Question

我需要在RecyclerView中放大/缩小整个内容。实际上，我需要按宽度和每个项目内的文本调整所有子视图的大小。

public class ViewHolder {

    Button btn;

    ...
}

当用户放大时，按钮的文本应减少到8sp，如果用户继续放大，则消失。

所以，现在我陷入两难境地：我需要做什么？调整适配器中的项目大小，或在LayoutManager中调整它们的大小，并更新整个适配器。

这两种情况似乎都会影响视觉效果，所以我需要帮助。也许你给我一个更好的解决方案。

对于21/11/2016的州，我无法找到适用于此案例的任何箱子解决方案因此，我决定编写自己的视图，并在每个缩放比例因子更改中重新测量可见视图。

Answer 1

您使用哪种适配器？

我尝试过Horizontal LinearLayoutManager并调整适配器内的项目：

$FOLDER_ROOT = "F:\"
$OUTPUT_LOCATION = "F:DLS\OUT.txt"
Function DirX($directory)
{
    Remove-Item $OUTPUT_LOCATION

    foreach ($singleDirectory in (Get-ChildItem $directory -Recurse -Directory))
    {
        $count = Get-ChildItem $singleDirectory.FullName -File | Measure-Object | %{$_.Count}
        $summary = $singleDirectory.FullName+"    "+$count+"    "+$singleDirectory.LastAccessTime
        Add-Content $OUTPUT_LOCATION $summary
    }
}
DirX($FOLDER_ROOT)

活动/片段的

和setZoom（..）方法如下：

        @Override
        public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
           ...
           final ViewGroup.LayoutParams layoutParams = viewHolder.rootView.getLayoutParams();
           layoutParams.width = getItemWidth(position);   //width calculation using current zoom level
           layoutParams.height = mItemLayoutHeight;
           viewHolder.rootView.setLayoutParams(layoutParams);
           ...

但是我的自定义LayoutManager性能不好，似乎在LinearLayoutManager中有一个优化列表

Answer 2

用户此代码。它可以很好地缩放Recyclerview的所有内容。

import android.content.Context;
import android.graphics.Canvas;
import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;

/**
@author yogesh
* */
public class PinchRecyclerView extends RecyclerView {
    private static final int INVALID_POINTER_ID = -1;
    private int mActivePointerId = INVALID_POINTER_ID;
    private ScaleGestureDetector mScaleDetector;
    private float mScaleFactor = 1.f;
    private float maxWidth = 0.0f;
    private float maxHeight = 0.0f;
    private float mLastTouchX;
    private float mLastTouchY;
    private float mPosX;
    private float mPosY;
    private float width;
    private float height;


    public PinchRecyclerView(Context context) {
        super(context);
        if (!isInEditMode())
            mScaleDetector = new ScaleGestureDetector(getContext(), new ScaleListener());
    }

    public PinchRecyclerView(Context context, AttributeSet attrs) {
        super(context, attrs);
        if (!isInEditMode())
            mScaleDetector = new ScaleGestureDetector(getContext(), new ScaleListener());
    }

    public PinchRecyclerView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        if (!isInEditMode())
            mScaleDetector = new ScaleGestureDetector(getContext(), new ScaleListener());
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        width = MeasureSpec.getSize(widthMeasureSpec);
        height = MeasureSpec.getSize(heightMeasureSpec);
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    }

    @Override
    public boolean onInterceptTouchEvent(MotionEvent ev) {
        try {
            return super.onInterceptTouchEvent(ev);
        } catch (IllegalArgumentException ex) {
            ex.printStackTrace();
        }
        return false;
    }

    @Override
    public boolean onTouchEvent(@NonNull MotionEvent ev) {
        super.onTouchEvent(ev);
        final int action = ev.getAction();
        mScaleDetector.onTouchEvent(ev);
        switch (action & MotionEvent.ACTION_MASK) {
            case MotionEvent.ACTION_DOWN: {
                final float x = ev.getX();
                final float y = ev.getY();
                mLastTouchX = x;
                mLastTouchY = y;
                mActivePointerId = ev.getPointerId(0);
                break;
            }

            case MotionEvent.ACTION_MOVE: {
                /* this line is replaced because here came below isssue
                java.lang.IllegalArgumentException: pointerIndex out of range
                 ref http://stackoverflow.com/questions/6919292/pointerindex-out-of-range-android-multitouch
                */
                //final int pointerIndex = ev.findPointerIndex(mActivePointerId);

                final int pointerIndex = (action & MotionEvent.ACTION_POINTER_INDEX_MASK)
                        >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
                final float x = ev.getX(pointerIndex);
                final float y = ev.getY(pointerIndex);
                final float dx = x - mLastTouchX;
                final float dy = y - mLastTouchY;

                mPosX += dx;
                mPosY += dy;

                if (mPosX > 0.0f)
                    mPosX = 0.0f;
                else if (mPosX < maxWidth)
                    mPosX = maxWidth;

                if (mPosY > 0.0f)
                    mPosY = 0.0f;
                else if (mPosY < maxHeight)
                    mPosY = maxHeight;

                mLastTouchX = x;
                mLastTouchY = y;

                invalidate();
                break;
            }

            case MotionEvent.ACTION_UP: {
                mActivePointerId = INVALID_POINTER_ID;
                break;
            }

            case MotionEvent.ACTION_CANCEL: {
                mActivePointerId = INVALID_POINTER_ID;
                break;
            }

            case MotionEvent.ACTION_POINTER_UP: {
                final int pointerIndex = (action & MotionEvent.ACTION_POINTER_INDEX_MASK) >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
                final int pointerId = ev.getPointerId(pointerIndex);
                if (pointerId == mActivePointerId) {
                    final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
                    mLastTouchX = ev.getX(newPointerIndex);
                    mLastTouchY = ev.getY(newPointerIndex);
                    mActivePointerId = ev.getPointerId(newPointerIndex);
                }
                break;
            }
        }

        return true;
    }

    @Override
    public void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.save(Canvas.MATRIX_SAVE_FLAG);
        canvas.translate(mPosX, mPosY);
        canvas.scale(mScaleFactor, mScaleFactor);
        canvas.restore();
    }

    @Override
    protected void dispatchDraw(@NonNull Canvas canvas) {
        canvas.save(Canvas.MATRIX_SAVE_FLAG);
        if (mScaleFactor == 1.0f) {
            mPosX = 0.0f;
            mPosY = 0.0f;
        }
        canvas.translate(mPosX, mPosY);
        canvas.scale(mScaleFactor, mScaleFactor);
        super.dispatchDraw(canvas);
        canvas.restore();
        invalidate();
    }

    private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
        @Override
        public boolean onScale(ScaleGestureDetector detector) {
            mScaleFactor *= detector.getScaleFactor();
            mScaleFactor = Math.max(1.0f, Math.min(mScaleFactor, 3.0f));
            maxWidth = width - (width * mScaleFactor);
            maxHeight = height - (height * mScaleFactor);
            invalidate();
            return true;
        }
    }
}

从此StackOverflow回答中获取的代码：Android change recycler view column no. on pinch zoom

如何在RecyclerView中对整个内容进行缩放？

2 个答案: