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how to make thumbnail image with initials two char from name android?

I want to thumbnail initials with two word for my image view like "Peter Parker" but am able to get only one word "P"while running code how can get second word after space my code is.
holder.imgName?.text=teamData[position].userImage.substring(0,1)

You can do it functional way:
val peterParker = "Peter Parker"
val initials = peterParker
.split(' ')
.mapNotNull { it.firstOrNull()?.toString() }
.reduce { acc, s -> acc + s }
println(initials) //PP
This would cover cases when a person's name consists of more than 2 words.

I have done some Trick & implemented this avatar with a Button lol ;p
create profile_bg.xml
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<solid
android:color="#color/colorWhite"/>
<corners
android:radius="500dp"/>
</shape>
then main_activity.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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:background="#4300313A"
tools:context=".MainActivity">
<Button
android:onClick="clicked"
android:id="#+id/avatar"
android:clickable="false"
android:focusable="false"
android:textColor="#color/colorPrimary"
android:textSize="65sp"
android:focusableInTouchMode="false"
android:layout_width="150dp"
android:layout_height="150dp"
android:background="#drawable/profile_bg"
android:layout_centerHorizontal="true"
android:layout_marginTop="50dp"/>
<EditText
android:id="#+id/edtname"
android:layout_below="#+id/avatar"
android:layout_centerHorizontal="true"
android:layout_marginTop="50dp"
android:layout_width="250dp"
android:layout_height="wrap_content"
android:textSize="18sp"
android:hint="Enter your name"/>
<Button
android:onClick="clicked"
android:textColor="#color/colorBackground"
android:text="Submit Name"
android:textStyle="bold"
android:focusableInTouchMode="false"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerHorizontal="true"
android:layout_below="#+id/edtname"
android:layout_marginTop="50dp"/>
</RelativeLayout>
then in MainActivity.java (to split the string and get the first letter of each word ~ name in if condition with stringbuilder)
public class MainActivity extends AppCompatActivity {
EditText editText;
Button button;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
editText = (EditText) findViewById(R.id.edtname);
button = (Button) findViewById(R.id.avatar);
}
public void clicked(View view) {
String str = editText.getText().toString();
String[] strArray = str.split(" ");
StringBuilder builder = new StringBuilder();
//First name
if (strArray.length > 0){
builder.append(strArray[0], 0, 1);
}
//Middle name
if (strArray.length > 1){
builder.append(strArray[1], 0, 1);
}
//Surname
if (strArray.length > 2){
builder.append(strArray[2], 0, 1);
}
button.setText(builder.toString());
}
}

Hi you can using following way
String str = "FirstWord SecondWOrd";
String[] strArray = str.split(" ");
StringBuilder builder = new StringBuilder();
if (strArray.length > 0)
builder.append(strArray[0], 0, 1);
if (strArray.length > 1)
builder.append(strArray[1], 0, 1);
Log.d("New Text" , builder.toString());

it look's like your using substring to only grab the letters from position 0 to position 1, This is P in Petter
holder.imgName?.text=teamData[position].userImage
.substring(0,1)
If you'd like to grab the words Petter Parker, you have a few options.
• IndexOf & Substring - find the position of a string and get the subtext after.
• Substring - Subtext of string based on parameters
If you plan to change the text length at any stage, you'll need to find the start of the word ( int start = yourString.indexOf("Petter"));
and end of the word ( int end = yourString.indexOf(" "))
IndexOf will return the position of the first letter in your query - Your case it's P in Petter --- So start+"petter".length()
Here's an example of a barcode price checker app I'm working on
// STRING FORMAT 00000899999:0.99
String currentLine = "00000899999:0.99";
int breakPoint = currentLine.indexOf(":");
int end = currentLine.length();
int start = breakPoint + 1;
String Price = currentLine.substring(start,end);
Price will be starting after (:) With +1 or include (:) with no + 1 and end at the lines length.

I wrote an extension function in Kotlin to get initials for a name. You can use a custom view and use draw text and clip shape you want for avatar view.
val initials = "Vikas Patidar".asInitials()
fun String.asInitials(limit: Int = 2): String {
val buffer = StringBuffer()
trim().split(" ").filter {
it.isNotEmpty()
}.joinTo(
buffer = buffer,
limit = limit,
separator = "",
truncated = "",
) { s ->
s.first().uppercase()
}
return buffer.toString()
}

