Android自定义控件仿QQ编辑和选取圆形头像

android大家都有很多需要用户上传头像的需求，有的是选方形，有的是圆角矩形，有的是圆形。
首先我们要做一个处理图片的自定义控件，把传入的图片，经过用户选择区域，处理成一定的形状。

有的app是通过在图片上画一个矩形区域表示选中的内容，有的则是通过双指放大缩小，拖动图片来选取图片。圆形头像，还是改变图片比较好

圆形区域可调节大小。

这个自定义view的图像部分分为三个，背景图片，半透明蒙层，和亮色区域……还是直接贴代码得了

package com.example.jjj.widget;

import android.content.context;
import android.graphics.bitmap;
import android.graphics.canvas;
import android.graphics.color;
import android.graphics.paint;
import android.graphics.porterduff.mode;
import android.graphics.porterduffxfermode;
import android.graphics.rect;
import android.graphics.rectf;
import android.util.attributeset;
import android.util.log;
import android.view.motionevent;
import android.view.view;

public class roundeditimageview extends view {
 private bitmap bitmap;
 rectf clipbounds, dst, src;
 paint clearpaint;

 // 控件宽高
 private int w, h;
 // 选区半径
 private float radius = 150f;

 // 圆形选区的边界
 private rectf circlebounds;

 // 最大放大倍数
 private float max_scale = 2.0f;

 // 双指的距离
 private float distance;
 private float x0, y0;
 private boolean doublepoint;

 public roundeditimageview(context context, attributeset attrs, int defstyle) {
  super(context, attrs, defstyle);
  init();
 }

 public roundeditimageview(context context, attributeset attrs) {
  super(context, attrs);
  init();
 }

 public roundeditimageview(context context) {
  super(context);
  init();
 }

 private void init() {
  clearpaint = new paint(paint.anti_alias_flag);
  clearpaint.setcolor(color.gray);
  clearpaint.setxfermode(new porterduffxfermode(mode.clear));
 }

 @override
 protected void ondraw(canvas canvas) {
  super.ondraw(canvas);
  if (bitmap != null) {
   canvas.drawbitmap(bitmap, null, dst, null);//每次invalidate通过改变dst达到缩放平移的目的
  }
  // 保存图层,以免清除时清除了bitmap
  int count = canvas.savelayer(clipbounds, null, canvas.all_save_flag);
  canvas.drawcolor(0x80000000);
  canvas.drawcircle(w / 2, h / 2, radius, clearpaint);// 清除半透明黑色,留下一个透明圆
  canvas.restoretocount(count);
 }

 @override
 protected void onmeasure(int widthmeasurespec, int heightmeasurespec) {
  super.onmeasure(widthmeasurespec, heightmeasurespec);
 }

 @override
 protected void onsizechanged(int w, int h, int oldw, int oldh) {
  super.onsizechanged(w, h, oldw, oldh);
  this.w = w;
  this.h = h;
  // 记录view所占的矩形
  clipbounds = new rectf(0, 0, w, h);
  float l, r, t, b;
  if (bitmap != null) {
   // 判断长宽比,当长宽比太长会太宽是,以fitcenter的方式初始化图片
   if (w / (float) h > bitmap.getwidth() / (float) bitmap.getheight()) {
    // 图片太高
    float w_ = h * bitmap.getwidth() / (float) bitmap.getheight();
    l = w / 2f - w_ / 2f;
    r = w / 2f + w_ / 2f;
    t = 0;
    b = h;
   } else {
    // 图片太长,或跟view一样长
    float h_ = w * bitmap.getheight() / (float) bitmap.getwidth();
    l = 0;
    r = w;
    t = h / 2f - h_ / 2f;
    b = h / 2f + h_ / 2f;
   }
   dst = new rectf(l, t, r, b);// 这个矩形用来变换
   src = new rectf(l, t, r, b);// 这个矩形仅为保存第一次的状态

   max_scale = math.max(max_scale, bitmap.getwidth() / src.width());
  }
  circlebounds = new rectf(w / 2 - radius, h / 2 - radius, w / 2 + radius, h / 2 + radius);
 }

 public void setimagebitmap(bitmap bitmap) {
  this.bitmap = bitmap;
  invalidate();
 }

 @override
 public boolean dispatchtouchevent(motionevent e) {
  if (e.getpointercount() > 2) {// 不接受多于两指的事件
   return false;
  } else if (e.getpointercount() == 2) {
   doublepoint = true;// 标志位,记录两指事件处理后,抬起一只手也不处理拖动
   handledoublemove(e);
  } else {
   // 处理单指的拖动
   switch (e.getaction()) {
   case motionevent.action_down:
    x0 = e.getx();
    y0 = e.gety();
    break;
   case motionevent.action_move:
    if (doublepoint) {
     break;
    }
    float x = e.getx();
    float y = e.gety();
    float w = dst.width();
    float h = dst.height();

