Develop Reference

LineBackgroundSpan drawBackground() called repeatedly

Edit: I have been able to track the problem down to the use of EditText rather than TextView. The repeated calls only happen when a field is an EditText and the system behaves itself when the field is a TextView. I can find nothing in the documentation or online that indicates that LineBackgroundSpan will not work with EditText.
I have updated the MCVE to show how things work with TextView (it does) and with EditText (it doesn't - at least not well). My updated question is how to get LineBackgroundSpan working with EditText.
I have implemented a simple class to add a rounded background to text in an EditText using LineBackgroundSpan. Everything works OK but while debugging I noticed that the drawBackground method of my class is called repeatedly and, seemingly, without end for each span in the string even though no changes are being made. It is not apparent on the display, but is readily apparent if a breakpoint is set in the drawBackground method.
In trying to track down the issue, I was able to reduce the code down to an MCVE.The following code will simply highlight an entire line of text. The top line is an EditText and the bottom line is a TextView. (This is not what I am really trying to do, but it serves the purpose.)
This MCVE exhibits the problem for me on emulators running API 17 and API 24 as well as an actual phone running API 24. Setting the disableDraw argument to true for the constructor of RoundedBackgroudSpan() will disable background drawing action in drawBackground(). I am seeing the problem on the EditText even with background drawing disabled.
What is going on here? Am I misunderstanding how to work with spans? Will spans not work with EditText? Any help will be greatly appreciated.
MainActivity.java
package com.example.bgspanmcve;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.RectF;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.text.SpannableString;
import android.text.style.LineBackgroundSpan;
import android.util.Log;
import android.widget.EditText;
import android.widget.TextView;
import static android.text.Spanned.SPAN_INCLUSIVE_INCLUSIVE;
public class MainActivity extends AppCompatActivity {
final String dispString = "XAB CD EF";
private static int count = 0; // times drawBackground is called
#Override
protected void onCreate(Bundle savedInstanceState) {
EditText editText;
TextView textView;
RoundedBackgroundSpan bg;
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Set up the EditText field with a span.
// RoundedBackgroundSpan#drawBackground will be called forever for this EditText.
editText = ((EditText) findViewById(R.id.editText));
SpannableString ssEditText = new SpannableString(dispString);
bg = new RoundedBackgroundSpan(INHIBIT_DRAWING, false);
ssEditText.setSpan(bg, 0, ssEditText.length(), SPAN_INCLUSIVE_INCLUSIVE);
editText.setText(ssEditText);
// Set up the TextView field with a span.
// RoundedBackgroundSpan#drawBackground will be called once for this TextView.
textView = ((TextView) findViewById(R.id.textView));
SpannableString ssTextView = new SpannableString(dispString);
bg = new RoundedBackgroundSpan(INHIBIT_DRAWING, true);
ssTextView.setSpan(bg, 0, ssTextView.length(), SPAN_INCLUSIVE_INCLUSIVE);
textView.setText(ssTextView, TextView.BufferType.EDITABLE);
}
private static class RoundedBackgroundSpan implements LineBackgroundSpan {
private boolean mDisableDraw;
private boolean mIsTextView;
RoundedBackgroundSpan(boolean disableDraw, boolean isTextView) {
super();
mDisableDraw = disableDraw;
mIsTextView = isTextView;
}
#Override
public void drawBackground(
Canvas canvas, Paint paint, int left, int right, int top,
int baseline, int bottom, CharSequence text, int start, int end, int lnum) {
count++;
if (mIsTextView) {
Log.d(TAG, "<<<<drawBackground (TextView) #" + count);
} else {
Log.d(TAG, "<<<<drawBackground (EditText) #" + count);
}
if (mDisableDraw) return;
Paint localPaint = new Paint();
RectF rect = new RectF(left, top, right, bottom);
localPaint.setColor(BG_COLOR);
canvas.drawRoundRect(rect, RADIUS_X, RADIUS_Y, localPaint);
}
private final String TAG = RoundedBackgroundSpan.class.getSimpleName();
private final int BG_COLOR = 0xfF00FF00;
private final int RADIUS_X = 20;
private final int RADIUS_Y = 20;
}
private final static String TAG = MainActivity.class.getSimpleName();
private final boolean INHIBIT_DRAWING = true;
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<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"
tools:context="com.example.bgspanmcve.MainActivity">
<EditText
android:id="#+id/editText"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:layout_marginStart="0dp"
android:inputType="text"
android:paddingEnd="0dp"
android:paddingStart="0dp"
android:text="EditText"
android:textSize="20sp" />
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignStart="#id/editText"
android:layout_below="#id/editText"
android:layout_marginStart="0dp"
android:layout_marginTop="16dp"
android:paddingEnd="0dp"
android:paddingStart="0dp"
android:text="TextView"
android:textSize="20sp"
android:textStyle="bold" />
</RelativeLayout>