ImageView not updated in ItemList

I am trying to update the image inside ItemList, I am using the below method
This is how I am getting ImageView 'imgView' Object using the below methods -
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
if (pDialog.isShowing())
pDialog.dismiss();
/**
* Updating parsed JSON data into ListView
* */
ListAdapter adapter = new SimpleAdapter(JSONParsingMainActivity.this, contactList,
R.layout.list_item, new String[]{"name", "email", "mobile"}, new int[]{R.id.name,
R.id.email, R.id.mobile});
lv.setAdapter(adapter);
if(markedQuestion != null){
try {
JSONObject jsonObj = new JSONObject(markedQuestion);
JSONArray contacts = jsonObj.getJSONArray("data");
for (int i = 0; i < contacts.length(); i++) {
JSONObject c = contacts.getJSONObject(i);
String questionid = c.getString("questionid");
System.out.println("Question No :" + i + "Question Id is :" + questionid);
Long itemId = lv.getItemIdAtPosition(Integer.parseInt(questionid));
System.out.println("Item Id xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxasdasd" + itemId);
changedView = (CardView) getViewByPosition(Integer.parseInt(questionid),lv);
imgView = (ImageView) changedView.findViewById(R.id.imageViewstickId);
imgView.setImageResource(R.drawable.cancel);
}
} catch (JSONException e) {
e.printStackTrace();
}
}
lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
mp.start();
position++;
Intent intent = new Intent(context, DetailsActivity.class);
intent.putExtra("position", Integer.toString(position));
context.startActivity(intent);
}
});
}
public View getViewByPosition(int pos, ListView listView) {
final int firstListItemPosition = listView.getFirstVisiblePosition();
final int lastListItemPosition = firstListItemPosition + listView.getChildCount() - 1;
if (pos < firstListItemPosition || pos > lastListItemPosition ) {
return listView.getAdapter().getView(pos, null, listView);
} else {
final int childIndex = pos - firstListItemPosition;
return listView.getChildAt(childIndex);
}
}
This code is not updating the cancel image in the list item, when I debug I am getting correct id (i.e. 'imageViewstickId' as shown in XML), but the image is not updating, nor giving any error
imgView.setImageResource(R.drawable.cancel);
My XML code also -
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView
android:id="#+id/cardViewQuestionId"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:card_view="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="8dp"
app:cardCornerRadius="15dp"
card_view:cardElevation="2dp"
card_view:cardCornerRadius="5dp">
<LinearLayout
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:padding="10dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
>
<TextView
android:id="#+id/name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingBottom="2dp"
android:paddingTop="6dp"
android:text="test"
android:textColor="#color/gradientStart"
android:textSize="16sp"
android:textStyle="bold"
/>
<ImageView
android:id="#+id/imageViewstickId"
android:layout_width="30dp"
android:layout_height="30dp"
android:layout_gravity="center"
/>
</LinearLayout>
<TextView
android:id="#+id/email"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingBottom="2dip"
android:textColor="#color/gradientStop" />
<TextView
android:id="#+id/mobile"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#5d5d5d"
android:textStyle="bold" />
</LinearLayout>
</android.support.v7.widget.CardView>
I have tried everything modifying the code, etc. but nothing works for me
Any help shall be appreciated, thanks
Edits - (Added Debug screen Shot) Please check in debug window, CardViewId is same as XML ImageView id... Still not updating

Solution:
Instead of this:
imgView.setImageResource(R.drawable.cancel);
write:
imgView.setImageDrawable(ContextCompat.getDrawable(context, R.drawable.cancel));
Try it. Let's hope it works.

You can simply use this:
If you are in Activity then use this
int id = getResources().getIdentifier("cancel","drawable", getPackageName());
Or in Fragment
int id = context.getResources().getIdentifier("cancel","drawable", context.getPackageName());
// "cancel" drawable resource name
// "drawable" drawable directory
This will return the id of the drawable you want to access... then you can set the image in the imageview by doing the following
imgView.setImageResource(id);
hope this will work.

There are two best solutions for that:-
1) Instead of using this
imgView.setImageResource(R.drawable.cancel);
Use This Method:-
imgView.setImageDrawable(ContextCompat.getDrawable(context, R.drawable.cancel));
2)Using Glide Library
https://bumptech.github.io/glide/doc/download-setup.html

Your id is correct still it is not updating then it might be a problem that your Resource file (R.java) is not updating try cleaning your project and then check.
If this not works you can also try following code:-
Resources resources = getResources();
imgView.setImageDrawable(resources.getDrawable(R.drawable.cancel));

May be helpful for others to think this way -
I got Clue from this post - how to know when listview is finished loading data on android
My data may be getting updated, but the list was not fully loaded and thats why the data is over writing. I used the following code , thanks for the actual user who posted the above answer
lv.addOnLayoutChangeListener(new View.OnLayoutChangeListener() {
#Override
public void onLayoutChange(View view, int i, int i1, int i2, int i3, int i4, int i5, int i6, int i7) {
Log.d(TAG, "list got updated, do what ever u want");
if(markedQuestion != null){
try {
JSONObject jsonObj = new JSONObject(markedQuestion);
JSONArray contacts = jsonObj.getJSONArray("data");
for (int x = 0; x < contacts.length(); x++) {
JSONObject c = contacts.getJSONObject(x);
String questionid = c.getString("questionid");
System.out.println("Question No :" + x + "Question Id is :" + questionid);
System.out.println(getResources());
changedView = (CardView) getViewByPosition(Integer.parseInt(questionid),lv);
imgView = (ImageView) changedView.findViewById(R.id.imageViewstickId);
// imgView.setImageResource(R.drawable.cancel);
imgView.setImageDrawable(ContextCompat.getDrawable(context,R.drawable.cancel));
}
} catch (JSONException e) {
e.printStackTrace();
}
}
}
});

