我受到了新的 Material Design 动画的启发,我努力创建了一个类似的可绘制对象,用于新的支持 v7 Action Bar Drawer Toggle。
我创建了一个 CustomDrawable。我实际上所做的只是在画布上创建了一个播放三角形,并在可见画布的左边距左侧创建了一个暂停徽标。我根据进度旋转画布并恢复它。然后我使用 Xfermode 将旋转后的结果裁剪成圆形。
我找不到问题的解决方案。
问题是 xFermode 不适用于 180 度旋转的结果(在调用 canvas.restore() 之后)。
这是活动的代码。
public class MainActivity extends Activity{
ImageView iv;
CustomDrawable drawable = new CustomDrawable();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main_activity);
iv = (ImageView) findViewById(R.id.button);
iv.setLayerType(View.LAYER_TYPE_HARDWARE, null);
iv.setBackgroundDrawable(drawable);
iv.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
float[] values = { 0, 1 };
if (drawable.getProgress() != 0) {
values[0] = drawable.getProgress();
values[1] = 0;
}
ObjectAnimator animator = ObjectAnimator.ofFloat(drawable,
"progress", values);
animator.setDuration(2000);
animator.start();
}
});
}
}
以及 CustomDrawable 的代码
public class CustomDrawable extends Drawable {
private float mProgress = 0;
private Paint mPaint = new Paint();
private Path mPath = new Path();
private final float rootTwo = (float) Math.sqrt(2);
private final float rootThree = (float) Math.sqrt(3);
private float radius = 0;
private float side = 0;
private Point[] triangle = new Point[3];
Paint xferpaint = new Paint();
Canvas cropper;
Bitmap bitmap;
Interpolator interpolator = new AnticipateOvershootInterpolator();
private float width;
Rect rec1, rec2;
public CustomDrawable() {
mPaint.setAntiAlias(true);
mPaint.setStyle(Style.FILL);
xferpaint.setColor(Color.RED);
xferpaint.setStyle(Style.FILL);
xferpaint.setAntiAlias(true);
}
@Override
public void draw(Canvas canvas) {
canvas.getClipBounds(bound);
boundsf.set(bound);
if (radius == 0) {
radius = Math.min(bound.centerX(), bound.centerY());
radius -= 5;
bitmap = Bitmap.createBitmap(bound.width(), bound.height(),
Config.ARGB_8888);
cropper = new Canvas(bitmap);
cropper.drawCircle(bound.centerX(), bound.centerY(), radius,
xferpaint);
xferpaint.setXfermode(new PorterDuffXfermode(Mode.DST_IN));
side = rootTwo * radius;
triangle[0] = new Point(
(int) (bound.centerX() + (side / rootThree)),
bound.centerY());
triangle[1] = new Point(bound.centerX()
- (int) (side / (2 * rootThree)), bound.centerY()
- (int) (side / 2));
triangle[2] = new Point(bound.centerX()
- (int) (side / (2 * rootThree)), bound.centerY()
+ (int) (side / 2));
width = side / 4;
rec1 = new Rect((int) (-bound.centerX() - (3 * width / 2)),
(int) (bound.centerY() - (side / 2)),
(int) (-bound.centerX() - (width / 2)),
(int) (bound.centerY() + (side / 2)));
rec2 = new Rect((int) (-bound.centerX() + (width / 2)),
(int) (bound.centerY() - (side / 2)),
(int) (-bound.centerX() + (3 * width / 2)),
(int) (bound.centerY() + (side / 2)));
}
mPath.rewind();
mPath.moveTo(triangle[0].x, triangle[0].y);
mPath.lineTo(triangle[1].x, triangle[1].y);
mPath.lineTo(triangle[2].x, triangle[2].y);
mPath.close();
mPaint.setColor(Color.parseColor("#378585"));
canvas.drawPaint(mPaint);
mPaint.setColor(Color.parseColor("#FF0400"));
canvas.rotate(180 * interpolator.getInterpolation(mProgress), 0,
bound.centerY());
canvas.drawPath(mPath, mPaint);
canvas.drawRect(rec1, mPaint);
canvas.drawRect(rec2, mPaint);
canvas.restore();
canvas.drawBitmap(bitmap, 0, 0, xferpaint);
}
@Override
public int getOpacity() {
return mPaint.getAlpha();
}
@Override
public void setAlpha(int alpha) {
mPaint.setAlpha(alpha);
}
@Override
public void setColorFilter(ColorFilter filter) {
mPaint.setColorFilter(filter);
}
public float getProgress() {
return mProgress;
}
public void setProgress(float progress) {
mProgress = progress;
invalidateSelf();
}
}