问题
I am getting an exception here when I try to bring another view to the front. It happens in the last method of my BoardView class where it says if(lives == 0). Can anybody see where I should be calling this bringToFront method from??
public class BoardView extends SurfaceView implements SurfaceHolder.Callback{
Context mContext;
// thread initialization
private BoardThread thread;
Thread timer;
// 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);
// controls drawings
thread = new BoardThread(getHolder(),this, blossomVector, dataIterator, box_x, box_y,
boxWidth, boxHeight);
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();
//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");
//somehow these don't seem to be working
thread.startRunning(false);
thread.stop();
timer.interrupt();
timer.stop();
}
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)
{
// END THE GAME!!!
((BoardView) getParent()).findViewById(1).bringToFront();
}
}
}
public void writeFile()
{
}
}
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();
}
}
}
public class Board extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
//use a frame layout so you can also display a dialog box
// allows more than one view to be used
FrameLayout f1 = new FrameLayout(this);
LinearLayout l1 = new LinearLayout(this);
EditText edit = new EditText(this);
l1.setOrientation(LinearLayout.VERTICAL);
l1.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT));
edit.setText("Enter your name!");
l1.setId(1);
l1.addView(edit);
f1.setLayoutParams(new LayoutParams(LayoutParams.FILL_PARENT,
LayoutParams.FILL_PARENT));
f1.addView(l1);
f1.addView(new BoardView(this));
setContentView(f1);
//setContentView(new BoardView(this));
}
}
回答1:
You need to run the bring to front on the right thread. Try this:
final View v = ((BoardView) getParent()).findViewById(1);
v.post(new Runnable(){ public void run(){ v.bringToFront(); } });
See if that works.
回答2:
You must update the View using the UI thread (not the SurfaceView thread). If you would like to make some View change from within the SurfaceView thread you must create a new RunOnUiThread which performs the View updating.
// From within SurfaceView thread
new Thread() {
public void run() {
activity.runOnUiThread(new Runnable() {
@Override
public void run() {
// Update view here
}
});
}
}.start();
来源：https://stackoverflow.com/questions/5928755/called-from-wrong-thread-exception