ListView item background changes depending on scroll position

I'm running into a very strange ListView behaviour. I have a simple chat application which uses a ListView and a custom implementation of BaseAdapter to show messages.
The idea I had was to shade messages from the "local" user grey and have messages from the "remote" user white, to help the user distinguish between the two.
The two screenshots below show what's happening. The second is the exact same activity, xml etc etc, simply scrolled down a bit.
Scrolled up:
Scrolled down:
Look at the message sent by "Me" # 23:05. When at the top it has no contrast to its neighbours, but when it is scrolled to the bottom, the difference is clear to see.
This occurs on a nexus 4 and 7 on 4.2.2, and a GS3 running 4.1.2.
Here is the XML for one of the ListView items:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/activity_view_conversation_message_list_item_wrapper"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:paddingBottom="2dp"
android:paddingLeft="5dp"
android:paddingRight="10dp" >
<ImageView
android:id="#+id/activity_view_conversation_message_list_item_user_image"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_alignParentLeft="true"
android:layout_marginTop="5dp"
android:src="#drawable/default_user_image" />
<TextView
android:id="#+id/activity_view_conversation_message_list_item_heading"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:layout_marginTop="1dp"
android:layout_toRightOf="#+id/activity_view_conversation_message_list_item_user_image"
android:text="Martyn"
android:textColor="#000000"
android:textSize="18sp"
android:textStyle="bold" />
<TextView
android:id="#+id/activity_view_conversation_message_list_item_contents"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/activity_view_conversation_message_list_item_heading"
android:layout_marginLeft="10dp"
android:layout_marginRight="5dp"
android:layout_marginTop="2dp"
android:layout_toLeftOf="#+id/activity_view_conversation_message_list_item_ack"
android:layout_toRightOf="#+id/activity_view_conversation_message_list_item_user_image"
android:text="Hello this is some text"
android:textColor="#333333"
android:textIsSelectable="true"
android:textSize="18sp" />
<TextView
android:id="#+id/activity_view_conversation_message_list_item_time"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:layout_marginTop="2dp"
android:paddingLeft="5dp"
android:paddingRight="5dp"
android:paddingTop="2dp"
android:text="12:08"
android:textSize="14sp" />
<ImageView
android:id="#+id/activity_view_conversation_message_list_item_ack"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignTop="#+id/activity_view_conversation_message_list_item_time"
android:layout_marginRight="2dp"
android:layout_marginTop="8dp"
android:layout_toLeftOf="#+id/activity_view_conversation_message_list_item_time"
android:src="#drawable/red_dot_8dp" />
</RelativeLayout>
And here is where I set the colour of the RelativeLayout:
if(localUserId.equals(remoteUserId)){
itemLayout.setBackgroundColor(Color.parseColor("#F9F9F9"));
}
That code runs inside the getView() method of my Adapter.
I've Googled this a fair bit and turned up nothing, there are a lot of SO questions regarding the android:cacheColorHint issue but I don't think that is what is going on here.
Has anyone run into this before? I'm stumped!
EDIT: Here's the baseadapter code:
public class MessageListAdapter extends BaseAdapter {
private ArrayList<Message> messageList;
Context context;
/**
* Constructor
* #param newConversationsList An ArrayList of Conversation objects that this adapter will use
* #param newContext The context of the activity that instantiated this adapter
*/
MessageListAdapter(ArrayList<Message> newMessageList, Context newContext){
messageList = newMessageList;
//reload();
context = newContext;
}
public int getCount() {
return messageList.size();
}
public Object getItem(int position) {
return messageList.get(position);
}
public long getItemId(int position) {
return position;
}
/**
* Adds a message to the chat list
* #param message A Message object containing all the message's information
*/
public void add(Message message){
//nMessagesToShow++; //A new message has been added, so increase the number to show by one
Log.d(TAG, "COUNT: "+getCount());
//refresh();
}
public void refresh(){
this.notifyDataSetChanged();
}
public View getView(int position, View convertView, ViewGroup parent) {
View view = convertView;
if(view!=null){
//return view;
}
LayoutInflater vi = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
//Get the Message object from the list
Message message = messageList.get(position);
//Get the data from the message
String senderId = message.getFromUser();
int messageType = message.getType();
String senderFirstName;
ImageView userImage, messageImage;
TextView messageHeading, messageBody;
switch(messageType){
case Message.MESSAGE_TYPE_TEXT: //Standard text message
//The layout we inflate for this list item will vary depending on whether this message has the same sender as the previous
if(position>0 && senderId.equals(messageList.get(position-1).getFromUser())){ //True if this is not the first message AND the sender id matches that of the previous message
view = vi.inflate(R.layout.activity_view_conversation_message_list_item_alternate, null); //Inflate an alternate version of the list item which has no heading or user image
}
else{ //This is the first message OR the sender id is different to the previous
view = vi.inflate(R.layout.activity_view_conversation_message_list_item, null); //Inflate the standard version of the layout
