Develop Reference

Drawing a rectangle in an ImageView

I am trying to implement face detection using Google Mobile Vision in an Android app. In the app, I have an Imageview and a button with text, "Process".
When the button is clicked, the code connects with Google's Vision API and detects the face. After detecting the face, I am trying to draw a rectangle around the face. For that purpose I am using "Canvas" available in Android.
The error (not exactly) is I am unable to see the rectangle around the face. Here is the code in my MainActivity.java file:
package com.startertutorials.googlefacedetect;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.PointF;
import android.graphics.drawable.BitmapDrawable;
import android.os.Bundle;
import android.util.Log;
import android.util.SparseArray;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;
import com.google.android.gms.vision.Frame;
import com.google.android.gms.vision.face.Face;
import com.google.android.gms.vision.face.FaceDetector;
import com.google.android.gms.vision.face.Landmark;
public class MainActivity extends Activity {
ImageView imageView;
Button btnProcess;
Bitmap myBitmap;
Canvas canvas;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
imageView = (ImageView)findViewById(R.id.imageView);
btnProcess = (Button)findViewById(R.id.btnProcess);
myBitmap = BitmapFactory.decodeResource(getApplicationContext().getResources(), R.drawable.me);
//imageView.setImageBitmap(myBitmap);
Bitmap tempBitmap = Bitmap.createBitmap(myBitmap.getWidth(), myBitmap.getHeight(), myBitmap.getConfig());
canvas = new Canvas(tempBitmap);
btnProcess.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
FaceDetector faceDetector = new FaceDetector.Builder(getApplicationContext())
.setTrackingEnabled(false)
.setLandmarkType(FaceDetector.ALL_LANDMARKS)
.setMode(FaceDetector.FAST_MODE)
.build();
if (!faceDetector.isOperational()) {
Toast.makeText(MainActivity.this, "Face Detector Setup Failed!", Toast.LENGTH_SHORT).show();
return;
}
Frame frame = new Frame.Builder().setBitmap(myBitmap).build();
SparseArray<Face> sparseArray = faceDetector.detect(frame);
for (int i = 0; i < sparseArray.size(); i++) {
Face face = sparseArray.valueAt(i);
detectLandmarks(face);
}
}
});
}
private void detectLandmarks(Face face) {
float height = face.getHeight();
float width = face.getWidth();
PointF p = face.getPosition();
float cx = p.x;
float cy = p.y;
drawOnImageView(cx, cy, height, width);
/*
for(Landmark landmark:face.getLandmarks())
{
int cx = (int)landmark.getPosition().x;
int cy = (int)landmark.getPosition().y;
drawOnImageView(landmark.getType(),cx,cy);
}
*/
}
private void drawOnImageView(float cx, float cy, float height, float width) {
Paint myPaint = new Paint();
myPaint.setColor(Color.GREEN);
myPaint.setStyle(Paint.Style.STROKE);
myPaint.setStrokeWidth(2);
canvas.drawBitmap(myBitmap, 0, 0, null);
canvas.drawRect(0, 0, 200, 200, myPaint);
imageView.setImageBitmap(myBitmap);
Log.d("Success", "Face detected successfully");
}
#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);
}
}
The output after I click the "Process" button in the app is as follows:
In the logcat of Android studio, I can see the message "Face detected successfully". So, I am assuming that all my code is running. But I am unable to see the rectangle.
Please help me with displaying a rectangle first. Later I will adjust it to display around the face.

You have to extend the Detector class:
https://developers.google.com/android/reference/com/google/android/gms/vision/Detector
Defining your RectangleDetector class. The code to detect rectangles would be implemented by overriding the detect() method. You'd need to implement this yourself, since there isn't already code for detecting rectangles in mobile vision.
When you have this, you'd be able to use it with CameraSource and other parts of the mobile vision API.

