Using a layout with an activity - android

So I just started playing around with android and I'm trying to see what things I can do. I was following the very first android tutorial: http://developer.android.com/training/basics/firstapp/index.html and at the very end, you programmatically define a TextView. I wanted to change this to be defined in a new layout, so I wrote this (it is named display_message.xml):
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView android:id="#+id/text_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
</LinearLayout>
And in the DisplayMessage class, I changed it to this:
public class DisplayMessage extends Activity {
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.display_message);
// Get message from intent
Intent intent = getIntent();
String message = intent.getStringExtra(FirstActivity.EXTRA_MESSAGE);
// Get the text view
TextView textView = (TextView) findViewById(R.id.text_view);
textView.setText(message);
}
}
However, Eclipse says that it doesn't know what R.layout.display_message is, nor does it know what R.id.text_view is. Is there somewhere else I need to define them or something? Where did I mess up?

It seems correct but be sure that the R class imported is the correct one.
Sometimes Eclipse imports android.R but the R file you need to import is your.package.name.R

Related

Automatically Generating java code for xml layout in Eclipse

I have got an idea to get rid of some coding when we do initializion of views.
When we create an xml layout in android. At that movement same name class is created with UpperCase Letters with a dialogue with permission. And as i created views with ids. It should create Views and initialize them automatically.
for e.g
close.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<Button
android:id="#+id/closeBtn"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#drawable/close_img" />
<TextView
android:id="#+id/closeText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="Testing Text" />
</LinearLayout>
And automatically generated java code should be.
public class Close extends Activity
{
TextView CloseText;
Button CloseBtn;
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
CloseText = (TextView)findViewById(R.id.closeText);
CloseBtn = (Button)findViewById(R.id.closeBtn);
}
}
I can read xml and do the other stuff as I explained. But how could i add this module to eclipse and How could i create a service which work in Background all the time in eclipse.
Suggest me how to add this module(Plugin) to eclipse and i am going to use JAXB to generate Java Objects from XML document. Is there any better option.
Here in this website i find that just paste the xml and you will get your java code ready for activity class.
i had attached the link