userImage = (ImageView) view.findViewById(R.id.activity_view_conversation_message_list_item_user_image);
messageHeading = (TextView) view.findViewById(R.id.activity_view_conversation_message_list_item_heading);
//Use the sender's ID to get the sender's image and first name
Contact contact = database.getContact(senderId);
if(senderId.equals(localUserId)){ //True if the local user sent this message
senderFirstName = "Me";
}
else{
senderFirstName = contact.getFirstName();
}
userImage.setImageBitmap(contact.getImageBitmap(100, 100, 6));
messageHeading.setText(senderFirstName);
}
messageBody = (TextView) view.findViewById(R.id.activity_view_conversation_message_list_item_contents);
messageBody.setText(message.getContents(null));
break;
case Message.MESSAGE_TYPE_IMAGE: //Image message
view = vi.inflate(R.layout.activity_view_conversation_message_list_item_image, null); //Inflate a list item template for displaying an image
userImage = (ImageView) view.findViewById(R.id.activity_view_conversation_message_list_item_user_image);
//Sender's first name
messageHeading = (TextView) view.findViewById(R.id.activity_view_conversation_message_list_item_heading);
Contact contact = database.getContact(senderId);
if(senderId.equals(localUserId)){ //True if the local user sent this message
senderFirstName = "Me";
}
else{
senderFirstName = contact.getFirstName();
}
messageHeading.setText(senderFirstName);
messageImage = (ImageView) view.findViewById(R.id.activity_view_conversation_message_list_item_image);
String imageResourceId = null;
//The message is a JSON object containing several fields, one of which is the file name which we will use to get the image
try {
JSONObject messageJSON = new JSONObject(message.getContents(null));
String imagePath = Environment.getExternalStorageDirectory()+"/epicChat/resources/"+messageJSON.getString("fileName");
int imageWidth = messageJSON.getInt("width"); //We want the dimensions in order to calculate the aspect ratio of the image
int imageHeight = messageJSON.getInt("height");
if(messageJSON.has("resourceId")){
imageResourceId = messageJSON.getString("resourceId"); //This is used when opening the image gallery
}
int displayWidth = 300;
int displayHeight = (int) ((float) imageHeight / (float) imageWidth * (float) displayWidth);
String imagePathFull = imagePath+displayWidth+displayHeight; //For the caching
Bitmap originalImage = null;
//Check the bitmap cache exists. If not, reinstantiate it
if(MainActivity.bitmapCache==null){ //Cache is null
MainActivity.loadBitmapCache();
}
else{ //Cache is not null, so check it to see if this image is in it
originalImage = MainActivity.bitmapCache.get(imagePathFull);
}
if(originalImage==null){ //True if the bitmap was not in the cache. So we must load from disk instead
new Utils.LoadBitmapAsync(imagePath, messageImage, displayWidth, displayHeight, MainActivity.bitmapCache).execute();
messageImage.getLayoutParams().height = displayHeight;
}
else{
messageImage.setImageBitmap(originalImage);
}
}
catch (JSONException e) {
Log.e(TAG, "Error reading image JSON: "+e.toString());
}
if(imageResourceId!=null){ //Only attach the listener if we got a valid resource ID
final String recourceIdFinal = imageResourceId;
final String conversationIdFinal = message.getUserList();
messageImage.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
Intent showConversationImageGalleryIntent = new Intent(context, ViewConversationImageGalleryActivity.class);
showConversationImageGalleryIntent.putExtra("conversationId", conversationIdFinal);
showConversationImageGalleryIntent.putExtra("resourceId", recourceIdFinal);
startActivityForResult(showConversationImageGalleryIntent, ACTION_SHOW_CONVERSATION_IMAGE_GALLERY);
}
});
}
userImage.setImageBitmap(contact.getImageBitmap(100, 100, 6));
break;
case Message.MESSAGE_TYPE_INVALID:
default:
break;
}
//Some layout items are present in all layouts. Typically these are the status indicator and the message time
RelativeLayout itemLayout = (RelativeLayout) view.findViewById(R.id.activity_view_conversation_message_list_item_wrapper);
//If the message is from the local user, give it a subtle grey background
if(localUserId.equals(message.getFromUser())){
itemLayout.setBackgroundColor(Color.parseColor("#E9E9E9"));
}
else{
itemLayout.setBackgroundColor(Color.parseColor("#FFFFFF"));
}
TextView messageTimeText = (TextView) view.findViewById(R.id.activity_view_conversation_message_list_item_time);
messageTimeText.setText(message.getFormattedTime());
ImageView messageStatusImage = (ImageView) view.findViewById(R.id.activity_view_conversation_message_list_item_ack);
//Set the status image according to the status of the message
switch(message.getStatus()){
case Message.MESSAGE_STATUS_PENDING: //Pending messages should have a red dot
messageStatusImage.setImageResource(R.drawable.red_dot_8dp);
messageStatusImage.setVisibility(View.VISIBLE);
break;
case Message.MESSAGE_STATUS_ACK_SERVER: //Messages that reached the server should have an orange dot
messageStatusImage.setImageResource(R.drawable.orange_dot_8dp);
messageStatusImage.setVisibility(View.VISIBLE);
break;
case Message.MESSAGE_STATUS_ACK_RECIPIENT: //Messages that reached the recipient should have an green dot
messageStatusImage.setImageResource(R.drawable.green_dot_8dp);
messageStatusImage.setVisibility(View.VISIBLE);
break;
case Message.MESSAGE_STATUS_NOT_SET: //Not set typically means the message came from another user, in which case the status image should be hidden
default: //Also default here
messageStatusImage.setVisibility(View.INVISIBLE);
break;
}
return view;
}
}

