如何制作动态对角线视图列表

Question

我正在向RecyclerView 添加对角线切割布局，但我没有得到预期的结果。我的第二个观点start with end of first view, and thats obvious。但我想要的是每个视图都是这样的join with each-other。

我的输出：

这就是我想要的：

CutLayout.class：

public class CutLayout extends FrameLayout {
    private Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
    private Xfermode pdMode = new PorterDuffXfermode(PorterDuff.Mode.CLEAR);
    private Path path = new Path();

    public CutLayout(Context context) {
        super(context);
    }

    public CutLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public CutLayout(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    public CutLayout(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    @Override
    protected void dispatchDraw(Canvas canvas) {
        int saveCount = canvas.saveLayer(0, 0, getWidth(), getHeight(), null, Canvas.ALL_SAVE_FLAG);
        super.dispatchDraw(canvas);

        paint.setXfermode(pdMode);
        path.reset();
        path.moveTo(0, getHeight());
        path.lineTo(getWidth(), getHeight());
        path.lineTo(getWidth(), getHeight() - TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 50, getResources().getDisplayMetrics()));
        path.close();
        canvas.drawPath(path, paint);

        canvas.restoreToCount(saveCount);
        paint.setXfermode(null);
    }
}

item.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context=".SampleActivity">

    <com.yarolegovich.slidingrootnav.sample.helper.CutLayout
        android:layout_width="match_parent"
        android:layout_height="200dp">

        <ImageView
            android:scaleType="centerCrop"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:src="@drawable/homebulding" />
    </com.yarolegovich.slidingrootnav.sample.helper.CutLayout>
</LinearLayout>

Answer 1

将您的CutLayout 更改为在顶部具有相同的路径，如下所示：

public class CutLayout extends FrameLayout {
    private Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
    private Xfermode pdMode = new PorterDuffXfermode(PorterDuff.Mode.CLEAR);
    private Path path = new Path();

    public CutLayout(Context context) {
        super(context);
    }

    public CutLayout(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public CutLayout(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @TargetApi(Build.VERSION_CODES.LOLLIPOP)
    public CutLayout(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    @Override
    protected void dispatchDraw(Canvas canvas) {
        int saveCount = canvas.saveLayer(0, 0, getWidth(), getHeight(), null, Canvas.ALL_SAVE_FLAG);
        super.dispatchDraw(canvas);

        paint.setXfermode(pdMode);
        path.reset();

        path.moveTo(0, 0);
        path.lineTo(getWidth(), 0);
        path.lineTo(0, TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 50, getResources().getDisplayMetrics()));
        path.close();
        canvas.drawPath(path, paint);

        path.reset();

        path.moveTo(0, getHeight());
        path.lineTo(getWidth(), getHeight());
        path.lineTo(getWidth(), getHeight() - TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 50, getResources().getDisplayMetrics()));
        path.close();
        canvas.drawPath(path, paint);

        canvas.restoreToCount(saveCount);
        paint.setXfermode(null);
    }
}

那么您所要做的就是为您的 Recycler 视图创建一个可以接受负上边距的项目装饰器

public class NegativeTopItemDecorator extends RecyclerView.ItemDecoration{
    private final int mTopMargin;

    public NegativeTopItemDecorator(int topMargin) {
        this.mTopMargin = topMargin;
    }


    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        outRect.top = mTopMargin;
    }
}

并将其添加到您的 RecyclerView

int topMargin = - (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 50, getResources().getDisplayMetrics());
NegativeTopItemDecorator itemDecorator = new NegativeTopItemDecorator(topMargin);
mRecyclerView.addItemDecoration(itemDecorator);

这将为您提供类似于以下输出的内容