friends. I started to learn Android app developinng with Android Studio and Java. Now i am trying to make one progressbar. When app is started we have two EditText fields where first is 100 by default(how will be the max value for progressbar ) and one EditText field for increment by(this is step) for progressbar. When we click Start it must show up via dialog.
I write the code, there is no more errors, but app is closing when i hit the Start Button. The progressbar is not working
This is the code:
activity_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/txt_max"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Max Value" />
<EditText
android:id="#+id/maximum"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="100.0" />
<TextView
android:id="#+id/txt_increment"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Increment by"/>
<EditText
android:id="#+id/increment"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="5.0" />
<Button
android:id="#+id/butt_Start"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Start" />
</LinearLayout>
This is the MainActivity.java:
public class MainActivity extends AppCompatActivity {
int increment;
ProgressDialog dialog;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button startButton = (Button) findViewById(R.id.butt_Start);
startButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View view)
{
EditText et = (EditText) findViewById(increment);
increment = Integer.parseInt(et.getText().toString());
dialog = new ProgressDialog(MainActivity.this);
dialog.setCancelable(true);
dialog.setMessage("Loading...");
dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
dialog.setProgress(0);
EditText max = (EditText) findViewById(R.id.maximum);
int maximum = Integer.parseInt(max.getText().toString());
dialog.setMax(maximum);
dialog.show();
Thread background = new Thread(new Runnable()
{
public void run()
{
try
{
while (dialog.getProgress() <= dialog.getMax())
{
Thread.sleep(500);
progressHandler.sendMessage(progressHandler.obtainMessage());
}
} catch (java.lang.InterruptedException e)
{
}
}
});
background.start();
}
Handler progressHandler = new Handler() {
public void handleMessage(Message msg) {
dialog.incrementProgressBy(increment);
}
};
});
}
}
There are some error with that code.. I will comment each by reporting your snippet:
public class MainActivity extends AppCompatActivity {
int increment;
ProgressDialog dialog;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button startButton = (Button) findViewById(R.id.butt_Start);
startButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View view)
{
EditText et = (EditText) findViewById(increment);
Here is the first error: not really a wrong thing, but it's better to istantiate the EditText in your onCreate (outside the onClick), because this way you will re-create the EditText every time you click the button.
The error is double: you are using findViewById(increment) where, in your code, increment is an int variable whose value is actually 0. You have to use (as you did for the button)
findViewById(R.id.increment);
Going on:
increment = Integer.parseInt(et.getText().toString());
dialog = new ProgressDialog(MainActivity.this);
dialog.setCancelable(true);
dialog.setMessage("Loading...");
dialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
dialog.setProgress(0);
EditText max = (EditText) findViewById(R.id.maximum);
int maximum = Integer.parseInt(max.getText().toString());
Here the error is xml side: since you are assuming that max.getText().toString() is an Integer, add inputType to your xml with number value.
dialog.setMax(maximum);
dialog.show();
Thread background = new Thread(new Runnable()
{
public void run()
{
try
{
while (dialog.getProgress() <= dialog.getMax())
{
Thread.sleep(500);
progressHandler.sendMessage(progressHandler.obtainMessage());
}
} catch (java.lang.InterruptedException e)
{
}
}
});
background.start();
}
Handler progressHandler = new Handler() {
public void handleMessage(Message msg) {
dialog.incrementProgressBy(increment);
}
};
});
}
}
Another thing is that is better to avoid naming a variable with same name of your id, expecially because id should be representative of the control you are pointing at (for example call it "EditTextMaxValueMainActivity", this is a limit example but it is representative).
If I can suggest you, TheNewBoston channel/site is the best for tutorials, it has a couple of playlist with android basics to advanced and it is simple and really explicative. Good luck!
for other errors, we will need the logtrace
The Answer for me is here:
This line:
EditText et = (EditText) findViewById(increment);
Must be changed to:
EditText et = (EditText) findViewById**(R.id.increment)**;
And i go to design view of activity_main.xml and changed the inputType of increment EditText and maximum EditText to number.
And removed the decimal format from the numbers.
<EditText
android:id="#+id/increment"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="5" />
And here i had number with decimal, now i removed them.
