I know my question might be stupid but I am new in Android App development and the Eclipse things but reached to e problem that can't find solution in internet.
I am making multi-activity application and reached to a point where when i have two buttons in one of the activities and want each of them to lead to different other activities, the application crashes. When I lead them both to one activity, everything is fine. Here is my code and hope really my question not to be so stupid as I am thinking.
public class Home extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
Button myButton = (Button) findViewById(R.id.tables);
myButton.setOnClickListener(goToTables);
Button mySecondButton = (Button) findViewById(R.id.reservations);
mySecondButton.setOnClickListener(goToMenu);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.home, menu);
return true;
}
private OnClickListener goToTables = new OnClickListener(){
#Override
public void onClick(View v) {
doButton();
}};
private void doButton()
{
startActivity(new Intent(this, Tables.class));
}
private OnClickListener goToMenu = new OnClickListener(){
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
doSecondButton();
}};
private void doSecondButton()
{
startActivity(new Intent(this, Menu.class));
}
}
The goToTables works perfectly but I am missing something important to change in goToMenu. My other activities are: Tables and Menu. Can somebody please tell me where I am wrong? Thanks in advance!
android:onClick="dobutton" try adding this in your button tag in xml code rather then using onclicklistner.
Try changing the name of your Menu activity or add the full name path of Menu.class in your intent, eg. com.myapp.Menu.class
Related
I've been trying to find out the back navigation button to lead to another activity.
Every time when I pressed the back button, it goes to the previous activity which is not what I want. I would like to set the back button that goes to another activity I want, instead of previous one.
For example, I have Activity 1, 2 and 3. I was in Activity 2 and just moved to Activity 3. But when I press the back button, it goes automatically to the previous activity which is Activity 2. I want to make it to Activity 1 and not Activity 2. Can anyone suggest me a solution please?
You can make the button to go to a specific activity, instead of having the default behavior that you described.
It can be something like this:
#Override
public void onClick(View v) {
Intent intent = new Intent(Activity2.this, Activity3.class);
intent.putExtra("variable", information); //this is optional, but can be useful if you need to send a specific info to the next activity
startActivity(intent);
}
Activity 2 is parliamonar, and Activity 3 is federalparliamentary. I replaced parliamonar with Activity 1, but it still didn't solve the problem.
public class federalparliamentary extends AppCompatActivity {
Button federal;
private Object parliamonar;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_federalparliamentary);
federal = findViewById(R.id.back160);
federal.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent reserve = new Intent(getApplicationContext(), parliamonar.class);
startActivity(reserve);
}
});
federal = findViewById(R.id.next164);
federal.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent reserve = new Intent(getApplicationContext(), sar.class);
startActivity(reserve);
}
});
}
public void onClick(View V) {
Intent back = new Intent((Context) parliamonar, federalparliamentary.class);
startActivity(back);
}
}
public class federalparliamentary extends AppCompatActivity {
Button federal;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_federalparliamentary);
federal = findViewById(R.id.back160);
federal.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent reserve = new Intent(getApplicationContext(), parliamonar.class);
startActivity(reserve);
}
});
federal = findViewById(R.id.next164);
federal.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent reserve = new Intent(getApplicationContext(), sar.class);
startActivity(reserve);
}
});
}
public void Onclick(View v) {
Intent intent = new Intent(federalparliamentary.this, politicalsystem.class);
startActivity(intent);
}
}
Activity 1 is "politicalsystem".
I added with #Override method, but it says that I have to remove the method, so I added outside, then it says that I have to extract interface, so clicked on it, then it gave me a bunch of list. So I chose onClick(v:View ):void, but it still didn't solve the issue. I tried in another way without #Override, but nothing changed when I tested my app. I also tried inside onCreate method which did not modified the navigation as I desired.
I am a beginner in android app development.. i have made an app now and there is a pop up in it which shows a persons name and details.. i have added 3 buttons there like CALL,SMS,EMAIL.. i went for call activity, but its not working. no error is there still call button is not making calls.. The same code i have tried in a new project, there it works well.. but when i do it on that popup, call is not working... please help me
public class popupinv extends AppCompatActivity {
public Button b;
public void init(){
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_popupinv);
init();
b= (Button) findViewById(R.id.call);
b.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent callIntent=new Intent(Intent.ACTION_CALL);
callIntent.setData(Uri.parse("tel:123456));
startActivity(callIntent);
}
});
}
}
Don't know why this error is coming. I have used the same logic of adding #Override in my previous apps (Which I learned from Udacity).
