Android利用GridView实现单选效果

1.实现如图所示的单选效果

由于Android提供的单选按钮radiobutton只能单行或单列显示，且样式并不美观，故可用GridView进行改造，实现单选效果，而要实现这样的效果重点就在GridView的适配器这块了。

首先是GridView的item的XML：

里边很简单，就只用来放显示选中效果的imageView和文字的textView

接下来是适配器：

public class GridViewRadioAdapter extends baseAdapter {
 private Context mContext;
 private int lastPosition = -1;   //记录上一次选中的图片位置，默认不选中
 private String[] str = null;    //放问题内容文字的数组

 public GridViewRadioAdapter(Context mContext) {
  this.mContext = mContext;
 }

 public void setStr(String[] str){  //在activity中调用此方法传入问题的数组
  this.str = str;
 }

 public void setSelection(int position) { //在activity中GridView的onItemClickListener中调用此方法，来设置选中位置
  lastPosition = position;
 }

 @Override
 public int getCount() {
  return str.length;
 }

 @Override
 public Object getItem(int position) {
  return position;
 }

 @Override
 public long getItemId(int position) {
  return position;
 }

 @Override
 public View getView(int position, View convertView, ViewGroup parent) {
  ViewHolder viewHolder = null;
  if (convertView == null){
   viewHolder = new ViewHolder();
   convertView = LayoutInflater.from(mContext).inflate(R.layout.adapter_gridview_radio_item, null);
   viewHolder.textView = (TextView) convertView.findViewById(R.id.textView);
   viewHolder.imageView = (ImageView) convertView.findViewById(R.id.imageView);
   viewHolder.relativeLayout = (RelativeLayout) convertView.findViewById(R.id.options);
   convertView.setTag(viewHolder);
  }else {
   viewHolder = (ViewHolder) convertView.getTag();
  }
  viewHolder.textView.setText(str[position]);
  if (lastPosition == position){ //判断是否为选中项，选中项与非选中项设置不同的样式
   switch (position){  //选中状态下设置样式
    case 0:
     viewHolder.imageView.setBackgroundResource(R.drawable.option_a_checked);
     break;
    case 1:
     viewHolder.imageView.setBackgroundResource(R.drawable.option_b_checked);
     break;
    case 2:
     viewHolder.imageView.setBackgroundResource(R.drawable.option_c_checked);
     break;
    case 3:
     viewHolder.imageView.setBackgroundResource(R.drawable.option_d_checked);
     break;
   }
   viewHolder.relativeLayout.setBackgroundResource(R.drawable.shape_rect_orange);
  }else {  //非选中状态下设置样式
   switch (position){
    case 0:
     viewHolder.imageView.setBackgroundResource(R.drawable.option_a);
     break;
    case 1:
     viewHolder.imageView.setBackgroundResource(R.drawable.option_b);
     break;
    case 2:
     viewHolder.imageView.setBackgroundResource(R.drawable.option_c);
     break;
    case 3:
     viewHolder.imageView.setBackgroundResource(R.drawable.option_d);
     break;
   }
   viewHolder.relativeLayout.setBackgroundResource(R.drawable.shape_rect_gray);
  }
  return convertView;
 }

 class ViewHolder{
  private TextView textView;
  private ImageView imageView;
  private RelativeLayout relativeLayout;
 }
}

最后在activity中设置适配器：

GridViewRadioAdapter adapter = new GridViewRadioAdapter(mContext);
adapter.setStr(options); //传入问题的选项
mGridView.setAdapter(adapter);
mGridView.setonItemClickListener(new AdapterView.onItemClickListener() {
 @Override
 public void onItemClick(AdapterView arg0, View arg1, int position, long arg3) {
  adapter.setSelection(position); //传值更新
  adapter.notifyDataSetChanged(); //每一次点击通知adapter重新渲染
 }
}); 

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