Develop Reference

How to set text to value of listview items after time intervals

I am developing an android app where a user will input text to an EditText, then it will be added to a ListView.
But once a button with onClick value "start" is clicked, it will display each item of the ListView in a TextView with id displayText, in the order of each item and it will loop(Repeat) once it is exhausted.
Here is my Code
Math.java
public class Math extends AppCompatActivity {
private ArrayList<String> items;
private ArrayAdapter<String> itemsAdapter;
private ListView lvItems;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_math);
lvItems = (ListView) findViewById(R.id.lvItems);
items = new ArrayList<String>();
itemsAdapter = new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, items);
lvItems.setAdapter(itemsAdapter);
}
public void AddItem(View v) {
EditText etNewItem = (EditText) findViewById(R.id.etNewItem);
String itemText = etNewItem.getText().toString();
itemsAdapter.add(itemText);
etNewItem.setText("");
}
public void start(View v){
RelativeLayout lc = (RelativeLayout)findViewById(R.id.contentContainer);
lc.setVisibility(View.GONE);
RelativeLayout tc = (RelativeLayout)findViewById(R.id.tvContainer);
tc.setVisibility(View.VISIBLE);
}
}
activity_math.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"
tools:context=".Math">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/tvContainer"
android:visibility="gone">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:textSize="30sp"
android:id="#+id/displayText"/>
</RelativeLayout>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/contentContainer">
<ListView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/lvItems"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_above="#+id/btnAddItem" />
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/etNewItem"
android:layout_alignTop="#+id/btnAddItem"
android:hint="Enter a new item"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_toLeftOf="#+id/btnAddItem"
android:layout_toStartOf="#+id/btnAddItem"
android:layout_alignParentBottom="true" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Add Item"
android:id="#+id/btnAddItem"
android:layout_alignParentBottom="true"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:onClick="AddItem"/>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Start"
android:layout_alignParentBottom="true"
android:layout_toLeftOf="#id/btnAddItem"
android:onClick="start"/>
</RelativeLayout>

Okay, i think the issue is that you haven't given the TextView any thing to display. you have to convert the arrayList to a String array and use setText to display the Value.
add this part to the "start" method
String ls =System.getProperty("line.separator");// i used this to seperate the array items
String joint = TextUtils.join(ls, lvitems);
result.setText(joint);
That should work

spinner not displaying when clicked

hi currently im encountering a problem where the spinner is not showing up when clicked. when i run theres not any error so i dont know whats wrong . sorry im still new to android and java pls help....
public class SpinnerInfo extends MainProduct {
Spinner spinners;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
spinners = (Spinner) findViewById(R.id.spinner);
final ArrayAdapter adapter = ArrayAdapter.createFromResource(this, R.array.type_arrays, R.layout.support_simple_spinner_dropdown_item);
adapter.setDropDownViewResource(android.R.layout.simple_spinner_item);
spinners.setAdapter(adapter);
spinners.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
#Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
String [] dataArray = getResources().getStringArray(R.array.type_arrays);
String type = dataArray[position];}
#Override
public void onNothingSelected(AdapterView<?> parent) {
}
});
}}
my xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#android:color/darker_gray"
android:orientation="vertical"
android:elevation="1dp"
android:weightSum="1">
<TextView
android:text="Product List"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/textView"
android:textSize="24sp"
android:textStyle="normal|italic"
android:textAlignment="center"
android:fontFamily="casual"
android:textColor="#android:color/background_dark"
android:layout_marginTop="10dp"/>
<TextView
android:text="Select Type:"
android:layout_width="100dp"
android:layout_height="wrap_content"
android:id="#+id/textView2"
android:textAlignment="textStart"
android:textStyle="normal|bold" />
<Spinner
android:layout_width="126dp"
android:layout_height="wrap_content"
android:id="#+id/spinner"
/>
<ListView
android:id="#+id/listview_product"
android:layout_width="match_parent"
android:layout_marginLeft="10dp"
android:layout_marginRight="10dp"
android:layout_marginTop="10dp"
android:divider="#android:color/darker_gray"
android:dividerHeight="8dp"
android:background="#android:color/white"
android:layout_height="match_parent">
</ListView>

final ArrayAdapter adapter = ArrayAdapter.createFromResource(this, R.array.type_arrays, R.layout.support_simple_spinner_dropdown_item);
to
final ArrayAdapter adapter = ArrayAdapter.createFromResource(this, R.layout.support_simple_spinner_dropdown_item, R.array.type_arrays);