The call to drawBackground() is timed to the rate of the flashing cursor which is about 500 ms as suggested by #Suragch. I am now convinced that the call to drawBackground() is made as part of the cursor implementation.
As a quick, but not definitive test, I have set the EditText field to not show the cursor but to still be editable (android:cursorVisible="false"). When this attribute set to false, the repeated calls to drawBackground() cease.

Cannot resolve symbol (any ID's) Android Studio

I'm a noob Android studio programmer (this is hour 2 of learning!) and I expect this is a real rookie error I'm making!
I've got a Plain Text field in my application and I would like to set the text of this dynamically. I've given the plain text field the ID of: "resultText". Here's what I try;
public void calcnums(View v)
{
int x=firstNum + seondNum;
resultText.setText("Result: " + x);
}
For some reason I get 'resultText' highlighted in red and the hover over message is; Cannot resolve symbol 'resultText'.
I have the feeling that I'm doing something wrong by using the ID, but I'm lost!
Full code as suggested in comments;
import android.app.Application;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import java.util.Random;
public class AddNumbers extends AppCompatActivity {
private int firstNum;
private int seondNum;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_numbers);
}
public void calcnums(View v)
{
int x=firstNum + seondNum;
resultText.setText(String.format("Result: %d", x);
}
public void setNums(View v)
{
TextView tx= (TextView) findViewById(R.id.text);
Random r = new Random();
int x=r.nextInt(2) + 1; // r.nextInt(2) returns either 0 or 1
firstNum = x;
r = new Random();
x=r.nextInt(2) + 1;
seondNum = x;
num1.setText(""+firstNum);
num2.setText(""+seondNum);
}
}

It seems you need to declare the View resultText
Like,
EditText resultText = (EditText) findViewById(R.id.resultText);
Also make sure that the name you are using for the resultText View in xml is written correctly as provided in the method findViewById()
usually cannot resolve symbol means some problems in variable declarations.
I am too learning android and I stumbled upon this problem as well.

I don't have the whole snippet of your code.But the thing you might be missing is to point your EditText object to view in xml.
EditText resultText = (EditText) v.findViewById(R.id.result_edit_text);
<EditText
android:id="#+id/result_edit_text"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="#string/result_edit_text"
/>

Let's assume that we have an layout with an edittext
<EditText
android:id="#id/txt_user_email"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:inputType="text" />
It has an ID. In your actitivy you must find and cast the EditText as follow:
EditText txtUserEmail = (EditText) findViewById(R.id.txt_user_email);
txtUserEmail.setText("klaus.dieter#lusty-swingers.de");

You need to find your text view in onCreate(), like that:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_add_numbers);
TextView tx= (TextView) findViewById(R.id.text);
}

need to do calculation in android

I am newbie to android and trying to develop Income Tax Calculator as a part of my project. I have around 8 fields on a page and i want to sum up all those fields and display it in textview. I have written following code for that:
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnFocusChangeListener;
import android.widget.EditText;
import android.widget.TextView;
public class Tab2 extends Activity {
/** Called when the activity is first created. */
public int tot_ded=0;
public int value1=0;
public int value2=0;
public int value3=0;
public int value4=0;
public int value5=0;
public int value6=0;
public int value7=0;
public int value8=0;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.tab2);
EditText e1=(EditText)findViewById(R.id.txtHRA);
EditText e2=(EditText)findViewById(R.id.txt80C);
EditText e3=(EditText)findViewById(R.id.txthome_loan_inte);
EditText e4=(EditText)findViewById(R.id.txtmedi_ins_self);
EditText e5=(EditText)findViewById(R.id.txtmedi_ins_depe);
EditText e6=(EditText)findViewById(R.id.txtmedi_reim);
EditText e7=(EditText)findViewById(R.id.txtcon_allo);
EditText e8=(EditText)findViewById(R.id.txtprof_tax);
TextView Textv1 = (TextView)findViewById(R.id.txttotal_dedu);
//When I remove this code from comment, it stops my app.
/* value1=Integer.parseInt(e2.getText().toString());
value2=Integer.parseInt(e2.getText().toString());
value3=Integer.parseInt(e3.getText().toString());
value4=Integer.parseInt(e4.getText().toString());
value5=Integer.parseInt(e5.getText().toString());
value6=Integer.parseInt(e6.getText().toString());
value7=Integer.parseInt(e7.getText().toString());
value8=Integer.parseInt(e8.getText().toString());
tot_ded=value1+value2+value3+value4+value5+value6+value7+value8;*/
e7.setOnFocusChangeListener(new OnFocusChangeListener() {
public void onFocusChange(View v, boolean hasFocus) {
if (!hasFocus) {
//Textv1.setText(tot_ded);
}
}
});
}
}
Can anybody help me out. I know question is childish but I really dont know what to do. Pls help me out.

