Develop Reference

ArrayAdapter<Button> displays buttons and object reference behind it in ListView

this is my first "project" with android and I'm trying to make a single-activity app that displays a list of buttons using a listview. For some reason my ArrayAdapter displays the button correctly but behind it, it displays the object reference. So when I debug it using my phone, I see a button and right behind it its object reference.
My activity looks like this:
package com.example.madelenko.showcase;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import java.util.ArrayList;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
ArrayList<Button> projectList =
new ArrayList<Button>();
Button button1 = new Button(this);
Button button2 = new Button(this);
button1.setText("Spotify Streamer");
button2.setText("Scores App");
projectList.add(button1);
projectList.add(button2);
ArrayAdapter<Button> adapter =
new ArrayAdapter<Button>(this,R.layout.element_listview_layout,
R.id.list_item_string,projectList);
ListView listView = (ListView)findViewById(R.id.buttonListView);
listView.setAdapter(adapter);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
My button element layout looks like this:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:id="#+id/list_item_string"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_alignParentLeft="true"
android:paddingLeft="8dp"
android:textSize="18sp"
android:textStyle="bold"
android:text=""/>
<Button
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="#+id/projectButton"
android:text="Hello world!"
android:layout_alignTop="#+id/list_item_string"
android:layout_centerHorizontal="true" />
</RelativeLayout>
Finally, my listview looks like this:
<FrameLayout 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="com.example.madelenko.showcase.MainActivityFragment"
tools:showIn="#layout/activity_main">
<ListView
android:layout_width="wrap_content"
android:layout_height="401dp"
android:id="#+id/buttonListView"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_gravity="center" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="My nanodegree apps!"
android:id="#+id/textView"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true"
android:layout_gravity="center_horizontal|top" />
</FrameLayout>
Please, be patient with this newbie!

ArrayAdapter<Button> is not a recommended pattern. The adapter is supposed to be adapting model objects, whether those are trivial (e.g., ArrayAdapter<String>) or more complex (e.g., ArrayAdapter<Invoice>).
So, in this case:
You are creating an ArrayList<Button>, but those buttons will never be shown on the screen
You are inflating a layout for the rows that contains a TextView and a Button; those Button widgets will be the ones that are shown
You are telling ArrayAdapter to bind the String representation of the Button (from a call to toString() from the ArrayList to the list_item_string TextView in the row, when you create your ArrayAdapter<Button> instance
Also note that it is rather unusual to see buttons in ListView rows, since the user can click on the ListView rows themselves.
If you want to have a ListView with two rows for your two strings, you can do something like this:
public class ListViewDemo extends ListActivity {
private static final String[] items={"Spotify Streamer", "Scores App"};
#Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setListAdapter(new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1,
items));
}
}

Android Studio emulator opens but black screen

I'm new to programming. I've only learned the basics. Right now, I'm trying Android development out with Android Studio. My program simply has a title, and 2 buttons that are supposed to open a URL. There doesn't seem to be anything wrong with my code since nothing is underlined in red, so I don't understand why the layout model isn't showing up in the emulator.
What are some things that affects the emulator from running properly? I tried it on a windows computer and the emulator came after a minute or so. But nothing for the Mac. Anyway to speed up the process?
My code has no errors. Only problem I'm facing is the emulator not running in a timely manner. The app is supposed to open a URL for each of the 2 buttons in the browser.
Running on a Macbook Pro Mid 2010 13" with 8 GB RAM
**************************************Activity Code**********************************************
package com.first.bharg.firstapp;
import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
buttonOnClick();
}
public void buttonOnClick(){
Button b = (Button) findViewById(R.id.button);
Button b1 = (Button) findViewById(R.id.button2);
b.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent i1 =
new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.yahoo.com"));
startActivity(i1);
}
});
b1.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent i2 =
new Intent(Intent.ACTION_VIEW, Uri.parse("http://www.google.com"));
startActivity(i2);
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
************************************************Layout******************************************
<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:paddingLeft="#dimen/activity_horizontal_margin"
android:paddingRight="#dimen/activity_horizontal_margin"
android:paddingTop="#dimen/activity_vertical_margin"
android:paddingBottom="#dimen/activity_vertical_margin" tools:context=".MainActivity"
android:id="#+id/activity_main"
android:clickable="true"
android:background="#ffffa157"
android:focusable="true">
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Yahoo"
android:id="#+id/button"
android:layout_marginTop="107dp"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginLeft="51dp"
android:layout_marginStart="51dp" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Google"
android:id="#+id/button2"
android:layout_alignBottom="#+id/button"
android:layout_alignParentRight="true"
android:layout_alignParentEnd="true"
android:layout_marginRight="42dp"
android:layout_marginEnd="42dp" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textAppearance="?android:attr/textAppearanceLarge"
android:text="First App"
android:id="#+id/textView"
android:layout_alignParentTop="true"
android:layout_centerHorizontal="true" />
</RelativeLayout>

As far as windows concerns, I am afraid there's nothing you can do but wait for the emulator to load everything up. It always takes a lot of time, unless you use your own device (i.e connect your mobile phone to your laptop via USB).
For Mac it's a bit tricky. It's obviously not the only way, but I do suggest you to try another emulator if the one you actually have it's not working properly on it. It's gonna be faster than trying to solve whatever that's going on.
Apparently your code is ok. However if you are new to android I suggest you first get familiar with android activities life cycle before using intents. Here you may find some information related.
I've personally used eclipse's android SDK and it works fine on both OS.

