I have two layouts, what is the best way to switch between them programatically (not using an xml file).
And how can I do it?
Basically there are two ways.
1.) you got one XML containing all components you want to use. The ones which are not available at the moment, should bis hidden. When the user should have the possibility to use them, just make them visible
2.) this is definitly the better solution because Android is concipated for this method.
You have 2 Activities and 2 layout XML files. When you want to display another layout, start the second Activity.
in your first Activity:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.mainlayout);
Button btn = (Button) findViewById(R.id.button1);
btn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Intent i = new Intent(StackOverflowActivity.this, Login.class);
startActivityForResult(i, LOGIN_REQUEST);
}
});
}
your second Activity;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.login);
}
Related
I am new in Android.I get "Unfortunately app has stopped" when i run following code.
public class MainActivity extends Activity {
Button btn;
EditText edit;
#Override
protected void onCreate(Bundle savedInstanceState) {
btn=(Button)findViewById(R.id.button);
edit=(EditText)findViewById(R.id.text);
super.onCreate(savedInstanceState);
setContentView(R.layout.test_click);
btn.setOnClickListener(onClickList);
}
private OnClickListener onClickList= new OnClickListener() {
#Override
public void onClick(View v) {
btn.setText(edit.getText());
}
};
Wrong:
btn=(Button)findViewById(R.id.button);
edit=(EditText)findViewById(R.id.text);
super.onCreate(savedInstanceState);
setContentView(R.layout.test_click);
Issue:
You are trying to find views before setting layout to Activity. So call setContentView() first and then you can find whichever views you want.
Correct:
super.onCreate(savedInstanceState);
setContentView(R.layout.test_click);
btn=(Button)findViewById(R.id.button);
edit=(EditText)findViewById(R.id.text);
Currently you are accessing views from current Activity before setting layout for Activity .Call setContentView before accessing views from xml as:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.test_click); // set layout here
btn=(Button)findViewById(R.id.button);
edit=(EditText)findViewById(R.id.text);
btn.setOnClickListener(onClickList);
}
You should call findViewById() after you call setContentView().
On button click event I'm using setContentView(R.layout.activity_main); it works correctly.
When if I try to start new activity with Intent and startactivity commands it loads layout twice it looks like layout loading correctly then 1 second same layout loaded again.
Before start activity its loaded single time.
show.setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View v)
{
String selected = spinner0.getSelectedItem().toString();
if(selected.equals("Item 2"))
{
Intent intent = new Intent(second_layout.this,MainActivity.class);
setContentView(R.layout.activity_main);
startActivity(intent);
}
}
});
I'm guessing this line is the problem.-
setContentView(R.layout.activity_main);
setContentView will just change the layout for the current activity, so you're changing the current layout to activity_main, and then you open the Intent for MainActivity class.
Just remove that line.
When you are starting a new activity, there is no need of setContentView while starting the intent.
The intent which is getting started will have the code for loading the layout. So please remove this line.
I hope, in your MainActivity.class, you will already be writing setContentView(R.layout.activity_main) and this is enough for showing the required layout. So remove this extra line which you have included while starting the intent.
You can not set your second activity layout in your first activity before starting your second activity. It will set automatically in your second activity's onCreate() method. So you should write setContentView(R.layout.activity_main); in your MainActivity's onCreate() method. Just remove it from the onClick listener.
So write in your onClick as below:
show.setOnClickListener(new View.OnClickListener()
{
#Override
public void onClick(View v)
{
String selected = spinner0.getSelectedItem().toString();
if(selected.equals("Item 2"))
{
Intent intent = new Intent(second_layout.this,MainActivity.class);
startActivity(intent);
}
}
});
And in your MainActivity you have to set your layout as below:
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
}
Am relatively new to android, and this is the issue am having, i have a main layout which i would call layout A and another which i will call B for the purpose of this question, i included layout B in layout A with a include tag, layout B serves as a header in layout A, but layout B comes with a button, this button is not clickable in layout A, Please how can i make this button from layout B clickable.on the click of the button it is suppose to start another activity. thank you for your response. i will wait here for a while for any other questions you might have.
This is what you need to do to jump to second activity from your current activity.
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button button = (Button) findViewById(R.id.button1);// id of your button in layout.xml
button.setOnClickListener(new OnClickListener()
{
public void onClick(View v)
{
Intent myIntent = new Intent(CurrentActivity.this, SecondActivity.class);
CurrentActivity.this.startActivity(myIntent);
}
});
}
button.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
setContentView(R.layout.activity_chart);
}
});
Hi i have the above code wherein upon clicking a button i am trying to display them activity activity_chart. In that activity i want to display a graph. Here i am calling a method createIntent(). But my problem is that the graph is not getting plotted. Please help i am new to android.
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
createIntent();
}
public Intent createIntent()
{
...
}
Am i calling the method right.
A new Activity is called with:
startActivity(new Intent(currentActivity.this, nextActivity.class));
Then in your new Activities onCreate(Bundle savedInstance) method you can call setContentView(Layout layout); to set the new Layout.
So if you want to change the Activity when clicking on a Button you have to do the following:
button.setOnClickListener(new View.OnClickListener(){
public void onClick(View v){
startActivity(new Intent(currentActivity.this, nextActivity.class));
}
});
You are currently only changing the layout of the current Activity when clicking the button and not changing to another Activity.
I hope I understood you correctly. If not then provide me with some more code so I can try to understand what you want to do.
I have this onClickListener in onCreate method of my PreferenceActivity, but it gives me error.
Here is the PrefereceActivity:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
addPreferencesFromResource(R.xml.settings);
Button button = (Button) findViewById(R.id.button2);
button.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
// do something.
}
});
}
it gives me this error:
unable to start activity componentinfo java.lang.nullpointerexception
any idea what am I doing wrong?
EDIT: My SettingsPreference opens Dialog that holds that "button2".
The Button is causing your NullPointerException because you haven't set a layout and therefore it is null. You shouldn't need to use buttons in a PreferenceActivity anyway.
There's a perfectly good example of using PreferenceActivity over at the Android developer site: http://developer.android.com/reference/android/preference/PreferenceActivity.html