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

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.

Related

why is this setOnTouchListener for SurfaceView but onTouch for Activity

So I have followed this tutorial and the code works perfectly. However I have some trouble understanding how OnTouchListener and OnTouch work together. I have spent a long time trauling this forum, websites and documentation to understand but still, I do not.
In this code, a OnTouchListener is set for ourSurfaceView, and then the onTouch is called for the activity?!
Can someone please explain the relationship of OnTouchListener and OnTouch across different activities and views. Many Thanks!
package com.games.michael.waterproofme;
import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.View.OnTouchListener;
public class MainActivity extends Activity implements OnTouchListener{
MySurface ourSurfaceView;
float x,y,sX, sY, fX, fY;
Bitmap test, plus;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ourSurfaceView = new MySurface(this);
ourSurfaceView.setOnTouchListener(this);
x = 0;
y = 0;
sX = 0;
sY = 0;
fX = 0;
fY = 0;
test = BitmapFactory.decodeResource(getResources(), R.drawable.sportsball);//draw ball
plus = BitmapFactory.decodeResource(getResources(), R.drawable.plus);
setContentView(ourSurfaceView);
}
#Override
protected void onPause() {
super.onPause();
ourSurfaceView.pause();
}
#Override
protected void onResume() {
super.onResume();
ourSurfaceView.resume();
}
#Override
public boolean onTouch(View v, MotionEvent event) {
x = event.getX();
y = event.getY();
switch(event.getAction()){
case MotionEvent.ACTION_DOWN:
sX = event.getX();
sY = event.getY();
break;
case MotionEvent.ACTION_UP:
fX = event.getX();
fY = event.getY();
break;
}
return true;//false = finished dont loop through. true = loop through
}
public class MySurface extends SurfaceView implements Runnable{
SurfaceHolder ourHolder;
Thread ourThread = null;
boolean isRunning = false;
public MySurface(Context context){
super(context);
ourHolder = getHolder();
ourThread = new Thread(this);
ourThread.start();
}
public void pause(){
isRunning = false;
while(true){
try {
ourThread.join();
} catch (InterruptedException e) {
e.printStackTrace();
}
break;
}
ourThread = null;
}
public void resume(){
isRunning = true;
ourThread = new Thread(this);
ourThread.start();
}
public void run() {
while(isRunning){
if(!ourHolder.getSurface().isValid()) {/
continue;}
Canvas canvas = ourHolder.lockCanvas();
canvas.drawRGB(02, 02, 150);
if (x != 0 && y != 0){
canvas.drawBitmap(test, x-(test.getWidth()/2), y-(test.getHeight()/2), null);//bitmap, left, top, paint
}
if (sX != 0 && sY != 0){
canvas.drawBitmap(plus, sX-(plus.getWidth()/2), sY-(plus.getHeight()/2), null);//bitmap, left, top, paint
}
if (fX != 0 && fY != 0){
canvas.drawBitmap(plus, fX-(plus.getWidth()/2), fY-(plus.getHeight()/2), null);//bitmap, left, top, paint
}
ourHolder.unlockCanvasAndPost(canvas);
}
}
}
}
OnTouchListener is interface - class that implements it must override its methods. For android.view.View.OnTouchListener this is one method: boolean onTouch(View v, MotionEvent event)
When touch event occurs in your SurfaceView there is check if onTouchListener is set and if so its onTouch method is called
Can someone please explain the relationship of OnTouchListener and OnTouch across different activities and views.
Touch events on views are invoked if you register any callback to them. SurfaceView extends the View class.
ourSurfaceView.setOnTouchListener(this);
setContentView(ourSurfaceView);
So you just set the ourSurfaceView to the activity as their content view and registered the View.OnTouchListener. That means the abstract method onTouch is invoked on the ourSurfaceView instance and not the activity.
In this code, a OnTouchListener is set for ourSurfaceView, and then the onTouch is called for the activity?!
No, it delegates any touch event from ourSurfaceView instance as their content view to your MainActivity class because you registered the View.OnTouchListener
Just a simple Java example:
public class Main {
public static void main(String[] args){
SurfaceClass surfaceClass = new SurfaceClass();
ActivityClass activityClass = new ActivityClass();
surfaceClass.setOnFartListener(activityClass);
//Touch event :D
surfaceClass.fart();
}
public static class ActivityClass implements SurfaceClass.OnFartListener{
#Override
public void onFart(String kindOfFart) {
System.out.println(kindOfFart);
}
}
public static class SurfaceClass{
private SurfaceClass.OnFartListener onFartListener;
public void fart(){
if(onFartListener != null){
onFartListener.onFart("Huge One!!");
}
}
public void setOnFartListener(SurfaceClass.OnFartListener onFartListener){
this.onFartListener = onFartListener;
}
public interface OnFartListener{
void onFart(String kindOfFart);
}
}}
See touch event below :D
javac Main.java && java Main