Since there's no else statement matching your if, this is probably due to view recycling. When an item from a ListView scrolls off the screen, the operating system removes it and hands it back to the adapter in the same state it was removed. This means you need to set the background color when it's not the local user's message as well.

Creating a New Button in existing Source Code? [closed]

It's difficult to tell what is being asked here. This question is ambiguous, vague, incomplete, overly broad, or rhetorical and cannot be reasonably answered in its current form. For help clarifying this question so that it can be reopened, visit the help center.
Closed 9 years ago.
http://www.itechcode.com/2012/03/18/create-calculator-in-android-programming/
Im using his source code but it seems very different than the "Beginner Level" Programming I have been use to i.e. creating new project, modifying layout, referencing in main.java, etc.
I'm trying to use his source code and modify/create new operations and maybe add a activity. I would usually know how to do most of that stuff if it wasn't laid out differently. Thank You!
package com.pragmatouch.calculator;
import java.text.DecimalFormat;
import java.text.NumberFormat;
import java.util.Iterator;
import java.util.Stack;
import android.app.Activity;
import android.os.Bundle;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.TextView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.GridView;
import android.view.View;
import android.view.View.OnClickListener;
public class main extends Activity {
GridView mKeypadGrid;
TextView userInputText;
TextView memoryStatText;
Stack<String> mInputStack;
Stack<String> mOperationStack;
KeypadAdapter mKeypadAdapter;
TextView mStackText;
boolean resetInput = false;
boolean hasFinalResult = false;
String mDecimalSeperator;
double memoryValue = Double.NaN;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
DecimalFormat currencyFormatter = (DecimalFormat) NumberFormat
.getInstance();
char decimalSeperator = currencyFormatter.getDecimalFormatSymbols()
.getDecimalSeparator();
mDecimalSeperator = Character.toString(decimalSeperator);
setContentView(R.layout.main);
// Create the stack
mInputStack = new Stack<String>();
mOperationStack = new Stack<String>();
// Get reference to the keypad button GridView
mKeypadGrid = (GridView) findViewById(R.id.grdButtons);
// Get reference to the user input TextView
userInputText = (TextView) findViewById(R.id.txtInput);
userInputText.setText("0");
memoryStatText = (TextView) findViewById(R.id.txtMemory);
memoryStatText.setText("");
mStackText = (TextView) findViewById(R.id.txtStack);
// Create Keypad Adapter
mKeypadAdapter = new KeypadAdapter(this);
// Set adapter of the keypad grid
mKeypadGrid.setAdapter(mKeypadAdapter);
// Set button click listener of the keypad adapter
mKeypadAdapter.setOnButtonClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
Button btn = (Button) v;
// Get the KeypadButton value which is used to identify the
// keypad button from the Button's tag
KeypadButton keypadButton = (KeypadButton) btn.getTag();
// Process keypad button
ProcessKeypadInput(keypadButton);
}
});
mKeypadGrid.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View v,
int position, long id) {
}
});
}
private void ProcessKeypadInput(KeypadButton keypadButton) {
//Toast.makeText(this, keypadButton.getText(), Toast.LENGTH_SHORT).show();
String text = keypadButton.getText().toString();
String currentInput = userInputText.getText().toString();
int currentInputLen = currentInput.length();
String evalResult = null;
double userInputValue = Double.NaN;
switch (keypadButton) {
case BACKSPACE: // Handle backspace
// If has operand skip backspace
if (resetInput)
return;
int endIndex = currentInputLen - 1;
// There is one character at input so reset input to 0
if (endIndex < 1) {
userInputText.setText("0");
}
// Trim last character of the input text
else {
userInputText.setText(currentInput.subSequence(0, endIndex));
}
break;
case SIGN: // Handle -/+ sign
// input has text and is different than initial value 0
if (currentInputLen > 0 && currentInput != "0") {
// Already has (-) sign. Remove that sign
if (currentInput.charAt(0) == '-') {
userInputText.setText(currentInput.subSequence(1,
currentInputLen));
}
// Prepend (-) sign
else {
userInputText.setText("-" + currentInput.toString());
}
}
break;
case CE: // Handle clear input
userInputText.setText("0");
break;
case C: // Handle clear input and stack
userInputText.setText("0");
clearStacks();
break;
case DECIMAL_SEP: // Handle decimal seperator
if (hasFinalResult || resetInput) {
userInputText.setText("0" + mDecimalSeperator);
hasFinalResult = false;
resetInput = false;
} else if (currentInput.contains("."))
return;
else
userInputText.append(mDecimalSeperator);
break;
case DIV:
case PLUS:
case MINUS:
case MULTIPLY:
if (resetInput) {
mInputStack.pop();
mOperationStack.pop();
} else {
if (currentInput.charAt(0) == '-') {
mInputStack.add("(" + currentInput + ")");
} else {
mInputStack.add(currentInput);
}
mOperationStack.add(currentInput);
}
mInputStack.add(text);
mOperationStack.add(text);
dumpInputStack();
evalResult = evaluateResult(false);
if (evalResult != null)
userInputText.setText(evalResult);
