I'm new to android platform , I'd like to settext using textviews , I tried to write set text into two textviews but its just draws one textview why?
I can't draw two textviews
TextView tv1;
TextView tv2;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
layout = new LinearLayout(this);
tv1 = new TextView(this);
tv2 = new TextView(this);
tv1.setText("Hello");
tv2.setText("How are you?");
}
On Android, the user interface normally should be created using XML-files, instead of Java code. You should read up on the tutorials on android.com, especially:
http://developer.android.com/guide/topics/ui/declaring-layout.html
An example:
In your res/layout/main.xml, you define the text TextView's:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView android:id="#+id/TextView1" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="TextView 1"/>
<TextView android:id="#+id/TextView2" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="TextView 2"/>
</LinearLayout>
Then if you use setContentView in the activity to display this, the app will show to TextView's:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setContentView(R.layout.main);
}
If you want to programmatically set the text in the Activity, just use findViewById():
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setContentView(R.layout.main);
((TextView)this.findViewById(R.id.TextView1)).setText("Setting text of TextView1");
}
I definitely second TuomasR's suggestion to use XML layouts. However, if you're wanting to add new TextViews dynamically (i.e. you don't know how many you will need until runtime), you need to do a couple of other steps to what you are doing:
First, define your LinearLayout in main.xml (it's just easier that way than LayoutParams, IMO):
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/my_linear_layout"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical"
/>
Now, you can go to your code, and try the following:
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
//This inflates your XML file to the view to be displayed.
//Nothing exists on-screen at this point
setContentView(R.layout.main);
//This finds the LinearLayout in main.xml that you gave an ID to
LinearLayout layout = (LinearLayout)findViewById(R.id.my_linear_layout);
TextView t1 = new TextView(this);
TextView t2 = new TextView(this);
t1.setText("Hello.");
t2.setText("How are you?");
//Here, you have to add these TextViews to the LinearLayout
layout.addView(t1);
layout.addView(t2);
//Both TextViews should display at this point
}
Again, if you know ahead of time how many views that you need, USE XML.
Related
Please bear with me as I am new to the use of Views and Layouts.
I am trying to create an application in which the user can enter a text field, press a button and have a new text field appear and they can continue adding text fields in this way.
My solution was to have the top level be a scrollview and then have a relative view as a child within that(this way I can then programatically insert more editviews in my code with the OnClick() listener.
I have seen and read a couple of other posts pertaining to relative views but it seems there is still something that I am missing. I have tried
Here is the xml
<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/activity_create_accounts"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.nic.mybudget.CreateAccountsActivity">
<RelativeLayout
android:id="#+id/activity_create_accounts_relativeLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fillViewport="true"
>
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="#string/activity_name"
android:inputType="textAutoComplete"
android:layout_alignParentTop="true"
android:id="#+id/activity_createAccounts_relativeLayout_activityName"/>
<Button
android:text="+"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:layout_below="#+id/activity_createAccounts_relativeLayout_activityName"
android:id="#+id/activity_create_accounts_relativeLayout_activityName_addButton" />
<Button
android:text="Save"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentBottom="true"
android:layout_below="#+id/activity_create_accounts_relativeLayout_activityName_addButton"
android:layout_centerHorizontal="true"
android:id="#+id/activity_create_accounts_relativeLayout_activityName_saveButton" />
</RelativeLayout>
And here is the Code where I try to add new editviews.
public class CreateAccountsActivity extends Activity {
static private final String TAG = "MAIN-Activity";
int numAccounts = 0;
int lastAccountID;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_create_accounts);
final RelativeLayout Relative = (RelativeLayout) findViewById(R.id.activity_create_accounts_relativeLayout);
final TextView oldAccount = (TextView) findViewById(R.id.activity_createAccounts_relativeLayout_activityName);
final TextView newAccount = new TextView(this);
final Button addNewAccountButton = (Button) findViewById(R.id.activity_create_accounts_relativeLayout_activityName_addButton);
addNewAccountButton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Log.i(TAG, "addNewAccountOnClick");
numAccounts = numAccounts+1;
int newAccountID = oldAccount.getId() + numAccounts;
RelativeLayout.LayoutParams rlp = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,ViewGroup.LayoutParams.WRAP_CONTENT);
rlp.addRule(RelativeLayout.ALIGN_PARENT_TOP);
newAccount.setLayoutParams(rlp);
newAccount.setHint("Hint" );
newAccount.setId(newAccountID);
Relative.addView(newAccount);
RelativeLayout.LayoutParams blp = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,ViewGroup.LayoutParams.WRAP_CONTENT);
blp.addRule(RelativeLayout.BELOW, newAccountID-1);
addNewAccountButton.setLayoutParams(blp);
}
});
}
}
As you can see what I am trying (and failing) to do is add the new edit view at the top of the page and simply push everything else down the page. What am I getting wrong here with the relative layout?
Any help is appreciated.
First thing View with id activity_createAccounts_relativeLayout_activityName is EditText and you are casting it with TextView so that is wrong cast it to EditText.
And to your actual problem:
You are using same EditText instance with variable newAccount and adding it again in relative layout if you want to add one more EditText in relative layout you have to initialise EditText inside onclicklistener.
Just add one line newAccount= new EditText(context)in your onclicklistener code before line numAccounts = numAccounts+1;
Happy Coding !
