Develop Reference

Save settings button and back to previous activity

I have an activity that has edit text and you can type your name in it, and when you click Save button you will be redirected to MainActivity, but I don't want to open MainActivity by Intent, I make that save button save your name with shared prefs and everything works fine but I don't want to open my Main in Intent I want that when I clicked on save button the current activity that saves data close and previous activity open.
sorry for my bad English.
this is my code for save button
submitButt.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if (v.getId() == submitButt.getId()) {
String name = inputName.getText().toString().trim();
if (isValidInput(name)) {
Intent setint = new Intent(SettingsActivity.this, MainActivity.class);
setint.putExtra("name", name);
saveData();
startActivity(setint);
Toast.makeText(SettingsActivity.this, "Settings Saved", Toast.LENGTH_SHORT).show();
}
}
}

Then you just open the PreviousActivity instead of the MainActivity. Add a checker inside the PreviousActivity if "name" has data or not. You can also use finish(); this will kill the activity.
** Update **
In your MainActivity, let's say you have TextView name. Add:
#Override
public void onResume(){
super.onResume();
// Check your variable if it has value or none
textViewName.setText(variableForSharedPref)
}
Then you can proceed with usual process to go in Settings and Go Back to MainActivity.

Android, check if back Button was pressed

i have two views and activities.
On the first there is a spinner. On the second, you can create new entries (Stored in database for the spinner in activity 1).
If the user is finished and pressed the back button, i have to refresh the spinner on activity 1 (because of the new entries).
Ist there a possibility to check, if the app returns to activity 1, because the back button in activity 2 was pressed?
I know, i can do it with the onResume Method, but this method is called EVERYTIME i return to activity one and not ONLY because of the back button.
I want to refresh the spinner only when the back button was pressed.
Any solution? Can i Check if the back button was pressed in the onResume method?

You can override onBackPressed() in the Second Activity. This will get called when the user presses the back button.
You can pass the information as a boolean hasBackPressed = true in the setResult()
Starting Activity 2 from Activity 1:
Intent i = new Intent(this, SecondActivity.class);
startActivityForResult(i, 1);
Passing info back from Activity 2:
#Override
public void onBackPressed() {
Intent returnIntent = new Intent();
returnIntent.putExtra("hasBackPressed",true);
setResult(Activity.RESULT_OK,returnIntent);
finish();
}
Receiving data in Activity 1:
#Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if (requestCode == 1) {
if(resultCode == Activity.RESULT_OK){
boolean hasBackPressed = data.getBooleanExtra("hasBackPressed");
}
if (resultCode == Activity.RESULT_CANCELED) {
//Write your code if there's no result
}
}
}

You can start Activity 2 for result, using startActivityForResult(). On Activity 2 you can set the result to RESULT_OK when new items have been added. Then, in the onActivityResult() method of Activity 1 you can check the returned result and update your data, if needed.

Override the onBackPressed() method and take the action inside this function.
#Override
public void onBackPressed() {
// your stuff here
super.onBackPressed();
}

Use startActivityForResult() to start the second activity, and return some value in the onBackPressed() of the second activity. Catch that in onActivityResult(), and refresh the spinner there.
Look into this.

Android exit whole program syntax

currently I'm working on Android development, now I'm facing a problem to exit the whole application that had launched.
I'v tried .finish(), but it doesn't show what I want.
I have 2 Activities, A and B. Activity A will forward to Activity B when button click. In activity B, when I click button "Exit" (that I created) with the listener to trigger .finish(), it just back to Activity A but not to close whole application (what I want is back to home screen directly and kill the background process as well).
How can I exit whole application wherever in the application? Thank you.
button.setOnClickListener(new OnClickListener(){
#Override
public void onClick(View v) {
//here to exit whole application not just backwards to previous activity
}
});

You write in Activity A after
startActivity(new Intent(A.this, B.class))
finish()
then you also write in Activity B finish() on button click listener. It should works.
public class A extends Activity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
startActivity(new Intent(A.this, B.class));
finish(); // you must write this also in A activity to close whole application
}
});
}
public class B extends Activity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_1);
Button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
finish();
}
});
}

EDIT: I assumed there are cases when the underlying activity either should or shouldn't be terminated on return. This will allow you to handle both cases.
Case A)
Activity A starts activity B, which starts activity C. You want to close all of them from activity C. If they're all in the same task (i.e. probably your case) you can close the whole task by calling
finishAffinity();
According to docs this is what happens:
Finish this activity as well as all activities immediately below it in the current task that have the same affinity. This is typically used when an application can be launched on to another task (such as from an ACTION_VIEW of a content type it understands) and the user has used the up navigation to switch out of the current task and in to its own task. In this case, if the user has navigated down into any other activities of the second application, all of those should be removed from the original task as part of the task switch.
Note that this finish does not allow you to deliver results to the previous activity, and an exception will be thrown if you are trying to do so.
See Activity.finishAffinity().
Case B)
Activity A starts activity B, which starts activity C. You want to close activities B and C from activity C.
This is how you start activity C from B expecting and handling a result:
public class ActivityB extends Activity {
private static final int RC_ACTIVITY_C = 1;
public static final int RESULT_FINISH = 1;
...
public void startActivityC() {
Intent intent = new Intent(this, ActivityC.class);
startActivityForResult(intent, RC_ACTIVITY_C);
}
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == RC_ACTIVITY_C && resultCode == RESULT_FINISH) {
finish();
}
}
}
This is how you let activity B it has to finish from activity C. At any point before finishing activity C call:
setResult(ActivityB.RESULT_FINISH);
See Activity.startActivityForResult(Intent, int) and Activity.setResult(int).