resetInput = true;
break;
case CALCULATE:
if (mOperationStack.size() == 0)
break;
mOperationStack.add(currentInput);
evalResult = evaluateResult(true);
if (evalResult != null) {
clearStacks();
userInputText.setText(evalResult);
resetInput = false;
hasFinalResult = true;
}
break;
case M_ADD: // Add user input value to memory buffer
userInputValue = tryParseUserInput();
if (Double.isNaN(userInputValue))
return;
if (Double.isNaN(memoryValue))
memoryValue = 0;
memoryValue += userInputValue;
displayMemoryStat();
hasFinalResult = true;
break;
case M_REMOVE: // Subtract user input value to memory buffer
userInputValue = tryParseUserInput();
if (Double.isNaN(userInputValue))
return;
if (Double.isNaN(memoryValue))
memoryValue = 0;
memoryValue -= userInputValue;
displayMemoryStat();
hasFinalResult = true;
break;
case MC: // Reset memory buffer to 0
memoryValue = Double.NaN;
displayMemoryStat();
break;
case MR: // Read memoryBuffer value
if (Double.isNaN(memoryValue))
return;
userInputText.setText(doubleToString(memoryValue));
displayMemoryStat();
break;
case MS: // Set memoryBuffer value to user input
userInputValue = tryParseUserInput();
if (Double.isNaN(userInputValue))
return;
memoryValue = userInputValue;
displayMemoryStat();
hasFinalResult = true;
break;
case PRGM:
break;
default:
if (Character.isDigit(text.charAt(0))) {
if (currentInput.equals("0") || resetInput || hasFinalResult) {
userInputText.setText(text);
resetInput = false;
hasFinalResult = false;
} else {
userInputText.append(text);
resetInput = false;
}
}
break;
}
}
private void clearStacks() {
mInputStack.clear();
mOperationStack.clear();
mStackText.setText("");
}
private void dumpInputStack() {
Iterator<String> it = mInputStack.iterator();
StringBuilder sb = new StringBuilder();
while (it.hasNext()) {
CharSequence iValue = it.next();
sb.append(iValue);
}
mStackText.setText(sb.toString());
}
private String evaluateResult(boolean requestedByUser) {
if ((!requestedByUser && mOperationStack.size() != 4)
|| (requestedByUser && mOperationStack.size() != 3))
return null;
String left = mOperationStack.get(0);
String operator = mOperationStack.get(1);
String right = mOperationStack.get(2);
String tmp = null;
if (!requestedByUser)
tmp = mOperationStack.get(3);
double leftVal = Double.parseDouble(left.toString());
double rightVal = Double.parseDouble(right.toString());
double result = Double.NaN;
if (operator.equals(KeypadButton.DIV.getText())) {
result = leftVal / rightVal;
} else if (operator.equals(KeypadButton.MULTIPLY.getText())) {
result = leftVal * rightVal;
} else if (operator.equals(KeypadButton.PLUS.getText())) {
result = leftVal + rightVal;
} else if (operator.equals(KeypadButton.MINUS.getText())) {
result = leftVal - rightVal;
}
String resultStr = doubleToString(result);
if (resultStr == null)
return null;
mOperationStack.clear();
if (!requestedByUser) {
mOperationStack.add(resultStr);
mOperationStack.add(tmp);
}
return resultStr;
}
private String doubleToString(double value) {
if (Double.isNaN(value))
return null;
long longVal = (long) value;
if (longVal == value)
return Long.toString(longVal);
else
return Double.toString(value);
}
private double tryParseUserInput() {
String inputStr = userInputText.getText().toString();
double result = Double.NaN;
try {
result = Double.parseDouble(inputStr);
} catch (NumberFormatException nfe) {
}
return result;
}
private void displayMemoryStat() {
if (Double.isNaN(memoryValue)) {
memoryStatText.setText("");
} else {
memoryStatText.setText("M = " + doubleToString(memoryValue));
}
}
}
ENUM:
package com.pragmatouch.calculator;
public enum KeypadButton {
MC("MC",KeypadButtonCategory.MEMORYBUFFER)
, MR("MR",KeypadButtonCategory.MEMORYBUFFER)
, MS("MS",KeypadButtonCategory.MEMORYBUFFER)
, M_ADD("M+",KeypadButtonCategory.MEMORYBUFFER)
, M_REMOVE("M-",KeypadButtonCategory.MEMORYBUFFER)
, BACKSPACE("<-",KeypadButtonCategory.CLEAR)
, CE("CE",KeypadButtonCategory.CLEAR)
, C("C",KeypadButtonCategory.CLEAR)
, ZERO("0",KeypadButtonCategory.NUMBER)
, ONE("1",KeypadButtonCategory.NUMBER)
, TWO("2",KeypadButtonCategory.NUMBER)
, THREE("3",KeypadButtonCategory.NUMBER)
, FOUR("4",KeypadButtonCategory.NUMBER)
, FIVE("5",KeypadButtonCategory.NUMBER)
, SIX("6",KeypadButtonCategory.NUMBER)
, SEVEN("7",KeypadButtonCategory.NUMBER)
, EIGHT("8",KeypadButtonCategory.NUMBER)
, NINE("9",KeypadButtonCategory.NUMBER)
, PLUS(" + ",KeypadButtonCategory.OPERATOR)
, MINUS(" - ",KeypadButtonCategory.OPERATOR)
, MULTIPLY(" * ",KeypadButtonCategory.OPERATOR)
, DIV(" / ",KeypadButtonCategory.OPERATOR)
, RECIPROC("1/x",KeypadButtonCategory.OTHER)
, DECIMAL_SEP(",",KeypadButtonCategory.OTHER)
, SIGN("±",KeypadButtonCategory.OTHER)
, SQRT("SQRT",KeypadButtonCategory.OTHER)
, PERCENT("%",KeypadButtonCategory.OTHER)
, CALCULATE("=",KeypadButtonCategory.RESULT)
, PRGM("PRGM",KeypadButtonCategory.PRGM)
, DUMMY("",KeypadButtonCategory.DUMMY);
CharSequence mText; // Display Text
KeypadButtonCategory mCategory;
KeypadButton(CharSequence text,KeypadButtonCategory category) {
mText = text;
mCategory = category;
}
public CharSequence getText() {
return mText;
}
}
package com.pragmatouch.calculator;
public enum KeypadButtonCategory {
MEMORYBUFFER
, NUMBER
, OPERATOR
, DUMMY
, CLEAR
, RESULT
, OTHER
, PRGM
}

