I have 2 layouts. First layout has 2 textviews. And second layout has 1 button. I want to do when i pres buton textviews.text change. But i get null error about textviews.
textviews on musicactivity, button on homeactivity.
my first activity class --> homeactivity,secon activity class --> Musicactivity,textview-->ad1,textview-->ad2,textviews on musiclayouts,Button on homeactivity.
public class HomeActivity extends Activity {
Button btn;
TextView ad1;
TextView ad2;
private MusicActivity music;
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.home);
btn=(Button)findViewById(R.id.button1);
ad1=(TextView)findViewById(R.id.textView1);
ad2=(TextView)findViewById(R.id.textView2);
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
{
ad1.setText(null);
ad2.setText(null);
}
}
});
}
The error message you posted is for line 40, which is doing a close of v1. I don't know what a veritabani is, but it appears that error is happening there. I suspect the rest of the error trace might say more.
You are doing it wrong. You can't get the textViews if they are not in the layout. You say yourself they are not in the layout. You have to pass the values you want to set to the new activity (musicActivity) via an Intent. Then in musicActivity's you can get the textViews, you have the values, you set them.
Related
Quick notice: I am using SharedPreferences so that I can reload data when I re-open the app.
Problem
I have a LinearLayout in the main fragment of my application. Everything runs smoothly until I re-open the app and try to reinitialize the LinearLayout.
I am trying to initialize the LinearLayout with findViewById(). I have put the function in many different places. Currently I am trying to get it to work in onCreate and a function that is called from onCreate. Here is my code so far:
public class MainActivity extends AppCompatActivity {
LinearLayout linearLayout;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
linearLayout = findViewById(R.id.linearLayout);
// this is where is load the SharedPreferences
// this is where I implement them back into the app ('reload' the app)
reload();
}
public void reload() {
// bunch of other irrelevant stuff
linearLayout = findViewById(R.id.linearLayout);
linearLayout.addView(/*other view*/); // this is where it complains
}
// the is for when the button is clicked
public void submitEntry(View view) {
// this is fine according to Logcat
linearLayout = findViewById(R.id.linearLayout);
}
}
I would expect after initializing it twice, or at least trying to, that is would've caught on but no. Logcat complains that linearLayout is a null object reference. I don't know what to do at this point but it's probably something simple that I've overlooked. Any help would be appreciated.
LinearLayout linearLayout= new LinearLayout(context);
Initialize like this it will help you!
I try to do some changes(change text, change positon ...) but it doesn't work.
For example in this function i'll change text of button correctly(i checked with getText function) but in view doesn't change anything.
When a button pressed, this function calls and change view. After this function, i want set view back.
setButton.setText("CHANGE RANGE");
setContentView(R.layout.main_layout);
I also have another layout with imageView in this main layout. I also want change that image's position.
Try this :
public class TestActivity extends Activity
{
Button setButton;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main_layout);
setButton = (Button) findViewById(R.id.testButton);
setButton.setText("CHANGE RANGE");
}
}
setButton.setText("CHANGE RANGE"); should be called after setContentView(R.layout.main_layout);
Hope this helps.
I have a checkedbox that when, onClick (checked/unchecked), would setText to an activity.
When I run the application, it stopped and will return to the previous page.
What is wrong with my code?
My OrderActivity.java has:
public class OrderActivity extends ActionBarActivity {
CheckBox OrderMenuBiggDeal, OrderMenuCrispyChicken, OrderMenuExtremeBurger, OrderMenuTenderloinTips;
TextView ReceiptTextMenuBiggDeal, ReceiptTextMenuCrispyChicken, ReceiptTextMenuExtremeBurger, ReceiptTextMenuTenderloinTips;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_order);
OrderMenuBiggDeal = (CheckBox) findViewById(R.id.checkBoxMenu1);
ReceiptTextMenuBiggDeal = (TextView) findViewById(R.id.textViewReceiptMenuPrice1);
and
public void onClickBiggDeal(View view){
if(OrderMenuBiggDeal.isChecked()){
ReceiptTextMenuBiggDeal.setText("" + "hello");
}
else{
ReceiptTextMenuBiggDeal.setText(R.string.default_value);
}
the application closes on the ReceiptTextMenuBiggDeal.setText("" + "hello"); line.
The setContentView is activity_order.xml.
