<?xml version="1.0" encoding="utf-8"?>
<resources>
 <declare-styleable name="CustomGridView">
 <attr name="numColumns" format="integer" />
 <attr name="hSpace" format="integer" />
 <attr name="vSpace" format="integer" />
 </declare-styleable>
</resources>

 public CustomGridView(Context context, AttributeSet attrs, int defStyle) {
 super(context, attrs, defStyle);
 if (attrs != null) {
  TypedArray a = getContext().obtainStyledAttributes(attrs,
   R.styleable.CustomGridView);
  colums = a.getInteger(R.styleable.CustomGridLayout_numColumns, 3);
  hSpace = a.getInteger(R.styleable.CustomGridLayout_hSpace, 10);
  vSpace = a.getInteger(R.styleable.CustomGridLayout_vSpace, 10);
  a.recycle();
 }
 }

 public MyGridLayout(Context context, AttributeSet attrs) {
 this(context, attrs, 0);
 }

 public MyGridLayout(Context context) {
 this(context, null);
 }

public static class LayoutParams extends ViewGroup.LayoutParams {
  public int left = 0;
  public int top = 0;

  public LayoutParams(Context arg0, AttributeSet arg1) {
  super(arg0, arg1);
  }

  public LayoutParams(int arg0, int arg1) {
  super(arg0, arg1);
  }

  public LayoutParams(android.view.ViewGroup.LayoutParams arg0) {
  super(arg0);
  } 
 }

 @Override
 public ViewGroup.LayoutParams generateLayoutParams(AttributeSet attrs) {
 return new CustomGridLayout.LayoutParams(getContext(), attrs);
 }

 @Override
 protected ViewGroup.LayoutParams generateDefaultLayoutParams() {
 return new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
 }

 @Override
 protected ViewGroup.LayoutParams generateLayoutParams(ViewGroup.LayoutParams p) {
 return new LayoutParams(p);
 }

 @Override
 protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
 return p instanceof CustomGridLayout.LayoutParams;
 }

@Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
 int widthMode = MeasureSpec.getMode(widthMeasureSpec);
 int heightMode = MeasureSpec.getMode(heightMeasureSpec);
 int sizeWidth = MeasureSpec.getSize(widthMeasureSpec);
 int sizeHeight = MeasureSpec.getSize(heightMeasureSpec);

 //UNSPECIFIED一般都是父控件是AdapterView，通过measure方法传入的模式
 final int childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(sizeWidth, MeasureSpec.UNSPECIFIED);
 final int childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(sizeHeight, MeasureSpec.UNSPECIFIED);
 measureChildren(childWidthMeasureSpec, childHeightMeasureSpec);

 int childCount = this.getChildCount();
 int line = childCount % colums == 0 ? childCount / colums : (childCount + colums) / colums;

 //宽布局为wrap_content时，childWidth取childView宽的最大值，否则动态计算
 if (widthMode == MeasureSpec.AT_MOST) {
  for (int i = 0; i < childCount; i++) {
  View child = this.getChildAt(i);
  childWidth = Math.max(childWidth, child.getMeasuredWidth());
  }
 } else if (widthMode == MeasureSpec.EXACTLY) {
  childWidth = (sizeWidth - (colums - 1) * hSpace) / colums;
 }
 //高布局为wrap_content时，childHeight取childView高的最大值，否则动态计算
 if (heightMode == MeasureSpec.AT_MOST) {
  for (int i = 0; i < childCount; i++) {
  View child = this.getChildAt(i);
  childHeight = Math.max(childHeight, child.getMeasuredHeight());
  }
 } else if (heightMode == MeasureSpec.EXACTLY) {
  childHeight = (sizeHeight - (line - 1) * vSpace) / line;
 }