Google Android tutorial - not compiling

I did everything just as stated in this tutorial:
google android basic tutorial
and despite everything being done just as described, the code refuses to compile with 3 errors. Looks like the guys writing the turorial forgot to mention what are those things and where/how do I define them.
The errors I get:
Error:(24, 68) error: cannot find symbol variable container
Error:(36, 23) error: cannot find symbol variable action_settings
Error:(46, 54) error: cannot find symbol variable fragment_display_message
Neither of the 3 fields are defined anywhere (Perhaps one of the libraries is wrong?)
The file in question is:
package com.example.asteroth.first;
import android.app.Activity;
import android.app.Fragment;
import android.content.Intent;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.*;
import android.widget.TextView;
import android.R;
public class DisplayMessageActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent intent = getIntent();
String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
TextView textView = new TextView(this);
textView.setTextSize(40);
textView.setText(message);
setContentView(textView);
// setContentView(R.layout.activity_display_message);
if (savedInstanceState == null) {
getSupportFragmentManager().beginTransaction().add(R.id.container, new PlaceholderFragment()).commit();
}
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() { }
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_display_message, container, false);
return rootView;
}
}
}
I am using Android Studio I just downloaded and no question from search or Similar Questions points at the problem like this one, hence I suspect authors of tutorial forgot to mention something minor. I've seen suggestion to place the "container" as a new ID in one of the XML files, but to no avail.
EDIT:
'cannot find symbol ActionBarActivity' following Android Development Tutorial?
This post suggest a solution, however it changes ActionBarActivity to just Activity which is very different from what the tutorial uses and I don't know how serious repercussions would it cause
EDIT2:
Problems found and removed:
import android.R //causes action_settings error
container missing //had to add it in the xml file as an id
xml file named wrong //If I got that correctly, I'm still waiting for someone experienced to clarify, but seems like the tutorial used different name for the xml file then the one that the java code references
Remaining problem is similar to this one
Cannot resolve method placeholderfragment error
however, I both extend Fragment and include android.app.Fragment as can be seen in the included file.
I tried the same tutorial and here is how I fixed my errors:
R.id.container cannot be resolved error
I had to import android.support.v4.app.Fragment to fix this problem and add android:id = "#+id/container" to the RelativeLayout section in my activity_display_message.xml file.
fragment_display_message cannot be resolved error
Change R.layout.fragment_display_message to R.layout.activity_display_message instead. There is no need for creating a new xml file for fragment_display_message.
This should fix these two errors.
But you would probably be better off if you comment out the if(savedInstanceState............ statement as otherwise your program would crash once you try to run it if it doesn't give you any errors.
Your onCreate method should look like this:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.activity_display_message);
Intent intent=getIntent();
String message=intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
TextView textView=new TextView(this);
textView.setTextSize(40);
textView.setText(message);
setContentView(textView);
/*if (savedInstanceState==null){
getSupportFragmentManager().beginTransaction().add(R.id.container, new PlaceholderFragment()).commit();
}*/
}
I'm doing the tutorial for the first time now on Feb. 23, 2015 and ran into this compilation error though I feel like I've closely followed the steps. I changed fragment_display_message to activity_display_message which is an XML file they have us create in the tutorial. This seems to solve the error, and allow the app to run.
// A placeholder fragment containing a simple view.
public static class PlaceholderFragment extends Fragment {
public PlaceholderFragment() { }
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.activity_display_message,
container, false);
return rootView;
}
}
Add this line to take care of your first error: android:id = "#+id/container"
You get that error because container isn't in the XML.
Add <string name="action_settings">Action Settings</string>so that the "Action settings" which I'm assuming doesn't exist in your XML code since you have that error.
Create your own XML file with this exact name fragment_display_message.xmlto handle that error and check what code you might need to insert into it in your google tutorial. Often times with Eclipse, these files are not included for reasons outside my knowledge. So you have to create them or insert them yourself. (Make sure you have the latest version of the SDK by the way.
EDIT: Be sure to have the correct imports matching with your "tutorial". I took a gander at it and see you missing two imports. One of which another user answered.
It's a copy paste error.
If you paste code with "R." in it, the development environment always imports the android.R:
import android.R;
If you use R.id.... it is always looking up the android.R and not your own generated R class.
Delete the import and it should be fine. This general works for me.
After that you have to check if you already defined the id's and layout.
You can check Layouts by looking on the package explorer under res->layout. In your example there has to be an fragment_display_message.xml in it.
For id's you have to look up all of your layouts and check if there are the specific views like the container.
I got a similar error on the Building a Simple User Interface step:
Error:(18, 54) error: cannot find symbol variable toolbar
I've narrowed the cause down to res/layout/activity_my.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:orientation="horizontal">
<EditText android:id="#+id/edit_message"
android:layout_weight="1"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:hint="#string/edit_message" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/button_send" />
The original version that did compile (but no button or text box) is:
<?xml version="1.0" encoding="utf-8"?>
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
android:layout_height="match_parent" android:fitsSystemWindows="true"
tools:context=".MyActivity">
<android.support.design.widget.AppBarLayout android:layout_height="wrap_content"
android:layout_width="match_parent" android:theme="#style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar android:id="#+id/toolbar"
android:layout_width="match_parent" android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary" app:popupTheme="#style/AppTheme.PopupOverlay" />
</android.support.design.widget.AppBarLayout>
<include layout="#layout/content_my" />
<android.support.design.widget.FloatingActionButton android:id="#+id/fab"
android:layout_width="wrap_content" android:layout_height="wrap_content"
android:layout_gravity="bottom|end" android:layout_margin="#dimen/fab_margin"
android:src="#android:drawable/ic_dialog_email" />
fragment_display_message
Make sure you have a file named fragment_display_message.xml in your res/layout folder.
action_settings
Make sure you have that item in your menu.xml file in res/menu
<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
tools:context=
".MenuExampleActivity" >
<item
android:id="#+id/action_settings"
android:orderInCategory="1"
app:showAsAction="never"
android:title="My menu option"/>
</menu>
container
Make sure you have a layout (ex. RelativeLayout) with the id set to "container" in your activity_main.xml file in res/layout, given that it's the reference for the code to insert the fragment there.