    // 不允许拖过圆形区域,不能使圆形区域内空白
    dst.left += x - x0;
    if (dst.left > circlebounds.left) {
     dst.left = circlebounds.left;
    } else if (dst.left < circlebounds.right - w) {
     dst.left = circlebounds.right - w;
    }
    dst.right = dst.left + w;

    // 不允许拖过圆形区域,不能使圆形区域内空白
    dst.top += y - y0;
    if (dst.top > circlebounds.top) {
     dst.top = circlebounds.top;
    } else if (dst.top < circlebounds.bottom - h) {
     dst.top = circlebounds.bottom - h;
    }
    dst.bottom = dst.top + h;

    x0 = x;
    y0 = y;
    invalidate();
    break;
   case motionevent.action_up:
    doublepoint = false;// 恢复标志位
    break;
   }
  }

  return true;
 }

 // 处理双指事件
 private void handledoublemove(motionevent e) {
  switch (e.getaction() & motionevent.action_mask) {
  case motionevent.action_pointer_down:
   distance = sqrt(e);
   log.d("px", "down:distance=" + distance);
   break;
  case motionevent.action_move:
   scale(e);
   break;
  case motionevent.action_up:
   break;
  default:
   break;
  }
 }

 private void scale(motionevent e) {
  float dis = sqrt(e);
  // 以双指中心作为图片缩放的支点
  float px = e.getx(0) / 2f + e.getx(1) / 2f;
  float py = e.gety(0) / 2f + e.gety(1) / 2f;
  float scale = dis / distance;
  log.d("px", "move:distance=" + dis + ",scale to" + scale);
  float w = dst.width();
  float h = dst.height();

  if (w * scale < radius * 2 || h * scale < radius * 2 || w * scale > src.width() * max_scale) {
   // 无法缩小到比选区还小,或到达最大倍数
   return;
  }
  // 把dst区域放大scale倍
  dst.left = (dst.left - px) * scale + px;
  dst.right = (dst.right - px) * scale + px;
  dst.top = (dst.top - py) * scale + py;
  dst.bottom = (dst.bottom - py) * scale + py;

  // 缩放同样不允许使圆形区域空白
  if (dst.left > circlebounds.left) {
   dst.left = circlebounds.left;
   dst.right = dst.left + w * scale;
  } else if (dst.right < circlebounds.right) {
   dst.right = circlebounds.right;
   dst.left = dst.right - w * scale;
  }

  if (dst.top > circlebounds.top) {
   dst.top = circlebounds.top;
   dst.bottom = dst.top + h * scale;
  } else if (dst.bottom < circlebounds.bottom) {
   dst.bottom = circlebounds.bottom;
   dst.top = dst.bottom - h * scale;
  }
  invalidate();

  distance = dis;
 }

 private float sqrt(motionevent e) {
  return (float) math.sqrt((e.getx(0) - e.getx(1)) * (e.getx(0) - e.getx(1)) + (e.gety(0) - e.gety(1)) * (e.gety(0) - e.gety(1)));
 }

 // 生成目前选区指定大小的圆形bitmap
 public bitmap extractbitmap(int width) {
  bitmap outbitmap = bitmap.createbitmap(width, width, bitmap.config.argb_8888);
  canvas canvas = new canvas(outbitmap);
  paint p = new paint(paint.anti_alias_flag);
  p.setcolor(color.gray);
  canvas.drawcircle(width / 2, width / 2, width / 2, p);
  float scale = dst.width() / bitmap.getwidth();
  int w = (int) (circlebounds.width() / scale);
  int l = (int) ((circlebounds.left - dst.left) / scale);
  int r = l + w;
  int t = (int) ((circlebounds.top - dst.top) / scale);
  int b = t + w;
  rect resrect = new rect(l, t, r, b);
  paint paint = new paint();
  paint.setxfermode(new porterduffxfermode(mode.src_in));
  canvas.drawbitmap(bitmap, resrect, canvas.getclipbounds(), paint);
  return outbitmap;
 }
}

activity中用法

 @override
 protected void oncreate(bundle savedinstancestate) {
  super.oncreate(savedinstancestate);
  setcontentview(r.layout.activity_select_header);
  roundeditimageview imageview = (roundeditimageview) findviewbyid(r.id.roundeditimageview1);
  bitmap = bitmapfactory.decodefile(imagepath);
  imageview.setimagebitmap(bitmap);
 }

 @override
 public void onclick(view v) {
   //生成一个300*300的当前亮圆形中的图片
   bitmap result = imageview.extractbitmap(300);
   //压缩成png
   fileoutputstream out = new fileoutputstream(new file(filepath));
   result.compress(bitmap.compressformat.png, 100, out);
   //上传与显示
   ...
 }

需求是模仿qq的，本人不太会讲解，做着玩玩。

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。