Eclipse, Android, AdMob. No xml

I'm new to Android and this is my first app. I have problem with adding ads. Generally I've been following this tutorial http://www.kilobolt.com/unit-1-writing-basic-android-apps.html .
Then I tried following this official thing https://developers.google.com/admob/android/eclipse - I've modified android manifest file, strings.xml but I do not have activity_main.xml (Because I didn't check "create Activity" at the beginning...?).
So after a long searching I found this question:
Android AdMob without XML
So I tried this solution and now I have 2 errors:
AdSize cannot be resolved to a variable AndroidGame.java/gametitle/src/com/username/framework/implementation
The constructor AdRequest() is undefined AndroidGame.java/gametitle/src/com/username/framework/implementation
(I thought that sth may be wrong with the google play libs I've downloaded so I tried making a simple app from the official link mentioned above. There was no errors but the app didn't run - it just stopped at "launching 99%".)
Here's the full code for AndroidGame:
package com.username.framework.implementation;
import android.app.Activity;
import com.google.android.gms.ads.AdRequest;
import com.google.android.gms.ads.AdView;
import android.content.Context;
import android.content.res.Configuration;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.os.Bundle;
import android.os.PowerManager;
import android.os.PowerManager.WakeLock;
import android.view.Window;
import android.view.WindowManager;
import android.widget.RelativeLayout;
import com.username.framework.Audio;
import com.username.framework.FileIO;
import com.username.framework.Game;
import com.username.framework.Graphics;
import com.username.framework.Input;
import com.username.framework.Screen;
public abstract class AndroidGame extends Activity implements Game {
AndroidFastRenderView renderView;
Graphics graphics;
Audio audio;
Input input;
FileIO fileIO;
Screen screen;
WakeLock wakeLock;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
boolean isPortrait = getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT;
int frameBufferWidth = isPortrait ? 480: 800;
int frameBufferHeight = isPortrait ? 800: 480;
Bitmap frameBuffer = Bitmap.createBitmap(frameBufferWidth,
frameBufferHeight, Config.RGB_565);
float scaleX = (float) frameBufferWidth
/ getWindowManager().getDefaultDisplay().getWidth();
float scaleY = (float) frameBufferHeight
/ getWindowManager().getDefaultDisplay().getHeight();
renderView = new AndroidFastRenderView(this, frameBuffer);
graphics = new AndroidGraphics(getAssets(), frameBuffer);
fileIO = new AndroidFileIO(this);
audio = new AndroidAudio(this);
input = new AndroidInput(this, renderView, scaleX, scaleY);
screen = getInitScreen();
//setContentView(renderView);
RelativeLayout layout = new RelativeLayout(this);
AdView adView = new AdView(this, AdSize.BANNER, "a151bf25136cf46");
layout.addView(renderView);
layout.addView(adView);
setContentView(layout);
adView.loadAd(new AdRequest());
PowerManager powerManager = (PowerManager) getSystemService(Context.POWER_SERVICE);
wakeLock = powerManager.newWakeLock(PowerManager.FULL_WAKE_LOCK, "MyGame");
}
#Override
public void onResume() {
super.onResume();
wakeLock.acquire();
screen.resume();
renderView.resume();
}
#Override
public void onPause() {
super.onPause();
wakeLock.release();
renderView.pause();
screen.pause();
if (isFinishing())
screen.dispose();
}
#Override
public Input getInput() {
return input;
}
#Override
public FileIO getFileIO() {
return fileIO;
}
#Override
public Graphics getGraphics() {
return graphics;
}
#Override
public Audio getAudio() {
return audio;
}
#Override
public void setScreen(Screen screen) {
if (screen == null)
throw new IllegalArgumentException("Screen must not be null");
this.screen.pause();
this.screen.dispose();
screen.resume();
screen.update(0);
this.screen = screen;
}
public Screen getCurrentScreen() {
return screen;
}
}
And I do not want to switch to Android Studio. My computer is too poor for this. :(

How to calculate direction and speed from roll and pitch (tilt)?

I'm learning Android programming.
So I managed to implement a simple app that rolls a ball over the screen if you tilt yout phone. But right now it is as simple as:
if roll > 0 then xpos++ else xpos-- end and the same for ypos.
So I want to calculate a more exact direction and also I would like the ball to roll faster the more the phone is tilting.
So if I know the tilt in the roll direction and the pitch direction, how do I calculate the direction and speed of the ball?

