Android实现淘宝选中商品尺寸的按钮组实例

话不多说，先上个效果图：

现在我们就来说说里面的一些原理把！

一、原理：

1.其实这里我们用到的是一个ViewGroup控件组，把这些按钮加进去就有这种效果了！不过这里要继承ViewGroup（命名为：GoodsViewGroup）重写里面的一些方法。

2.主要的方法有：

GoodsViewGroup按钮组的控件大小

protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)

里面的按钮每个的位置坐标

protected void onLayout(boolean changed, int l, int t, int r, int b) 

这两个方法的具体使用大家可以网上查阅资料，这里就不多说了！

二、代码：

/**
 * Created by ShaoLin on 2016/8/22.
 * 这里是类似淘宝中商品尺寸按钮组（这里做了支持button,textview）
 */
public class GoodsViewGroup<X extends TextView> extends ViewGroup {

 public static final String BTN_MODE = "BTNMODE"; //按钮模式
 public static final String TEV_MODE = "TEVMODE"; //文本模式

 private static final String TAG = "IViewGroup";
 private final int HorInterval = 10; //水平间隔
 private final int VerInterval = 10; //垂直间隔

 private int viewWidth; //控件的宽度
 private int viewHeight; //控件的高度

 private ArrayList<String> mTexts = new ArrayList<>();
 private Context mContext;
 private int textModePadding = 15;

 //正常样式
 private float itemTextSize = 18;
 private int itemBGResNor = R.drawable.goods_item_btn_normal;
 private int itemTextColorNor = Color.parseColor("#000000");

 //选中的样式
 private int itemBGResPre = R.drawable.goods_item_btn_selected;
 private int itemTextColorPre = Color.parseColor("#ffffff");

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

 public GoodsViewGroup(Context context, AttributeSet attrs) {
  super(context, attrs);
  mContext = context;
 }

 /**
  * 计算控件的大小
  */
 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  super.onMeasure(widthMeasureSpec, heightMeasureSpec);
  viewWidth = measureWidth(widthMeasureSpec);
  viewHeight = measureHeight(heightMeasureSpec);
  Log.e(TAG, "onMeasure:" + viewWidth + ":" + viewHeight);
  // 计算自定义的ViewGroup中所有子控件的大小
  measureChildren(widthMeasureSpec, heightMeasureSpec);
  // 设置自定义的控件MyViewGroup的大小
  setMeasuredDimension(viewWidth, getViewHeight());
 }


 private int measureWidth(int pWidthMeasureSpec) {
  int result = 0;
  int widthMode = MeasureSpec.getMode(pWidthMeasureSpec);
  int widthSize = MeasureSpec.getSize(pWidthMeasureSpec);
  switch (widthMode) {
   /**
    * mode共有三种情况，取值分别为MeasureSpec.UNSPECIFIED, MeasureSpec.EXACTLY,
    * MeasureSpec.AT_MOST。
    *
    *
    * MeasureSpec.EXACTLY是精确尺寸，
    * 当我们将控件的layout_width或layout_height指定为具体数值时如andorid
    * :layout_width="50dip"，或者为FILL_PARENT是，都是控件大小已经确定的情况，都是精确尺寸。
    *
    *
    * MeasureSpec.AT_MOST是最大尺寸，
    * 当控件的layout_width或layout_height指定为WRAP_CONTENT时
    * ，控件大小一般随着控件的子空间或内容进行变化，此时控件尺寸只要不超过父控件允许的最大尺寸即可
    * 。因此，此时的mode是AT_MOST，size给出了父控件允许的最大尺寸。
    *
    *
    * MeasureSpec.UNSPECIFIED是未指定尺寸，这种情况不多，一般都是父控件是AdapterView，
    * 通过measure方法传入的模式。
    */
   case MeasureSpec.AT_MOST:
   case MeasureSpec.EXACTLY:
    result = widthSize;
    break;
  }
  return result;
 }

 private int measureHeight(int pHeightMeasureSpec) {
  int result = 0;
  int heightMode = MeasureSpec.getMode(pHeightMeasureSpec);
  int heightSize = MeasureSpec.getSize(pHeightMeasureSpec);
  switch (heightMode) {
   case MeasureSpec.UNSPECIFIED:
    result = getSuggestedMinimumHeight();
    break;
   case MeasureSpec.AT_MOST:
   case MeasureSpec.EXACTLY:
    result = heightSize;
    break;
  }
  return result;
 }

