Androidのキャンバスにいくつかのオブジェクトを拡張SurfaceViewして描画する例を作成しましたが、2つの問題に直面しています。Thread
戻るボタンを押すと、アプリケーションが閉じて、「残念ながら、例が停止しました」と表示されます。
向きを「縦」から「横」またはVSに変更すると、アプリケーションは新しい画面の調整に失敗し、描画を更新しません。その後、クラッシュして同じメッセージが表示されます。「残念ながら、例は停止しました。」
コードを確認してください：
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// TODO implement this method
holder.getSurface().setSize(width, height);
holder.setFormat(format);
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
// at this point the surface is created and
// we can safely start the game loop
thread.setRunning(true);
thread.start();
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// 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
}
}
}
logcatを確認すると、この部分に問題があるという次の行が見つかりました
@Override
public void run() {
Canvas canvas;
// initialise timing elements for stat gathering
initTimingElements();
long beginTime; // the time when the cycle begun
long timeDiff; // the time it took for the cycle to execute
int sleepTime; // ms to sleep (<0 if we're behind)
int framesSkipped; // number of frames being skipped
sleepTime = 0;
while (running) {
canvas = null;
// try locking the canvas for exclusive pixel editing
// in the surface
try {
canvas = this.surfaceHolder.lockCanvas();
LoggerHandler.log("canvas : " + canvas);
synchronized (surfaceHolder) {
beginTime = System.currentTimeMillis();
framesSkipped = 0; // resetting the frames skipped
// update game state
this.gamePanel.update();
// render state to the screen
// draws the canvas on the panel
this.gamePanel.render(canvas);
// calculate how long did the cycle take
timeDiff = System.currentTimeMillis() - beginTime;
// calculate sleep time
sleepTime = (int) (FRAME_PERIOD - timeDiff);
if (sleepTime > 0) {
// if sleepTime > 0 we're OK
try {
// send the thread to sleep for a short period
// very useful for battery saving
Thread.sleep(sleepTime);
} catch (InterruptedException e) {
}
}
while (sleepTime < 0 && framesSkipped < MAX_FRAME_SKIPS) {
// we need to catch up
this.gamePanel.update(); // update without rendering
sleepTime += FRAME_PERIOD; // add frame period to check
// if in next frame
framesSkipped++;
}
// for statistics
framesSkippedPerStatCycle += framesSkipped;
// calling the routine to store the gathered statistics
storeStats();
}
} finally {
// in case of an exception the surface is not left in
// an inconsistent state
if (canvas != null) {
surfaceHolder.unlockCanvasAndPost(canvas);
}
} // end finally
}
}
この行の問題：
canvas = this.surfaceHolder.lockCanvas();
null向きを変えると戻ります。