Here is how:
package benyamephrem.tiltball;
import android.graphics.Point;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import java.util.Timer;
import java.util.TimerTask;
import android.app.Activity;
import android.os.Handler;
import android.view.Display;
import android.view.Window;
import android.view.WindowManager.LayoutParams;
import android.widget.FrameLayout;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorManager;
import android.content.Context;
import android.content.res.Configuration;
import android.hardware.SensorEventListener;
import android.widget.Toast;
public class TiltBall extends ActionBarActivity {
BallView mBallView = null;
Handler RedrawHandler = new Handler(); //so redraw occurs in main thread
Timer mTmr = null;
TimerTask mTsk = null;
int mScrWidth, mScrHeight;
android.graphics.PointF mBallPos, mBallSpd;
#Override
protected void onCreate(Bundle savedInstanceState) {
requestWindowFeature(Window.FEATURE_NO_TITLE); //hide title bar
//set app to full screen and keep screen on
getWindow().setFlags(0xFFFFFFFF, LayoutParams.FLAG_FULLSCREEN | LayoutParams.FLAG_KEEP_SCREEN_ON);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_tilt_ball);
//create pointer to main screen
final FrameLayout mainView = (android.widget.FrameLayout) findViewById(R.id.main_view);
//get screen dimensions
Display display = getWindowManager().getDefaultDisplay();
mScrWidth = display.getWidth();
mScrHeight = display.getHeight();
mBallPos = new android.graphics.PointF();
mBallSpd = new android.graphics.PointF();
//create variables for ball position and speed
mBallPos.x = mScrWidth / 2;
mBallPos.y = mScrHeight / 5;
mBallSpd.x = 0;
mBallSpd.y = 0;
//create initial ball
mBallView = new BallView(this, mBallPos.x, mBallPos.y, 75);
mainView.addView(mBallView); //add ball to main screen
mBallView.invalidate(); //call onDraw in BallView
//listener for accelerometer, use anonymous class for simplicity
((SensorManager) getSystemService(Context.SENSOR_SERVICE)).registerListener(
new SensorEventListener() {
#Override
public void onSensorChanged(SensorEvent event) {
//set ball speed based on phone tilt (ignore Z axis)
//***Change speed here by multiplying event values by bigger numbers***
mBallSpd.x = -event.values[0] * (30/10);
mBallSpd.y = event.values[1] * (30/10);
//timer event will redraw ball
}
#Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
} //ignore
},
((SensorManager) getSystemService(Context.SENSOR_SERVICE))
.getSensorList(Sensor.TYPE_ACCELEROMETER).get(0),
SensorManager.SENSOR_DELAY_NORMAL);
//listener for touch event
mainView.setOnTouchListener(new android.view.View.OnTouchListener() {
public boolean onTouch(android.view.View v, android.view.MotionEvent e) {
//set ball position based on screen touch
mBallPos.x = e.getX();
mBallPos.y = e.getY();
//timer event will redraw ball
return true;
}
});
} //OnCreate
//listener for menu button on phone
#Override
public boolean onCreateOptionsMenu(Menu menu) {
menu.add("Exit"); //only one menu item
return super.onCreateOptionsMenu(menu);
}
//listener for menu item clicked
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle item selection
if (item.getTitle() == "Exit") //user clicked Exit
finish(); //will call onPause
return super.onOptionsItemSelected(item);
}
//For state flow see http://developer.android.com/reference/android/app/Activity.html
#Override
public void onPause() //app moved to background, stop background threads
{
mTmr.cancel(); //kill\release timer (our only background thread)
mTmr = null;
mTsk = null;
super.onPause();
}
#Override
public void onResume() //app moved to foreground (also occurs at app startup)
{
//create timer to move ball to new position
mTmr = new Timer();
mTsk = new TimerTask() {
public void run() {
//if debugging with external device,
// a log cat viewer will be needed on the device
Log.d("TiltBall", "Timer Hit - " + mBallPos.x + ":" + mBallPos.y);
//move ball based on current speed
mBallPos.x += mBallSpd.x;
mBallPos.y += mBallSpd.y;
//if ball goes off screen, reposition to opposite side of screen
if (mBallPos.x > mScrWidth) mBallPos.x = 0;
if (mBallPos.y > mScrHeight) mBallPos.y = 0;
if (mBallPos.x < 0) mBallPos.x = mScrWidth;
if (mBallPos.y < 0) mBallPos.y = mScrHeight;
//update ball class instance
mBallView.x = mBallPos.x;
mBallView.y = mBallPos.y;
//redraw ball. Must run in background thread to prevent thread lock.
RedrawHandler.post(new Runnable() {
public void run() {
mBallView.invalidate();
}
});
}
}; // TimerTask
mTmr.schedule(mTsk, 10, 10); //start timer
super.onResume();
} // onResume
#Override
public void onDestroy() //main thread stopped
{
super.onDestroy();
//wait for threads to exit before clearing app
System.runFinalizersOnExit(true);
//remove app from memory
android.os.Process.killProcess(android.os.Process.myPid());
}
//listener for config change.
//This is called when user tilts phone enough to trigger landscape view
// we want our app to stay in portrait view, so bypass event
#Override
public void onConfigurationChanged(Configuration newConfig)
{
super.onConfigurationChanged(newConfig);
}
} //TiltBallActivity
Here is the BallView class;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.view.View;
public class BallView extends View {
public float x;
public float y;
private final int r;
private final Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
//construct new ball object
public BallView(Context context, float x, float y, int r) {
super(context);
//color hex is [transparncy][red][green][blue]
mPaint.setColor(0xFF1325E0); //not transparent. color is blue
this.x = x;
this.y = y;
this.r = r; //radius
}
//qcalled by invalidate()
#Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawCircle(x, y, r, mPaint);
}
public int getRadius(){
return r;
}
}
This is not my code but I forgot its source so credits to whoever made it. I am using it for a current project I'm working on.