e8.setOnFocusChangeListener(new OnFocusChangeListener() {
public void onFocusChange(View v, boolean hasFocus) {
if (!hasFocus) {
value1=Integer.parseInt(e1.getText().toString());
value2=Integer.parseInt(e2.getText().toString());
value3=Integer.parseInt(e3.getText().toString());
value4=Integer.parseInt(e4.getText().toString());
value5=Integer.parseInt(e5.getText().toString());
value6=Integer.parseInt(e6.getText().toString());
value7=Integer.parseInt(e7.getText().toString());
value8=Integer.parseInt(e8.getText().toString());
tot_ded=value1+value2+value3+value4+value5+value6+value7+value8;
Textv1.setText(tot_ded);
}
}
});

You first need to add a button to sum up all the edit texts.
Set InputType of every edittext to number likeandroid:inputType="number"
3.on button click check for every edittext for empty value like
if(et1.getText().toString.equals("")||et2.getText().toString.equals("")||et3.getText().toString.equals(""))
{
Toast.makeText("No value should be empty");
}
else
{
value1=Integer.parseInt(e1.getText().toString());
value2=Integer.parseInt(e2.getText().toString());
value3=Integer.parseInt(e3.getText().toString());
value4=Integer.parseInt(e4.getText().toString());
value5=Integer.parseInt(e5.getText().toString());
value6=Integer.parseInt(e6.getText().toString());
value7=Integer.parseInt(e7.getText().toString());
value8=Integer.parseInt(e8.getText().toString());
tot_ded=value1+value2+value3+value4+value5+value6+value7+value8;
Textv1.setText(tot_ded);
}
Hope this will work....

if you do this
value1=Integer.parseInt(e2.getText().toString());
and all the code after that when you remove the comments you are getting absolutely nothing from the editText and you cannot
Integer.parseInt("");
it will throw a NumberFormatException
id say your best bet is to make a button and make sure all the edit texts actually have int's in them before you do your calculation

Android- How can I show text selection on textview?

I am implementing a epub reading app where I am using textview for showing text of epub. I want to select text from textview when user long presses on textview and then do multiple operations on selected text of textview like highlight etc..
So, How can I show those cursors to user to select text whatever user wants.
*I dont want to use EditText and make it look like textview. May be overriding textview is prefered.
*I have attached screenshot to explain what I am looking for-

This is asked long time ago, when I had this problem myself as well. I made a Selectable TextView myself for my own app Jade Reader. I've hosted the solution to GitHub. (The code at BitBucket ties to the application, but it's more complete and polished.)
Selectable TextView (on GitHub)
Jade Reader (on BitBucket)
Using the following code will make your TextView selectable.
package com.zyz.mobile.example;
import android.app.Activity;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
public class MainActivity extends Activity {
private SelectableTextView mTextView;
private int mTouchX;
private int mTouchY;
private final static int DEFAULT_SELECTION_LEN = 5;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// make sure the TextView's BufferType is Spannable, see the main.xml
mTextView = (SelectableTextView) findViewById(R.id.main_text);
mTextView.setDefaultSelectionColor(0x40FF00FF);
mTextView.setOnLongClickListener(new View.OnLongClickListener() {
#Override
public boolean onLongClick(View v) {
showSelectionCursors(mTouchX, mTouchY);
return true;
}
});
mTextView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
mTextView.hideCursor();
}
});
mTextView.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
mTouchX = (int) event.getX();
mTouchY = (int) event.getY();
return false;
}
});
}
private void showSelectionCursors(int x, int y) {
int start = mTextView.getPreciseOffset(x, y);
if (start > -1) {
int end = start + DEFAULT_SELECTION_LEN;
if (end >= mTextView.getText().length()) {
end = mTextView.getText().length() - 1;
}
mTextView.showSelectionControls(start, end);
}
}
}

