Develop Reference

No Visible Icons on Action Bar (Android Programming)

I have searched the forums and discovered that using app:showAsAction is a recommendation for my question. However, I am using app:showAsAction and still cannot get my icons to display on the action bar. ALSO, I have to set my actionbar title manually in my Main.java because when using xml, the title does not appear on the actionbar. QUESTION: How do I get my icons to appear on the action bar and why can't I set my action bar title in xml? Are these issues related? Here is my code:
Main XML:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="#000000"
tools:context="example.com.listview.MainActivity">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<android.support.v7.widget.Toolbar
android:id="#+id/myToolbar"
android:layout_width="match_parent"
android:layout_height="56dp"
android:background="#8380"
android:elevation="4dp"
android:theme="#style/ThemeOverlay.AppCompat.ActionBar"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light"
android:titleTextColor="#android:color/holo_green_light"
app:titleTextColor="#android:color/holo_green_light"
/>
</RelativeLayout>
<android.support.v7.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/my_recycler_view"/>
</LinearLayout>
Main JAVA:
package example.com.listview;
import android.app.Activity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuInflater;
public class MainActivity extends Activity {
private RecyclerView recyclerView;
private RecyclerView.Adapter mAdapter;
private RecyclerView.LayoutManager mLayoutManager;
Repository myDataset;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar myToolbar = (Toolbar) findViewById(R.id.myToolbar);
myToolbar.setTitle("ListView");
myDataset = new Repository();
myDataset.addCause("Happy");
myDataset.addCause("Sad");
myDataset.addCause("Love");
myDataset.causes.get(0).addOccurrence();
myDataset.causes.get(0).addOccurrence();
myDataset.causes.get(1).addOccurrence();
myDataset.causes.get(2).addOccurrence();
recyclerView = (RecyclerView) findViewById(R.id.my_recycler_view);
recyclerView.setHasFixedSize(true);
mLayoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(mLayoutManager);
mAdapter = new MyAdapter(myDataset);
recyclerView.setAdapter(mAdapter);
}
#Override
public boolean onCreateOptionsMenu(Menu menu){
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.activity_main_actions, menu);
return super.onCreateOptionsMenu(menu);
}
}
Main MenuActions:
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<item android:id="#+id/addCause"
android:title="Add Cause"
android:orderInCategory="0"
android:icon="#drawable/plussign"
app:showAsAction="never"/>
<item android:id="#+id/removeCause"
android:orderInCategory="1"
android:title="Remove Cause"
app:showAsAction="never"
android:icon="#drawable/minussign"/>
</menu>
Manifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="example.com.listview">
<application
android:allowBackup="true"
android:icon="#mipmap/ic_launcher"
android:label="#string/app_name"
android:supportsRtl="true"
android:theme="#style/Theme.AppCompat.Light.NoActionBar">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>

How do I get my icons to appear on the action bar
Extend from AppCompatActivity, not Activity
Hook the toolbar up to the Activity by calling setSupportActionBar(myToolbar);
why can't I set my action bar title in xml
Adding app:title="My Title" in your XML should work.

Getting my location on android 4.2.2

I am a beginner in android development. I was trying a very simple code to get my location through the device gps and post it in a textView. I am not having any errors though when I start the application on the emulator it fails to start and I get this message "unfortunately test1 has stopped ".
This is my manifest file:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.test1"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="18" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.test1.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
`
this is my activity_main code :
<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" >
<TextView
android:id="#+id/text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="#string/hello_world" />
This is my main_activity.class code :
package com.example.test1;
import android.location.Location;
import android.location.LocationManager;
import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.view.Menu;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView textView;
textView = (TextView) findViewById(R.id.text);
LocationManager manager =
(LocationManager)getSystemService(Context.LOCATION_SERVICE);
Location loc = manager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
textView.setText("latitude: " + loc.getLatitude()
+ "\nlongitude: " + loc.getLongitude());
}
#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;
}
}
Any help on making it work ??

Why can't I send an array of 1000000 ints from one Activity to another?