<EditText
android:id="#+id/maximum"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="100" />
Related
private Button mfactbutton;
private TextView mfacttext;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my_fun_fact);
Button mfactbutton = (Button) findViewById(R.id.button);
TextView mfacttext = (TextView) findViewById(R.id.textView2);
// now we need to make out button to click
View.OnClickListener Listener = new View.OnClickListener() {
#Override
public void onClick(View v) {
String[] facts = {
"Ants stretch when they wake up in the morning.",
"Ostriches can run faster than horses.",
"Olympic gold medals are actually made mostly of silver.",
"You are born with 300 bones; by the time you are an adult you will have 206.",
"It takes about 8 minutes for light from the Sun to reach Earth.",
"Some bamboo plants can grow almost a meter in just one day.",
"The state of Florida is bigger than England.",
"Some penguins can leap 2-3 meters out of the water.",
"On average, it takes 66 days to form a new habit.",
"Mammoths still walked the earth when the Great Pyramid was being built." };
String fact = "";
// randomly select a fact
Random randomGenerator = new Random();
int randomNumber = randomGenerator.nextInt(facts.length);
fact = facts[randomNumber] + "";
}
};
mfactbutton.setOnClickListener(Listener);
}
}
Hey everyone! i need help! my button doesn't just simply clicl!!!!! heeeeeeeeelp!i'm just trying to make a simple button that changes the textview2 with each click! at first it was working but now it started not to work.
Your Button clicked properly but the main thing is you did not set fact value to TextView.
#. As you have declared Button and TextView outside onCreate(), no need to declare it again inside onCreate().
Use:
mfactbutton = (Button) findViewById(R.id.button);
mfacttext = (TextView) findViewById(R.id.textView2);
Instead of:
Button mfactbutton = (Button) findViewById(R.id.button);
TextView mfacttext = (TextView) findViewById(R.id.textView2);
#. In onClick() method show fact value on TextView or show Toast message:
// TextView
mfacttext.setText(fact);
// Toast
Toast.makeText(getApplicationContext(), "Fact: " + fact, Toast.LENGTH_SHORT).show();
Here is the working code:
public class MainActivity extends AppCompatActivity {
private Button mfactbutton;
private TextView mfacttext;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mfactbutton = (Button) findViewById(R.id.button);
mfacttext = (TextView) findViewById(R.id.textView2);
// now we need to make out button to click
View.OnClickListener Listener = new View.OnClickListener() {
#Override
public void onClick(View v) {
String[] facts = {
"Ants stretch when they wake up in the morning.",
"Ostriches can run faster than horses.",
"Olympic gold medals are actually made mostly of silver.",
"You are born with 300 bones; by the time you are an adult you will have 206.",
"It takes about 8 minutes for light from the Sun to reach Earth.",
"Some bamboo plants can grow almost a meter in just one day.",
"The state of Florida is bigger than England.",
"Some penguins can leap 2-3 meters out of the water.",
"On average, it takes 66 days to form a new habit.",
"Mammoths still walked the earth when the Great Pyramid was being built." };
String fact = "";
Random randomGenerator = new Random();
int randomNumber = randomGenerator.nextInt(facts.length);
fact = facts[randomNumber] + "";
mfacttext.setText(fact);
Toast.makeText(getApplicationContext(), "Fact: " + fact, Toast.LENGTH_SHORT).show();
}
};
mfactbutton.setOnClickListener(Listener);
}
}
OUTPUT:
Do you set your selected fact to your textView ? Add
mfacttext.setText(fact);
after selecting your random fact.
Random randomGenerator = new
int randomNumber = randomGenerator.nextInt(facts.length);
fact = facts[randomNumber] + "";
mfacttext.setText(fact);
use this
mfactbutton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
// Your code goes here
}
});
Hi I just created a simple project. if you click on the button, it will generate random text on the textview2.