 //遍历每个子view，将它们左上角坐标保存在它们的LayoutParams中，为后面onLayout服务
 for (int i = 0; i < childCount; i++) {
  View child = this.getChildAt(i);
  LayoutParams lParams = (LayoutParams) child.getLayoutParams();
  lParams.left = (i % colums) * (childWidth + hSpace);
  lParams.top = (i / colums) * (childHeight + vSpace);
 }
 //当宽高为wrap_content时，分别计算出的viewGroup宽高
 int wrapWidth;
 int wrapHeight;
 if (childCount < colums) {
  wrapWidth = childCount * childWidth + (childCount - 1) * hSpace;
 } else {
  wrapWidth = colums * childWidth + (colums - 1) * hSpace;
 }
 wrapHeight = line * childHeight + (line - 1) * vSpace;
 setMeasuredDimension(widthMode == MeasureSpec.AT_MOST? wrapWidth:sizeWidth,heightMode == MeasureSpec.AT_MOST? wrapHeight:sizeHeight);
 }

@Override
 protected void onLayout(boolean changed, int l, int t, int r, int b) {
 int childCount = this.getChildCount();
 for (int i = 0; i < childCount; i++) {
  View child = this.getChildAt(i);
  LayoutParams lParams = (LayoutParams) child.getLayoutParams();
  child.layout(lParams.left, lParams.top, lParams.left + childWidth, lParams.top + childHeight);
 }
 }

 public interface GridAdatper {
 View getView(int index);
 int getCount();
 }

 /** 设置适配器 */
 public void setGridAdapter(GridAdatper adapter) {
 this.adapter = adapter;
 // 动态添加视图
 int size = adapter.getCount();
 for (int i = 0; i < size; i++) {
  addView(adapter.getView(i));
 }
 }

public interface OnItemClickListener {
 void onItemClick(View v, int index);
 }

 public void setOnItemClickListener(final OnItemClickListener listener) {
 if (this.adapter == null)
  return;
 for (int i = 0; i < adapter.getCount(); i++) {
  final int index = i;
  View view = getChildAt(i);
  view.setOnClickListener(new OnClickListener() {
  @Override
  public void onClick(View v) {
   listener.onItemClick(v, index);
  }
  });
 }
 }

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res/com.hx.customgridview"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:background="#303030"
 android:orientation="vertical" >

 <com.hx.customgridview.CustomGridLayout
 android:id="@+id/gridview"
 android:layout_width="200dp"
 android:layout_height="300dp"
 android:background="#1e1d1d"
 app:hSpace="10"
 app:vSpace="10"
 app:numColumns="3"/>
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:gravity="center"
 android:orientation="vertical" >
 <ImageView
 android:id="@+id/iv"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:scaleType="fitXY"/>
</LinearLayout>

protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 grid = (CustomGridLayout) findViewById(R.id.gridview);
 grid.setGridAdapter(new GridAdatper() {
  @Override
  public View getView(int index) {
  View view = getLayoutInflater().inflate(R.layout.grid_item, null);
  ImageView iv = (ImageView) view.findViewById(R.id.iv);
  iv.setImageResource(srcs[index]);
  return view;
  }

  @Override
  public int getCount() {
  return srcs.length;
  }
 });
 grid.setOnItemClickListener(new OnItemClickListener() {
  @Override
  public void onItemClick(View v, int index) {
  Toast.makeText(MainActivity.this, "item="+index, Toast.LENGTH_SHORT).show();
  }
 });
 }
}

<com.hx.customgridview.CustomGridLayout
  android:id="@+id/gridview"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content"
  android:background="#1e1d1d"
  app:hSpace="10"
  app:vSpace="10"
  app:numColumns="3"/>

<com.hx.customgridview.CustomGridLayout
  android:id="@+id/gridview"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:background="#1e1d1d"
  app:hSpace="10"
  app:vSpace="10"
  app:numColumns="3"/>

<com.hx.customgridview.CustomGridLayout
  android:id="@+id/gridview"
  android:layout_width="wrap_content"  

  android:layout_height="wrap_content"
  android:background="#1e1d1d"
  app:hSpace="10"
  app:vSpace="10"
  app:numColumns="4"/>