I'm currently doing the Multiscreen Apps course. Do let me know if anyone else have completed this course or having the same error.
Here's what I wrote:
//Find the view that shows family category
TextView family = (TextView) findViewById(R.id.family);
//Send a clicklistner on that view
family.setOnClickListener(new View.OnClickListener()
{
#Override //here's the error
public void onClick (View v){
// create a new intent to open the {#link FamilyActivity}
Intent familyIntent = new Intent(MainActivity.this, FamilyActivity.class);
// start the new activity
startActivity(familyIntent);
}
});
Thanks,
Kvaibhav01.
Did you try this?
family.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
}
});
As I remember textView doesn't have onClickListener, it has onTouchListener and maybe this's a problem
I am new to programming in Java, i've managed to create a little calculator as a little test app.
But i think i am using way to much code for my needs.
So i've given a Button a name: buttonname
Now to change it's text when clicked i need to:
public class MyActivity extends Activity {
Button buttonname;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my);
buttomname = (Buttom) findViewById(R.id.buttomname);
}
public void buttonnameOnClick(View v) {
button1.setText ("NewText")
}
}
(i've bolted everything i had to add)
So i had to do everything above + connect the buttonClick through the xml file.
So i was wondering if there is a easier way to define all objects so i dont have to do: Button buttonname; and buttomname = (Buttom) findViewById(R.id.buttomname); all the time.
And i was wondering if there is a easier way to auto create button events.
(I am used to Visual Studio, but now i am kinda lost in Android Studio. So on Visual Studio i just had to double click the button and type: buttonname.Text = "NewText";)
There is a library called Butter Knife to do approximately that
However, I'm not sure if you really need it.
Oh, and you don't have to find the same Button every time. You find it once in onCreate and store in a field.
First of all you have typo in
buttomname = (Buttom) findViewById(R.id.buttomname);
It should be
buttomname = (Button) findViewById(R.id.buttomname);
and you forgot ; in one line "didn't your IDE show error to you!!" and also small correction in
public void buttonnameOnClick(View v) {
button1.setText ("NewText")
}
it should be
buttomname.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
buttomname.setText ("NewText");
}
});
inside protected void onCreate.
2nd method:
And if you have define android:onclick="buttonnameOnClick" in XML then
public void buttonnameOnClick(View v) {
button1.setText ("NewText")
}
To be corrected to
public void buttonnameOnClick(View v) {
buttomname.setText ("NewText");
}
You can do it in a loop if you have a lot of identical buttons to process
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my);
for (int btn_id : new int[]{
R.id.buttomname
, R.id.buttomname2
, R.id.buttomname3
}) {
View v = view.findViewById(btn_id);
if (v != null) {
v.setOnClickListener(onClickButton);
}
}
}
//
private View.OnClickListener onClickButton = new View.OnClickListener() {
#Override
public void onClick(View view) {
// .. handle click
if (view.getId()==R.id.buttomname2){
}
}
Your code is partly correct,
however the
(Buttom) is wrong change it to (Button)
the other thing
public void buttonnameOnClick(View v) {
button1.setText ("NewText")
}
can just be changed to:
public void buttonnameOnClick(View v) {
Button buttonTemp = (Button)v;
buttonTemp.setText ("NewText");
}
Assuming you are calling the method from layout xml file.
you must use the onClickListener() method for Button object.
Your code like this structure;
buttonname = (Button)findViewById(R.id.buttonname);
buttonname.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// Perform action on click
}
});
I recommend to your visit Button | Android Dev page for Button.