MainActivity.java
public class MainActivity extends AppCompatActivity {
TextView secondTextView;
String[] Textlist = { "Hello man ", "sonam", "tashi","i am man","hellow world"};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
secondTextView = (TextView) findViewById(R.id.textView2);
Button mybtn = (Button) findViewById(R.id.btn);
mybtn.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
changeTextView_two_text();
}
});
}
private void changeTextView_two_text() {
Random random = new Random();
String rand = Textlist[random.nextInt(Textlist.length)];
// String randomText = TextList[random.nextInt(TextList.length)];
secondTextView.setText(rand);
}
}
and activity_main.xml
<LinearLayout 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:orientation="vertical"
tools:context="com.example.hello.googlemap.MainActivity">
<Button
android:id="#+id/btn"
android:text="click me"
android:layout_width="368dp"
android:layout_height="wrap_content"
tools:layout_editor_absoluteY="0dp"
tools:layout_editor_absoluteX="8dp" />
<TextView
android:gravity="center"
android:id="#+id/textView2"
android:text="no text"
android:layout_width="match_parent"
android:layout_height="wrap_content"/></LinearLayout>
Hope this helps you.
I have just started with developing apps in android, but when I am trying to create an email intent I am getting an error. The file crashes when the buttoon is clicked. The code is as follows:
MainActivity.java:-
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
Button myButton;
myButton = (Button)findViewById(R.id.enter);
myButton.setOnClickListener(new OnClickListener() {
#Override
private void onClick () {
submit();
}
}
);
public void submit() {
// Getting text from the EditText View
EditText editText = (EditText) findViewById(R.id.name);
String text = editText.getText().toString();
// Creating an email intent
Intent email = new Intent(Intent ACTION_SEND);
email.putExtra(Intent.EXTRA_EMAIL, newString[]{"youremail#gmail.com"});
email.putExtra(Intent.EXTRA_SUBJECT, text);
email.setType("message/rfc822");
startActivity(Intent.createChooser(email, "Choose an Email client :"));
}
}
activity_main.xml:-
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:orientation="vertical" >
<EditText
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/name"
android:hint="Name"/>
<Button
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:text="#string/submit"
android:onClick="submit"
android:id="#+id/enter" />
</LinearLayout>
You don't need the line:
if (intent.resolveActivity(getPackageManager()) != null) {
Also, I believe that Intent.EXTRA_EMAIL takes a string array. Instead, try this:
Intent intent = new Intent(Intent.ACTION_SEND);
intent.setType("*/*");
intent.setData(Uri.parse("mailto:"));
intent.putExtra(Intent.EXTRA_EMAIL, new String[]{"xyz#gmail.com"});
intent.putExtra(Intent.EXTRA_SUBJECT, text);
startActivity(Intent.createChooser(intent, "Send Email"));
Yeah, what mattfred has answered is correct. Do as he told. And then also if that not work then remove
onClick:"Submit"
from your Button attribute.
Give your button a specfic id and initialize Button in your activity.
Button myButton;
Then activity's onCreate
myButton = (Button)findViewById(R.id.yourButtonId);
myButton.setOnClickListener(new OnClickListener(){
#Override
private void onClick(){
submit();
}
});
I think I have found a bug.
Replace your submit method as I have done
public void submit(){
// Getting text from the EditText View
EditText editText = (EditText)findViewById(R.id.name);
String text = editText.getText().toString();
// Creating an email intent
Intent email =new Intent(Intent ACTION_SEND);
email.setType("text/plain");
email.putExtra(Intent.EXTRA_EMAIL,new String[]{"youremail#gmail.com"});
email.putExtra(Intent.EXTRA_SUBJECT, text);
startActivity(Intent.createChooser(email,"Choose an Email client :"));
What you were doing wrong is you were getting text from a TextView. You have to get it from an EditText
Moreover, in your submit method you have initialized TextView with ID R.id.name. But there is no TextView in your xml and in your xml, your EditText is initialized with ID R.id.name.
More bug is found...
In your xml's Button attribute you have written
android:onClick="Submit"
But your method name is
submit() not Submit()
Remember, Java is case sensitive...
Also see, I think you can simply use
public void submit(){}
You have no reason to use
public void submit(View v){}
After all, change every code as I have told. Not only the method. You also remove
android:onClick="submit"
also from your XML's button attribute.