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

Scroll Background Like Lunar Lander or Ninja Jump Game - Android

I'm developing a 2d Game using Canvas/Surfaceview and have a problem with scrolling my background image.
Check out the game - http://youtu.be/4Gi5rRqzZ3M
In the NinJump game, the character Ninja is just jumping in X coordinates and Background image is scrolling at a very high speed, making Ninja look like it is actually running.
I have created the basic setup, created the Ninja, added jump functionality, added background. Now I want to repeat the same background over and over again. How can I accomplish that?
Below are my source files - Main Activity Class
package com.abc.apps;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.Window;
import android.view.WindowManager;
public class LadderActivity extends Activity {
private static final String TAG = LadderActivity.class.getSimpleName();
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// requesting to turn the title OFF
requestWindowFeature(Window.FEATURE_NO_TITLE);
// making it full screen
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
// set our MainGamePanel as the View
setContentView(new MainGameBoard(this));
Log.d(TAG, "View added");
}
#Override
protected void onDestroy() {
Log.d(TAG, "Destroying...");
super.onDestroy();
}
#Override
protected void onStop() {
Log.d(TAG, "Stopping...");
super.onStop();
}
}
Game Board extends SurfaceView
package com.abc.apps;
import android.app.Activity;
import android.content.Context;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.util.Log;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
public class MainGameBoard extends SurfaceView implements SurfaceHolder.Callback{
private MainGameLoop thread;
private Monkey monkey;
private static final String TAG = MainGameLoop.class.getSimpleName();
int currentX, currentY;
public MainGameBoard(Context context) {
super(context);
// TODO Auto-generated constructor stub
// adding the callback (this) to the surface holder to intercept events
//This line sets the current class (MainGamePanel) as the handler for the events happening on the actual surface
getHolder().addCallback(this);
// create monkey and load bitmap INITIALIZE AT LEFT
monkey = new Monkey(BitmapFactory.decodeResource(getResources(), R.drawable.actor),60, 340);
// create the game loop thread
thread = new MainGameLoop(getHolder(), this);
// make the GamePanel focusable so it can handle events.
setFocusable(true);
}
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// TODO Auto-generated method stub
}
public void surfaceCreated(SurfaceHolder holder) {
// TODO Auto-generated method stub
thread.setRunning(true);
thread.start();
}
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
// tell the thread to shut down and wait for it to finish
// this is a clean shutdown
boolean retry = true;
while (retry) {
try {
thread.join();
retry = false;
}
catch (InterruptedException e) {
// try again shutting down the thread
}
}
}
#Override
public boolean onTouchEvent(MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN) {
//For jumping Left
if (event.getX() < (getWidth()/2 - 32)) {
// Log.d(TAG, "Coords: x=" + event.getX() + ",y=" + event.getY());
//Log.d(TAG, "Jump Left");
// Sleep so that the main thread doesn't get flooded with UI events.
try {
Thread.sleep(32);
monkey.setX((getWidth()/2 - 60));
monkey.setY(monkey.getY()-70);
} catch (InterruptedException e) {
// No big deal if this sleep is interrupted.
}
}
//For Jumping Right
if (event.getX() > (getWidth()/2 + 32)) {
//Log.d(TAG, "Coords: x=" + event.getX() + ",y=" + event.getY());
//Log.d(TAG, "Jump Right");
// Sleep so that the main thread doesn't get flooded with UI events.
try {
Thread.sleep(32);
monkey.setX((getWidth()/2 + 60));
monkey.setY(monkey.getY()-70);
} catch (InterruptedException e) {
// No big deal if this sleep is interrupted.
}
}
/* //Middle Portion
if (event.getX() > (getWidth()/2 - 32) && event.getX() < (getWidth()/2 +32)) {
