我已经建立了一个带有TextView覆盖层的ImageViews网格。我的ImageAdapter代码如下:
public View getView(int position, View convertView, ViewGroup parent) {
ImageView imageView;
View grid;
LayoutInflater inflater = (LayoutInflater) mContext
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (convertView == null) {
grid = new View(mContext);
grid = inflater.inflate(R.layout.image, null);
TextView textView = (TextView)grid.findViewById(R.id.mastery_text);
imageView = (ImageView)grid.findViewById(R.id.mastery_image);
grid.setLayoutParams(new GridView.LayoutParams(150, 150));
imageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
grid.setPadding(8, 8, 8, 8);
grid.setBackgroundResource(R.color.orange);
imageView.setImageResource(mThumbIds[position]);
} else {
grid = (View) convertView;
}
return grid;
}
我的ImageAdapter的相应XML布局是这样的:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/layout_practitioner"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<ImageView
android:id="@+id/mastery_image"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scaleType="centerCrop"
/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_gravity="bottom"
android:background="#bbffffff"
android:focusable="false"
android:focusableInTouchMode="false" >
<TextView android:id="@+id/mastery_text"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="0dp"
android:textColor="@color/black"
android:gravity="bottom|center"
android:textSize="12sp"
android:textAllCaps="true"
android:paddingBottom="0dp"
android:text="3/3"
/>
</LinearLayout>
</FrameLayout>
我的GridView的XML代码(活动类):
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<GridView xmlns:android="http://schemas.android.com/apk/res/android"
android:paddingTop="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:id="@+id/gridview"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:numColumns="4"
android:verticalSpacing="10dp"
android:horizontalSpacing="10dp"
android:stretchMode="columnWidth"
android:gravity="center" />
</LinearLayout>
这是我主要活动的onCreate方法:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_masteries);
GridView gridview = (GridView) findViewById(R.id.gridview);
ImageAdapter adapter = new ImageAdapter(this);
gridview.setAdapter(adapter);
gridview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View v,
int position, long id) {
Toast.makeText(Masteries.this, "" + position,
Toast.LENGTH_SHORT).show();
}
});
}
我想在使用图像初始化网格后,根据我的活动类更改ImageViews之一,并考虑其在网格上的位置。我该怎么做?
我不是要更改图像以响应onItemClick。
提前致谢!
编辑:
我正在考虑在我的适配器中创建一个
changeImage(int position, int imageId)
方法,并从我的活动类中调用它。那是正确的方法吗? 最佳答案
在您的适配器中:
public void updateImage(int position, int resourceId)
{
mThumbIds[position] = resourceId;
notifyDataSetChanged();
}
在您的活动中:
mAdapter.updateImage(<position>, <image_resource_id>);
笔记
您将必须使适配器成为您活动的成员
主要思想是您修改后备数据并通知
GridView
这已更改,是时候重新绘制了您的
getView()
方法实现需要大量改进。一旦系统开始回收视图,它将引起很多错误(convertView
参数的值等于上次使用的位置!= null)这是您的getView()外观的草图:
@Override
public View getView(int position, View convertView, ViewGroup parent)
{
ViewHolder viewHolder;
LayoutInflater inflater = (LayoutInflater)mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
if (convertView == null) {
convertView = inflater.inflate(R.layout.image, parent, false);
// next three lines would not be necessary if:
// a) it is the same for every item;
// b) you inflate properly (using the parent);
// c) you specify this in the item's xml (R.layout.image)
convertView.setLayoutParams(new GridView.LayoutParams(150, 150));
convertView.setPadding(8, 8, 8, 8);
convertView.setBackgroundResource(android.R.color.holo_red_light);
viewHolder = new ViewHolder();
viewHolder.mTextView = (TextView)convertView.findViewById(R.id.mastery_text);
viewHolder.mImageView = (ImageView)convertView.findViewById(R.id.mastery_image);
// this could also be set in xml perhaps
viewHolder.mImageView.setScaleType(ImageView.ScaleType.CENTER_CROP);
convertView.setTag(viewHolder);
} else {
viewHolder = (ViewHolder)convertView.getTag();
}
// update the values every time we are being asked to update the item,
// because the item might have been reused from a different position
viewHolder.mImageView.setImageResource(mThumbIds[position]);
//viewHolder.mTextView.setText("myText");
return convertView;
}
public static class ViewHolder
{
TextView mTextView;
ImageView mImageView;
}