UIThread is causing problems when I want to open a new Activity
I have a SurfaceView in an Activity, and I want to open up a new Activity when something occurs in the SurfaceView(when you run out of lives - lives == 0). I've tried different things, but I keep having problems with it. If I stop my UIThread first, then of course it won't keep running and so won't be able to execute the startActivity statement. If I do start the activity, it freezes up on me and force closes - having to do with my UIThread I believe. Has anybody run into this problem before - and if so, do you have any idea how I might go about achieving this. At the very least, if I can't open up a new Activity, how could I CLOSE this current Activity (from inside the SurfaceView).
public class BoardView extends SurfaceView implements SurfaceHolder.Callback{
Context mContext;
// thread initialization
private BoardThread thread;
Thread timer;
Thread timer2;
// box variables
Bitmap box =
(BitmapFactory.decodeResource
(getResources(), R.drawable.box));
private int box_x = 140;
private int box_y = 378;
private int boxWidth = box.getWidth();
private int boxHeight = box.getHeight();
// storage
private Vector<Blossom> blossomVector = new Vector<Blossom>();
Iterator<Blossom> dataIterator = blossomVector.iterator();
// counters
private int blossomNum = 0;
private String score;
private int currentScore = 0;
private int lives = 3;
boolean mode = false;
boolean game = false;
OutputStreamWriter out = null;
FileOutputStream fOut = null;
private static final String TAG = "Debug";
final Paint scorePaint = new Paint();
public BoardView(Context context){
super(context);
scorePaint.setColor(Color.BLACK);
scorePaint.setTextSize(12);
scorePaint.setTypeface(Typeface.MONOSPACE);
//surfaceHolder provides canvas that we draw on
getHolder().addCallback(this);
//set up read/write data
File root = Environment.getExternalStorageDirectory();
File highscoresFile = new File(root, "highscores.txt");
// controls drawings
thread = new BoardThread(getHolder(),this, blossomVector, dataIterator, box_x, box_y,
boxWidth, boxHeight);
timer2 = new Thread(){
public void run(){
while(game == false){
uiCallback.sendEmptyMessage(0);
try{
Thread.sleep(5000); // change to be random
}
catch (InterruptedException e){
e.printStackTrace();
}
}
}
};
timer = new Thread(){
public void run(){
//makes sure the player still has 3 lives left
while(game == false){
uiCallback.sendEmptyMessage(0);
try {
Thread.sleep(2000); // wait two seconds before drawing the next flower
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} //sleep for 2 seconds
}
}
};
timer.start();
timer2.start();
//intercepts touch events
setFocusable(true);
}
@Override
public void onDraw(Canvas canvas){
canvas.drawColor(Color.WHITE);
score = "SCORE: " + currentScore;
//note: pay attention to order you draw things
//don't change order or else blossoms will fall
//on top of box, not "into" it.
//display the scoreboard
canvas.drawText(score,240,420,scorePaint);
// uses a synchronized method to prevent concurrent modification
DrawBlossoms(canvas);
canvas.drawBitmap(box, box_x, box_y, null);
}
@Override
public boolean onTouchEvent(MotionEvent event){
//handles movement of box
if(event.getAction() == MotionEvent.ACTION_DOWN){
if(event.getX() > box_x & event.getY() > box_y &
event.getX() < box_x + boxWidth & event.getY() < box_y + boxHeight)
{
mode = true;
}
}
if(event.getAction() == MotionEvent.ACTION_MOVE) {
if(event.getX() > box_x & event.getY() > box_y &
event.getX() < box_x + boxWidth & event.getY() < box_y + boxHeight)
{
mode = true;
}
if(mode == true){
box_x = (int)event.getX();
}
}
if(event.getAction() == MotionEvent.ACTION_UP){
mode = false;
}
invalidate();
return true;
}
@Override
public void surfaceChanged(SurfaceHolder holder,
int format, int width, int height ){
Log.v(TAG, "Surface Changed");
//somehow these don't seem to be working
}
@Override
public void surfaceCreated(SurfaceHolder holder){
thread.startRunning(true);
thread.start();
}
@Override
public void surfaceDestroyed(SurfaceHolder holder){
Log.v(TAG, "Surface Destroyed");
try {
thread.join();
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
private Handler uiCallback = new Handler(){
public synchronized void handleMessage(Message msg){
//add a new blossom to the blossom Vector!!
