Develop Reference

onCreate is called twice

I have 2 activities - MainActivity and page1. I have intent from the first like this:
button_forward.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
Intent intent = new Intent(MainActivity.this, Page1.class);
startActivity(intent);
return true ;
}
However, my Page1 class's onCreate is called twice! i can detect it with toast message: it appears twice on the screen:
#Override
protected void onCreate(Bundle savedInstanceState) {
Toast.makeText(Page1.this, "onCreate 1", Toast.LENGTH_SHORT).show();
super.onCreate(savedInstanceState);
setContentView(R.layout.page1);
//some code here like findview by id...
}
});`
I do have some methods that use countdowntimer in my Page1 activity, timers that wait for 2 secs, i commented them out, but onCreate() still gets called twice.
I added code to prevent screen rotating, but the error persists

The problem is that your touch listener doesn't check which type of event we have, this means that your onTouch should be called like 100 times per second, but it actually is called only twice because the new Activity UI covers the button. Use this code to check which event we have:
#Override
public boolean onTouch(View v, MotionEvent event) {
if (event.getAction() != MotionEvent.ACTION_DOWN) return false;
Intent intent = new Intent(MainActivity.this, Page1.class);
startActivity(intent);
return true;
}
If the action is ACTION_DOWN it means that the user has just touched the button. If it is ACTION_UP it means that the user lifted his / her finger.

Drawable's movement with buttons

I've been learning android for almost a month, and I want to make a simple game with a custom class that extends from View, and it's included on main_activity.xml. In Main Activity.class I create an instance of the View, and control the movement of the sprite on the GameView with buttons, so each button has a method that control sprite's movement like this:
public void move_up(View v){
gameview.sprite.move(Dir.UP);}
The problem is that it only works when the button is released, and it's executed one time. I want the method to be executed while the botton is pressed but I can't figure out how to do this.

I'm assuming by the name of your method that you're adding the onClick property to the xml layout file in order to handle the event. While this may seem convenient at first it will not give you what you need.
Instead, you should implement the OnTouchListener which gives you information about what touch event is currently happening, in your case you'd want to handle the ACTION_DOWN action:
findViewById(R.id.btn_up).setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
if(event.getAction() == MotionEvent.ACTION_DOWN){
gameview.sprite.move(Dir.UP); //Or whatever
return true; //In case you wan to handle ACTION_UP
}
return false;
}
});
Although you could make your Activity implement the listener and handle multiple buttons there. This is achieved simply by telling your activity to implement OnTouchListener, imeplementing the method onTouch as in the code above but instead as a method of your activity.
And the resulting set, would be simplified to findViewById(R.id.btn_up).setOnTouchListener(this); where R.id.btn_up is the id you've defined in the xml file.
This would make it start moving when they press, instead of when they release, if what you want is to make it move until they release (which would make sense), do something like:
if(event.getAction() == MotionEvent.ACTION_DOWN){
gameview.sprite.move(Dir.UP); //Or whatever
return true; //In case you wan to handle ACTION_UP
}else
if(event.getAction() == MotionEvent.ACTION_UP){
gameview.sprite.stop(); //Or whatever you call the stop method
return false;
}

Navigating between activities

I'm developing an app. for my semester project.App. is simple true&false game.I did something about it but i choked up one point.My problem is that handling activities.
Here is the quick view of the design.
http://imgur.com/2Fhsrn8
I created all activities and my codes working correct.But there is an issue.When i'm on third or fourth page(activity) and press back button on my phone it returns the second page then i automatically have another chance to answer question.All i want is turn the first screen when back button is pressed and clear all the data such as assign score as 0.
I'will be grateful for any kind of help.

Use
finish();
for your current activity when you start the new intent(e.g. when going from activity 3 to activity on your picture) and add this to your activity's 2-3 if you want to start again when you click back, otherwise it will close your app.
#Override
public boolean onKeyDown(int keyCode, KeyEvent event)
{
if ((keyCode == KeyEvent.KEYCODE_BACK))
{
//implement code to start 1st activity here!
}
return super.onKeyDown(keyCode, event);
}

you should override onBackPressed on your third, and fourth activity ->
#Override
public void onBackPressed() {
// here you should create intent to your firstActivity
// and assign variables -> e.g.
// score = 0;
}

Finished activity automatically reopens

I have a problem in a very simple application.
I have a main activity, and on button click I open a second activity:
newEntryButton.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View view, MotionEvent motionEvent) {
Intent intent = new Intent(MainActivity.this, NewSpendingActivity.class);
MainActivity.this.startActivity(intent);
return true;
}
});
When I close this activity (for example by tapping the back button) or by calling finish() the view loads once again. It only closes if I tap the back button again. What may be the cause of this?

It's probably because you're using an OnTouchListener, which triggers on press, move and release. Try using an OnClickListener instead.

This should not give you problems:
newEntryButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
Intent activityChangeIntent = new Intent(MainActivity.this,NewSpendingActivity.class);
MainActivity.this.startActivity(activityChangeIntent);
}
});

Android Back Button Utilization Inside ActivityGroup

I am developing an application using TabHost. I am using android default back button to move back to previous activity from current activity by overriding onBackPressed() method inside ActivityGroup of each tab.
Now , the problem is , in one of my activity i have an EditText which get focused when the activity starts. Then , if i press back , it does not go to previous activity , instead it closes the application. By searching about the problem on internet what i have found is that when the EditText get focused which is a child view of activity's view , the activity loss focus and then if back button is pressed , for lack of focus on the current activity it closes the application. Still i am little bit confused or can be say not clear about the problem.
So, any how , i have managed to set and remove focus over EditText on run time using code. But still now , as the EditText does not have focus , if the back button is pressed , it closes the application. I am really confused what's actually going on. So , if anyone have any idea or solution about the problem , please help on the issue. I will appreciate that very much. Thanks.

You can override this behavior by adding Key Listener to your EditText. Try this out,
name_edit.setOnKeyListener(new OnKeyListener() {
public boolean onKey(View v, int keyCode, KeyEvent event) {
if (event.getAction() == KeyEvent.ACTION_DOWN
&& event.getKeyCode() == KeyEvent.KEYCODE_BACK) {
Log.i("Back event Trigered", "Back event");
activitygroup.back();
}
return false;
}
});

try this..
#Override
public void onBackPressed() {
onKeyDown(KeyEvent.KEYCODE_BACK, new KeyEvent(KeyEvent.ACTION_DOWN,KeyEvent.KEYCODE_BACK));
super.onBackPressed();
}

try this
public void onBackPressed() {
startActivity(new Intent(currentActivity.this, previousActivity.class));
finish();
}