我在xml中定义了TransitionDrawable
,如下所示:
transition.xml
<?xml version="1.0" encoding="utf-8"?>
<transition xmlns:android="http://schemas.android.com/apk/res/android">
<item android:drawable="@drawable/ic_disabled" />
<item android:drawable="@drawable/ic_enabled" />
</transition>
我用它来设置复选框状态更改的动画:
val stateDrawable = ContextCompat.getDrawable(this, R.drawable.transition) as TransitionDrawable
checkbox.buttonDrawable = stateDrawable
checkbox.setOnCheckedChangeListener { icon, checked ->
if (checked) {
stateDrawable.startTransition(300)
} else {
stateDrawable.reverseTransition(300)
}
}
如果@drawable/ic_disabled
和@drawable/ic_enabled
是png
个文件,那么一切正常。但如果它们是矢量绘图,那么转换就不起作用了。我错过了什么? TransitionDrawable
不支持vector drawables吗?
答案 0 :(得分:1)
由于我只想通过淡入淡出来更改图像,因此我实现了TransitionDrawable
的简单版本,该版本似乎适用于固定大小的矢量可绘制对象。
public class SimpleTransitionDrawable extends Drawable {
private static final int TRANSITION_STARTING = 0;
private static final int TRANSITION_RUNNING = 1;
private static final int TRANSITION_NONE = 2;
private int state = TRANSITION_NONE;
private long startTimeMillis;
private int duration;
private @Nullable Drawable source;
private Drawable target;
public void setTarget(Drawable target) {
this.source = this.target;
this.target = target;
target.setBounds(0, 0, target.getIntrinsicWidth(), target.getIntrinsicHeight());
}
public void startTransition(int durationMillis) {
duration = durationMillis;
state = TRANSITION_STARTING;
invalidateSelf();
}
@Override
public void draw(Canvas canvas) {
int alpha;
switch (state) {
case TRANSITION_STARTING:
startTimeMillis = SystemClock.uptimeMillis();
alpha = 0;
state = TRANSITION_RUNNING;
break;
case TRANSITION_RUNNING:
float normalized = (float) (SystemClock.uptimeMillis() - startTimeMillis) / duration;
alpha = (int) (0xff * Math.min(normalized, 1.0f));
break;
default:
if (target == null) return;
alpha = 0xff;
break;
}
if (source != null && alpha < 0xff) {
source.setAlpha(0xff - alpha);
source.draw(canvas);
}
if (alpha > 0) {
target.setAlpha(alpha);
target.draw(canvas);
}
if (alpha == 0xff) {
state = TRANSITION_NONE;
return;
}
invalidateSelf();
}
@Override public void setAlpha(int alpha) {}
@Override public void setColorFilter(ColorFilter colorFilter) {}
@Override public int getOpacity() {return PixelFormat.TRANSLUCENT;}
}
像这样初始化它:
ImageView view = findViewById(R.id.image_view);
SimpleTransitionDrawable drawable = new SimpleTransitionDrawable();
view.setImageDrawable(drawable);
然后使用淡入淡出更改可绘制对象:
drawable.setTarget(AppCompatResources.getDrawable(this, R.drawable.my_vector));
drawable.startTransition(350);
答案 1 :(得分:0)
我知道这很旧,但是我遇到了同样的问题...您必须先将Vector转换为BitmapDrawable,然后再添加到TransitionDrawable中。这是一个例子
TransitionDrawable td = new TransitionDrawable(new Drawable[]{
getBitmapDrawableFromVectorDrawable(this, R.drawable.vector1),
getBitmapDrawableFromVectorDrawable(this, R.drawable.vector2)
});
td.setCrossFadeEnabled(true); // probably want this
// set as checkbox button drawable...
实用程序方法//请参见https://stackoverflow.com/a/38244327/114549
public static BitmapDrawable getBitmapDrawableFromVectorDrawable(Context context, int drawableId) {
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
return (BitmapDrawable) ContextCompat.getDrawable(context, drawableId);
}
return new BitmapDrawable(context.getResources(), getBitmapFromVectorDrawable(context, drawableId));
}
public static Bitmap getBitmapFromVectorDrawable(Context context, int drawableId) {
Drawable drawable = ContextCompat.getDrawable(context, drawableId);
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.LOLLIPOP) {
drawable = (DrawableCompat.wrap(drawable)).mutate();
}
Bitmap bitmap = Bitmap.createBitmap(drawable.getIntrinsicWidth(),
drawable.getIntrinsicHeight(), Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
drawable.setBounds(0, 0, canvas.getWidth(), canvas.getHeight());
drawable.draw(canvas);
return bitmap;
}