blossomVector.add(new Blossom(
(BitmapFactory.decodeResource
(getResources(), R.drawable.blossom))));
dataIterator = blossomVector.iterator();
blossomNum++;
Log.v(TAG, "Number of Blossoms =" + blossomNum);
}
};
private synchronized void DrawBlossoms(Canvas c) // method to draw flowers on screen and test for collision
{
Canvas canvas = c;
dataIterator = blossomVector.iterator();
while (dataIterator.hasNext())
{
Blossom tempBlossom = dataIterator.next();
tempBlossom.Draw(canvas);
if (tempBlossom.hit(box_x,box_y, box_x + boxWidth, box_y + boxHeight, blossomVector) == true)
{
Log.v(TAG, "ITERATOR WORKS!");
dataIterator.remove();
currentScore += 100;
}
if (tempBlossom.dropped() == true)
{
dataIterator.remove();
Log.v(TAG, "Blossom dropped");
lives--;
}
if (lives == 0)
{
// stop the thread that makes blossoms
game = true;
//save the highscore
try {
File root = Environment.getExternalStorageDirectory();
if(root.canWrite()){
File highscoresFile = new File(root, "highscores.txt");
FileWriter writer = new FileWriter(highscoresFile);
BufferedWriter out = new BufferedWriter(writer);
//out.newLine();
out.write(score);
out.close();
}
} catch (FileNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
File root = Environment.getExternalStorageDirectory();
File highscoresFile = new File(root, "highscores.txt");
FileReader reader = new FileReader(highscoresFile);
BufferedReader in = new BufferedReader(reader);
try {
String scoreTest = in.readLine();
Log.v(TAG, "Score: " + scoreTest);
reader.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} catch (FileNotFoundException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
try {
thread.join();
} catch (InterruptedException e) {
// TO开发者_运维知识库DO Auto-generated catch block
e.printStackTrace();
}
}
}
}
}
Board Thread`public class BoardThread extends Thread {
private SurfaceHolder surfaceHolder;
private BoardView boardView;
private Vector<Blossom> blossomVector;
private int boxX;
private int boxY;
private int boxWidth;
private int boxHeight;
private boolean mrun =false;
private Iterator<Blossom> iterator;
private static final String TAG = "Debug";
public BoardThread(SurfaceHolder holder, BoardView boardView2,
Vector<Blossom> blossomVector1, Iterator<Blossom> dataIterator,
int box_x, int box_y, int boxW, int boxH) {
surfaceHolder = holder;
boardView=boardView2;
blossomVector = blossomVector1;
iterator = dataIterator;
boxX = box_x;
boxY = box_y;
boxW = boxWidth;
boxH = boxHeight;
}
public void startRunning(boolean run) {
mrun=run;
}
@Override
public void run() {
super.run();
Canvas canvas;
while (mrun) {
canvas=null;
try {
canvas = surfaceHolder.lockCanvas(null);
synchronized (surfaceHolder) {
//update position
//Position(blossomVector, boxX, boxY, boxWidth, boxHeight);
// draw flowers
boardView.onDraw(canvas);
}
} finally {
if (canvas != null) {
surfaceHolder.unlockCanvasAndPost(canvas);
}
}
}
}
private synchronized void Position(Vector<Blossom> blossomVector,int box_x, int box_y,
int boxWidth, int boxHeight)
{
//for(Blossom blossom: blossomVector)
iterator = blossomVector.iterator();
while (iterator.hasNext())
{
Blossom tempBlossom = iterator.next();
tempBlossom.UpdatePosition();
}
}
}
`
Sounds like the SurfaceView is running in a different thread than the main UI thread and can't modify the View objects. You'll want to create a Handler in your activity and make it accessible to your SurfaceView. Then you can send a message to the handler and it can update the UI (or launch a new activity) in the main UI thread.
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