Android仿QQ个性标签功能
龙旋
共 7620字,需浏览 16分钟
·
2021-04-25 12:51
QQ效果:
最终效果:
分析
字体的矩形面积越来越小
字体大小越来越小
2.1 问题分解
假设我们只有一个标签文字,可以选择自定义View(当然可以选择自定义ViewGroup),然后随机标签文字的left和top,文字大小从30sp开始,然后在onDraw里面绘制矩形,在矩形里面绘制文字。
绘制第一个标签文字之后,我们想绘制第二个标签文字,如果我们还在当前的View里面去随机一个Rect,可能会和第一个标签重合,那怎么办?我们想到了裁剪,看下图:
2.2 如果Rect宽大于高
2.3 如果Rect高大于宽
第一个标签绘制完成之后,继续在标签的右边重复绘制第一个标签大小的标签,一直到Rect右边剩余的空间不足以绘制一个当前的大小的标签,然后将剩下的空间切成Rect①和Rect②,重复以上步骤。
核心代码
3.1 定义Tag对象
public class Tag {
private String name;
private int left;
private int top;
private int right;
private int bottom;
private int textsize;
// 省略构造函数和setter getter
}
这个class的作用类似记录器,记录每一个Tag的位置和文字大小信息。
3.2 核心函数
public void computeSingleRect(List<String> tags, int textSize, int pLeft, int pTop, int pRight, int pBottom) {
if (tags == null || tags.size() == 0 || textSize < MIN_TEXT_SIZE || pBottom == 0 || pRight == 0 || pLeft >= pRight || pTop >= pBottom) {
return;
}
int cLeft = 0;
int cTop = 0;
int cRight = 0;
int cBottom = 0;
int textWidth = 0;
int textHeight = 0;
int size = tags.size();
int index = (int) (Math.random() * (size - 1));
String name = tags.get(index);
//计算当前rect的宽高
int rectWidth = pRight - pLeft;
int rectHeight = pBottom - pTop;
if (rectWidth > rectHeight) {
//父布局长大于高,横向布局合适
paint.setTextSize(textSize);
textWidth = (int) paint.measureText(name);
textHeight = (int) (paint.getFontMetrics().bottom - paint.getFontMetrics().top);
if (textHeight > rectHeight) {
//记录之前的textsize
int beforeTextSize = textSize;
while (textHeight > rectHeight) {
textSize--;
paint.setTextSize(textSize);
textHeight = (int) (paint.getFontMetrics().bottom - paint.getFontMetrics().top);
}
textWidth = (int) paint.measureText(name);
while (textWidth > rectWidth) {
textSize--;
paint.setTextSize(textSize);
textWidth = (int) paint.measureText(name);
}
if(textSize < MIN_TEXT_SIZE){
return;
}
textHeight = (int) (paint.getFontMetrics().bottom - paint.getFontMetrics().top);
cLeft = pLeft;
cTop = pTop;
cRight = textWidth + pLeft;
cBottom = textHeight + pTop;
showTags.add(new Tag(name, textSize, cLeft, cTop, cRight, cBottom));
textWidth = (int) paint.measureText(name);
if (pRight - cRight > textWidth) {
//右
computeSingleRect(tags, beforeTextSize, cRight, pTop, pRight, pBottom);
} else {
//右
computeSingleRect(tags, --textSize, cRight, pTop, pRight, pBottom);
}
} else {
if (textWidth >= rectWidth) {
while (textWidth > rectWidth) {
textSize--;
paint.setTextSize(textSize);
textWidth = (int) paint.measureText(name);
}
if(textSize < MIN_TEXT_SIZE){
return;
}
textHeight = (int) (paint.getFontMetrics().bottom - paint.getFontMetrics().top);
cLeft = pLeft;
cTop = pTop;
cRight = pRight;
cBottom = cTop + textHeight;
showTags.add(new Tag(name, textSize, cLeft, cTop, cRight, cBottom));
//下
textSize += 4;
computeSingleRect(tags, textSize, cLeft, cBottom, cRight, pBottom);
} else {
cLeft = (int) (Math.random() * (rectWidth / 3)) + pLeft; // 除以3是为了尽快找到合适的位置
while (cLeft + textWidth > pRight) {
cLeft--;
}
cTop = (int) (Math.random() * (rectHeight / 2)) + pTop;
while (cTop + textHeight > pBottom) {
cTop--;
}
cRight = cLeft + textWidth;
cBottom = cTop + textHeight;
showTags.add(new Tag(name, textSize, cLeft, cTop, cRight, cBottom));
//左
computeSingleRect(tags, --textSize, pLeft, pTop, cLeft, cBottom);
//上
computeSingleRect(tags, --textSize, cLeft, pTop, pRight, cTop);
//右
computeSingleRect(tags, --textSize, cRight, cTop, pRight, pBottom);
//下
computeSingleRect(tags, --textSize, pLeft, cBottom, cRight, pBottom);
}
}
} else {
//父布局高大于长,纵向布局合适
int beforeTextSize = textSize;
paint.setTextSize(textSize);
textHeight = (int) (paint.getFontMetrics().bottom - paint.getFontMetrics().top);
while (textHeight * name.length() > rectHeight) {
textSize--;
paint.setTextSize(textSize);
textHeight = (int) (paint.getFontMetrics().bottom - paint.getFontMetrics().top);
}
if(textSize < MIN_TEXT_SIZE){
return;
}
textWidth = (int) (paint.measureText(name) / name.length());
int length = name.length();
if (pLeft + textWidth > pRight) {
//右 右边空间不足
computeSingleRect(tags, --textSize, pLeft, pTop, pRight, pBottom);
return;
}
for (int i = 0; i < length; i++) {
cLeft = pLeft;
cTop = pTop + i * textHeight;
cRight = cLeft + textWidth;
cBottom = cTop + textHeight;
showTags.add(new Tag(String.valueOf(name.charAt(i)), textSize, cLeft, cTop, cRight, cBottom));
}
if (pRight - cRight > textWidth) {
//右
computeSingleRect(tags, beforeTextSize, cRight, pTop, pRight, cBottom);
//下
computeSingleRect(tags, --textSize, pLeft, cBottom, pRight, pBottom);
} else {
//右
computeSingleRect(tags, --textSize, cRight, pTop, pRight, cBottom);
//下
computeSingleRect(tags, --textSize, pLeft, cBottom, pRight, pBottom);
}
}
}
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