Develop Reference

how to save Editable s value in afterTextChanged?

I am going to save the value in one textview after the length of input string is fulfilled. but saved value is empty if the value of textview is used. If Editable s value in afterTextChanged is used, it causes crash.
Some codes as following:
number = (EditText) findViewById(R.id.number);
final String numberStr = number.getText().toString();
if following afterTextChanged is used, empty value is saved even I already input sth.
#Override
public void afterTextChanged(Editable s) {
if (s.length() == 11) {
Toast.makeText(MainActivity.this, numberStr , Toast.LENGTH_SHORT).show();
saveSettingNote(MainActivity.this, "number_save", "number", numberStr);
number.setText(getSettingNote(MainActivity.this,"number_save", "number"));
}
}
if following code is used, it will cause crash:
#Override
public void afterTextChanged(Editable s) {
if (s.length() == 11) {
Toast.makeText(MainActivity.this, s.toString(), Toast.LENGTH_SHORT).show();
saveSettingNote(MainActivity.this, "number_save", "number", s.toString());
number.setText(getSettingNote(MainActivity.this,"number_save", "number"));
}
}
Saving and getting are based on SharedPreferences, which works well in other situation.
Actually, what I want to implement is saving String after the criteria is fulfilled for input string.
Please help to identify what is wrong in above code or suggest a new to get that function. Thanks a lot in advance.

Your app is crashing because your listener is looping indefinitely with the same value passed in over and over.
The ugly truth is that you've to unbind your listener, set the value and then bind it again:
#Override
public void afterTextChanged(Editable s) {
if (s.length() == 11) {
// unbind your listener
editText.addTextChangedListener(null);
// do your stuff
Toast.makeText(MainActivity.this, s.toString(), Toast.LENGTH_SHORT).show();
saveSettingNote(MainActivity.this, "number_save", "number", s.toString());
number.setText(getSettingNote(MainActivity.this,"number_save", "number"));
// bind your listener again
editText.addTextChangedListener(MainActivity.this);
}
}
Using RxBinding you can achieve this in a more elegant way:
RxTextView.textChanges(editText)
.map { it.toString() }
.filter({ it.length == 11 })
.distinctUntilChanged() // <-- the important part
.subscribe(
{ s -> /* do your stuff here */}
)

you set text in editext afterTextChanged(Editable s) which calls text change listener again and again and cause the application to crash. call number.setText(getSettingNote(MainActivity.this,"number_save", "number")); outside the text change listener.

My guess it that by declaring numberStr as you did, you expect to change its value each time the edit text change its content. However, this is not the case; it will be initialised with an empty string "" (unless you don't have any other string in the edit text at that moment) and then it will NEVER change its value, thus resulting in the empty value that you save. As solution I would suggest to make numberStr non final and update its value (like you already did) each time before showing the Toast.

if-else block not working properly in android

Scenario: when the focus is lost from an EditText, I'm checking if it contains null (in the first if block).
If so, then I'll show a Toast.
In the else-if block I'm checking if the EditText doesn't contain letters.
Then I'll show a toast, but when I run the application, the Toast is shown even on a correct input.
I.e.: If I enter any letter the Toast should not be shown, it should be shown only when a null or digit/special symbol is entered.
Here is the code
et1.setOnFocusChangeListener(new View.OnFocusChangeListener() {
#Override
public void onFocusChange(View v, boolean hasFocus) {
// TODO Auto-generated method stub
if(!hasFocus)
{
a = et1.getText().toString();
if (a.equals(""))
{
Toast.makeText(getApplicationContext(), "Your entry is incorrect!!", Toast.LENGTH_LONG).show();
}
else if (!a.contains("[a-z]")||!a.contains("[A-Z]")) {
Toast.makeText(getApplicationContext(), "Your entry is incorrect!!", Toast.LENGTH_LONG).show();
}
else
{
}
Please help

The '==' operator only compares references. To compare string values you must use the equals() method.
Instead of
if (a == "")
use
if (a.equals(""))
See: What is the difference between == vs equals() in Java?

It's not working because:
if (a == "")
won't work in Java
Use
if (a.equals(""))
instead
Also, String.contains doesn't use regular expressions, but CharacterSequences.
So, unless your string doesn't contain the exact character sequences "[a-z]" or "[A-Z]" (and only one of these 2 strings), you'll never get a match.
See: http://developer.android.com/reference/java/lang/String.html#contains(java.lang.CharSequence)

The problem is:
if (a == "")
Strings can't be compared like this. Instead, check for size equal to 0, or against a specific string with the equals() method.

Getting "Link text" of the link displayed in WebView

I have Android WebView which displays some links as: Link1TextLink2Text Now I would like to retrieve Link1Text and Link2Text when I long press these links. I have contextMenu implemented in the code and I could successfully get the link urls (http://link1.html, http://link2.html) using HitTestResult getExtra() method but how ccan I get those link texts ?FYI, I require those link texts for implementing "Copy link text" option in the contextMenu.