 /**
  * 覆写onLayout，其目的是为了指定视图的显示位置，方法执行的前后顺序是在onMeasure之后，因为视图肯定是只有知道大小的情况下，
  * 才能确定怎么摆放
  */
 @Override
 protected void onLayout(boolean changed, int l, int t, int r, int b) {
  // 遍历所有子视图
  int posLeft = HorInterval;
  int posTop = VerInterval;
  int posRight;
  int posBottom;
  for (int i = 0; i < getChildCount(); i++) {
   View childView = getChildAt(i);
   // 获取在onMeasure中计算的视图尺寸
   int measureHeight = childView.getMeasuredHeight();
   int measuredWidth = childView.getMeasuredWidth();
   if (posLeft + getNextHorLastPos(i) > viewWidth) {
    posLeft = HorInterval;
    posTop += (measureHeight + VerInterval);
   }
   posRight = posLeft + measuredWidth;
   posBottom = posTop + measureHeight;
   childView.layout(posLeft, posTop, posRight, posBottom);
   posLeft += (measuredWidth + HorInterval);
  }
 }

 //获取控件的自适应高度
 private int getViewHeight() {
  int viewwidth = HorInterval;
  int viewheight = VerInterval;
  if (getChildCount() > 0) {
   viewheight = getChildAt(0).getMeasuredHeight() + VerInterval;
  }
  for (int i = 0; i < getChildCount(); i++) {
   View childView = getChildAt(i);
   // 获取在onMeasure中计算的视图尺寸
   int measureHeight = childView.getMeasuredHeight();
   int measuredWidth = childView.getMeasuredWidth();
   if (viewwidth + getNextHorLastPos(i) > viewWidth) {
    viewwidth = HorInterval;
    viewheight += (measureHeight + VerInterval);
   } else {
    viewwidth += (measuredWidth + HorInterval);
   }
  }
  return viewheight;
 }

 private int getNextHorLastPos(int i) {
  return getChildAt(i).getMeasuredWidth() + HorInterval;
 }

 private OnGroupItemClickListener onGroupItemClickListener;

 public void setGroupClickListener(OnGroupItemClickListener listener) {
  onGroupItemClickListener = listener;
  for (int i = 0; i < getChildCount(); i++) {
   final X childView = (X) getChildAt(i);
   final int itemPos = i;
   childView.setOnClickListener(new OnClickListener() {
    @Override
    public void onClick(View view) {
     onGroupItemClickListener.onGroupItemClick(itemPos);
     chooseItemStyle(itemPos);
    }
   });
  }
 }

 //选中那个的样式
 public void chooseItemStyle(int pos) {
  clearItemsStyle();
  if (pos < getChildCount()) {
   X childView = (X) getChildAt(pos);
   childView.setBackgroundResource(itemBGResPre);
   childView.setTextColor(itemTextColorPre);
   setItemPadding(childView);
  }
 }

 private void setItemPadding(X view) {
  if (view instanceof Button) {
   view.setPadding(textModePadding, 0, textModePadding, 0);
  } else {
   view.setPadding(textModePadding, textModePadding, textModePadding, textModePadding);
  }
 }

 //清除Group所有的样式
 private void clearItemsStyle() {
  for (int i = 0; i < getChildCount(); i++) {
   X childView = (X) getChildAt(i);
   childView.setBackgroundResource(itemBGResNor);
   childView.setTextColor(itemTextColorNor);
   setItemPadding(childView);
  }
 }

 public void addItemViews(ArrayList<String> texts, String mode) {
  mTexts = texts;
  removeAllViews();
  for (String text : texts) {
   addItemView(text, mode);
  }
 }

 private void addItemView(String text, String mode) {
  X childView = null;
  switch (mode) {
   case BTN_MODE:
    childView = (X) new Button(mContext);
    break;
   case TEV_MODE:
    childView = (X) new TextView(mContext);
    break;
  }
  childView.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT,
    LayoutParams.WRAP_CONTENT));
  childView.setTextSize(itemTextSize);
  childView.setBackgroundResource(itemBGResNor);
  setItemPadding(childView);
  childView.setTextColor(itemTextColorNor);
  childView.setText(text);
  this.addView(childView);
 }