By the way you are accessing to the string resources when you can do this parent.getItemAtPosition(position)

ListView Elements Not Displaying

ListView elements are not displaying even though I've used almost identical code before. Sorry that I have to ask this type of question, but I seriously just don't understand why it's not working. None of the other similar questions I looked at were useful.
The heights of the items and ListView should be fine. Not sure what's going on. Thanks guys.
Here's the code dump:
Main Acitivity:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_select_city);
findViewById(R.id.loadingPanel).setVisibility(View.GONE); // remove loading animation
ArrayList<String> citiesList = new ArrayList<>();
citiesList.add("Waterloo");
citiesList.add("Guelph");
populateCities(citiesList);
}
public void populateCities(ArrayList<String> citiesList) {
// see what the list is
Toast.makeText(getApplicationContext(),citiesList.toString(),Toast.LENGTH_LONG).show();
// populate the ListView
CitiesListAdapter citiesListAdapter = new CitiesListAdapter(this, citiesList);
ListView citiesListView = (ListView)findViewById(R.id.cities_list);
citiesListView.setAdapter(citiesListAdapter);
// listen for when a city in the list is clicked
citiesListView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
// go to the bar list activity (send the city and province with it)
TextView lblCity = (TextView)view.findViewById(R.id.lblCity);
String city = lblCity.getText().toString();
Toast.makeText(getApplicationContext(), city, Toast.LENGTH_LONG).show();
}
});
}
Here's the list adapter code (CitiesListAdapter):
import android.app.Activity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.TextView;
import java.util.ArrayList;
public class CitiesListAdapter extends ArrayAdapter<String> {
private final Activity context;
private final ArrayList<String> cities;
public CitiesListAdapter(Activity context, ArrayList<String> cities) {
super(context, R.layout.cityitem);
this.context = context;
this.cities = cities;
}
#Override
public View getView(int position, View view, ViewGroup parent) {
LayoutInflater inflater = context.getLayoutInflater();
View rowView = inflater.inflate(R.layout.cityitem, null, true);
TextView lblCity = (TextView)rowView.findViewById(R.id.lblCity);
lblCity.setText(this.cities.get(position));
return rowView;
}
}
Then here's the main layout:
<?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:fitsSystemWindows="true"
tools:context="com.myapp.SelectCity">
<RelativeLayout
android:id="#+id/loadingPanel"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:gravity="center" >
<ProgressBar
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:indeterminate="true"
android:id="#+id/progressBar" />
</RelativeLayout>
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/btnBack"
android:layout_marginTop="5dp"
android:layout_marginLeft="5dp"
android:onClick="back"
android:src="#mipmap/ic_menu_back"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true" />
<ImageButton
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="#+id/btnRefresh"
android:layout_marginTop="5dp"
android:layout_marginLeft="5dp"
android:onClick="refresh"
android:src="#mipmap/ic_action_refresh"
android:layout_alignParentTop="true"
android:layout_alignParentRight="true" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="Select City"
android:id="#+id/lblTitle"
android:layout_below="#+id/btnBack"
android:layout_centerHorizontal="true" />
<RelativeLayout
android:id="#+id/listViewLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="#+id/lblTitle"
android:layout_marginLeft="20dp"
android:layout_marginRight="20dp"
android:layout_marginBottom="20dp"
android:layout_marginTop="20dp">
<ListView
android:background="#F00"
android:id="#+id/cities_list"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_alignParentBottom="true"
android:layout_alignParentTop="true" />
</RelativeLayout>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="New Button"
android:id="#+id/button"
android:layout_below="#+id/listViewLayout"
android:layout_centerHorizontal="true" />
</RelativeLayout>
Then the ListView item layout (cityitem.xml):
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:orientation="vertical"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceMedium"
android:text="City"
android:id="#+id/lblCity" />
</LinearLayout>
Edit: Looks like I'm also getting this stupid error that Android can't seem to fix (just sneaks in the LogCat):
E/Surface: getSlotFromBufferLocked: unknown buffer: 0xab7ccc40
Not sure if that's why nothing is displaying.
Screenshot: http://prntscr.com/avpy9s

