先求一个windows版本的gif制作工具！！！

这个代码只是做了简单的选择功能，图片的压缩与展示没做。可以自己在接口的方法中去实现。

写这个自定义view的初衷是为了学习LayoutParams，参考博客：http://www.jianshu.com/p/138b...

自定义一些属性

 <declare-styleable name="PhotoSelector"><attr name="columns" format="integer"/>//列<attr name="horizontal_space" format="dimension"/>//水平分割宽度<attr name="vertical_space" format="dimension"/>//竖直分割宽度</declare-styleable>

在布局中使用

 <com.idealcn.define.view.view.PhotoSelectorandroid:layout_width="match_parent"android:layout_height="wrap_content"ideal:columns="3"ideal:horizontal_space="3dp"ideal:vertical_space="3dp"><!-- 默认添加一个添加按钮的图片 --><ImageViewandroid:layout_width="100dp"android:layout_height="100dp"android:src="@drawable/ic_suggestions_add"/></com.idealcn.define.view.view.PhotoSelector>

自定义这个ViewGroup

public class PhotoSelector extends ViewGroup {public PhotoSelector(Context context) {this(context,null);}public PhotoSelector(Context context, AttributeSet attrs) {this(context, attrs,0);}public PhotoSelector(Context context, AttributeSet attrs, int defStyleAttr) {super(context, attrs, defStyleAttr);}
}

获取默认的添加按钮

  @Overrideprotected void onFinishInflate() {super.onFinishInflate();//获取默认的添加按钮addView = getChildAt(0);viewList.add(addView);}

为添加按钮添加点击事件

 @Overrideprotected void onAttachedToWindow() {super.onAttachedToWindow();addView.setOnClickListener(new View.OnClickListener(){@Overridepublic void onClick(View v) {//这里添加选择图片的代码  }});}

子View的测量和布局

这里要重写onMeasure和onLayout。定义ViewGroup.LayoutParams的子类来保存view的left和top的属性。

public static class PhotoParams extends LayoutParams{public int left,top;public PhotoParams(Context c, AttributeSet attrs) {super(c, attrs);}public PhotoParams(int width, int height) {super(width, height);}public PhotoParams(LayoutParams source) {super(source);}}

测量时，view的宽高一致，屏幕宽度减去水平分割线的宽度，然后平分给每个view。

     @Overrideprotected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {super.onMeasure(widthMeasureSpec, heightMeasureSpec);int width = MeasureSpec.getSize(widthMeasureSpec);int childWidth = (int) ((width - horizontalSpace * columns)/columns + .5f);int childHeight = childWidth;int childCount = viewList.size();for (int x = 0; x < childCount; x++) {//这里要从保存view的集合中取出viewView child = viewList.get(x);PhotoParams lp = (PhotoParams) child.getLayoutParams();if (lp==null) {lp = new PhotoParams(childWidth, childHeight);}lp.width = childWidth;lp.height = childHeight;//这里确定了view的left和top属性值，在onLayout中只需取出即可lp.left = x%columns * childWidth + (x%columns+1) * horizontalSpace;lp.top = x/columns * (childHeight + verticalSpace) + verticalSpace;child.setLayoutParams(lp);}if (childCount<=columns)setMeasuredDimension(childWidth*childCount,childHeight);else {int heightCount = childCount%columns!=0?(childCount/columns+1):childCount/columns;setMeasuredDimension(childWidth*columns,childHeight*heightCount);}//测量并确定子view的大小measureChildren(widthMeasureSpec,heightMeasureSpec);}

放置子view

 @Overrideprotected void onLayout(boolean changed, int l, int t, int r, int b) {int childCount = viewList.size();for (int x = 0; x < childCount; x++) {View child = viewList.get(x);PhotoParams lp = (PhotoParams) child.getLayoutParams();child.layout(lp.left,lp.top,lp.left + child.getMeasuredWidth() + horizontalSpace,lp.top + child.getMeasuredHeight() + verticalSpace);}}

添加图片

定义一个List集合，添加的图片存放于集合中。然后调用requestLayout()。定义一个接口，将添加图片的操作交给所在的Activity处理。

定义接口

public interface OnAddPhotoListener {Bitmap addByCamera();//拍照Bitmap addByGallery();//相册
}

所在的Activity实现接口

public class TableActivity extends AppCompatActivity implements OnAddPhotoListener {...//省略一部分代码//只要把获取图片的操作在这里做处理即可@Overridepublic Bitmap addByCamera() {Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher_round);return bitmap;}@Overridepublic Bitmap addByGallery() {Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher_round);return bitmap;}
}

源码参考：https://github.com/idealcn/De...