背景

项目中涉及到群组聊天的功能，由于前期项目比较紧张，群组头像并没有按照群成员头像去自动生成，即类似微信群组头像的效果，今天进行一下效果优化，效果如下：

仿微信生成群组头像

实现步骤

获取群组成员头像

可以采用开源图片加载库把图片加载至本地即可。说明一下，这里并没有在线去加载头像，而是考虑到在其它地方有单独加载头像的地方，所以头像都是从本地直接读取。

生成群组头像

先上代码

public Bitmap generateGroupAvator(List data) {

switch (data == null ? 0 : data.size()) {

case 1: {

return data.get(0);

}

case 2: {

int widthSize = mSize / 2;

int heightSize = mSize / 2;

Bitmap groupAvator = Bitmap.createBitmap(mSize, mSize, Bitmap.Config.ARGB_8888);

Canvas canvas = new Canvas(groupAvator);

canvas.drawColor(0xFFe1e2e3);

for (int i = 0; i < data.size(); i++) {

Bitmap bitmap = data.get(i);

int width = bitmap.getWidth();

int height = bitmap.getHeight();

Matrix matrix = new Matrix();

matrix.postScale(widthSize * 1.0f / width, heightSize * 1.0f / height);

Bitmap newBit = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, false);

canvas.drawBitmap(newBit, i % 2 * widthSize, (mSize - heightSize) / 2 + i / 2 * heightSize, null);

}

canvas.save();

canvas.restore();

return groupAvator;

}

case 3: {

int widthSize = mSize / 2;

int heightSize = mSize / 2;

Bitmap groupAvator = Bitmap.createBitmap(mSize, mSize, Bitmap.Config.ARGB_8888);

Canvas canvas = new Canvas(groupAvator);

canvas.drawColor(0xFFe1e2e3);

for (int i = 0; i < data.size(); i++) {

Bitmap bitmap = data.get(i);

int width = bitmap.getWidth();

int height = bitmap.getHeight();

Matrix matrix = new Matrix();

matrix.postScale(widthSize * 1.0f / width, heightSize * 1.0f / height);

Bitmap newBit = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, false);

if (i == 0) {

canvas.drawBitmap(newBit, (mSize - widthSize) / 2, 0, null);

} else {

canvas.drawBitmap(newBit, i / 2 * widthSize, heightSize, null);

}

}

canvas.save();

canvas.restore();

return groupAvator;

}

case 4: {

int widthSize = mSize / 2;

int heightSize = mSize / 2;

Bitmap groupAvator = Bitmap.createBitmap(mSize, mSize, Bitmap.Config.ARGB_8888);

Canvas canvas = new Canvas(groupAvator);

canvas.drawColor(0xFFe1e2e3);

for (int i = 0; i < data.size(); i++) {

Bitmap bitmap = data.get(i);

int width = bitmap.getWidth();

int height = bitmap.getHeight();

Matrix matrix = new Matrix();

matrix.postScale(widthSize * 1.0f / width, heightSize * 1.0f / height);

Bitmap newBit = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, false);

canvas.drawBitmap(newBit, i % 2 * widthSize, i / 2 * heightSize, null);

}

canvas.save();

canvas.restore();

return groupAvator;

}

case 5: {

int widthSize = mSize / 3;

int heightSize = mSize / 3;

Bitmap groupAvator = Bitmap.createBitmap(mSize, mSize, Bitmap.Config.ARGB_8888);

Canvas canvas = new Canvas(groupAvator);

canvas.drawColor(0xFFe1e2e3);

for (int i = 0; i < data.size(); i++) {

Bitmap bitmap = data.get(i);

int width = bitmap.getWidth();

int height = bitmap.getHeight();

Matrix matrix = new Matrix();

matrix.postScale(widthSize * 1.0f / width, heightSize * 1.0f / height);

Bitmap newBit = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, false);

if (i < 2) {

canvas.drawBitmap(newBit, widthSize / 2 + i * widthSize, heightSize / 2, null);

