How to switch layouts? First, I have a class Main where is onCreate (setContentView(R.layout.main);) and then I call, another class with command:
setContentView(secondClass);
In this class, I draw with Canvas and this work just fine. I also create button to go back in first "class" (R.layout.main), but I don't know how to do it.
Now my program is basic a graph shower. In first class you type your function and them second class draw it. But how to go back in first class to type another function. This "back" button or arrow witch every Android phone have, send me out of program not back on insert part.
In secondClass I can't create onCreate method, but I also tried the following and they didn't work:
Intent abc = new Intent("bla.bla.bla.FIRSTCLASS");
startActivity(abc);
and
Intent abc = new Intent(SecondClass.this,FirstClass.class);
startActivity(greNaPrvoOkno);
If you want to use a custom view (as I understood, you are extending the View class), you can do it in the following way;
Consider you are showing the second class from your Main activity like this;
setContentView(new SecondClass(getApplicationContext(), MainActivity.this));
And you Second class is this (suppose);
// I am using onClickListener to go back to main view. You do whatever you like.
public class SecondClass extends View implements OnClickListener {
// This is needed to switch back to the parent activity
private Activity mParentActivity = null;
public SecondClass(Context context, Activity parentActivity) {
super(context);
mParentActivity = parentActivity;
setOnClickListener(this);
}
#Override
public void onClick(View v) {
// Set the Main view back here.
mParentActivity.setContentView(R.layout.main);
}
}
Disclaimer: This code will do what you have asked for, but may cause other problems.
As advised by #Mudassir, you should use two different activities for two screens. It will give you better control, and your code will be easy to understand and maintain.
On the Onclick event of the button you have to write finish(); that's it..
Both of your classes are Activities yes? IF so then in your second activity you will simply call finish() and your activity will close revealing your first activity again.
When I have used multiple intents in my android application, I have created a new activity through:
Intent abc = new Intent(this, SecondClass.class);
startActivity(abc);
When the button is pressed in your second class, I would then either call finish(); on the class, or create a new intent like so:
Intent abc = new Intent(this, FirstClass.class);
startActivity(abc);
However, this method has the disadvantage that if a user wanted to use the back button, they may have to scroll through many layers of activities.
You should create another activity for your second class but not just set the main activity to a new view setContentView(secondClass).
For an easier modification, You could try to set the view back to setContentView(R.layout.main) first.
You still need to configure the widgets(e.g. TextView) on it when you set it back.
You don't have to startActivity again to go back.
Just call finish() in your second activity when you want to finish the current activity and go back:
e.g. When user press the back button in your second activity
mButtonBack.setOnClickListener(new Button.OnClickListener()
{
public void onClick(View v)
{
finish();
}
}
Related
I am trying to finish one activity from another.
For that purpose I am having only the component name of that activity.
How can i finish that ?
1.Make your activity A in manifest file: launchMode = "singleInstance"
2.When the user clicks new, do FirstActivity.fa.finish(); and call the new Intent.
3.When the user clicks modify, call the new Intent or simply finish activity B.
FIRST WAY
In your first activity, declare one Activity object like this,
public static Activity fa;
onCreate()
{
fa = this;
}
now use that object in another Activity to finish first-activity like this,
onCreate()
{
FirstActivity.fa.finish();
}
SECOND WAY
While calling your activity FirstActivity which you want to finish as soon as you move on, You can add flag while calling FirstActivity
intent.addFlags(Intent.FLAG_ACTIVITY_NO_HISTORY);
But using this flag the activity will get finished evenif you want it not to. and sometime onBack if you want to show the FirstActivity you will have to call it using intent.
You can do it in very simple way.
First create a static instance of your activity e.g. MainActivity, whom you want to finish like,
public static MainActivity act=MainActivity.this;
and now in another actvity e.g. MainActivity2 just call this line,
MainActivity.act.finish();
Try extending that activity and override the finish method
public class ma extends MainActivity{
#Override
public void finish()
{
super.finish();
}
}
You want to exit application after log out.
that time to user this
i.addCategory(Intent.CATEGORY_HOME);
i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
i.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
or try to another way like
#Override
public void onBackPressed() {
// TODO Auto-generated method stub
super.onBackPressed();
moveTaskToBack(true);
finish();
}
I have a main activity that forks a second activity, I wanted to go back from second activity to the main activity without reinitialize it. In other words, I wanted to immediately show the main activity after second activity disappears, instead of re-rendering the first activity. I have tried methods like finish, onBackPressed, none of this goes back directly achieved the effect I desired. Rather it seems that they go back and re-render the activity , which feels like all your previous data that renders the view is lost, and it has to do it from scratch again.
So How can I go back directly without re-rendering again?
Thanks
----------------------Update--------------------
Clase MainActivity extends Activity{
public onCreate(Bundle savedInstanceState){
super.onCreate(SaveInstanceState);
setContentView(R.layout.mainview);
GoogleMap gmap = ...
Route route = ...