Hope you have understood
--Sorry for my mistyped code. Actually now I am on Mobile device
Making a to-do list. Having 2 issues, The not so important issue is that for some reason I can't see the TextView's that I set up as "labels". The more important thing is that when I click the create new task button, my alert pops up, I can put values in my EditText boxes, but when I hit create, it crashes and I get a NullPointer exception saying I'm trying to call getText() on a null object reference. I can't figure out if I'm inflating incorrectly or if I'm not linking the EditTexts to the alert properly. The annoying thing is that my edittext alert box works just fine editing existing list items(that I hardcoded for testing). Here's my layout and activity, I commented the line in which it breaks. Sorry about all the Log.d's I'm really trying to visualize how all this works.
The Layout
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent" android:layout_height="match_parent">
<EditText
android:layout_width="55dp"
android:layout_height="wrap_content"
android:inputType="number"
android:ems="10"
android:id="#+id/txtCreatePriority"
android:layout_centerVertical="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginLeft="25dp"
android:hint="1"
android:textAlignment="center" />
<EditText
android:layout_width="235dp"
android:layout_height="wrap_content"
android:id="#+id/txtCreateItemContent"
android:layout_centerVertical="true"
android:layout_toRightOf="#+id/txtCreatePriority"
android:layout_toEndOf="#+id/txtCreatePriority"
android:layout_marginLeft="15dp"
android:hint="Do Laundry"
android:textAlignment="center" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="Priority"
android:id="#+id/lblPriority"
android:layout_above="#+id/txtCreatePriority"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginLeft="17dp"
android:textStyle="bold"
android:textSize="23dp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="Task to-do"
android:id="#+id/lblItemContent"
android:layout_above="#+id/txtCreateItemContent"
android:layout_toRightOf="#+id/lblPriority"
android:layout_toEndOf="#+id/lblPriority"
android:layout_marginLeft="65dp"
android:textStyle="bold"
android:textSize="23dp" />
</RelativeLayout>
The Activity
public class MainActivity extends AppCompatActivity {
private ListDataSource ds;
private ListView listViewToDo;
private Button btnAddNew;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final Context context = this;
Log.d("MainActivity","Attempting to create data source");
try {
ds = new ListDataSource();
}
catch(Exception e)
{
e.printStackTrace();
Log.d("MainActivity","Failed to create data source");
}
btnAddNew = (Button)findViewById(R.id.btnAddNew);
Log.d("Main Activity","Attempting to link empty list view to on screen view");
listViewToDo = (ListView)findViewById(R.id.listOfLists);
Log.d("Main Activity", "Views linked, Attempting to set adapter to listView");
listViewToDo.setAdapter(new ListDataSourceAdapter(this, ds));
Log.d("Main Activity", "Successfully set Adapter");
btnAddNew.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Log.d("addItem", "Entered onclick, Attempting to create AlertDialog");
AlertDialog.Builder addItem = new AlertDialog.Builder(context);
Log.d("addItem", "AlertDialog Built, attempting to create inflater");
LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
addItem.setView(inflater.inflate(R.layout.create_item_layout, null));
Log.d("addItem", "inflater built linking text boxes");
final TextView txtCreatePriority = (TextView)findViewById(R.id.txtCreatePriority);
final TextView txtCreateCellContent = (TextView)findViewById(R.id.txtCreateItemContent);
final TextView lblPriority = (TextView)findViewById(R.id.lblPriority);
final TextView lblItemContent = (TextView)findViewById(R.id.lblItemContent);
addItem.setTitle("Create new item");
addItem
.setCancelable(false)
.setPositiveButton("Create", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
Log.d("editText onClick", "in onClick method, preparing to add entry");
// This is where the code breaks
ds.getList().add(Integer.valueOf(txtCreatePriority.getText().toString()), new CellContent(Integer.valueOf(txtCreatePriority.getText().toString()) + 1, txtCreateCellContent.getText().toString().trim()));
Log.d("editText onClick", "added new entry");
ListDataSourceAdapter adapter = new ListDataSourceAdapter(context, ds);
Log.d("editText onClick", "reestablished link to adapter");
listViewToDo.setAdapter(adapter);
Log.d("editText onClick", "adapter set");
adapter.notifyDataSetChanged();
Log.d("editText onClick", "DataSetChanged");
}
})
.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
dialog.cancel();
}
});
AlertDialog alertDialog = addItem.create();
alertDialog.show();
}
});
// add button listener
listViewToDo.setOnItemClickListener(new AdapterView.OnItemClickListener()