 public String getChooseText(int itemID) {
  if (itemID >= 0) {
   return mTexts.get(itemID);
  }
  return null;
 }

 public void setItemTextSize(float itemTextSize) {
  this.itemTextSize = itemTextSize;
 }

 public void setItemBGResNor(int itemBGResNor) {
  this.itemBGResNor = itemBGResNor;
 }

 public void setItemTextColorNor(int itemTextColorNor) {
  this.itemTextColorNor = itemTextColorNor;
 }

 public void setItemBGResPre(int itemBGResPre) {
  this.itemBGResPre = itemBGResPre;
 }

 public void setItemTextColorPre(int itemTextColorPre) {
  this.itemTextColorPre = itemTextColorPre;
 }

 public interface OnGroupItemClickListener {
  void onGroupItemClick(int item);
 }
}

上面提供了可以设置按钮组的item的一些样式，还有这个GoodsViewGroup为什么要写成GoodsViewGroup<X extends TextView>这样呢？其实这里我是想做一个泛型，可以使用与Button跟TextView，而这里的Button本生就是继承TextView所以在代码中还要进行一个判断，可以看上面方法setItemPadding(X view) 。那到了这里，有些好友可能就会问，为什么要搞两个呢？

其实这里因为TextView的不会自动有设置padding的，而button是有自动设置padding。这个时候你就要看看你是先要那种效果！不过通过我的代码中如果是选择TextView的话，这里也设置了一个padding给他，不然会很难看！

两种模式的写法：

1.Button :

GoodsViewGroup<Button> mGroup;
mGroup.addItemViews(viewtexts, GoodsViewGroup.BTN_MODE);

2.TextView

GoodsViewGroup<TextView> mGroup;
mGroup.addItemViews(viewtexts, GoodsViewGroup.TEV_MODE);

三、Drawable文件：上面涉及到的按钮选中与正常的两个Drawable

1.goods_item_btn_normal.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
 <item>
  <shape>
   <solid android:color="#F5F5F5" />
   <corners android:radius="15.0dip" />
  </shape>
 </item>
</layer-list>

2.goods_item_btn_selected.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
 <item>
  <shape>
   <solid android:color="#FE4F00" />
   <corners android:radius="15.0dip" />
  </shape>
 </item>
</layer-list>

四、例子：

ButtonGroupActivity

/**
 * Created by ShaoLin on 2016/8/22.
 */
public class ButtonGroupActivity extends Activity implements GoodsViewGroup.OnGroupItemClickListener, View.OnClickListener {

 private GoodsViewGroup<TextView> mGroup;
 private Button mSubmitBtn;
 private ArrayList<String> viewtexts = new ArrayList<>();

 private int chooseID = -1;
 private String chooseText;

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  setContentView(R.layout.activity_buttongroup);

  mGroup = (GoodsViewGroup) findViewById(R.id.viewGroup);
  mSubmitBtn = (Button) findViewById(R.id.submitBtn);

  String text;
  for (int i = 0; i < 10; i++) {
   text = "L" + i;
   viewtexts.add(text);
  }
  mGroup.addItemViews(viewtexts, GoodsViewGroup.TEV_MODE);
  mGroup.setGroupClickListener(this);
  mSubmitBtn.setOnClickListener(this);
  super.onCreate(savedInstanceState);
 }

 @Override
 public void onGroupItemClick(int item) {
  chooseID = item;
  chooseText = mGroup.getChooseText(item);
 }

 @Override
 public void onClick(View view) {
  if (chooseID >= 0) {
   showToast("ID:" + chooseID + ";text:" + chooseText);
  } else {
   showToast("请选择");
  }
 }

 private void showToast(String text) {
  Toast.makeText(ButtonGroupActivity.this, text, Toast.LENGTH_SHORT).show();
 }
}

activity_buttongroup.xml

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

 <com.example.jisuanqi.GoodsViewGroup
  android:id="@+id/viewGroup"
  android:layout_width="match_parent"
  android:layout_height="wrap_content">
 </com.example.jisuanqi.GoodsViewGroup>

 <Button
  android:id="@+id/submitBtn"
  android:text="确定"
  android:layout_width="match_parent"
  android:layout_height="wrap_content" />

</LinearLayout>

总结

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