} else {

canvas.drawBitmap(newBit, i % 3 * widthSize, heightSize / 2 + heightSize, null);

}

}

canvas.save();

canvas.restore();

return groupAvator;

}

case 6: {

int widthSize = mSize / 3;

int heightSize = mSize / 3;

Bitmap groupAvator = Bitmap.createBitmap(mSize, mSize, Bitmap.Config.ARGB_8888);

Canvas canvas = new Canvas(groupAvator);

canvas.drawColor(0xFFe1e2e3);

for (int i = 0; i < data.size(); i++) {

Bitmap bitmap = data.get(i);

int width = bitmap.getWidth();

int height = bitmap.getHeight();

Matrix matrix = new Matrix();

matrix.postScale(widthSize * 1.0f / width, heightSize * 1.0f / height);

Bitmap newBit = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, false);

canvas.drawBitmap(newBit, i % 3 * widthSize, heightSize / 2 + i / 3 * heightSize, null);

}

canvas.save();

canvas.restore();

return groupAvator;

}

case 7: {

int widthSize = mSize / 3;

int heightSize = mSize / 3;

Bitmap groupAvator = Bitmap.createBitmap(mSize, mSize, Bitmap.Config.ARGB_8888);

Canvas canvas = new Canvas(groupAvator);

canvas.drawColor(0xFFe1e2e3);

for (int i = 0; i < data.size(); i++) {

Bitmap bitmap = data.get(i);

int width = bitmap.getWidth();

int height = bitmap.getHeight();

Matrix matrix = new Matrix();

matrix.postScale(widthSize * 1.0f / width, heightSize * 1.0f / height);

Bitmap newBit = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, false);

if (i == 0) {

canvas.drawBitmap(newBit, widthSize, 0, null);

} else {

canvas.drawBitmap(newBit, (i + 2) % 3 * widthSize, (i + 2) / 3 * heightSize, null);

}

}

canvas.save();

canvas.restore();

return groupAvator;

}

case 8: {

int widthSize = mSize / 3;

int heightSize = mSize / 3;

Bitmap groupAvator = Bitmap.createBitmap(mSize, mSize, Bitmap.Config.ARGB_8888);

Canvas canvas = new Canvas(groupAvator);

canvas.drawColor(0xFFe1e2e3);

for (int i = 0; i < data.size(); i++) {

Bitmap bitmap = data.get(i);

int width = bitmap.getWidth();

int height = bitmap.getHeight();

Matrix matrix = new Matrix();

matrix.postScale(widthSize * 1.0f / width, heightSize * 1.0f / height);

Bitmap newBit = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, false);

if (i < 2) {

canvas.drawBitmap(newBit, widthSize / 2 + i * widthSize, 0, null);

} else {

canvas.drawBitmap(newBit, (i + 1) % 3 * widthSize, (i + 1) / 3 * heightSize, null);

}

}

canvas.save();

canvas.restore();

return groupAvator;

}

case 9: {

int widthSize = mSize / 3;

int heightSize = mSize / 3;

Bitmap groupAvator = Bitmap.createBitmap(mSize, mSize, Bitmap.Config.ARGB_8888);

Canvas canvas = new Canvas(groupAvator);

for (int i = 0; i < data.size(); i++) {

Bitmap bitmap = data.get(i);

int width = bitmap.getWidth();

int height = bitmap.getHeight();

Matrix matrix = new Matrix();

matrix.postScale(widthSize * 1.0f / width, heightSize * 1.0f / height);

Bitmap newBit = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, false);

canvas.drawBitmap(newBit, i % 3 * widthSize, i / 3 * heightSize, null);

}

canvas.save();

canvas.restore();

return groupAvator;

}

default:

break;

}

return null;

}

- 实现思路

根据图片张数，计算出每张头像在群组头像中的尺寸，然后缩放头像，最后把缩放后的头像画到合适的位置即可。