android project not resolving and reseting androids studio doesn't work

I have a problem where files that should be showing up in my android project are not appearing. For example, in the following code:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="60dp"
android:layout_gravity="bottom|left"
android:orientation="horizontal"
>
<ImageButton
android:id="#+id/pencil"
android:layout_width="60dp"
android:layout_height="60dp"
android:layout_gravity="left"
android:src="#drawable-mdpi/pencil"
/>
<ImageButton
android:id="#+id/eraser"
android:layout_width="60dp"
android:layout_height="60dp"
android:layout_gravity="center"
android:src="#drawable-mdpi/eraser"
/>
</LinearLayout>
I get errors for the pencil and eraser src lines, despite having the two bitmap images in that exact folder (and being able to see it in my directory). Similar problems exist for this code:
import android.app.Activity;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
public class DrawingActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_drawing);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(res.menu.drawing, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == res.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
Where it cannot find drawing.xml (at line with res.menu.drawing), even though again it is visible in the directory.
Is there something else I'm supposed to do first? Maybe some kind of import beyond putting the items in the folder and rebuilding? I've read in some other cases that these kinds of problems were resolved by exiting and re-opening Android Studio, but I've now done that twice with no effect (as well as multiple cleans and rebuilds of the project). As such, I can only assume that I'm missing something more essential.
Any help would be greatly appreciated.

Get TimePicker Current Time on Button Click

Friends
I am new on Android App Developing. I have nearly completed my app.
In the last stage, I'm facing difficulties and trying for the last three days to solve it but could not.
I need to get the current hour and minutes from a time picker (without Dialog) when the user clicks a button. I want to save this data to a database on this button click.
Would you anybody please help me providing just an XML and JAVA file as below.
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"
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="com.example.timepicker.MainActivity" >
<TimePicker
android:id="#+id/timePicker"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginTop="21dp" />
<Button
android:id="#+id/button"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/timePicker1"
android:layout_centerHorizontal="true"
android:layout_marginTop="77dp"
android:text="Button" />
</RelativeLayout>
Java:
package com.example.timepicker;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.view.Menu;
import android.view.MenuItem;
public class MainActivity extends ActionBarActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}

Using Calendar instance you can get current hour and minutes-
Calendar c;
private int mhour;
private int mminute;
initialize -
c = Calendar.getInstance();
mhour = c.get(Calendar.HOUR);
mminute = c.get(Calendar.MINUTE);
// you will get current hour and minutes of device time
Also refer this Calendar

Button not showing up on screen Android Application

I have created an application where users can send and share text that they have input, if they click the send button, the text that they input will be displayed, if they click the share button, the application opens up a list of sharing methods (GMail, Messaging etc..), what I want is though, to allow the users to view there text and then share it, hwoever, when the user clicks send and it goes to the file activity_display, the text shows, but the button does not. Any ideas why? Could you fix this? Here's the code;
activity_display_message.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"
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=".DisplayMessageActivity" >
<TextView
android:id="#+id/text_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/hello_world" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="shareMessage"
android:layout_below="#+id/text_view"
android:text="test" />
</RelativeLayout>
MAIN PROBLEM: Button Share does not show.
EDIT: I suspect I may need to include something to this file, here's the code, any help?
DisplayMessageActivity.java:
package com.example.myfirstapp;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.TextView;
import android.support.v4.app.NavUtils;
import android.annotation.TargetApi;
import android.content.Intent;
import android.os.Build;
public class DisplayMessageActivity extends Activity {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Get the message from the intent
Intent intent = getIntent();
String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
// Create the text view
TextView textView = new TextView(this);
textView.setTextSize(20);
textView.setText(message);
// Set the text view as the activity layout
setContentView(textView);
}
/**
* Set up the {#link android.app.ActionBar}, if the API is available.
*/
#TargetApi(Build.VERSION_CODES.HONEYCOMB)
private void setupActionBar() {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
getActionBar().setDisplayHomeAsUpEnabled(true);
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.display_message, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case android.R.id.home:
// This ID represents the Home or Up button. In the case of this
// activity, the Up button is shown. Use NavUtils to allow users
// to navigate up one level in the application structure. For
// more details, see the Navigation pattern on Android Design:
//
// http://developer.android.com/design/patterns/navigation.html#up-vs-back
//
NavUtils.navigateUpFromSameTask(this);
return true;
}
return super.onOptionsItemSelected(item);
}
}

Since you are using RelativeLayout you need to specify where to layout your views. Try this for example:
<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=".DisplayMessageActivity" >
<TextView
android:id="#+id/text_view"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/hello_world" />
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:onClick="shareMessage"
android:layout_below="#+id/text_view"
android:text="test" />

you are using relative layout. use linear layout instead. this will solve your problem.

You are using a relative layout. The objects are overlapping because you have not set them up to be LeftOf or Below or something like that.

Just replace your button with:
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/textView1"
android:layout_below="#+id/textView1"
android:onClick="shareMessage"
android:text="#string/button_share" />
And TextView with this:
<TextView
android:id="#+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/hello_world" />