I have a great answer for you. I recently wanted to create my own button in android but I wanted to do it in a simple way. Follow these steps and in a few minutes I will post pictures.
1) create a new layout. start with a LinearLayout. Nest a FramedLayout and another LinearLayout inside of it.
2) then add a TextView to it. This is where practice makes perfect. Play around with the attributes. Learn what they do. when you have the general information of how you want your button to be display go to the next step.
3) what your are going to do is include this in another view as a button. You can use a specific attribute to make it look like a button as well.
Give me a few minutes and I will post some code and a picture.
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/CBN_LinearLayout"
style="#android:style/Widget.Button"
android:layout_width="match_parent"
android:layout_height="50dp"
android:orientation="vertical" >
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent" >
<TextView
android:id="#+id/CBV_texview1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:layout_marginRight="10dp"
android:layout_weight="1"
android:gravity="right"
android:text="#string/checkorder"
android:textColor="#color/Black" />
<FrameLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:layout_weight="1" >
<ImageView
android:id="#+id/CBV_imageView1"
android:layout_width="23dp"
android:layout_height="15dp"
android:layout_gravity="center_vertical"
android:contentDescription="#string/redcirclenotify"
android:src="#drawable/rednotify"
android:visibility="visible" />
<TextView
android:id="#+id/CBV_textview2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_vertical"
android:layout_marginLeft="8dp"
android:gravity="left"
android:text="#string/zero"
android:visibility="visible" />
</FrameLayout>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<TextView
android:id="#+id/CBV_textview3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:fadingEdge="horizontal"
android:gravity="center_horizontal"
android:text="#string/blankstring" />
<TextView
android:id="#+id/CBV_textview4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1"
android:gravity="center_horizontal"
android:text="#string/blankstring" />
</LinearLayout>
when you add it to another view as a button you use:
<include
android:id="#+id/MI_checkorder"
style="android:buttonStyle"
android:layout_width="wrap_content"
android:layout_height="50dp"
android:layout_gravity="bottom"
android:layout_marginTop="5dp"
android:layout_weight="1"
layout="#layout/custombtnview"
android:background="#style/AppTheme"
android:clickable="true"
android:focusable="true" />
The important part of this is setting the Style for the root LinearLayout to #android:style/Widget.Button
Once this is done it will look like a button and work like a button.
Below is an image of the final product:
another part of your question. Adjust sizes of standard buttons in android:
1) almost everything can be controled with how you use the XML. This can all be controled in the area to right, in the ADK. These attributes help you to control almost every aspect.
for example as in the calculator...
you have 4 buttons in a row so you want to add 4 buttons inside of a horizontal LinearLayout. Then you can give the a weight of 1 for each button then set their Width to FillParent. This will auto size the buttons to be displayed in the width of the screen equally.
Am I better off making my own calc or modify the existing code?
I would never tell someone to recreate the wheel, however, if you do not understand the code well enough to pickup where they left off then this can be an uphill struggle for you. Your best bet if you are having trouble understanding the code given to you or how to modify it, would be to actually post the code in another question and be very specific and ask for example how can I change what this particular button displays and what the result of clicking it would be. This forum depends on the people asking the questions to be clear and concise. If not then questions will closed as fast as they are opened. Generalizations are severely frowned upon on the site.
In the end, what I am trying to do is make my own scientific calculator but I don't want to spend extra time doing the simple operations.
The best way to answer this is to take a look at how the calculator is assembled in the GUI or Graphical Layout. Try changing a button and what it does. for example make the plus a minus just for the learning curve.
1) look for , PLUS(" + ",KeypadButtonCategory.OPERATOR) and notice that is a string for plus. change it to " T " see if it changes in the app. If it does then go into the code. In the code you will find case CALCULATE: for for the = sign in the ENUM and then inside that you find evalResult = evaluateResult(true);. If you follow this you reach:
if (operator.equals(KeypadButton.DIV.getText())) {
result = leftVal / rightVal;
} else if (operator.equals(KeypadButton.MULTIPLY.getText())) {
result = leftVal * rightVal;
} else if (operator.equals(KeypadButton.PLUS.getText())) {
result = leftVal + rightVal;
} else if (operator.equals(KeypadButton.MINUS.getText())) {
result = leftVal - rightVal;
}
so now you can change result = leftVal + rightVal; to result = leftVal - rightVal; and you have just changed it. so it will take some time to understand the code but you have to do some trial and error to understand it. I hope this helps answer your question.

