我正在尝试制作一个带有选项的 GridView 来选择一项。必须预先选择 GridView 中的第一项。我找到了一种方法,它可以工作*,但我认为有一种更有效的方法可以做到这一点。
- 如果有人想制作具有相同目的的 GridView 或 ListView,此代码可以帮助您。有用。
我的代码:
来自 ImageAdapter 的 getView():
public View getView(final int position, View convertView, ViewGroup parent) {
final ImageView imageView;
if (convertView == null) { // if it's not recycled, initialize some attributes
imageView = new ImageView(mContext);
imageView.setLayoutParams(new GridView.LayoutParams(85, 85));
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
imageView.setPadding(8, 8, 8, 8);
} else {
imageView = (ImageView) convertView;
}
// Sets the background for the first item (that should be pre-selected.
if(position == 0) imageView.setBackgroundResource(Color.GRAY);
imageView.setImageResource(mThumbIds[position]);
return imageView;
}
活动:
final GridView gridview = (GridView) view.findViewById(R.id.gridView);
gridview.setAdapter(new ImageAdapter(MainActivity.this));
gridview.setSelection(0);
gridview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
View previous = null; // The previous selected item
boolean flag = true;
@Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
if(flag) {
/*
* Checks if there is no selected item.
* If true (=until now nothing has been selected)
* it will set the first item as the "previously" selected one.
*/
previous = gridview.getChildAt(0);
flag = false;
}
if(previous != view) {
/*
* Checks if the current selected item has been already selected or no.
* If true (=new item selected) it will change
* the background of the new selected item.
*/
view.setBackgroundResource(Color.GRAY);
if(previous != view) previous.setBackgroundResource(0);
previous = view; // Sets the "new" selected item as the previous one.
}
}
});
XML 文件:
<GridView
android:id="@+id/gridView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="16dp"
android:gravity="center"
android:numColumns="4" >
</GridView>
我试图使它易于理解,我希望你能理解我所做的正确。
如果您对更有效的方法有建议,我会很高兴听到。
谢谢!