一个item有选中效果的Gridview

不难，所以不废话，直接上代码

/**
 * 点击item背景的gridView
 * 至于为什么前缀为radio，因为这是单选的，你也可以改为多选的，原理一样，有空我再写
 * Created by payne.
 */
public class RadioGridView extends GridView implements AdapterView.OnItemClickListener {
  private int currentPosition = 0;
  private OnRadioItemClickListener mListener;
  private int mBgImageSelected;
  private int mBgImageUnselected;

  public RadioGridView(Context context, AttributeSet attrs) {
    super(context, attrs);
    initView(context, attrs);
  }
//可以在xml文件直接设置item背景，是不是很方便
  private void initView(Context context, AttributeSet attrs) {
    TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.RadioGridView);
    mBgImageSelected = typedArray.getResourceId(R.styleable.RadioGridView_item_selected,
        R.drawable.item_selected);
    mBgImageUnselected = typedArray.getResourceId(R.styleable.RadioGridView_item_unselected,
        R.drawable.item_unselected);
    typedArray.recycle();
    setOnItemClickListener(this);
  }

  @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
//一个很小的逻辑，刚开始用的for循环，感觉太low了，改为这种
    int lastPosition = currentPosition;
    currentPosition = position;
    parent.getChildAt(lastPosition).setBackgroundResource(mBgImageUnselected);//未被选择时的背景
    view.setBackgroundResource(mBgImageSelected);//被选择是的背景
    if (mListener != null) {  
        mListener.onItemClick(getId(), position);
    }
  }

//设置高度，因为我发现高度变小了，不是正常高度
  @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    int expandSpec = MeasureSpec.makeMeasureSpec(
        Integer.MAX_VALUE >> 2, MeasureSpec.AT_MOST);
    super.onMeasure(widthMeasureSpec, expandSpec);
  }

  /**
   * 设置item点击监听器
   *
   * @param listener item点击监听器
   */
  public void setOnRadioItemClickListener(OnRadioItemClickListener listener) {
    mListener = listener;
  }

  /**
   * item点击监听器
   */
  public interface OnRadioItemClickListener {
    /**
     * @param gridViewId gridView id
     * @param position item 位置
     */
    void onItemClick(int gridViewId, int position);
  }
}

attrs文件

 <declare-styleable name="RadioGridView">
    <attr format="reference" name="item_selected"/>
    <attr format="reference" name="item_unselected"/>
  </declare-styleable>

背景文件是单纯的白色和紫红色，就不上传了

xml文件中的使用

<?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-auto"
  xmlns:tools="http://schemas.android.com/tools"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:orientation="vertical"
  android:paddingLeft="16dp"
  android:paddingRight="16dp"
  android:paddingTop="20dp">

  <com.payne.demo.RadioGridView
    android:id="@+id/rgv"
    android:background="#ffffff"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:numColumns="3"
    app:item_selected="@drawable/item_selected"
    app:item_unselected="@drawable/item_unselected"
    tools:listitem="@layout/view_device_version_item"/>
</LinearLayout>

效果