The location of the TextView that I want to setText (ReceiptTextMenuBiggDeal) is on a different xml file, the activity_receipt.xml
You should change this
setContentView(R.layout.activity_order);
to
setContentView(R.layout.activity_receipt);
It's because your TextView with id textViewReceiptMenuPrice1 belong to activity_receipt layout and you trying to find it on activity_order layout.
You cannot set text on textview that is in other xml, just in one that is set in setcontentview
I'm changing my ContentView of the Activity at some point. (to View2).
After changing it back to View1, the listeners are not more working.
I already tried putting the Listener in the onResume() method.
Is it common anyway to use setContentView() to display e.g. a Progress screen/please wait,...(while an asyncTask is running).
Or should you only have ONE mainView for each Activity? (and replacing the content dynamically).
//EDIT: To be more specific:
I am looking for something like
LinearLayout item = (LinearLayout) findViewById(R.id.mainView);
View child = getLayoutInflater().inflate(R.layout.progress, null);
item.addView(child);
but instead of adding the "progress.xml", it should remove the current layout and ONLY show "progress.xml".
Do I need an "container" and show/hide mainView/progress?
But that doesn't seem very proper to me...
See also code below (stripped)
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.view1);
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
doSomething();
}
});
}
setContentView(R.layout.view2);
[...]
setContentView(R.layout.view1);
//Listener not more working
Thank you all, for your reply. You made me realize, the onClickListeners are getting lost when I remove or replace (using setContentView()) the main view. I ended up this way now:
onCreate:
setContentView(R.layout.parse);
LinearLayout container = (LinearLayout) findViewById(R.id.container);
container.addView(getLayoutInflater().inflate(R.layout.dialog, null));
container.addView(getLayoutInflater().inflate(R.layout.progress, null));
onStartDoingSomething:
findViewById(R.id.dialog).setVisibility(View.INVISIBLE);
findViewById(R.id.progress).setVisibility(View.VISIBLE);
onEndDoingSomehting:
findViewById(R.id.dialog).setVisibility(View.VISIBLE);
findViewById(R.id.progress).setVisibility(View.INVISIBLE);
I might change View.INVISIBLE to View.GONE, like nmr said, but since I have never used View.GONE, I have to check the Android doku first ;)
Assuming you use 'findViewById' to initialize 'button', you would need to do that every time that you do setContentView(R.layout.view1);
You can only have one UI for each Activity, you should create another activity and in its onCreate method set the content view
Steps:
Create Activity
Use the following code to set the content View:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.view2);
}
Define the Activity in the applications manifest as such :
Create an intent in the first Activity:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.view1);
Button button = (Button) findViewById(R.id.button);
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
intent();
}
});
}
void intent(){
Intent intent = new Intent();intent.setClass(Activity1.this, Activity2.class);
startActivity(intent);
}
And there you go c:
I know this is a very basic question, however as a newbie i cant get to work around it.
So, I want to have multiple activities to use same the xml layout(consist for example of 1 imagebutton, and multiple textviews with different IDs). Now, for every activity, I want them to view the same layout but override the views with data unique to every activity. What is the best way to do this? And also, the imagebutton should open different URLs in a video player(youtube links).
And can somebody tell me what is the most practical way to learn android programming?
UPDATE
This is my current code:
public class TemakiActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.contentviewer);
}
}
For example I have a textview with ID "descriptionviewer", and a button with ID "videolink", now, how do you code those in?
You can share the same layout file and the set the attributes for views in the onCreate(..) method of each activity.
If you want a different URL to open for each image button you could set it at runtime as follows
public void onCreate(Bundle b) {
Button button =(Button)findViewById(R.id.button);
button.setOnClickListener(new OnClickListener(){
public void onClick(View v) {
//different action for each activity
}
});
}
Yes you can! I had multiple activities inflate the same layout but they save different shared preferences.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.same_layout);
TextView urlDesc = (TextView)findViewById(R.id.descriptionviewer);
urlDesc.setText("url_1"); //now in other activities-- urlDesc.setText("url_2");
ImageButton aButton = (ImageButton)findViewById(R.id.videolink);
aButton.setOnClickListener(aButtonListener);
}
private OnClickListener aButtonListener = new OnClickListener() {
public void onClick(View v) {
// go open url_1 here. In other activities, open url_x, url_y, url_z
finish();
}
};
Same code just swapping the text you want to set for the TextView and url to open in OnClickListener(). No more to change.