How to make a Textview display a number?

I'm new to Android development. I tried to make a Textview display a text or number and it crashes. Please Help.
This is the button in activity_main.xml:
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/textView1"
android:layout_alignParentBottom="true"
android:text="#string/Change"
android:onClick="change"/>
and this is the Main Activity:
public void change(){
TextView tv = new TextView(this);
tv.setText("" + 4);
}
the application crashes when i start it. I wanted to create a basic calculator with two text boxes and a button which when pressed adds the value in two text boxes and display it. can anybody tell me where I am going wrong with the code?

public void change()
{
TextView tv = new TextView(this);
tv.setText("4");
}
and if it is any kind of integer variable, then
public void change()
{
TextView tv = new TextView(this);
tv.setText("" + integer_variable);
}
and also, check if the textView is plumbed with the code
TextView tv = (TextView) findViewById(R.Id.textView1);
should have worked fine, I hope.. :)
If it crashes again, then the information in the question may be incomplete.
Happy Coding..!

public void change(){
TextView tv =(TextView)findViewById(R.id.textView1);
tv.setText(Integer.toString(4));
}

layout_contact.xml:
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:layout_marginTop="10dp"
android:text="#string/number1" />
strings.xml:
<?xml version="1.0" encoding="utf-8"?>
<resources>
<string name="number1">0091010</string>
</resources>
ContactFragment.java:
String num = "0091010";
textView8.setText(someContactNum);
Output:
0091010

You have to give id of the text view properly in the xml like
<TextView
....
android:id="#+id/tvID"/>
Check it you gave it properly or not..
Otherwise here share your textview code from your xml file..
And also checkit, you import the Textview in your code or not like this:
import android.widget.TextView;

Here is the answer for how to display the dynamic numbers in a single text view
StringBuilder stringBuilder = new StringBuilder();
for (int j = fromNumber; j <= toNumber; j++) {
for (int i = 2; i <= j / 2; i++) {
if (j % i == 0) {
isPrimeNumber = false;
break;
} else {
isPrimeNumber = true;
}
}
if (isPrimeNumber) {
stringBuilder.append(j);
stringBuilder.append(",");
} else {
}
}
tvResult.setText(stringBuilder.toString());