The super call in your constructor doesn't include the ArrayList, nor are you overriding getCount() to return the list size, so your Adapter is returning 0 for the item count, and the ListView won't try to retrieve any Views. You could include the ArrayList in the super call, or override the getCount() method to return cities.size().
However, you don't necessarily need a custom Adapter for a simple ArrayList of Strings. You could simply use the constructor for ArrayAdapter that takes a layout and a TextView resource ID.
ArrayAdapter<String> citiesListAdapter = new ArrayAdapter<>(this,
R.layout.cityitem,
R.id.lblCity,
cities);

There's no layout in the ListView. You need to add layout(Linear or Relative) inside the ListView. Like this!
<ListView
<RelativeLayout />
/>
In the layout, you declare what you wanna show - TextView or ImageView or etc.

Button in simple ListView onClick

So I have simple listview with a list item that contains a textview, and two imageviews.
I want both of the imageviews to act as buttons. Unfortunately, I can't even get one of them to work. The list view loads but then the app crashes when either image is touched. Here is the xml for the listitem:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#drawable/bg_card">
<TextView
android:layout_width="wrap_content" android:layout_height="wrap_content"
android:textColor="#color/Black"
android:id="#+id/name"
android:textSize="20sp"
android:padding="16dp">
</TextView>
<LinearLayout
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="match_parent"
android:layout_gravity="right"
android:gravity="right">
<ImageView
android:layout_width="40dp"
android:layout_height="fill_parent"
android:id="#+id/email"
android:clickable="true"
android:src="#drawable/ic_action_email"
android:layout_margin="8dp"/>
<View
android:layout_width="2dp"
android:layout_height="match_parent"
android:background="#color/LightGrey" />
<ImageView
android:layout_width="40dp"
android:layout_height="fill_parent"
android:id="#+id/internet"
android:clickable="true"
android:layout_margin="8dp"
android:src="#drawable/ic_action_web_site" />
</LinearLayout>
</LinearLayout>
Here is the layout with the listview:
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<ListView
android:id="#+id/lvDepartments"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:divider="#android:color/transparent"
android:dividerHeight="8dp"
android:padding="8dp"
android:smoothScrollbar="true"
android:scrollbarStyle="insideOverlay"
android:listSelector="#color/Navy"/>
</LinearLayout>
Here is the related java code:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.staff_layout);
staffmemberlist = (ListView)findViewById(R.id.lvDepartments);
ArrayAdapter<String> arrayAdapter =new ArrayAdapter<String> (getApplicationContext(),R.layout.emailbrowsingcard,R.id.name, d);
staffmemberlist.setAdapter(arrayAdapter);
mailbutton=(ImageView)findViewById(R.id.email);
mailbutton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Toast.makeText(getApplicationContext(),
"This line would appear on clicking this icon",
Toast.LENGTH_LONG).show();
}
});
}

this isnt going to work because the ImageView is in the item list so you should consider doing..
mailButton = (ImageView) row.findViewById(R.id.email);
where row is the item list. remember the ImageView isn't in staff_layout, it is in your item_layout.
to make it works you need to move this block:
mailbutton=(ImageView)findViewById(R.id.email);
mailbutton.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Toast.makeText(getApplicationContext(),
"This line would appear on clicking this icon",
Toast.LENGTH_LONG).show();
}
});
to the getView() in your adapter class. and let the View get findViewById or have an instance of the item_layout view in order to reach the buttons.

