我正在尝试同时显示两个动画。应用程序构建成功,但在模拟器中崩溃。
我在一个线程中创建了一个 Anim 类,该线程在 while 循环中处理动画。我认为我的绘制方法有问题,但我似乎无法弄清楚。
感谢您对此的任何帮助,谢谢
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.myproject/com.example.myproject.MainActivity}: java.lang.IllegalArgumentException: Cannot add a null child view to a ViewGroup
和
java.lang.ArrayIndexOutOfBoundsException: length=2; index=2
at com.example.my_project.PlayActivity$surfaceView$Anim.run(PlayActivity.java:109)
public class PlayActivity extends AppCompatActivity {
surfaceView view;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
view = new surfaceView(this);
setContentView(view);
public class surfaceView extends SurfaceView {
public surfaceView(Context context) {
super(context);
new Anim().start();
}
private class Anim extends Thread {
int counter = 0;
int counter2 = 0;
@Override
public void run() {
long last_updated_time = 0;
long delay = 250;
int[] purple_bird = {
R.drawable.bird1,
R.drawable.bird2
};
int[] red_bird = {
R.drawable.red1,
R.drawable.red2,
R.drawable.red3,
R.drawable.red4
};
while (true) {
boolean playing = true;
if (playing) {
long current_time = System.currentTimeMillis();
if (current_time > last_updated_time + delay) {
if ((counter >= 2) && (counter2 >= 4)) {
counter = 0;
counter2 = 0;
}
draw(purple_bird[counter], red_bird[counter2]);
last_updated_time = current_time;
counter++;
counter2++;
}
}
}
}
private void draw(int red_bird, int purple_bird) {
SurfaceHolder holder = getHolder();
Canvas canvas = holder.lockCanvas();
if (canvas != null) {
canvas.drawColor(Color.WHITE);
Paint paint = new Paint();
Bitmap purpleBird = BitmapFactory.decodeResource(getContext().getResources(), purple_bird);
Bitmap redBird = BitmapFactory.decodeResource(getContext().getResources(), red_bird);
Bitmap resizedRedBird = Bitmap.createScaledBitmap(redBird, (int) (redBird.getWidth() * 0.4), (int) (redBird.getHeight() * 0.4), true);
Bitmap resizedPurpleBird = Bitmap.createScaledBitmap(purpleBird, (int) (purpleBird.getWidth() * 0.2), (int) (purpleBird.getHeight() * 0.2), true);
canvas.drawBitmap(resizedRedBird, 500, 500, paint);
canvas.drawBitmap(resizedPurpleBird, 100, 100, paint);
holder.unlockCanvasAndPost(canvas);
}
}
}
}
}
因为访问 SurfaceView(使用 Canvas)是独占的,所以你不能同时绘制它。
holder.lockCanvas();
(...) // the canvas is locked during this
holder.unlockCanvasAndPost(canvas);
因此,您可能的解决方案是在同一线程的相同绘制方法(在锁定和解锁之间)中操作和绘制红鸟和蓝鸟。
对于另一个错误 2:
if ((counter >= 2) && (counter2 >= 4)) {
counter = 0;
counter2 = 0;
}
这个条件是错误的。因为只有当 counter 和 counter2 都超过时,它们才会被重置。他们应该分开:
if (counter >= 2) {
counter = 0;
}
if (counter2 >= 4) {
counter2 = 0;
}
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我来说两句