{
#Override
public void onItemClick(AdapterView<?> parent, View view, final int position, long id)
{
AlertDialog.Builder editItem = new AlertDialog.Builder(context);
final EditText edittext = new EditText(context);
editItem.setTitle("Change item");
editItem
.setMessage("Set new todo item")
.setView(edittext)
.setCancelable(false)
.setPositiveButton("Submit", new DialogInterface.OnClickListener()
{
public void onClick(DialogInterface dialog, int id)
{
Log.d("editText onClick","in onClick method, preparing to remove previous entry");
ds.getList().remove(position);
Log.d("editText onClick", "removed previous entry");
ds.getList().add(position, new CellContent(position + 1, edittext.getText().toString().trim()));
Log.d("editText onClick", "added new entry");
ListDataSourceAdapter adapter = new ListDataSourceAdapter(context,ds);
Log.d("editText onClick","reestablished link to adapter");
listViewToDo.setAdapter(adapter);
Log.d("editText onClick", "adapter set");
adapter.notifyDataSetChanged();
Log.d("editText onClick", "DataSetChanged");
}
})
.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int id) {
dialog.cancel();
}
});
AlertDialog alertDialog = editItem.create();
alertDialog.show();
}
});
}
}
The Error
java.lang.NullPointerException: Attempt to invoke virtual method 'android.text.Editable android.widget.EditText.getText()' on a null object reference
You're calling "(EditText)v.findViewById" on the view v.
The view v is the view passed back in the onClickListener, which is the button itself.
Since that button does not contain the EditTexts within it, those views are null. And crash when you try to access them.
I'm a little uncertain where the layout with the edit texts is in this code. Is it in the same layout as the listview, or in create_item_layout?
If its create_item_layout, that needs to be inflated before getting the EditTexts. Use the view you inflate to findViewById.
Imagine a number 10, then after user clicks a button it changes to 100. But how to make an efficient transition
10 -> 100,
that will display values like
12, 15, 18, ..., 97, 100 over 1 second.
I've seen something like that in "Cookie clicker" but couldn't find anything about that kind of transition in the source code.
I had an idea of a loop (for number1 < number2, do number1++), it will work fine for small numbers, but if 10 changes to 1 billion, then the loop will probably freeze the whole app.
Second idea is to get added value (100-10=90) and divide by 30 or 60 frames, and add this value with each frame. But what will happen if frame is dropped? - Probably value will not be added. What if user makes double click or the system adds values automatically?
Hope it gives an idea of what kind of number transition I need.
Maybe I overlooked and there is a simple approach? Any help is appreciated.
Hope this little demo using a ValueAnimator will inspire you to find an appropriate solution.
You can specify the duration of the animation (see code) and even adjust the frame-rate by saying mAnimator.setFrameDelay(frameDelay);.
By using animator.isRunning() or animator.isStarted() you can prevent double-click malfunction or other unwanted behaviour while the current animation is runnning.
The Main Activity:
/** ValueAnimator demo */
public class MainActivity extends Activity {
ValueAnimator mAnimator;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
final TextView tv = (TextView) findViewById(R.id.textview);
mAnimator = ValueAnimator.ofInt(1, 100).setDuration(1000);
mAnimator.setInterpolator(new AccelerateDecelerateInterpolator());
mAnimator.addUpdateListener(new AnimatorUpdateListener() {
#Override
public void onAnimationUpdate(final ValueAnimator animator) {
final Integer value = (Integer) animator.getAnimatedValue();
tv.setText(String.format("%04d", value));
}
});
mAnimator.addListener(new AnimatorListenerAdapter() {
#Override
public void onAnimationEnd(Animator animator) {
super.onAnimationEnd(animator);
final int endValue = Integer.parseInt((String) tv.getText());
mAnimator.setIntValues(endValue, endValue + 100);
}
});
}
/** Button callback */
public void onClick(final View view) {
if (!mAnimator.isStarted() && !mAnimator.isRunning()) {
mAnimator.start();
}
}
}
Simple demo layout:
<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="vertical" >
<TextView
android:id="#+id/textview"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="25sp"
android:typeface="monospace"
android:text="0001" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Gimme +100"
android:onClick="onClick">
</Button>
Here's another demo (hope this answers your 2. question), which implements different behaviour dependent on single click or double-click on the button. Just experiment with it, you now have the basic building blocks to construct own behavour ...