//thread.setRunning(false);
//((Activity)getContext()).finish();
}*/
}
return true;
}
public void render(Canvas canvas) {
canvas.drawBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.monkey_sc), 0, 0,null);
monkey.draw(canvas);
}
/* #Override
protected void onDraw(Canvas canvas){
canvas.drawBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.monkey_scene), 0, 0,null);
monkey.draw(canvas);
}*/
}
Main Game Loop
package com.abc.apps;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.util.Log;
import android.view.SurfaceHolder;
public class MainGameLoop extends Thread {
private SurfaceHolder surfaceHolder;
private MainGameBoard gameBoard;
private Monkey monkey;
private static final String TAG = MainGameLoop.class.getSimpleName();
// flag to hold game state
private boolean running = true;
public void setRunning(boolean running) {
this.running = running;
}
#Override
public void run() {
Canvas canvas;
Log.d(TAG, "Starting game loop");
while (running) {
canvas = null;
// try locking the canvas for exclusive pixel editing on the surface
try {
canvas = surfaceHolder.lockCanvas();
synchronized (surfaceHolder) {
// update game state
// render state to the screen
// draws the canvas on the panel
gameBoard.render(canvas);
}
}
finally {
// in case of an exception the surface is not left in
// an inconsistent state
if (canvas != null) {
surfaceHolder.unlockCanvasAndPost(canvas);
}
} // end finally
}
}
public MainGameLoop(SurfaceHolder surfaceHolder, MainGameBoard gameBoard) {
super();
this.surfaceHolder = surfaceHolder;
this.gameBoard = gameBoard;
}
}//MainThread
Monkey Class
package com.abc.apps;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.view.MotionEvent;
public class Monkey {
private Bitmap bitmap; // the actual bitmap
private int x; // the X coordinate
private int y; // the Y coordinate
private boolean touched; // if monkey is touched
public Monkey(Bitmap bitmap, int x, int y) {
this.bitmap = bitmap;
this.x = x;
this.y = y;
}
public Bitmap getBitmap() {
return bitmap;
}
public void setBitmap(Bitmap bitmap) {
this.bitmap = bitmap;
}
public int getX() {
return x;
}
public void setX(int x) {
this.x = x;
}
public int getY() {
return y;
}
public void setY(int y) {
this.y = y;
}
public boolean isTouched() {
return touched;
}
public void setTouched(boolean touched) {
this.touched = touched;
}
public void draw(Canvas canvas) {
Paint paint = new Paint();
paint.setAntiAlias(true);
paint.setFilterBitmap(true);
paint.setDither(true);
canvas.drawBitmap(bitmap, x - (bitmap.getWidth() / 2), y, paint);
}
}
It looks like you are drawing your background in your MainGameBoard class in the render method.
public void render(Canvas canvas) {
canvas.drawBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.monkey_sc), 0, 0,null);
monkey.draw(canvas);
}
You should just need 2 drawBitmap calls instead of 1 there.
canvas.drawBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.monkey_sc), 0, y_offset1,null);
canvas.drawBitmap(BitmapFactory.decodeResource(getResources(), R.drawable.monkey_sc), 0, y_offset2,null);
I'm making an assumption that each background image has the same height or greater than the screen height; if it is less than the screen height you would need more than 2 instances.
Then you start 1 image at y_offset1 = 0 and the other at y_offset2 = -image_height.
Each draw you would increase y_offset1 and y_offset2 by the same amount. You would then need to do a check for both offsets to see if either has an amount greater than the screen height. If it does then the y_offset that is now "below screen" should be reset to the other y_offset minus the image_height. This will create a scroll image that loops indefinitely.
When using this type of technique it is important to think about your image edges; the image should be designed such that they tile seamlessly, otherwise at the looping point there is a noticeable visual artifact along the edge.

