java Android：为 recyclerView 项目添加边框和四舍五入
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时间：2020-11-03 08:12:34 来源:igfitidea点击:
Android: Adding a border and rounding to recyclerView items
提问by Fred White
I have a recyclerView currently set up to add a drop shadow to the bottom of each item with spacing which works well. I want to add a thin gray border around each item as well as a soft rounding if possible. Code so far:
我有一个 recyclerView 目前设置为在每个项目的底部添加一个投影，间距效果很好。如果可能的话，我想在每个项目周围添加一个细的灰色边框以及一个柔和的四舍五入。到目前为止的代码：
public class VerticalSpaceItemDecorator extends RecyclerView.ItemDecoration {
private final int verticalSpaceHeight;
public VerticalSpaceItemDecorator(int verticalSpaceHeight) {
this.verticalSpaceHeight = verticalSpaceHeight;
}
@Override
public void getItemOffsets(Rect outRect,
View view,
RecyclerView parent,
RecyclerView.State state) {
// 1. Determine whether to add a spacing decorator
if (parent.getChildAdapterPosition(view) != parent.getAdapter().getItemCount() - 1) {
// 2. Set the bottom offset to the specified height
outRect.bottom = verticalSpaceHeight;
}
}
}
public class ShadowVerticalSpaceItemDecorator extends RecyclerView.ItemDecoration {
private Drawable divider;
public ShadowVerticalSpaceItemDecorator(Context context) {
// Use the default style divider
final TypedArray styledAttributes = context.obtainStyledAttributes(
new int[] { android.R.attr.listDivider });
this.divider = styledAttributes.getDrawable(0);
styledAttributes.recycle();
}
public ShadowVerticalSpaceItemDecorator(Context context, int resId) {
// Use a custom divider specified by a drawable
this.divider = ContextCompat.getDrawable(context, resId);
}
@Override
public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
// 1. Get the parent (RecyclerView) padding
int left = parent.getPaddingLeft();
int right = parent.getWidth() - parent.getPaddingRight();
// 2. Iterate items of the RecyclerView
for (int childIdx = 0; childIdx < parent.getChildCount(); childIdx++) {
// 3. Get the item
View item = parent.getChildAt(childIdx);
// 4. Determine the item's top and bottom with the divider
RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) item.getLayoutParams();
int top = item.getBottom() + params.bottomMargin;
int bottom = top + divider.getIntrinsicHeight();
// 5. Set the divider's bounds
this.divider.setBounds(left, top, right, bottom);
// 6. Draw the divider
this.divider.draw(c);
}
}
}
Custom layout of recyclerView items:
recyclerView 项目的自定义布局：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@android:color/white"
android:orientation="vertical">
<ImageView
android:id="@+id/imageView"
android:layout_width="match_parent"
android:layout_height="80dp"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:paddingLeft="5dp"
android:paddingRight="5dp"
app:srcCompat="@mipmap/ic_launcher" />
<TextView
android:id="@+id/textView_title"
style="@style/AudioFileInfoOverlayText"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/imageView"
android:layout_alignLeft="@+id/imageView"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignStart="@+id/imageView"
android:layout_gravity="left"
android:paddingLeft="5dp"
android:paddingRight="5dp"
android:text="TextView"
android:textColor="@android:color/white"
android:textSize="22sp" />
<TextView
android:id="@+id/textView_info"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/imageView"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignStart="@+id/textView_title"
android:layout_below="@+id/imageView"
android:layout_marginTop="12dp"
android:paddingLeft="5dp"
android:paddingRight="5dp"
android:text="TextView" />
<Button
android:id="@+id/button_one"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
android:layout_below="@+id/textView_info"
android:layout_marginBottom="5pt"
android:layout_marginRight="5pt"
android:background="@drawable/circle_button"
android:text="One"
android:textColor="@android:color/white" />
<Button
android:id="@+id/button_two"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/imageView"
android:layout_below="@+id/textView_info"
android:layout_marginBottom="5pt"
android:layout_marginLeft="5pt"
android:background="@drawable/circle_button"
android:backgroundTint="?android:attr/colorControlHighlight"
android:text="Two"
android:textColor="@android:color/white" />
</RelativeLayout>
</LinearLayout>
drop_shadow code:
drop_shadow 代码：
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<size android:height="4dp" />
<solid android:color="@color/darkGray" />
<corners android:topLeftRadius="0dp" android:topRightRadius="0dp"
android:bottomLeftRadius="5dp" android:bottomRightRadius="5dp"/>
</shape>
Border:
边界：
<?xml version="1.0" encoding="UTF-8"?>
<stroke android:width="3dp"
android:color="@color/gray"
/>
<padding android:left="1dp"
android:top="1dp"
android:right="1dp"
android:bottom="1dp"
/>
<corners android:bottomRightRadius="7dp"
android:bottomLeftRadius="7dp"
android:topLeftRadius="7dp"
android:topRightRadius="7dp"/>
回答by ND1010_
Create Xml on Drawable folder named border.xml
在名为 border.xml 的 Drawable 文件夹上创建 Xml
<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle">
<stroke android:color="@color/colorAccent" android:width="1dp"/>
<corners android:radius="5dp" />
</shape>
then after change background of RelativeLayout
然后在RelativeLayout改变背景之后
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/border"
android:orientation="vertical">
<ImageView
android:id="@+id/imageView"
android:layout_width="match_parent"
android:layout_height="80dp"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignParentTop="true"
android:paddingLeft="5dp"
android:paddingRight="5dp"
app:srcCompat="@mipmap/ic_launcher" />
<TextView
android:id="@+id/textView_title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/imageView"
android:layout_alignLeft="@+id/imageView"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignStart="@+id/imageView"
android:layout_gravity="left"
android:paddingLeft="5dp"
android:paddingRight="5dp"
android:text="TextView"
android:textColor="@android:color/white"
android:textSize="22sp" />
<TextView
android:id="@+id/textView_info"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/imageView"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_alignStart="@+id/textView_title"
android:layout_below="@+id/imageView"
android:layout_marginTop="12dp"
android:paddingLeft="5dp"
android:paddingRight="5dp"
android:text="TextView" />
<Button
android:id="@+id/button_one"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentEnd="true"
android:layout_alignParentRight="true"
android:layout_below="@+id/textView_info"
android:layout_marginBottom="5pt"
android:layout_marginRight="5pt"
android:text="One"
android:textColor="@android:color/white" />
<Button
android:id="@+id/button_two"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="@+id/imageView"
android:layout_below="@+id/textView_info"
android:layout_marginBottom="5pt"
android:layout_marginLeft="5pt"
android:backgroundTint="?android:attr/colorControlHighlight"
android:text="Two"
android:textColor="@android:color/white" />
</RelativeLayout>
</LinearLayout>
If you want to bold the border then <stroke android:color="@color/colorAccent" android:width="5dp"/>
如果你想加粗边框然后 <stroke android:color="@color/colorAccent" android:width="5dp"/>