To get the text of an achor link:
I. Hook a touchstart listener to every web pages in the onPageFinished() callback of WebViewClient via evaluateJavascript. like:
//Javascripts to evaluate in onPageFinished
const w=window;
w.addEventListener('touchstart',wrappedOnDownFunc);
function wrappedOnDownFunc(e){
if(e.touches.length==1){
w._touchtarget = e.touches[0].target;
}
console.log('hey touched something ' +w._touchtarget);
}
note we've saved the touch target.
II. Then implement OnLongClicklisenter for webview. use evaluateJavascript again when you long pressed on a link object:
#Override
public boolean onLongClick(View v) {
WebView.HitTestResult result = ((WebView)v).getHitTestResult();
if (null == result) return false;
int type = result.getType();
switch (type) {
case WebView.HitTestResult.SRC_ANCHOR_TYPE:
if(result.getExtra()!=null){
((WebView)v).evaluateJavascript("window._touchtarget?window._touchtarget.innerText:''", new ValueCallback<String>() {
#Override
public void onReceiveValue(String value) {
System.out.println("hey received link text : "+value);
}
});
}
return true;
}
return false;
}
What's more, we can even choose to select the text of the anchor element! Actually this is one of the options that samsung browser offers when you long-pressed an tag .
To achieve this, we still need that recorded touch target. Besides we need 2 new javascript methods:
function selectTouchtarget(){
var tt = w._touchtarget;
if(tt){
w._touchtarget_href = tt.getAttribute("href");
tt.removeAttribute("href");
var sel = w.getSelection();
var range = document.createRange();
range.selectNodeContents(tt);
sel.removeAllRanges();
sel.addRange(range);
}
}
function restoreTouchtarget(){
var tt = w._touchtarget;
if(tt){
tt.setAttribute("href", w._touchtarget_href);
}
}
Finnaly in the onLongClick listener, instead of just fetch the innerText, we programmatically set the selection, trigger the action menu bar, and restore the removed href attribute of our touch target.
case WebViewmy.HitTestResult.SRC_ANCHOR_TYPE:
if(result.getExtra()!=null){
WebViewmy mWebView = ((WebViewmy)v);
mWebView.evaluateJavascript("selectTouchtarget()", new ValueCallback<String>() {
#Override
public void onReceiveValue(String value) {
/* bring in action mode by a fake click on the programmatically selected text. */
MotionEvent te = MotionEvent.obtain(0,0,KeyEvent.ACTION_DOWN,mWebView.lastX,mWebView.lastY,0);
mWebView.dispatchTouchEvent(te);
te.setAction(KeyEvent.ACTION_UP);
mWebView.dispatchTouchEvent(te);
te.recycle();
//if it's not delayed for a while or the href attribute is not removed, then the above code would click into
// the anchor element instead of select it's text.
/* restore href attribute */
mWebView.postDelayed(() -> mWebView.evaluateJavascript("restoreTouchtarget()", null), 100);
}
});
}
return true;
In my case, I've extended the WebView as WebViewmy to record last touched positions, lastX and lastY, in the onTouchEvent method.

Unfortunately, a clear, official way to do this is not available. Although, there are two APIs (selectText and copySelection) which are pending API council approval, that may help to do this, but they are not available at the moment.