I'm trying to second an array of 1000000 ints from one Activity to another. It works fine with smaller numbers, but when I try 1000000, startActivity does nothing, and causes this to show in logcat:
E/JavaBinder(2239): !!! FAILED BINDER TRANSACTION !!!
Why?
Here's some code demonstrating the issue:
MainActivity.java
package com.example.a;
import android.os.Bundle;
import android.view.View;
import android.app.Activity;
import android.content.Intent;
public class MainActivity extends Activity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void startSecond(View v) {
startActivity(new Intent(this, SecondActivity.class).putExtra(
"a", new int[1000000]));
}
}
SecondActivity.java
package com.example.a;
import android.os.Bundle;
import android.app.Activity;
public class SecondActivity extends Activity {
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
}
}
activity_main.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=".MainActivity" >
<Button
android:id="#+id/button1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="56dp"
android:layout_marginTop="31dp"
android:onClick="startSecond"
android:text="click clack" />
</RelativeLayout>
activity_second.xml
<?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" >
</LinearLayout>
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.a"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.a.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<activity android:name="com.example.a.SecondActivity"></activity>
</application>
</manifest>

Why?
Because you are limited to 1MB per Binder transaction, and Binder underlies the Intent system. The size of your Intent, including all extras, needs to be under 1MB.

Helloworld Doesn't run on Emulator

Okay, this is really ticking me off. I ran it on both my emulator and on an android device. The code does NOT display "Helloworld, Android -mykong.com". I start the app, find it on the emulator, click on it, and it goes to interface of the app. However, it is just a blank screen! This error is not an issue of me finding the app, its not with the emulator or the android phone, the issue has to lie either in the code or in the way the code is structured/built. I know the the helloworld code is 100% correct because its from a reputable tutorial site. These are my three pairs of code. Please help, I am in desperate need!
AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.test123"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="17" />
<application
android:allowBackup="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.example.test123.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
MainActivity.java
package com.example.test123;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
public class MainActivity extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void activity()
{
Intent helloWorld = new Intent(getApplicationContext(), HelloWorldjavaactivity.class );
startActivity( helloWorld );
}
#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;
}
}
HelloWorldjavaactivity.java
package com.example.test123;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
public class HelloWorldjavaactivity extends Activity {
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
TextView text = new TextView(this);
text.setText("Hello World, Android - mkyong.com");
setContentView(text);
}
}
Activity_main.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=".MainActivity" >
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="35dp"
android:layout_marginTop="57dp"
android:text=""
/>
</RelativeLayout>

You're not starting the HelloWorldjavaactivity.java activity. You need something like the following in your MainActivity:
Intent helloWorld = new Intent(getApplicationContext(), HelloWorldjavaactivity.class );
startActivity( helloWorld );
Of course, you need that code to be triggered by some even, a button press for example.
It would be easier to just eliminate the second activity (since your MainActivity isn't doing anything anyway) and put the code in your MainActivity instead. You'll also need to edit the layout for your MainActivity so that it includes the appropriate views.

Android: i am a newbie. I declared a button in java file but i didnt see it in xml-file and on an emulator

I tried to run first example from "Beginning Android Games" book (by Mario Zechner, Apress.com):
I copied this code to my project (MainActivity.java file):
HelloWorldActivity.java
package com.helloworld;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
public class MainActivity extends Activity implements View.OnClickListener {
Button button;
int touchCount;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
button = new Button(this);
button.setText( "Touch me!" );
button.setOnClickListener(this);
setContentView(button);
}
public void onClick(View v) {
touchCount++;
button.setText("Touched me " + touchCount + " time(s)");
}
}
but when I have run this simple application, I didn't see any button on the emulator (I have seen only an "Android" label. I tried "project-->clean..": no result. (and "project-->Build Automatically is swiched on). Where do I need to declare and describe this button? But I followed all steps described in the book. And at the end, I removed xml-file from layout folder at all.
Thanks.
________________Edited: Added xml-files___________
res-->layout-->activity_main.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=".MainActivity" >
</RelativeLayout>
AndroidManifest.xml:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.firstbuttontest2"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="4"
android:targetSdkVersion="11" />
<application
android:allowBackup="true"
android:debuggable="true"
android:icon="#drawable/ic_launcher"
android:label="#string/app_name"
android:theme="#style/AppTheme" >
<activity
android:name="com.firstbuttontest2.MainActivity"
android:label="#string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>

Try this it might help you.
Add button to particular layout. Like this
LinearLayout linearLayout=(LinearLayout)findViewById(R.id.linearLayout);
linearLayout.addView(button);

I know that there is a addContentView method which may be more what you are looking for as opposed to setContentView.

Try
setContentView(R.layout.activity_main)
then
button = (Button) findviewbyid(R.id.Button1);
this may solve your problem