//draw a route in the google map
// now the map bears a route on it
Intent intent = new Intent(this, secondActivity.class)
}
}
Class SecondActivity extends Activity{
public onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.secondview);
Button backbut =(Button) findViewById(R.id.backbutton);
}
//backbut is associated with a call back onClick in the xml
private onClick(View){
finish();//after this the second activity disappears, but previously drawn route on google map also disappears, and it takes time to redraw them again. feels like onCreate in firstActivity is reentered again
}
}
You need to use this two flag to accomplish what you want:--
Intent.FLAG_ACTIVITY_CLEAR_TOP
Intent.FLAG_ACTIVITY_SINGLE_TOP
Just use this code:--
Intent intent = new Intent(SecondActivity.this,
MainActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP
| Intent.FLAG_ACTIVITY_SINGLE_TOP);
startActivity(intent);
you should not call finish() on going second activity then the first activity is running on background and after calling finish() on second activity the first activity appears without re-initialize as privious state.
Hop this will help you.
MainActivity extends Activity{
Context context;
oncreate(){
context = this;
Intent intent = new Intent (context , SecondActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_LAUNCHED_FROM_HISTORY);
/* here finish() method is not called, if called MaintActivity objects will destory*/
}
}
Guys thank you all for your kind help! I think I kinda solved my problem. They key is that I made the onClick method private so my xml cannot find my onClick and issues an Exception, which caused activity to destroy and re-render themselves. Hope this explanation makes sense
Quick question: I have an activitygroup. Within that Activitygroup I have an activity. If I press back while inside this activity. the onBackPressed method of the activity is called - Not the Activitygroups onBackPressed - Why is that ?
EDIT: Got my answer but the problem remains. Here follows code and explanation of my original issue:
I am using ActivityGroups within a TabHost and as such have been "forced" into overriding onBackPressed. I can navigate through my application without issue by pressing back on my phone and by pressing the tabs on my tabhost. But I cannot interact with the interface after pressing Back.
Once I press one of the tabs on the tabhost again I can interact with everything like normal. Why is this happening? Do I need to override onResume?
Relevant code
SettingsActivityGroup :
public class SettingsActivityGroup extends ActivityGroup
{
// Keep this in a static variable to make it accessible for all the nested activities, lets them manipulate the view
public static SettingsActivityGroup group;
// Need to keep track of the history if you want the back-button to work properly, don't use this if your activities requires a lot of memory.
private ArrayList<View> history;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
// Allocate history
this.history = new ArrayList<View>();
// Set group
group = this;
// Start root (first) activity
Intent myIntent = new Intent(this, SettingsActivity.class); // Change to the first activity of your ActivityGroup
myIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
ReplaceView("SettingsActivity", myIntent);
}
/*
* Replace the activity with a new activity and add previous one to history
*/
public void ReplaceView(String pId, Intent pIntent)
{
Window window = getLocalActivityManager().startActivity(pId, pIntent);
View view = (window != null) ? window.getDecorView() : null;
// Add the old activity to the history
history.add(view);
// Set content view to new activity
setContentView(view);
}
/*
* Go back from previous activity or close application if there is no previous activity
*/
public void back()
{
if(history.size() > 1)
{
// Remove previous activity from history
history.remove(history.size()-1);
// Go to activity
View view = history.get(history.size() - 1);
Activity activity = (Activity) view.getContext();
// "Hack" used to determine when going back from a previous activity
// This is not necessary, if you don't need to redraw an activity when going back
activity.onWindowFocusChanged(true);
// Set content view to new activity
setContentView(view);
}
else
{
// Close the application
finish();
}
}
/*
* Overwrite the back button
*/
#Override
public void onBackPressed()
{
// Go one back, if the history is not empty
// If history is empty, close the application
SettingsActivityGroup.group.back();
return;
}
}
Arbitrary child of SettingsActivityGroup(CallForwardActivity)
public class CallForwardActivity extends ListActivity
{
....
#Override
public void onBackPressed()
{
// Go one back, if the history is not empty
// If history is empty, close the application
SettingsActivityGroup.group.back();
return;
}
}
Because I believe calling onBackPressed() of the currently selected activity is the desired behavior.
It's also worth noting that ActivityGroup is deprecated, but I assume you are coding for <3.0 and don't fancy working with the support libraries.
Regarding your edited question:
Another question on this site cites this article as a good ActivityGroup example, and I would agree http://ericharlow.blogspot.com/2010/09/experience-multiple-android-activities.html
This example just calls finish() on the current activity when back is pressed, and lets the os restart the previous activity, which is simpler than what you are doing, and will hopefully work! You can just call getParent() in your child activities too to avoid using that static reference (just seems easier to read to me that way!).
I have a fragment in an activity that I am using as a navigation drawer. It contains buttons that when clicked start new activities (startActivity from a fragment simply calls startActivity on the current activity).
For the life of me I can't seem to figure out how I would finish the current activity after starting a new one.
I am looking to achieve something like this in the fragment:
#Override
public void onClick(View view) {
// TODO Auto-generated method stub
if (view == mButtonShows) {
Intent intent = new Intent(view.getContext(), MyNewActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(intent);
finish();
}
}
But it seems Fragment.class does not implement finish() (like it implements startActivity(...)).
