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));
press(pressFormat.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脚本之家。