I have this preferences class (below) that saves two ListPreferences, but if the ListPreferences are changed and the back button is pressed, the changes don't take affect unless the application is restarted. Did I miss something? Have been looking everywhere, but just can't seem to find an answer the fits or works. Please help.
public class Preferences extends PreferenceActivity {
#Override
public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.preferences);
}
#Override
public void onPause() {
super.onPause();
}
#Override
public void onResume() {
super.onResume();
}
}
Application Code
public class Quotes extends Activity implements OnClickListener {
ProgressDialog dialog;
private WebView webview;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
SharedPreferences SP = PreferenceManager.getDefaultSharedPreferences(getBaseContext());
String q = SP.getString("appViewType","http://www.google.com");
String c = SP.getString("appRefreshRate","20");
webview = (WebView) findViewById(R.id.scroll);
webview.getSettings().setJavaScriptEnabled(true);
webview.setWebViewClient(new QuotesWebView(this));
webview.loadUrl(q);
ScheduledExecutorService timer = Executors.newSingleThreadScheduledExecutor();
timer.scheduleAtFixedRate(new Runnable() {
#Override
public void run() {
webview.reload();
}
}, 10, Long.parseLong(c),TimeUnit.SECONDS);
findViewById(R.id.refresh).setOnClickListener(this);
}
#Override
public void onPause(){
super.onPause();
}
#Override
public void onResume(){
super.onResume();
}
public void onClick(View v){
switch(v.getId()){
case R.id.refresh:
webview.reload();
break;
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu, menu);
MenuItem about = menu.getItem(0);
about.setIntent(new Intent(this, About.class));
MenuItem preferences = menu.getItem(1);
preferences.setIntent(new Intent(this, Preferences.class));
return true;
}
}
You need to somehow reload your preferences when the preferences activity finishes. I thought Dirol's suggestion of loading them in onResume() instead of onCreate() was excellent; have you tried it? Or am I misunderstanding the problem as well.
In my own case, I launched the preferences activity with startActivityForResult() and then on the activity result callback, I reloaded the preferences.
Code snippets:
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case MENU_PREFERENCES:
Intent intent = new Intent().setClass(this, CalcPreferences.class);
startActivityForResult(intent, MENU_PREFERENCES);
break;
default: return super.onOptionsItemSelected(item);
}
return true;
}
#Override
protected void onActivityResult(int req, int result, Intent data) {
switch( req ) {
case MENU_PREFERENCES:
SharedPreferences sp =
PreferenceManager.getDefaultSharedPreferences(this);
updatePreferences(sp);
break;
default:
super.onActivityResult(req, result, data);
break;
}
}
#Override
protected void updatePreferences(SharedPreferences sp) {
super.updatePreferences(sp);
keyclick = sp.getBoolean("keyclick", keyclick);
}
Anyway, this is what works for me. I may try moving my updatePreferences() call to onResume() myself to see if that works too.
Try overriding the onBackPressed() method.
If your "Up" button (top left <-) provides the correct result, then you can set the Back button to behave like the Up button.
#Override
public void onBackPressed() {
super.onBackPressed();
NavUtils.navigateUpFromSameTask(this);
}
You load preferences only on onCreate() method. That method called only when a fresh activity starts up. The addPreferencesFromResource inflates the xml file into the preferences, so you only get the info, which is already has been stored in the xml at the moment addPreferencesFromResource was called, not after.
Try to move that method to onResume. But watch for the memory leak. I don't know exactly what the addPreferencesFromResource do, but from the documentation - I would be very suspicious about that method activity.
I had the same problem and solved it as follows:
The main activity class implements OnSharedPreferenceChangeListener:
public class Activity_name extends Activity implements OnSharedPreferenceChangeListener {
...
}
Inside the main activity class the onSharedPreferenceChanged is run whenever a preference entry changes. I simply update all my variables from the preferences as i did in onCreate:
#Override
public void onSharedPreferenceChanged(SharedPreferences prefs, String key) {
<read all preferences as you did in onCreate()>
}
This does the trick and I hope it saves you some time in searching for a solution.
I've had the same problem...
Try to create preference instance and load its data in every class and every activity where you need it.
It worked for me...Hope it helps.
You will need to reload your view or whatever object which uses those preferences, preferably when preference activity closes.
Preference activities do not change nothing but an internal file with your preferences(key=value list). When it is changed, preferenceActivity calls onPreferenceChaged() and nothing more. It doesn't refresh your stuff by itself. You need to reload prefs and to reuse them in onResume() method or equivalent.