Androidでキャンバス画の勉強を始めたので、簡単なアプリを作りたいと思っています。
アプリの起動時に、いわゆる「ヘビ」が画面上で動き始めます。ユーザーが画面をタップすると、「ヘビ」が方向を変えます。
私はこれを簡単に達成しましたが、少し問題があります：
ユーザーが画面をタップすると、ヘビはその瞬間、数ミリ秒後に方向を変えることがあります。そのため、ユーザーはインタラクションが期待どおりに反応しないことを明確に感じることができます。たとえあなたが非常に集中していても、ヘビが向きを変える正確な瞬間はかなり予測できません. これを行うには、私が行った方法よりも優れた方法が他にあるはずです。
私のコードを確認してください。Runnable で Handler を使用してヘビを移動します。(キャンバスに描画し、それをビューの背景として設定するたびに、つまり setContentView をアクティビティに設定するたびに.
コード：
public class MainActivity extends Activity implements View.OnClickListener {
Paint paint = new Paint();
Canvas canvas;
View contentView; ///<The view to set by setContentView
int moveSize; ///<Sze in px to move drawer to draw another square
int leftIndex; ///<Indexes for square drawing
int topIndex;
int rightIndex;
int bottomIndex;
int maxBoundsX; ///<The max number of squares in X axis
int maxBoundsY; ///<The max number of squares in Y axis
int moveSpeedInMillis = 25; ///<One movement square per milliseconds
Bitmap bitmapToDrawOn; ///<We draw the squares to this bitmap
Direction currentDirection = Direction.RIGHT; ///< RIGHT,LEFT,UP,DOWN directions. default is RIGHT
Handler handler = new Handler(); ///<Handler for running a runnable that actually 'moves' the snake by drawing squares to shifted positions
Runnable runnable = new Runnable() {
@Override
public void run() {
Log.i("runnable", "ran");
//Drawing a square to the current destination
drawRectPls(currentDirection);
//After some delay we call again and again and again
handler.postDelayed(runnable, moveSpeedInMillis);
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
/*getting area properties like moveSize, and bounds*/
moveSize = searchForOptimalMoveSize();
maxBoundsX = ScreenSizer.getScreenWidth(this) / moveSize;
maxBoundsY = ScreenSizer.getScreenHeight(this) / moveSize;
Log.i("moveSize", "moveSize: " + moveSize);
Log.i("maxBounds: ", "x: " + maxBoundsX + " ; " + "y: " + maxBoundsY);
/*setting start pos*/
//We start on the lower left part of the screen
leftIndex = moveSize * (-1);
rightIndex = 0;
bottomIndex = moveSize * maxBoundsY;
topIndex = moveSize * (maxBoundsY - 1);
//Setting contentView, bitmap, and canvas
contentView = new View(this);
contentView.setOnClickListener(this);
bitmapToDrawOn = Bitmap.createBitmap(ScreenSizer.getScreenWidth(this), ScreenSizer.getScreenHeight(this), Bitmap.Config.ARGB_8888);
canvas = new Canvas(bitmapToDrawOn);
contentView.setBackground(new BitmapDrawable(getResources(), bitmapToDrawOn));
setContentView(contentView);
/*starts drawing*/
handler.post(runnable);
}
/**
* Draws a square to the next direction
*
* @param direction the direction to draw the next square
*/
private void drawRectPls(Direction direction) {
if (direction.equals(Direction.RIGHT)) {
leftIndex += moveSize;
rightIndex += moveSize;
} else if (direction.equals(Direction.UP)) {
topIndex -= moveSize;
bottomIndex -= moveSize;
} else if (direction.equals(Direction.LEFT)) {
leftIndex -= moveSize;
rightIndex -= moveSize;
} else if (direction.equals(Direction.DOWN)) {
topIndex += moveSize;
bottomIndex += moveSize;
}
addRectToCanvas();
contentView.setBackground(new BitmapDrawable(getResources(), bitmapToDrawOn));
Log.i("drawRect", "direction: " + currentDirection);
}
private void addRectToCanvas() {
paint.setColor(Color.argb(255, 100, 100, 255));
canvas.drawRect(leftIndex, topIndex, rightIndex, bottomIndex, paint);
}
/**
* Upon tapping the screen the the snake is changing direction, one way simple interaction
*/
@Override
public void onClick(View v) {
if (v.equals(contentView)) {