Unable to use example class posted here in my project

I have been trying everything to get this to work, but to no avail. I tried to use the (AutoResizeTextView) posted here: Auto Scale TextView Text to Fit within Bounds
I created a new class file in my project with the name "AutoResizeTextView" and pasted the above code.
Then i opened the main.xml file and put n the following code:
<?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">
<com.mn.rl.AutoResizeTextView android:id="#+id/tv"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
</LinearLayout>
in the mainActivity.java file, i have the following code:
package com.mn.rl;
import android.app.Activity;
import android.os.Bundle;
public class rlActivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
com.mn.rl.AutoResizeTextView txt = (com.mn.rl.AutoResizeTextView) findViewById(R.id.tv);
txt.setText("Hello");
}
}
I have no errors in the code, and it runs but there is no autoresizing. the text remains the same size. in the xml i have the autoresize textview layout_width and layout_height set to fill parent, yet the font remains small. also tried txt.resize().
What am i doing wrong? Please Help.
there is a slight possibility that that class is only meant for resizing down. not up.

Two Layout in one Activity, searching for solution

First Basically I need to have layout when application starts.
Second I am getting data from views i have in this layout.
Third Im setting next layout and doing hard code work with data, that I got in step 2.
I can't figure out how to do this.
You can re-use the framework class ViewAnimator without any animations. It's not the prettiest solution, but should get the job done.
main.xml:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical">
<ViewAnimator xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_height="fill_parent"
android:layout_width="fill_parent"
android:id="#+id/viewFlipper" />
</LinearLayout>
MyActivity.java:
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
viewAnimator = (ViewAnimator)findViewById(R.id.viewFlipper);
viewOne = createViewOne();
viewTwo = createViewTwo();
viewAnimator.addView(viewOne);
viewAnimator.addView(viewTwo);
...
}
private void someMethod() {
... do my background task ...
viewAnimator.setDisplayedChild(1); // viewTwo
}
have you gone through the google notepad tutorials? They explain using a list screen and loading a edit/add screen used to modify you sqlite database

Android UI Beginner question

I'm new to Android/java, coming from C#/Visual Studio.
It's not a too hard jump from C# to java while coding the logic, but with the UI, I'm having problems.
I've now added a simple TextView to my main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent" android:orientation="vertical">
<TextView android:layout_width="wrap_content" android:editable="true" android:layout_height="wrap_content" android:id="#+id/textView1" android:text="TextView">
</TextView>
</LinearLayout>
Now I wanted to access the textView1 by code:
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
this.textView1 = (TextView)this.findViewById(android.R.id.textView1);
}
private TextView textView1;
but I get the error: textView1 cannot be resolved.
What am I doing wrong?
Thanks
James
Replace findViewById(android.R.id.textView1) by findViewById(R.id.textView1);
android.R is resorce packege of SDK while R is of your app which will create along with successfully build of app .
and set the background color to #ffffff in xml .... it seems more attractive..
Instead of android.R.id.textView1, just use R.id.textView1. The android prefix is for resources from Android itself, rather than from your project.
Replace findViewById(android.R.id.textView1) by findViewById(R.id.textView1);
android.R is resorce packege of SDK while R is of your app which will create along with successfully build of app .
try this
private TextView textView1;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
this.textView1 = (TextView)this.findViewById(R.id.textView1);
textView1.setText("Hello World !!!");
}

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