Develop Reference

Android: onClick causing me to go back an Activity

I am trying to build a dynamic UI, but when I add the onClick method to the button whenever I push the button I go back to my previous activity. Any ideas on how to fix it?
my button's code: (the addMenu method is never run in the activities class)
<Button
android:text="New Menu"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/newButton"
android:layout_weight="1"
android:onClick="addMenu"/>
here is my addmenu code although no matter what goes in here(even if nothing at all) it still won't work
public void addMenu()
{
LinearLayout layout = (LinearLayout) findViewById(R.id.backLayer);
Button newButton = new Button(this);
newButton.setText("menu "+menu);
layout.addView(newButton);
menu++;
}

whenever I push the button I go back to my previous activity.
Sounds like your app is crashing and restarting... read the logcat, and you'd see something along the lines that your method signature is wrong.
android:onClick="addMenu" needs a method of public void addMenu(View v).
Or just use Java to set the button listener and remove android:onClick.
findViewById(R.id.newButton).setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
addMenu();
}
}

try this
/**
* #param v android:id="#+id/newButton"
*/
public void addMenu(View v)
{
LinearLayout layout = (LinearLayout) findViewById(R.id.backLayer);
Button newButton = new Button(this);
newButton.setText("menu "+menu);
layout.addView(newButton);
menu++;
}

Change View Text Color by code

Well, I developed a menu with eight Buttons for an App. So, every time the user clicks on in one of the buttons, such button changes its background. And I would would like to change its color as well. But I got now idea how, since setTextColor does not work with Views.
I'm using View because its part of onClick method that I override in order to achieve what I want. So, here go the code:
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
v.setBackgroundResource(R.drawable.degrade_menu);
}
So, how could I change the text color?
Cheers,

Cast your v to TextView and then set the text color. Do not forget to read color from resourse
((TextView)v).setTextColor(getResources().getColor(R.color.errorColor));

quick solution:
final Button button = (Button) findViewById(<id>);
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
button.setTextColor(<color>);
}
};
better solution: use states

Cast the view to a button. Then you can use settextcolor

Android Calculator Error

I have two questions:
How do I adjust the buttons in a table, like a normal calculator?
Whenever I click the 'equal' button the app is closing -Force
Close.
I think the problem comes from the int sum=0; whenever I use it at the equal place it gives the error.
code

use this code it may help
display.setText(sum+"");
because you have declared sum as int and setText property accepts CharSequence

For adjusting buttons, use TableLayout or RelativeLayout, where you can position buttons relatively to others.
Concerning second question, just change
display.setText(sum);
to
display.setText(String.valueOf(sum));
To make your calculator work at least a little bit change equal.setOnClickListener to this:
equal.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
// TODO Auto-generated method stub
display.setText(String.valueOf(counter+sum));
counter=0;
sum=0;
}
});

How to display a something from an EditText?

I thought making thing part of the app would be easy, however I was wrong. I wish to have a textView display whatever the user wrote in the editText. This is what I tried.
add.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
// TODO Auto-generated method stub
myTextView.setText(myEditText.getText().toString());
// of course I would use variables in place of the
// myTextView and myEditText
}
});
This is another way I tried to get this done.
add.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
// TODO Auto-generated method stub
//num1 is my String variable
num1 = myEditText.getText().toString();
myTextView.setText(num1);
}
});
Both times the textView comes up with nothing in it.
Thank you for any help!

onClickListener merely responds to user clicks. You need to implement a TextWatcher on your EditText. The most straightforward way of doing this is to implement TextWatcher in your class, then make a call to myEditText.addTextChangedListener(this).
I recommend adding something like the following to your onTextChanged method:
#Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
myTextView.setText(myTextView.getText()+s);//or something like this...
}

I usually use GetDlgItemText.
char Buffer[120];
GetDlgItemText(hwndDlg, (control), buffer, sizeof(buffer));
This will read it and store it in buffer.

In the EditText the getText call should you return the String, I don't believe you need to call the ToString method on it. The way you are using it in the onClickListener implies you have a button that should be calling a function to set the text into the textview. If you want it dynamically you should be able to use onTextChanged to fill in the data.

First of all check whether the control is coming to your setOnClickListener(). Put in a Log to find that out.
Next make sure that "add" is the button or item that u r using to initiate the copy process.
This statement of yours is correct.
myTextView.setText(myEditText.getText().toString());
Though you do not require the toString(). Doesnt really make a difference. I suggest you check that your textview and edittext is fine.

have you check the visibility of textview ?before clicking add button it is invisible rite?then u have to set the visibility on add button click.

From your code i understood that there is a button here too so try this should work:
public class Activity1 extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button btn = (Button)findViewById(R.id.mybutton);
btn.setOnClickListener(btncall);
}
private OnClickListener btncall = new OnClickListener()
{
public void onClick(View v)
{
TextView mytextView = (TextView) findViewById(R.id.MytextView);
EditText myeditText = (EditText) findViewById(R.id.MyeditText);
mytextView.setText(myeditText.getText().toString());
}
};
}

Android, screwy behavior

Cant figure this out (am a noob) but I have a default activity that starts with just one image button, clicking that image button opens the second activity that contains a bunch of image buttons but only one has an onclick, this is the exact code:
<ImageButton android:src="#drawable/level1"
android:layout_width="wrap_content" android:id="#+id/imageButton1"
android:layout_height="wrap_content"
android:onClick="button_clicked1">
</ImageButton>
in the java file this is my code:
public void button_clicked1(View v) {
//text1.setText("clicked");
//ib2.setImageResource(R.drawable.level5);
}
The screwy part, if that above function is empty nothing happens but no matter what I put in the above function... for example even a simple settext like the above commented one, and it force closes on me :((
the full java file if you are interested: http://pastebin.com/W4sJUKXH
and the manifest file (as the problem might be there, like I said, am a noobie) http://pastebin.com/yEuG1su7
** Where i think the error is:
In the manifest file I only have declared the second activity, nothing else...

Set id for the ImageViews, this is how you handle many Buttons with one method
public void button_clicked1(View v) {
switch(v.getId())
{
case R.id.myfirstimage:
//do something
break;
case R.id.mysecondimage:
// do something
break;
// add more cases
default:
// do something if none of the cases is your image view or do nothing
}
}
Set setContentView( ) before you do anything with the UI components. (Thats why you get some Exception)
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.start_levels_screen);
text1 = (TextView) findViewById(R.id.textView1);
ib2 = (ImageButton) findViewById(R.id.imageButton2);
}