Android 更改DragShadowBuilder使用的视图的外观
我想在recyclerview中实现拖放功能。一切都进行得很顺利,直到我想要自定义被拖动视图的外观(不是拖动事件开始的视图,我想要修改“阴影”并保持原始视图不变) 我试着用正在传递的视图制作位图,但最终结果是原始项和阴影都被修改,原始视图在列表中失去了位置。。。WTF 这是我的密码:Android 更改DragShadowBuilder使用的视图的外观,android,android-layout,drag-and-drop,android-support-library,Android,Android Layout,Drag And Drop,Android Support Library,我想在recyclerview中实现拖放功能。一切都进行得很顺利,直到我想要自定义被拖动视图的外观(不是拖动事件开始的视图,我想要修改“阴影”并保持原始视图不变) 我试着用正在传递的视图制作位图,但最终结果是原始项和阴影都被修改,原始视图在列表中失去了位置。。。WTF 这是我的密码: public class ImageDragShadowBuilder extends View.DragShadowBuilder { private Bitmap shadow; Linear
public class ImageDragShadowBuilder extends View.DragShadowBuilder {
private Bitmap shadow;
LinearLayout linearLayout;
private ImageDragShadowBuilder() {
super();
}
public static ImageDragShadowBuilder create(Context context, View view) {
ImageDragShadowBuilder builder = new ImageDragShadowBuilder();
builder.linearLayout = (LinearLayout) view.findViewById(R.id.metric_item);
builder.linearLayout.setBackgroundResource(R.drawable.background_item_dragging);
builder.shadow = createBitmapFromView(builder.linearLayout);
return builder;
}
public View getLayout() {
return linearLayout;
}
private static Bitmap createBitmapFromView(View v) {
Bitmap b = Bitmap.createBitmap(v.getWidth(), v.getHeight(), Bitmap.Config.ARGB_8888);
v.layout(0, 0, v.getWidth(), v.getHeight());
v.draw(new Canvas(b));
return b;
}
@Override
public void onDrawShadow(Canvas canvas) {
canvas.drawBitmap(shadow, 0, 0, null);
}
@Override
public void onProvideShadowMetrics(Point shadowSize, Point shadowTouchPoint) {
shadowSize.x = shadow.getWidth();
shadowSize.y = shadow.getHeight();
shadowTouchPoint.x = shadowSize.x / 2;
shadowTouchPoint.y = shadowSize.y / 2;
}
}
有什么想法吗?我认为有两个问题:
- 在附加到RecyclerView的视图上设置背景会影响原始项目和阴影
- 触发布局会更改项目的子项位置
public static ImageDragShadowBuilder create(Context context, View view) {
ImageDragShadowBuilder builder = new ImageDragShadowBuilder();
builder.linearLayout = (LinearLayout) view.findViewById(R.id.metric_item);
// do not change the original view
// we will draw the background directly later
// builder.linearLayout.setBackgroundResource(R.drawable.background_item_dragging);
builder.shadow = createBitmapFromView(builder.linearLayout);
return builder;
}
private static Bitmap createBitmapFromView(View v) {
Bitmap b = Bitmap.createBitmap(v.getWidth(), v.getHeight(), Bitmap.Config.ARGB_8888);
// do not change the original view
// v.layout(0, 0, v.getWidth(), v.getHeight());
Canvas c = new Canvas(b);
// draw the background
Drawable background = v.getContext().getDrawable(R.drawable.background_item_dragging);
background.setBounds(0, 0, b.getWidth(), b.getHeight());
background.draw(c);
v.draw(c);
return b;
}
v.getContext().getDrawable()
只能从21开始使用,我只能从16开始使用。还有其他选择吗?我尝试了ContextCompat.getDrawable(v.getContext()
,ID),但这不会改变背景。这就是说,原来的项目不再移动,所以这是一个良好的开端!更多信息。我怀疑我是因为其他原因,这似乎是因为原始视图已经有了背景!这与我获取可绘制图像的方式无关(无论是21还是16),所以下一个问题是。。。有可能应用效果并保留背景吗???Context.getDrawable()
只是Context.getResources().getDrawable(…)
我想重点是:只要不更改视图,你可以在位图中绘制你想要的视图、可绘制的视图或其他东西:你不拥有它,它仍然附着在RecyclerView中