Moving bitmap with SurfaceView is slow

I am developing a game for android. Between stages, i want to show a part of a map with a route, and move it from a city to city (stage to stage).
First i want to do it on my phone, this a Samsung Galaxy Y, 240x320 Qvga ldpi.
So i have the map file in jpg format. This picture is 2463x602, this is a world map.
I did it, everything is done except one thing. This "animation" is slow for me.
When i start with this, i thought, it will be so fast, and i will handle the speed with a Thread.sleep(); but the matter is, it is not fast.
How can i make it more faster this?
Here is my code:
package hu.mycompany.myproject;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.media.AudioManager;
import android.media.SoundPool;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class MapActivity extends Activity {
DrawView drawView;
SoundPool soundPool;
int soundId;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.setVolumeControlStream(AudioManager.STREAM_MUSIC);
soundPool = new SoundPool(1, AudioManager.STREAM_MUSIC, 0);
soundId = soundPool.load(this, R.raw.airplane, 1);
drawView = new DrawView(this);
setContentView(drawView);
}
public void playSound() {
soundPool.play(soundId, 1f, 1f, 1, 0, 1f);
}
#Override
public void onResume() {
super.onResume();
playSound();
drawView.resume();
}
#Override
public void onPause() {
super.onPause();
drawView.pause();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_map, menu);
return true;
}
public class DrawView extends SurfaceView implements Runnable {
Bitmap gameMap = null;
Thread gameLoop = null;
SurfaceHolder surface;
Rect rect;
volatile boolean running;
volatile boolean moved;
public DrawView(Context context) {
super(context);
moved = false;
surface = getHolder();
gameMap = BitmapFactory.decodeResource(getResources(),
R.drawable.map);
}
public void resume() {
running = true;
gameLoop = new Thread(this);
gameLoop.start();
}
public void pause() {
running = false;
while (true) {
try {
gameLoop.join();
} catch (InterruptedException e) {
}
}
}
#Override
public void run() {
Rect canvasSize = new Rect(0, 0, 240, 320);
Paint paint = new Paint();
paint.setAntiAlias(true);
while (running) {
if (!surface.getSurface().isValid()) {
continue;
}
if (!moved) {
int i;
for (i = 80; i <= 830; i++) {
Canvas canvas = surface.lockCanvas();
rect = new Rect(i, 250, (i + 240), 570);
canvas.drawBitmap(gameMap, rect, canvasSize, paint);
surface.unlockCanvasAndPost(canvas);
}
moved = true;
}
}
}
}
}

1-try to reduce picture size by exporting it save for web in photoshop and select png as extension type
2- You should create two class one for handling thread and other for rendering and game logic. The thread will manage it by locking canvas when system is rendering. Take a look at this link
http://android-er.blogspot.com/2010/05/android-surfaceview.html