It depends on the minimum Android version that you'd like to support.
On 3.0+, you have the textIsSelectable attribute on the TextView, which enables this behavior. E.g.:
<TextView android:id="#+id/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:padding="#dimen/padding_medium"
android:text="#string/hello_world"
android:bufferType="spannable"
android:textIsSelectable="true"
android:textSize="28dip"
tools:context=".MainActivity" />
Below that, you best bet is to use an EditText that looks and behaves like a TextView (apart from the slection thing). Or you can implement this feature yourself using spans.

need help programming math between editText

I need help understanding how to accomplish math between different EditText views. I am not asking someone to write me the code but maybe explain what is involved to get this done.
I wanted to post a picture of this but as a new user I can not. Basicly I have a EditText for the following: Width, Length, Eave Height, Pitch.
I have ID's for all the TextViews I just dont know how to program the behind the scenes math involved to make them work. I do have the equations needed to perform the math just not sure where and how to put them in java.
Basicly I need the user to enter a number in each of the top 4 boxes. I need to use an equation to generate the answer that will be displayed in the "SQFT" box. The user will also input a number in a cost box which will generat a "Total" that needs to be displayed in a separate TextView.
Any help would be appreciated, even if it is to point me in a direction of a tutorial to get me started. Thanks for your help.
Just to show what type of math I need to use, below is the equation I use for excel to calulate.
(length+width)*(Eave+1)*2 + (((width/2)/12*Pitch)*(width/2)*2)

I'm not sure if you don't know how to extract the numbers entered in the EditTexts, how to actually do the math calculation, how to let the user initiate the calculate or how to present it.
I created a small demo that has 2 EditTexts, and a TextView that displays the sum of the numbers entered. The user does not need to press any buttons to perform the calculation, it is performed automatically every time the user updates the text (I assumed this is what you wanted).
Please note this code is not good code, it uses lots of internal anonymous classes etc but it supposed to demonstrate the mechanics of how to do this.
This is the main.xml layout file:
<?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="horizontal" >
<EditText
android:id="#+id/a"
android:hint="input a"
android:inputType="number"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:minWidth="60dp"/>
<EditText
android:id="#+id/b"
android:hint="input b"
android:inputType="number"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:minWidth="60dp"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:text="a+b = " />
<TextView
android:id="#+id/total"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_margin="10dp" />
</LinearLayout>
And this is the sample Activity:
package com.example;
import android.app.Activity;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.util.Log;
import android.widget.EditText;
import android.widget.TextView;
public class SumActivity extends Activity
{
private int a;
private int b;
private TextView totalOutput;
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
EditText inputA = (EditText) findViewById(R.id.a);
EditText inputB = (EditText) findViewById(R.id.b);
totalOutput = (TextView) findViewById(R.id.total);
inputA.addTextChangedListener(new TextChangedListener()
{
#Override
public void numberEntered(int number)
{
a = number;
updateTotal();
}
});
inputB.addTextChangedListener(new TextChangedListener()
{
#Override
public void numberEntered(int number)
{
b = number;
updateTotal();
}
});
}
private void updateTotal()
{
int total = a + b; // This is where you apply your function
totalOutput.setText("" + total); // need to do that otherwise int will
// be treated as res id.
}
private abstract class TextChangedListener implements TextWatcher
{
public abstract void numberEntered(int number);
#Override
public void afterTextChanged(Editable s)
{
String text = s.toString();
try
{
int parsedInt = Integer.parseInt(text);
numberEntered(parsedInt);
} catch (NumberFormatException e)
{
Log.w(getPackageName(), "Could not parse '" + text + "' as a number", e);
}
}
#Override
public void beforeTextChanged(CharSequence s, int start, int count, int after)
{
}
#Override
public void onTextChanged(CharSequence s, int start, int before, int count)
{
}
}
}