if (currentDirection.equals(Direction.RIGHT)) {
currentDirection = Direction.UP;
} else if (currentDirection.equals(Direction.UP)) {
currentDirection = Direction.LEFT;
} else if (currentDirection.equals(Direction.LEFT)) {
currentDirection = Direction.DOWN;
} else if (currentDirection.equals(Direction.DOWN)) {
currentDirection = Direction.RIGHT;
}
}
}
/**
* Just getting the size of a square. Searching for an integer that divides both screen's width and height
* @return
*/
private int searchForOptimalMoveSize() {
int i;
for (i = 16; i <= 64; i++) {
Log.i("iter", "i= " + i);
if (ScreenSizer.getScreenWidth(this) % i == 0) {
Log.i("iter", ScreenSizer.getScreenWidth(this) + "%" + i + " =0 !");
if (ScreenSizer.getScreenHeight(this) % i == 0) {
Log.i("iter", ScreenSizer.getScreenHeight(this) + "%" + i + " =0 !");
return i;
}
}
}
return -1;
}
/**
* Stops the handler
*/
@Override
protected void onDestroy() {
super.onDestroy();
handler.removeCallbacks(runnable);
}
}
編集：
コードを変更しました。ビューにすべての詳細が含まれるようになり、フィリップが提案したようにonDrawメソッドと無効化メソッドを使用します。
結果は少し良くなりましたが、ユーザーの操作によって方向転換が遅れていることをはっきりと感じることができます。
おそらく私はスレッドで何かをすべきですか？
public class SpiralView extends View implements View.OnClickListener {
int leftIndex; ///<Indexes for square drawing
int topIndex;
int rightIndex;
int bottomIndex;
int speedInMillis = 50;
int moveSize; ///<Sze in px to move drawer to draw another square
int maxBoundsX; ///<The max number of squares in X axis
int maxBoundsY; ///<The max number of squares in Y axis
Paint paint = new Paint();
Direction currentDirection = Direction.RIGHT; ///< RIGHT,LEFT,UP,DOWN directions. default is RIGHT
public void setUp(int moveSize, int maxBoundsX, int maxBoundsY) {
this.moveSize = moveSize;
this.maxBoundsX = maxBoundsX;
this.maxBoundsY = maxBoundsY;
this.leftIndex = moveSize * (-1);
this.rightIndex = 0;
this.bottomIndex = moveSize * (maxBoundsY);
this.topIndex = moveSize * (maxBoundsY - 1);
}
public SpiralView(Context context, AttributeSet attrs) {
super(context, attrs);
setOnClickListener(this);
}
/**
* Draws a square to the next direction
*
* @param direction the direction to draw the next square
*/
private void drawOnPlease(Direction direction, Canvas canvas) {
if (direction.equals(Direction.RIGHT)) {
leftIndex += moveSize;
rightIndex += moveSize;
} else if (direction.equals(Direction.UP)) {
topIndex -= moveSize;
bottomIndex -= moveSize;
} else if (direction.equals(Direction.LEFT)) {
leftIndex -= moveSize;
rightIndex -= moveSize;
} else if (direction.equals(Direction.DOWN)) {
topIndex += moveSize;
bottomIndex += moveSize;
}
Log.i("drawRect", "direction: " + currentDirection);
Log.i("drawRect", "indexes: "+topIndex+" , "+rightIndex+" ," +bottomIndex+" , "+leftIndex);
addRectToCanvas(canvas);
}
private void addRectToCanvas(Canvas canvas) {
paint.setColor(Color.argb(255, 100, 100, 255));
canvas.drawRect(leftIndex, topIndex, rightIndex, bottomIndex, paint);
}
@Override
protected void onDraw(Canvas canvas) {
try {
drawOnPlease(currentDirection, canvas);
synchronized (this) {
wait(speedInMillis);
}
invalidate();
} catch (InterruptedException e) {
e.printStackTrace();
}
}
@Override
public void onClick(View v) {
if (currentDirection.equals(Direction.RIGHT)) {
currentDirection = Direction.UP;
} else if (currentDirection.equals(Direction.UP)) {
currentDirection = Direction.LEFT;
} else if (currentDirection.equals(Direction.LEFT)) {
currentDirection = Direction.DOWN;
} else if (currentDirection.equals(Direction.DOWN)) {
currentDirection = Direction.RIGHT;
}
//..?
invalidate();
}
}