Manipulating variables in an activity with a method in another class

I am working on a game and have run into some issues. My architecture is something like this:
class GameView is used to draw bitmaps on my surfaces
class GameLoopThread is used to implement my game loop (if it wasn't obvious...)
class MovementUtils is used to hold all of my utilities related to moving objects
I want to house methods like gravity and movement controls in MovementUtils, but I'm having trouble actually updating the values in GameView. I tried using an intent, to no avail. I'll post my code, and maybe someone can show me what I should do. Also, ignore the Accelerometer lines, that's another problem entirely...
GameView.java
package com.example.connorgame;
import java.util.EventObject;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceHolder.Callback;
import android.view.SurfaceView;
public class GameView extends SurfaceView {
private Bitmap platform;
private Bitmap character;
private Bitmap background;
private SurfaceHolder holder;
private GameLoopThread gameLoopThread;
private MainActivity mainactivity;
private MovementUtils moveutil;
public float charX = 0;
public float charY = 0;
private boolean isFalling = true;
private boolean isJumping = false;
private float initialJumpY = 0;
private int initialFrame;
private int currentFrame;
private int frameDifference;
public GameView(Context context) {
super(context);
gameLoopThread = new GameLoopThread(this);
mainactivity = (MainActivity) context;
moveutil = new MovementUtils();
holder = getHolder();
holder.addCallback(new Callback() {
#Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
#Override
public void surfaceCreated(SurfaceHolder holder) {
// TODO Auto-generated method stub
gameLoopThread.setRunning(true);
gameLoopThread.start();
}
#Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// TODO Auto-generated method stub
}
});
platform = BitmapFactory.decodeResource(getResources(), R.drawable.platform);
character = BitmapFactory.decodeResource(getResources(), R.drawable.character);
background = BitmapFactory.decodeResource(getResources(), R.drawable.background);
}
#Override
protected void onDraw(Canvas canvas) {
canvas.drawColor(Color.BLACK);
canvas.drawBitmap(background, 0, 0, null);
canvas.drawBitmap(platform, 30, 700, null);
canvas.drawBitmap(character, charX, charY, null);
moveutil.gravity(charY, isFalling);
if (charY > getHeight() - character.getHeight()) {
initialFrame = gameLoopThread.numFrames;
initialJumpY = charY;
isFalling = false;
isJumping = true;
}
if (isJumping == true && isFalling == false) {
currentFrame = gameLoopThread.numFrames;
frameDifference = (currentFrame - initialFrame);
charY = charY - 5;
if (charY == initialJumpY - 100) {
isJumping = false;
isFalling = true;
}
}
}
}
MovementUtils.java
package com.example.connorgame;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
public class MovementUtils {
public void gravity (float charY, boolean isFalling) {
if(isFalling == true){
charY = charY + 5;
}
}
}

If I understand what you're doing correctly, you're trying to have charY in the GameView class modified by the gravity function. The issue is that float is a primitive, so it is based by value and only the local copy will be modified. If you passed an object instead, the object would be modified.
One solution is probably to just return the new Y position instead of trying to make gravity() change the Y position.
Another solution is to pass the GameView to MovementUtils and let MovementUtils modify it.
In other words, you would pass the GameView like this new MovementUtils(this);
And the gravity function would call a void setCharY(int y); in GameView.
public class MovementUtils {
private GameView gameView;
public MovementUtils(GameView view) {
this.gameView = view;
}
public void gravity (float charY, boolean isFalling) {
if(isFalling == true){
charY = charY + 5;
gameView.setCharY(charY);
}
}
}

Java only supports passing by value
So when you call moveutil.gravity(charY, isFalling);
and change it within the function, e.g.
public void gravity (float charY, boolean isFalling) {
if(isFalling == true){
charY = charY + 5;
}
Such change only occur in the local copy of the variable charY and does not affect the instance variable charY defined in your GameView class
To solve this, you can define your variables as objects as well as the argument to your functions, e.g.
public void gravity (Float charY, boolean isFalling) {}
And in your GameView class:
private Float charX = 0; // why you define them public !?
private Float charY = 0;
Alternatively, you can pass an instance of your GameView class or create a ValueObject class (similar to Context object in android) and use it to pass arguments