you should use a custom adapter for that and in custom adapter use findViewById for finding imageviews and setting listener
this is a good tutorial: http://www.vogella.com/articles/AndroidListView/article.html

How to manage layout with checkbox in Android

I have multiple layout in a xml file and I want with checkbox from another xml file to show or hide the layout who is checked or unchecked.
This is the main layout and I want to show or hide Linearlayout1 or LinearLayout2 etc.
So I click on the button "Layout" and I can activate or desactivate layout by checking a checkbox
<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"
android:paddingBottom="#dimen/activity_vertical_margin"
android:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
tools:context=".MainActivity" >
<LinearLayout
android:id="#+id/linearLayout1"
android:layout_width="wrap_content"
android:layout_height="wrap_content" >
<Button
android:id="#+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button1" />
<TextView
android:id="#+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Layout 1" />
</LinearLayout>
<LinearLayout
android:id="#+id/linearLayout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/linearLayout1"
android:layout_below="#+id/linearLayout1" >
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Button2" />
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Layout 2" />
</LinearLayout>
<LinearLayout
android:id="#+id/linearLayout2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/linearLayout"
android:layout_below="#+id/linearLayout" >
<Button
android:id="#+id/button3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Layout 3" />
<TextView
android:id="#+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TextView" />
</LinearLayout>
<Button
android:id="#+id/button4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/linearLayout2"
android:layout_centerVertical="true"
android:layout_marginLeft="14dp"
android:text="Layout" />
</RelativeLayout>
With the java code:
package com.dlayout;
import android.os.Bundle;
import android.app.Activity;
import android.content.Intent;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class MainActivity extends Activity implements OnClickListener{
Button button4;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button4 = (Button)findViewById(R.id.button4);
button4.setOnClickListener(new View.OnClickListener(){
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
startActivity(new Intent("com.dlayout.Checkbox"));
}
});
}
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
startActivity(new Intent("com.dlayout.Checkbox"));
}
}
and my other xml file with the checkbox
<?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:orientation="vertical" >
<CheckBox
android:id="#+id/cb1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="CheckBox1" />
<CheckBox
android:id="#+id/cb2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="CheckBox2" />
<CheckBox
android:id="#+id/cb3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="CheckBox3" />
</LinearLayout>
And my java code of my checkbox class:
package com.dlayout;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.CheckBox;
import android.widget.LinearLayout;
public class Checkbox extends MainActivity {
CheckBox cb1;
CheckBox cb2;
CheckBox cb3;
LinearLayout linearLayout1;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.checkbox);
cb1 = (CheckBox) findViewById(R.id.cb1);
cb2 = (CheckBox) findViewById(R.id.cb2);
cb3 = (CheckBox) findViewById(R.id.cb3);
}
// *******************I know, this code is not working***************
public void onCheckboxClicked(View view){
boolean checked = ((CheckBox) view) .isChecked();
switch(view.getId()){
case R.id.cb1:
if (checked)
//linearLayout1.setVisibility(View.INVISIBLE);
else
//linearLayout1.setVisibility(View.VISIBLE);
break;
case R.id.cb2:
if (checked)
//LinearLayout2.setVisibility(View.INVISIBLE);
else
//linearLayout2.setVisibility(View.VISIBLE);
break;
case R.id.cb3:
if (checked)
//LinearLayout3.setVisibility(View.INVISIBLE);
else
//linearLayout2.setVisibility(View.VISIBLE);
break;
//**************************************************************
}
}
}
So when the checkbox1 is checked, the layout1 is visible when isn't, the layout1 is invisible.
Can you suggest me any ideas?

If this is all in one Activity and you want to show/hide a layout from a different xml file then you will first need to inflate that layout so you have a reference to it. Then you can use a checkChangedListener to know when the Checkbox state has changed and change the visibility of that layout.
If it is going from one Activity to another then you can simply check the state of the CheckBox in your onClick() and send some type of extra data in your intent to check in the next Activity to know to show/hide the layout.