Accessibility function implementation problems in Android

I'm developing application that views books. There is a screen (Activity) which shows a book. It has custom view, something similar to ViewSwitcher and every page is a bitmap that is rendered by a custom View.
Now I should implement accessibility function - book should be read by the phone (audio).
I've read Accessibility section here https://developer.android.com/guide/topics/ui/accessibility/index.html but it is not clear enough.
I use SupportLibrary for accessibility management and now I have this code in ViewGroup (which manages book pages). Code 1:
private class EditionPagesViewSwitcherAccessibilityDelegate extends AccessibilityDelegateCompat {
private int mPageCount;
private double[] mPageRange;
#Override
public void onInitializeAccessibilityEvent(final View host, final AccessibilityEvent event) {
super.onInitializeAccessibilityEvent(host, event);
event.setClassName(EditionPagesViewSwitcher.class.getName());
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
event.setScrollable(canScroll());
}
if (event.getEventType() == AccessibilityEventCompat.TYPE_VIEW_SCROLLED && updatePageValues()) {
event.setItemCount(mPageCount);
// we use +1 because of user friendly numbers (from 1 not 0)
event.setFromIndex((int) (mPageRange[0] + 1));
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
event.setToIndex((int) (mPageRange[1] + 1));
}
}
}
#Override
public void onInitializeAccessibilityNodeInfo(final View host, final AccessibilityNodeInfoCompat info) {
super.onInitializeAccessibilityNodeInfo(host, info);
info.setClassName(EditionPagesViewSwitcher.class.getName());
info.setScrollable(canScroll());
info.setLongClickable(true);
if (canScrollForward()) {
info.addAction(AccessibilityNodeInfoCompat.ACTION_SCROLL_FORWARD);
}
if (canScrollBackward()) {
info.addAction(AccessibilityNodeInfoCompat.ACTION_SCROLL_BACKWARD);
}
}
#Override
public boolean performAccessibilityAction(final View host, final int action, final Bundle args) {
if (super.performAccessibilityAction(host, action, args)) {
return true;
}
switch (action) {
case AccessibilityNodeInfoCompat.ACTION_SCROLL_FORWARD: {
if (canScrollForward()) {
showNext();
return true;
}
}
return false;
case AccessibilityNodeInfoCompat.ACTION_SCROLL_BACKWARD: {
if (canScrollBackward()) {
showPrevious();
return true;
}
}
return false;
}
return false;
}
Here is code from page view Code 2:
#Override
public void onInitializeAccessibilityEvent(final View host, final AccessibilityEvent event) {
super.onInitializeAccessibilityEvent(host, event);
event.setClassName(EditionPageView.class.getName());
if (hasText()) {
event.getText().add(getPageRangeText());
final String trimText = mSurfaceUpdateData.getPageText().trim();
if (trimText.length() > MAX_TEXT_LENGTH) {
event.getText().add(trimText.substring(0, MAX_TEXT_LENGTH));
// event.getText().add(trimText.substring(MAX_TEXT_LENGTH, trimText.length()));
}
else {
event.getText().add(trimText);
}
}
}
#Override
public void onInitializeAccessibilityNodeInfo(final View host, final AccessibilityNodeInfoCompat info) {
super.onInitializeAccessibilityNodeInfo(host, info);
info.setClassName(EditionPageView.class.getName());
}
Because page text data loads asynchronous first time accessibility don't have any text while executes onInitializeAccessibilityEvent code. And then when data have been loaded I fire AccessibilityEvent.TYPE_VIEW_SELECTED and AccessibilityEvent.TYPE_VIEW_TEXT_CHANGED events. Then onInitializeAccessibilityEvent executes again and phone "read" book text.
So my questions:
Is my Accessibility implementation right? May be it is design wrong? Because I didn't find any good tutorial about this feature.
Why I need to use SDK versions checks in Support implementations in Code 1? Why support implementation doesn't handle it correctly?
Is firing TYPE_VIEW_SELECTED and TYPE_VIEW_TEXT_CHANGED really needed? Or may be some other code should be implemented?
The main question. In Code 2 there is commented code line. This code statement substring text to be less then MAX_TEXT_LENGTH (it's 3800) because if text is bigger nothing is played. Nothing. Is it accessibility restriction? Any other text that is less then this value is played well.
Does anyone know where I can find any good tutorial? (yes I saw samples).
Does anyone have any custom realizations to look through?
UPDATED
Well. Here is some answers:
As I can see TYPE_VIEW_SELECTED and TYPE_VIEW_TEXT_CHANGED events are not needed if you don't want this text to be read as soon as you get it.
On Nexus 7 all large text is played well (text up to 8000 symbols), so this issue doesn't reproduce on it, but on Samsung Galaxy Tab 10.1 (Android 4.0.4) and Genymotion emulator of Tab 10.1 with Android 4.3 does. And this is strange...

4.. According to the documentation of String.substring()
The first argument you pass is the start index in the original string, the second argument is the end index in the original string.
Example:
String text = "Hello";
partOfText = text.substring(2,text.length() - 1);
partOfText equals to "llo" (the first char is index 0)
So by putting your constant MAX_TEXT_LENGTH as a first argument, it would start at index 3800 to take out the substring.
http://developer.android.com/reference/java/lang/String.html#substring(int)

You are right MAX_TEXT_LENGTH is 3800.
About your doubt,
this code:
event.getText().add(trimText.substring(MAX_TEXT_LENGTH, trimText.length()));
}
you are trying to substring "trimText" from MAX_TEXT_LENGTH to trimText.length() !
Supposing that trimText = "STACK", trimText.length() = 5, then trimText.substring(3800,5) is going to be ?
At first, this doesn't have sense, using correctly would be like this:
trimText.substring(0,2) = "ST";

Standalone return expression explanation

I was online looking at some android coding examples and i came across a method that had a return expression by itself,and i was wondering if someone could explain what that means.
Here is the code sample:
if(tempText.getText().length() ==0){
Toast.makeText(this, "Please enter a valid number", Toast.LENGTH_LONG).show();
return;
}

This is the If condition which checks for the length of the text which is "0" or not. If its "0" then it will show the Toast message and will return from or exit from the if loop an no further execution will processed.

using if condition you are checking for the length of text, if it is 0 then you are showing Toast
Using a return Keyword within a class, with a method
A method returning nothing
public void Void_Method()
{
<statements>
return;
}
A method returning a String
public String String_Method()
{
String s = "its Ridiculous to do such kind of work, people here are just aim less";
return s;
}
A method returning an Int value
public int Int_Method()
{
int i = 5;
return(i);
}
I hope this will help you understand the use of return keyword, and as name suggest - The return keyword is always used with a method only to specify that the method is going to return something.