I have a custom layout java file that I create and add views to like this:
PredicateLayout layout = new PredicateLayout(this);
for (int i = 0; i < someNumberThatChangesEveryTime; i++)
{
TextView t = new TextView(this);
t.setText("Hello");
t.setBackgroundColor(Color.RED);
t.setSingleLine(true);
layout.addView(t, new PredicateLayout.LayoutParams(2, 0));
}
setContentView(layout);
What I would like to do is define my TextView in an xml, so I can add it like so:
TextView t = (TextView) findViewById(R.id.textview);
And of couse also add other kinds of views. I have no idea how to write this xml file, or how to connect it to this activity. The layout I'm using is this one: Line-breaking widget layout for Android
Find the id of the root layout in xml and add other ui elements programatically to the root layout.
activity_main.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
andorid:id="#+id/ll
tools:context=".MainActivity" >
<TextView
android:id="#+id/tv"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_marginTop="20dp"
android:text="Blank text" />
</RelativeLayout>
Your MainActivity
public class MainActivity extends Activity{
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
RelativeLayout ll = (RelativeLayout) findViewById(R.id.ll);
TextView tv= (TextView) findViewById(R.id.tv);
// add other ui elements to the root layout ie Relative layout
}
}
I just started android and I tried below questions to get this answer before posting it here:
Android - Adding layout at runtime to main layout
Add button to a layout programmatically
Dynamically adding a child to LinearLayout with getting each child's position
And I am still not able to add a button to linear layout :(
Below is the code for activity, please let me know where I am wrong:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
LinearLayout layout = (LinearLayout) View.inflate(this, R.layout.activity_main, null);
Button btn = new Button(this);
btn.setId(123);
btn.setText("Welcome to WI FI World");
layout.addView(btn);
}
And xml looks like below:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
</LinearLayout>
Try assigning an id to your layout then add the button to the layout.
Im pretty sure those 2 layouts are not the same, so you are infact adding a button to a layout that is never displayed.
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
LinearLayout layout = (LinearLayout) findViewById(R.id.lnr_main);
Button btn = new Button(this);
btn.setId(123);
btn.setText("Welcome to WI FI World");
layout.addView(btn);
}
With Layout assigned an id
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/lnr_main"
android:layout_width="match_parent"
android:layout_height="match_parent" >
</LinearLayout>
Take the Id for LinearLayout in XML and in jave code use that id of LinearLayout from XML
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/linear" >
</LinearLayout>
In onCreate():
LinearLayout linear=(LinearLayout)findViewById(R.id.linear);
//Select widgets
linear.addView()
Give an id to your linearLayout.
Then in your code
LinearLayout layout = (LinearLayout)findViewById(R.id.given_id);
Keep the rest the same, should work.
I'm relatively new to Android programming, and am having a problem with inflation. I'm trying to create a simple activity that spits out a few descriptive fields from a previously selected ListView item.
I can access the source data from the ListView without any problems, but the subsequent activity to display the selected data isn't working. Specifically, the following XML layout excerpt (in layout/info.xml) and corresponding code generates an activity that comes up OK, but doesn't display the string "XYZZY" as desired (as indicated above, the string is normally obtained dynamically from the ListView, but is simplified to a hard-coded string for this example).
What am I doing wrong? Here's the XML excerpt:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:background="#color/black"
android:padding="10dp" >
<!-- Info text -->
<TextView
android:id="#+id/infoname"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_margin="12dp"
android:gravity="center_horizontal"
android:textColor="#color/white"
android:textSize="24sp" />
...
</RelativeLayout>
And here's the java excerpt:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.info);
LayoutInflater li = getLayoutInflater();
View infoView = li.inflate(R.layout.info, null);
TextView name = (TextView) infoView.findViewById(R.id.infoname);
name.setText("XYZZY");
...
}
by setting the contentView() you don't need to do the inflating yourself. The reason you are not seeing your text is that the inflated layout is not added to the view hierarchy.
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.info);
TextView name = (TextView) findViewById(R.id.infoname);
name.setText("XYZZY");
...
}
You can't do setContentView(R.layout.info) and inflate in the same activity for the same layout, choose one of the approaches. For your example above there is the right code:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
LayoutInflater li = getLayoutInflater();
View infoView = li.inflate(R.layout.info, null);
setContentView(infoView);
TextView name = (TextView) infoView.findViewById(R.id.infoname);
name.setText("XYZZY");
...
}
I'm new to Android (and surely I'm not an expert Java developer), so I'm sorry for the dumb question
I would like to "capture" the id of a textView and to set its text value dynamically,
here is how I'm trying to do this:
public class AndStringTestActivity extends Activity {
/** Called when the activity is first created. */
String abc = "abcabc";
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
TextView tv = (TextView)findViewById(R.id.test);
tv.setText(abc);
setContentView(R.layout.main);
}
}
and here is the Xml from which i'm reading the id of the textview i would like to write inside
// main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:id="#+id/test"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
/>
</LinearLayout>
the error i receive is the usual Application stopped unexpectedly
Thanks.
Call setContentView before trying to find the TextView. The TextView does not exist before you have called setContentView (which will inflate your XML layout)
Call setContentView(R.layout.main) before you call findViewById().