You can try System.exit(0). That should do the job.
EDIT: Take a look at this post for the difference between finish() and System.exit(). Difference between finish() and System.exit(0)

Multiple activities and buttons?

I want to make buttons once I click on the button I go to another activity?
and the problem is only the first button is working!
public class Main extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button PageOneButton = (Button) findViewById(R.id.btnPageOne);
PageOneButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent myIntent = new Intent(v.getContext(), PageOne.class);
v.getContext().startActivity(myIntent);
Button PageTwo = (Button) findViewById(R.id.btnPageTwo);
PageTwoButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent myIntent = new Intent(v.getContext(), PageTwo.class);
v.getContext().startActivity(myIntent);
}
{}
});
}
});
}
}

Think it is because most of your code is closed inside the scope of the first onClickListener, try something like this.
Button PageOneButton = (Button) findViewById(R.id.btnPageOne);
PageOneButton.setOnClickListener(new View.OnClickListener(){
public void onClick(View v) {
Intent myIntent = new Intent(Main.this, PageOne.class);
startActivity(myIntent);
});
Button PageTwoButton = (Button) findViewById(R.id.btnPageTwo);
PageTwoButton.setOnClickListener(new View.OnClickListener(){
public void onClick(View v) {
Intent myIntent = new Intent(Main.this, PageTwo.class);
startActivity(myIntent);
});
Using v.getContext() should be ok, this is just how I usually would do as the Activity itself is indeed a valid context. I guess it just seems more readable to me.
Edit:
Just as a clarification to the current state of your code. The second button is assigned a onClickListener only after the first button is pressed. But since the first button takes the app to a new Activity, inherently destroying the Main Activity, the second button will never have a chance to reach it's onClickListener.
Hope it makes sense, nevertheless the code above should fix the issue.

There are a couple of issues currently in your code. The first issue is that your second button is being defined inside the first button's declaration. The next issue is that you're setting the second OnClickListener to the wrongly named button. You've made a typo and instead of PageTwo, which you've called the Button (presumably you wanted to call it PageTwoButton in accordance with the first Button) and then set the OnClickListener to PageTwoButton instead. Seeing as you're also using multiple Buttons, it's a lot cleaner and more efficient to use a GroupOnClickListener. I'd probably also suggest using 'this' instead of 'v.getContext()' as well when setting up your Intents. Change your code to be like so:
Button PageOneButton = (Button) findViewById(R.id.btnPageOne);
Button PageTwoButton = (Button) findViewById(R.id.btnPageTwo);
PageOneButton.setOnClickListener(addGroupOnClickListener);
PageTwoButton.setOnClickListener(addGroupOnClickListener);
private OnClickListener addGroupOnClickListener = new OnClickListener() {
public void onClick(View v) {
if (v == PageOneButton) {
Intent myIntent = new Intent(Main.this, PageOne.class);
startActivity(myIntent);
} else if (v == PageTwoButton) {
Intent myIntent = new Intent(Main.this, PageTwo.class);
startActivity(myIntent);
}
}
};
Hope this helps!

Two words: Code Indentation
Were you to indent your code properly, you would have noticed that you're setting OnClickListener INSIDE your first buttons' listener. Move it outside your first listener, as has already been advised by others.
There's also an extra pair of {}, which is redundant.
Also, #edwoollard noticed that for the second button, you're using two different names, PageTwo and PageTwoButton. Keep that in mind, unless it's a typo.

android onClick not firing?

EDIT: onClick is working properly now. The issue was that the button was trying to fire the onClick from the Parent class. now that is fixed. Of course that means a new issue is happening, that is the onActivityResult is never getting called.
So I am not really sure what the hell is going on, when I hit the button nothing happens, nothing in logcat, nothing, as if there is not code, but I am pretty sure this is written correctly, any thoughts?
public class myClass extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.store_selector);
Button getStore = (Button)findViewById(R.id.getStore);
getStore.setOnClickListener(buttonGetStoreOnClickListener);
}
Button.OnClickListener buttonGetStoreOnClickListener
= new Button.OnClickListener(){
public void onClick(View arg0) {
Intent intent = new Intent("com.blah.Blah.client.android.SCAN");
intent.setPackage("com.blah.Blah");
intent.putExtra("com.blah.Blah.client.android.SCAN.SCAN_MODE", "QR_CODE_MODE");
startActivityForResult(intent, 0);
};
};
#Override
public void onActivityResult(int requestCode, int resultCode, Intent intent)
{
if (requestCode == 0)
{
if (resultCode == RESULT_OK)
{
String contents = intent.getStringExtra("SCAN_RESULT");
String format = intent.getStringExtra("SCAN_RESULT_FORMAT");
Log.i("debug tag", "contents: "+contents+" format: "+format);
Intent myIntent = new Intent(this, Ads.class);
myIntent.putExtra("key", contents);
startActivity(myIntent);
setContentView(R.layout.activity_ads);
// Handle successful scan
}
else if (resultCode == RESULT_CANCELED)
{
// Handle cancel
Log.i("xZing", "Cancelled");
}
}
}
};

This is the class you need to import:
import android.view.View.OnClickListener;
And this is the method you should have:
OnClickListener onButtonListener = new OnClickListener() {
#Override
public void onClick(View v) {
// Your code here
}
};
Test it and let me know if it worked.
Regards

Are you sure you got the right button with Button getStore = (Button)findViewById(R.id.getStore); ?
If yes, then it can be something that sometimes happens to me sometimes.
When this happens, my logcat doesn't show anything. What I do to solve this, is to open the Devices view (Window, show view, other, Android, Devices) and select my device. Then when I look at the logcat again, everything's there.