I would like the activity backstack cleared when they launch the 2nd activity. (so pressing back from the new activity would technically drop them back to the launcher)
When working with fragments, instead of using this or refering to the context, always use getActivity(). You should call
Java
getActivity().finish();
Kotlin
activity.finish()
to finish your activity from fragment.
Well actually...
I wouldn't have the Fragment try to finish the Activity. That places too much authority on the Fragment in my opinion. Instead, I would use the guide here: http://developer.android.com/training/basics/fragments/communicating.html
Have the Fragment define an interface which the Activity must implement. Make a call up to the Activity, then let the Activity decide what to do with the information. If the activity wishes to finish itself, then it can.
As mentioned by Jon F Hancock, this is how a fragment can 'close' the activity by suggesting the activity to close. This makes the fragment portable as is the reason for them. If you use it in a different activity, you might not want to close the activity.
Code below is a snippet from an activity and fragment which has a save and cancel button.
PlayerActivity
public class PlayerActivity extends Activity
implements PlayerInfo.PlayerAddListener {
public void onPlayerCancel() {
// Decide if its suitable to close the activity,
//e.g. is an edit being done in one of the other fragments?
finish();
}
}
PlayerInfoFragment, which contains an interface which the calling activity needs to implement.
public class PlayerInfoFragment extends Fragment {
private PlayerAddListener callback; // implemented in the Activity
#Override
public void onAttach(Activity activity) {
super.onAttach(activity);
callback= (PlayerAddListener) activity;
}
public interface PlayerAddListener {
public void onPlayerSave(Player p); // not shown in impl above
public void onPlayerCancel();
}
public void btnCancel(View v) {
callback.onPlayerCancel(); // the activity's implementation
}
}
You should use getActivity() method in order to finish the activity from the fragment.
getActivity().finish();
This does not need assertion, Latest update in fragment in android JetPack
requireActivity().finish();
In Fragment use getActivity.finishAffinity()
getActivity().finishAffinity();
It will remove all the fragment which pushed by the current activity from the Stack with the Activity too...
Every time I use finish to close the fragment, the entire activity closes. According to the docs, fragments should remain as long as the parent activity remains.
Instead, I found that I can change views back the the parent activity by using this statement:
setContentView(R.layout.activity_main);
This returns me back to the parent activity.
I hope that this helps someone else who may be looking for this.
Very simple...
1- just grab activity by getActivity() in the fragment
2- then call finish();
So just getActivity().finish(); will finish the parent activity.
Try this. There shouldn't be any warning...
Activity thisActivity = getActivity();
if (thisActivity != null) {
startActivity(new Intent(thisActivity, yourActivity.class)); // if needed
thisActivity.finish();
}
You have two options for Java and Kotlin. However, logic of both ways are same. You should call activity after call finish() method.
Answer for Kotlin,
If your activity cannot be null, use Answer_1. However, if your activity can be null, use Answer_2.
Answer_1: activity!!.finish()
Answer_2: activity?.finish()
Answer for Java,
getActivity().finish();
To finish activity in a Fragment use:
getActivity().finish();
Simple solution:
activity?.finish()
yes Fragment.class does not implement finish()
When working with fragments, instead of using this or refering to the context, always use getActivity(). You should call
I guess this is just a simple question (I’m such a noob…)
I have this custom dialog box that has 3 buttons in it.
Now I want to call an activity from one of the buttons so
I tried this:
public class picturedialog extends Dialog implements OnClickListener {
Button Camera;
public picturedialog (Context context){
super (context);
setContentView(R.layout.picturedialog);
Camera = (Button) this.findViewById(R.id.pdButton1);
Camera.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
dismiss();
Intent myIntent = new Intent(view.getContext(), CameraActivity.class);
startActivity(myIntent);
}
});
...
}
Then the red squiggly line appears on startActivity(myIntent).
Upon hovering on it, eclipse tells me this: “The method startActivity(Intent) is undefined for the type new View.OnClickListener(){}”
Ehhh? Please orient me on how to do this properly.
Any help would be appreciated.
Suppose the name of your Activity is A, then you just do:
A.this.startActivity(myIntent);
The problem arises because "this" inside your inner class refers to the object of that inner class, when what you want is the object of the enclosing Activity. A.this will refer to that.
If you aren't enclosing this class in an Activity, then try calling the startActivity from method using the context that you passed into the method, e.g. context.startActivty(myIntent).
The startActivity method belongs to the Context class.
I am sure you are overcomplicating with subclassing from Dialog. Try to follow to the dialog tutorial - https://developer.android.com/guide/topics/ui/dialogs.html#ShowingADialog
Note that dialogs are created on the fly (in Activity.onCreateDialog()) without the need to have your own custom dialog classes. Since you set a listener being inside of the wrapping activity (if you follow the tutorial), then you are able to call startActivity(myIntent), because all the fields/methods of a wrapping class instance are available for an instance of an inner class.