Drawing an dynamic arrow pointing to a particular location on earth

I have implemented a program that is able to get the distance and direction of other person. Now I want to show this information by a dynamic arrow pointing to the other person direction (like a needle) and as the user moves his phone, the arrow will change its direction to still point the other person direction.
So, it is to be implemented like this: an activity will pass the direction (of the other person) in degrees (0<= x <=360) to another activity whose task is to graphically show the arrow.
I know how to know the azimuth value and thereby calculate the degree of rotation of arrow for a particular direction value (x). I know the logic of implementation but I have no knowledge about graphic, animation etc.
Any quick Help is highly appreciated.
This is the code which meets the requirement. I dont know but a better solution may exists :-
package com.visd.giraffe;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Matrix;
import android.graphics.drawable.BitmapDrawable;
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.widget.ImageView;
import android.widget.TextView;
public class arrowhandler extends Activity implements SensorEventListener {
Matrix mtx = new Matrix();
ImageView img;
Bitmap bmp ;
int w,h;
float d = 0;
float oldval = 0,currentrot = 0, rotate = 0,senserotat;
private SensorManager sensorManager = null;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Get a reference to a SensorManager
sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
setContentView(R.layout.mmmain);
String[] arrs = getIntent().getExtras().getStringArray("SMSR");
int degr = arrs[0].indexOf("Dgr:");
String msgg = "Location of " + arrs[0].substring((arrs[0].indexOf("nosss"))+5) + "\n\n" + arrs[0].substring(0, degr);
Log.d("AOA",arrs[0].substring(degr+4));
d = (Float.valueOf(arrs[0].substring(degr+4, arrs[0].indexOf("nosss")))).floatValue();
Log.d("AOA dv", Float.toString(d));
if (d>0)
{
d = d+180;
}
else if (d<0)
{
d = 180 - (Math.abs(d));
}
Log.d("AOA dv", "2" + Float.toString(d));
Log.d("AOA",Float.toString(d));
TextView t = (TextView) findViewById(R.id.textView1);
t.setText(msgg);
img=(ImageView)findViewById(R.id.imageView1);
bmp = BitmapFactory.decodeResource(getResources(), R.drawable.bluearrow);
// Getting width & height of the given image.
w = bmp.getWidth();
h = bmp.getHeight();
}
// This method will update the UI on new sensor events
public void onSensorChanged(SensorEvent sensorEvent) {
synchronized (this) {
if (sensorEvent.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {
}
if (sensorEvent.sensor.getType() == Sensor.TYPE_ORIENTATION) {
senserotat = d-sensorEvent.values[0];
if (senserotat < 0)
{
senserotat = 360 - (Math.abs(senserotat));
}
rotate = (360-currentrot)+senserotat;
if (rotate>360)
{
rotate = rotate-360;
}
mtx.postRotate(rotate);
// Rotating Bitmap
Bitmap rotatedBMP = Bitmap.createBitmap(bmp, 0, 0, w, h, mtx, true);
BitmapDrawable bmd = new BitmapDrawable(rotatedBMP);
img.setImageDrawable(bmd);
currentrot = senserotat;
//Log.d("TTTT", Float.toString(sensorEvent.values[0]));
}
}
}
public void onAccuracyChanged(Sensor arg0, int arg1) {
// TODO Auto-generated method stub
}
#Override
protected void onResume() {
super.onResume();
// Register this class as a listener for the accelerometer sensor
sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER), SensorManager.SENSOR_DELAY_NORMAL);
// ...and the orientation sensor
sensorManager.registerListener(this, sensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION), SensorManager.SENSOR_DELAY_NORMAL);
}
#Override
protected void onStop() {
// Unregister the listener
sensorManager.unregisterListener(this);
super.onStop();
}
}

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