Android EffectFactory example

It's a good example of using android.media.effect.EffectFactory. It can be found in your Android SDK folder, normally at:
.../Android/sdk/samples/android-21/legacy/HelloEffects

The EffectFactory class defines the list of available Effects, and provides functionality to inspect and instantiate them.

Display emoji from byte[], encoded using UTF-8

Example show how to display emoji on TextView, encoded from byte[].

To convert byte array to String using charset of UTF-8, we can call the constructor of String:
new String(bytes, "UTF-8")

Example:

package com.example.androidemoji;

import java.io.UnsupportedEncodingException;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.widget.TextView;

public class MainActivity extends ActionBarActivity {

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  
  TextView emojiText = (TextView)findViewById(R.id.emojitext);
  
  //byte[] bytes = {(byte) 0xF0, (byte) 0x9F, (byte) 0x98, (byte) 0x81};
  //byte[] bytes = {(byte) 0xF0, (byte) 0x9F, (byte) 0x98, (byte) 0x84};
  byte[] bytes = {(byte) 0xF0, (byte) 0x9F, (byte) 0x98, (byte) 0x89};
  try {
   emojiText.setText(new String(bytes, "UTF-8"));
  } catch (UnsupportedEncodingException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  
  //Direct type in the emoji
  //emojiText.setText("😁");  //maybe cannot displayed on browser

 }

}

<LinearLayout 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:orientation="vertical"
    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.androidemoji.MainActivity" >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="android-coding.blogspot.com"
        android:textSize="28dp"
        android:textStyle="bold" />

    <TextView
        android:id="@+id/emojitext"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:textSize="100dp"
        android:textStyle="bold" />

</LinearLayout>

The page Emoji Unicode Tables show commonly-supported Emoji that map to standardized Unicode characters.

Android ListView, scroll to specified position

How to scroll Android ListView to top, bottom or specified position.

package com.example.androidlistviewscrolling;

import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.ListView;
import android.os.Bundle;

public class MainActivity extends ActionBarActivity {

 String[] months = { "January", "February", "March", "April", "May", "June",
   "July", "August", "September", "October", "November", "December" };

 ListView listView;
 int toPosition = months.length;
 
 Button btnScrollTop, btnScrollBottom, btnScrollTo;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  listView = (ListView) findViewById(R.id.listview);
  ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
    android.R.layout.simple_list_item_1, months);
  listView.setAdapter(adapter);
  
  listView.setOnItemClickListener(new OnItemClickListener(){

   @Override
   public void onItemClick(AdapterView<?> parent, View view,
     int position, long id) {
    toPosition = position;
    btnScrollTo.setText("Scroll to position " + toPosition);
   }});
  
  btnScrollTop = (Button)findViewById(R.id.scrolltop);
  btnScrollTop.setOnClickListener(new OnClickListener(){

   @Override
   public void onClick(View v) {
    listView.smoothScrollToPosition(0);
   }});
  
  btnScrollBottom = (Button)findViewById(R.id.scrollbottom);
  btnScrollBottom.setOnClickListener(new OnClickListener(){

   @Override
   public void onClick(View v) {
    listView.smoothScrollToPosition(listView.getCount()-1);
   }});
  
  btnScrollTo = (Button)findViewById(R.id.scrollto);
  btnScrollTo.setText("Scroll to position " + toPosition);
  btnScrollTo.setOnClickListener(new OnClickListener(){

   @Override
   public void onClick(View v) {
    listView.smoothScrollToPosition(toPosition);
   }});
 }

}

<LinearLayout 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:orientation="horizontal"
    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.androidlistviewscrolling.MainActivity" >

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:orientation="vertical" >

        <ListView
            android:id="@+id/listview"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />
    </LinearLayout>

    <LinearLayout
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:orientation="vertical" >

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:textStyle="bold"
            android:textSize="28dp"
            android:text="android-coding.blogspot.com" />
        
        <Button
            android:id="@+id/scrolltop"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Scroll to Top" />
        <Button
            android:id="@+id/scrollbottom"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:text="Scroll to Bottom" />
        <Button
            android:id="@+id/scrollto"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />
    </LinearLayout>

</LinearLayout>

List running service of Android device

The method getRunningServices(int maxNum) of ActivityManager return a list of the services that are currently running. (Note: this method is only intended for debugging or implementing service management type user interfaces)

package com.example.androidgetrunning;

import java.util.List;

import android.support.v7.app.ActionBarActivity;
import android.text.method.ScrollingMovementMethod;
import android.app.ActivityManager;
import android.os.Bundle;
import android.widget.TextView;

public class MainActivity extends ActionBarActivity {

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  //setContentView(R.layout.activity_main);
  
  ActivityManager activityManager = (ActivityManager)getSystemService(ACTIVITY_SERVICE);

  /*
   * maxNum: the maximum number of entries to return in the list. 
   * The actual number returned may be smaller, 
   * depending on how many services are running.
   */
  int maxNum = 100;
  List<ActivityManager.RunningServiceInfo> list = activityManager.getRunningServices(maxNum);
  
  StringBuilder info = new StringBuilder();
  info.append("android-coding.blogspot.com" + "\n\n");
  info.append("no. of running service: " + list.size() + "\n\n");
  for(int i=0; i<list.size(); i++){
   info.append(list.get(i).service + "\n\n");
  }
  
  TextView texView = new TextView(this);
  texView.setMovementMethod(new ScrollingMovementMethod());
  texView.setText(info);
  setContentView(texView);
 }

}

List running application processes of Android device

Call getSystemService(ACTIVITY_SERVICE) to get instance of the ActivityManager. With it, your app can interact with the overall activities running in the system. The method getRunningAppProcesses() return a list of application processes that are running on the device. (Note: this method is only intended for debugging or building a user-facing process management UI)

Example:

package com.example.androidgetrunning;

import java.util.List;

import android.support.v7.app.ActionBarActivity;
import android.text.method.ScrollingMovementMethod;
import android.app.ActivityManager;
import android.os.Bundle;
import android.widget.TextView;

public class MainActivity extends ActionBarActivity {

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  
  ActivityManager activityManager = (ActivityManager)getSystemService(ACTIVITY_SERVICE);
  
  List<ActivityManager.RunningAppProcessInfo> list = activityManager.getRunningAppProcesses();
  
  StringBuilder info = new StringBuilder();
  info.append("android-coding.blogspot.com" + list.size() + "\n\n");
  info.append("no. of running application processes: " + list.size() + "\n");
  for(int i=0; i<list.size(); i++){
   info.append(list.get(i).processName + "\n");
  }
  
  TextView texView = new TextView(this);
  texView.setMovementMethod(new ScrollingMovementMethod());
  texView.setText(info);
  setContentView(texView);
 }

}