Android自定義ViewGroup實現堆疊頭像的點贊Layout

2019-12-12 01:51:43

字體：大中小

來源：轉載

供稿：網友

簡介

這里寫圖片描述

這樣的點贊列表怎么樣？之前做社區的時候也有類似的點贊列表，但是沒有這樣重疊，一個小小的改變，個人感覺逼格提高不少。

這個很有規則，就是后一個頭像會覆蓋一部分到前一個頭像上，頭像多了就像一串糖葫蘆了。

這個實現起來不難，自定義ViewGroup，關鍵重寫onLayout方法。

關于自定義控件的基礎知識可以看一看這個，整理的很詳細： https://github.com/GcsSloop/AndroidNote

實現

自定義屬性

屬性名	說明	默認值
vertivalSpace	行距	4dp
pileWidth	重疊寬度	10dp

onMeasure方法,每行的寬度不再是child的寬度和了，而是要減掉重疊部分的寬度和

@Override  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {    super.onMeasure(widthMeasureSpec, heightMeasureSpec);    int widthSpecMode = MeasureSpec.getMode(widthMeasureSpec);    int widthSpecSize = MeasureSpec.getSize(widthMeasureSpec);    int heightSpecMode = MeasureSpec.getMode(heightMeasureSpec);    int heightSpecSize = MeasureSpec.getSize(heightMeasureSpec);    //AT_MOST    int width = 0;    int height = 0;    int rawWidth = 0;//當前行總寬度    int rawHeight = 0;// 當前行高    int rowIndex = 0;//當前行位置    int count = getChildCount();    for (int i = 0; i < count; i++) {      View child = getChildAt(i);      if(child.getVisibility() == GONE){        if(i == count - 1){          //最后一個child          height += rawHeight;          width = Math.max(width, rawWidth);        }        continue;      }      //這里調用measureChildWithMargins 而不是measureChild      measureChildWithMargins(child, widthMeasureSpec, 0, heightMeasureSpec, 0);      MarginLayoutParams lp = (MarginLayoutParams) child.getLayoutParams();      int childWidth = child.getMeasuredWidth() + lp.leftMargin + lp.rightMargin;      int childHeight = child.getMeasuredHeight() + lp.topMargin + lp.bottomMargin;      if(rawWidth + childWidth - (rowIndex > 0 ? pileWidth : 0)> widthSpecSize - getPaddingLeft() - getPaddingRight()){        //換行        width = Math.max(width, rawWidth);        rawWidth = childWidth;        height += rawHeight + vertivalSpace;        rawHeight = childHeight;        rowIndex = 0;      } else {        rawWidth += childWidth;        if(rowIndex > 0){          rawWidth -= pileWidth;        }        rawHeight = Math.max(rawHeight, childHeight);      }      if(i == count - 1){        width = Math.max(rawWidth, width);        height += rawHeight;      }      rowIndex++;    }    setMeasuredDimension(        widthSpecMode == MeasureSpec.EXACTLY ? widthSpecSize : width + getPaddingLeft() + getPaddingRight(),        heightSpecMode == MeasureSpec.EXACTLY ? heightSpecSize : height + getPaddingTop() + getPaddingBottom()    );  }

onLayout 每一行，第一個正常放，之后的重疊放

@Override  protected void onLayout(boolean changed, int l, int t, int r, int b) {    int viewWidth = r - l;    int leftOffset = getPaddingLeft();    int topOffset = getPaddingTop();    int rowMaxHeight = 0;    int rowIndex = 0;//當前行位置    View childView;    for( int w = 0, count = getChildCount(); w < count; w++ ){      childView = getChildAt(w);      if(childView.getVisibility() == GONE) continue;      MarginLayoutParams lp = (MarginLayoutParams) childView.getLayoutParams();      // 如果加上當前子View的寬度后超過了ViewGroup的寬度，就換行      int occupyWidth = lp.leftMargin + childView.getMeasuredWidth() + lp.rightMargin;      if(leftOffset + occupyWidth + getPaddingRight() > viewWidth){        leftOffset = getPaddingLeft(); // 回到最左邊        topOffset += rowMaxHeight + vertivalSpace; // 換行        rowMaxHeight = 0;        rowIndex = 0;      }      int left = leftOffset + lp.leftMargin;      int top = topOffset + lp.topMargin;      int right = leftOffset+ lp.leftMargin + childView.getMeasuredWidth();      int bottom = topOffset + lp.topMargin + childView.getMeasuredHeight();      childView.layout(left, top, right, bottom);      // 橫向偏移      leftOffset += occupyWidth;      // 試圖更新本行最高View的高度      int occupyHeight = lp.topMargin + childView.getMeasuredHeight() + lp.bottomMargin;      if(rowIndex != count - 1){        leftOffset -= pileWidth;//這里控制重疊位置      }      rowMaxHeight = Math.max(rowMaxHeight, occupyHeight);      rowIndex++;    }  }

效果圖

這里寫圖片描述