyEvent()(API Level 1, Android 1.0)
Refer to my answer use dispatchKeyEvent to disable back button
#Override
public boolean dispatchKeyEvent(KeyEvent event) {
// TODO Auto-generated method stub
if (event.getKeyCode() == KeyEvent.KEYCODE_BACK) {
return true;
}
return super.dispatchKeyEvent(event);
}
Solution 2, overriding onBackPressed()
onBackPressed() (API Level 5, Android 2.0)
Refer to Use onBackPressed() to disable back button
#Override
public void onBackPressed() {
}
Solution 3, overriding onKeyDown()
onKeyDown() (API Level 1, Android 1.0)
Refer to Use onKeyDown() to disable back button
#Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
//preventing default implementation previous to android.os.Build.VERSION_CODES.ECLAIR
return true;
}
return super.onKeyDown(keyCode, event);
}
You have add below code in Activity for disable activity back pressed
#Override
public void onBackPressed() {
}
Add this below code in java file :
WebView mwebView;
Button backButton1;
backButton1 = findViewById(R.id.backButton1);
mwebView = findViewById(R.id.mwebView);
backButton1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
mWebView.destroy();
}
});
My application has an activity with so many fragments. I want to disable the back button press in some fragment. I tried with the below code. But it doesn't work.
In the main activity:
#Override
public void onBackPressed() {
super.onBackPressed();
OrderFragment.onBackPress();
}
In the fragment,
public static void onBackPressed()
{
Log.d(TAG,"It listen");
}
I have the log message but, how can I disable the back button from my fragment.
You should keep a reference to the fragment you want to disable/handle back press event on your main activity:
class MainActivity{
OrderFragment mOrderFragment;
#Override
public void onBackPressed() {
if(mOrderFragment.isVisible())
mOrderFragment.onBackPressed();
else
super.onBackPressed();
}
}
In OrderFragment:
public void onBackPressed() {
//handle back press event
}
In your oncreateView() method you need to write this code and in KEYCODE_BACk return should true then it will stop the back button option for particular fragment
View v = inflater.inflate(R.layout.xyz, container, false);
//Back pressed Logic for fragment
v.setFocusableInTouchMode(true);
v.requestFocus();
v.setOnKeyListener(new View.OnKeyListener() {
#Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (event.getAction() == KeyEvent.ACTION_DOWN) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
return true;
}
}
return false;
}
});
getView().setFocusableInTouchMode(true);
getView().requestFocus();
getView().setOnKeyListener(new View.OnKeyListener() {
#Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
if( keyCode == KeyEvent.KEYCODE_BACK ) {
// leave this blank in order to disable the back press
return true;
} else {
return false;
}
}
});
I think you have to Override onResume method in fragments which you need to disable the back press.Tryout the following code.
#Override
public void onResume() {
super.onResume();
this.getView().setFocusableInTouchMode(true);
this.getView().requestFocus();
this.getView().setOnKeyListener(new View.OnKeyListener() {
#Override
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
return true;
}
return false;
}
});
}
Have you tried like this, Actually it works for me before.
you can set listener for Back key. if you add it, i guess it works.
youfragment.getView().setOnKeyListener( new OnKeyListener()
{
#Override
public boolean onKey( View v, int keyCode, KeyEvent event )
{
if( keyCode == KeyEvent.KEYCODE_BACK )
{
return true;
}
return false;
}
}
);
super.onBackPressed in the activity is the default implementation. Remove this if you don't want it.
I know this is an old question and because of navigation components and new ways this situation rarely occurs, still, maybe my answer helps someone.
I came across a similar situation where I needed the back button to be disabled and I couldn't change the activity as well. So in a fragment, I added this code block.
Language: Kotlin
override fun onResume() {
super.onResume()
this.requireView().isFocusableInTouchMode = true
this.requireView().requestFocus()
this.requireView().setOnKeyListener { _, keyCode, _ ->
keyCode == KeyEvent.KEYCODE_BACK
}
}
This will disable your back press on that specific fragment
#Override
public void onBackPressed() {
Fragment currentFragment = getSupportFragmentManager().findFragmentById(R.id.fragment_container);
if (currentFragment instanceof YourFragment) {
currentFragment.onBackPressed();
} else
super.onBackPressed();
}
override fun onBackPressed() {
val currentFragment = findNavController(R.id.nav_host_fragment).currentDestination?.id
if (currentFragment == R.id.YourFragment) {
return
}
super.onBackPressed()
If you don't want your fragment to be in the backstack you can do so, by not adding it to the backstack in the transaction. So do NOT call FragmentTransaction.addToBackStack(); on the fragments you do not want in your backstack.
onBackPressed works like this:
public void More onBackPressed() {
if (!mFragments.popBackStackImmediate()) {
finish();
}
}
Thus when you call super.onBackPressed() you pop the BackStack before finishing the activity. The best way to sort this out is to make sure you do not add the fragments to the BackStack. It is normally done like this:
fragmentTransaction.addToBackStack(TAG);
An alternative solution, but uglier since you have still useless code left, would be making onBackPressed() directly call finish() to end the activity.
I would strongly advise you not use getView().setOnKeyListener(...) since it is code smell.
Try this
public void onBackPressed() {
if (!mFragments.popBackStackImmediate()) {
finish();
}else{
super.onBackPressed();}
}
I have this hierarchy of the views:
Activity -> ViewPager -> MyViewGroup
In MyViewGroup (and only there) I override onKeyUp event:
#Override
public boolean onKeyUp(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
Log.i(TAG, "Back");
return true;
} else {
return super.onKeyUp(keyCode, event);
}
}
But when I press "Back" key, this override is not called and the app is closed. Why?
By default, the back button finishes the activity. From the android source:
Called when the activity has detected the user's press of the back key. The default implementation simply finishes the current activity, but you can override this to do whatever you want.
public void onBackPressed() {
if (!mFragments.popBackStackImmediate()) {
finish();
}
}
If you wish to alter this behavior you have to override onBackPressed in your Activity and make it not call super. Then you can implement your own behavior.
public #Override void onBackPressed()
{
if (doSomeThingOnBackPressed) {
// do some stuff
return;
}
super.onBackPressed();
}