/** ValueAnimator demo */
public class MainActivity extends Activity {
ValueAnimator mAnimator;
TextView mTv;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mTv = (TextView) findViewById(R.id.textview);
mAnimator = ValueAnimator.ofInt(1, 100).setDuration(1000);
mAnimator.setInterpolator(new AccelerateDecelerateInterpolator());
mAnimator.addUpdateListener(new AnimatorUpdateListener() {
#Override
public void onAnimationUpdate(final ValueAnimator animator) {
final Integer value = (Integer) animator.getAnimatedValue();
mTv.setText(String.format("%04d", value));
}
});
final Button button = (Button) findViewById(R.id.button);
final GestureDetector gestureDetector = new GestureDetector(this,
new GestureDetector.SimpleOnGestureListener() {
#Override
public boolean onDoubleTap(MotionEvent e) {
performAnimation(100);
return true;
}
#Override
public boolean onSingleTapConfirmed(MotionEvent e) {
performAnimation(0);
return true;
}
});
button.setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
return gestureDetector.onTouchEvent(event);
}
});
}
/** starts animation */
private void performAnimation(final int offset) {
if (!mAnimator.isStarted() && !mAnimator.isRunning()) {
final int endValue = Integer.parseInt((String) mTv.getText());
mAnimator.setIntValues(endValue + offset, endValue + 100 + offset);
mAnimator.start();
}
}
}
Don't forget to replace your layout file, since the click-attribute of the button has been removed:
<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="vertical" >
<TextView
android:id="#+id/textview"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="25sp"
android:typeface="monospace"
android:text="0001" />
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Gimme +100" >
</Button>
</LinearLayout>
I guess you can do it by using different threads. Only main thread works with UI so you can divide the interval into small intervals and make a transitions in different threads.After send them to main thread and print. Hope it will help.
I create simple Android app (https://www.linux.com/learn/docs/683628-android-programming-for-beginners-part-1) with latest Android Studio. Code:
public class test_act extends Activity {
private static final int MILLIS_PER_SECOND = 1000;
private static final int SECONDS_TO_COUNTDOWN = 30;
private android.widget.TextView countdownDisplay;
private android.os.CountDownTimer timer;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.full_act);
countdownDisplay = (android.widget.TextView) findViewById(R.id.time_display_box);
android.widget.Button startButton = (android.widget.Button) findViewById(R.id.startbutton);
startButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
try {
showTimer(SECONDS_TO_COUNTDOWN * MILLIS_PER_SECOND);
} catch (NumberFormatException e) {
// method ignores invalid (non-integer) input and waits
// for something it can use
}
}
});
}
private void showTimer(int countdownMillis) {
if(timer != null) { timer.cancel(); }
timer = new android.os.CountDownTimer(countdownMillis, MILLIS_PER_SECOND) {
#Override
public void onTick(long millisUntilFinished) {
countdownDisplay.setText("counting down: " +
millisUntilFinished / MILLIS_PER_SECOND);
}
#Override
public void onFinish() {
countdownDisplay.setText("KABOOM!");
}
}.start();
}
}
My 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" >
<TextView
android:id="#+id/time_display_box"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_marginTop="60dp"
android:text="#string/_00_30"
android:textAppearance="?android:attr/textAppearanceLarge"/>
<Button
android:id="#+id/startbutton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/time_display_box"
android:layout_centerHorizontal="true"
android:layout_marginTop="41dp"
android:text="#string/start" />
</RelativeLayout>
In emulator it's good working. But on my Galaxy S2 with CyanogenMod10.1(Android 4.2.2) app wrong updating TextView. Screenshot:
How I can resolve this problem?
upd: after screen rotate TextView is updating once.
You might want to try invalidating your layout every time it is updated. I am guessing with how often the text is being updated the phone is not having enough time to redraw the layout. This would also explain why it works when you rotate your phone, because then the layout is forced to update.
countdownDisplay.invalidate();
Let me know if that does not work.
It commonly happens when you put UI updates inside try blocks, try to avoid it or wrap with runOnUiThread.
EDIT:
Another reason - you update it to fast - you code does 1000 updates per second i dont think it can handle it.