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曾经仅仅是简单的重写个BaseAdapter，将getView方法保持抽象。而ViewHolder没有抽象过。
。。
ViewHolder (用了一个集合+泛型管理存取view)
public class StoneViewHolder {
private int mPosition;
private View mConvertView;
private SparseArray mViews; //管理listView-item中的view
public StoneViewHolder(Context context, int layoutId, int position, ViewGroup parent) {
this.mPosition = position;
this.mConvertView = LayoutInflater.from(context).inflate(layoutId, parent, false);
this.mConvertView.setTag(this);
this.mViews = new SparseArray();
}
public View getConvertView() {
return mConvertView;
}
public static StoneViewHolder getInstance(Context context, int layoutId, int position, View
convertView, ViewGroup parent) {
if (convertView == null) {
return new StoneViewHolder(context, layoutId, position, parent);
} else {
StoneViewHolder holder = (StoneViewHolder) convertView.getTag();
holder.mPosition = position; //更新复用的convertView中 position
return holder;
}
}
public T getView(int viewId) {
View view = mViews.get(viewId);
if (view == null) {
view = mConvertView.findViewById(viewId);
mViews.put(viewId, view);
}
return (T) view;
}
public void setTag(int viewId, T tag) {
getView(viewId).setTag(tag);
}
public T getTag(int viewId) {
return (T) getView(viewId).getTag();
}
public StoneViewHolder setText(int viewId, String text) {
((TextView)getView(viewId)).setText(text);
return this;
}
public StoneViewHolder setText(int viewId, int resId) {//R.string.
((TextView)getView(viewId)).setText(resId);
return this;
}
public StoneViewHolder setImageBitmap(int viewId, Bitmap bitmap) {
((ImageView)getView(viewId)).setImageBitmap(bitmap);
return this;
}
public StoneViewHolder setImageResource(int viewId, int resId) {
((ImageView)getView(viewId)).setImageResource(resId);
return this;
}
}
Adapter
public abstract class StoneListAdapter extends BaseAdapter {
private List mData;
private Context mContext;
private int mLayoutID;
public StoneListAdapter(Context context, int layoutID, List data) {
this.mContext = context;
this.mLayoutID = layoutID;
this.mData = data == null ? new ArrayList() : data;
}
@Override
public int getCount() {
return mData.size();
}
@Override
public T getItem(int position) {
return mData.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
StoneViewHolder holder = StoneViewHolder.getInstance(mContext, mLayoutID, position,
convertView, parent);
getView(mContext, holder, position);
return holder.getConvertView();
}
protected abstract void getView(Context context, StoneViewHolder holder, int position);
}
在ListViewActivity中使用
stoneBaseAdapter = new StoneListAdapter(ListViewActivity.this, R.layout.activity_listview_item, mData) {
@Override
protected void getView(Context context, final StoneViewHolder holder, final int position) {
User user = getItem(position);
holder.setText(R.id.tv_id, user.getId()).setText(R.id.tv_name, user.getName())
.setText(R.id.tv_age, user.getAge() + "");
holder.getView(R.id.btn_test).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
}
});
}
};
关于Adapter中View抢焦点：
假设 listView.setOnItemClickListener(listener)； 且item中的 button.setOnClickListener(listener);
无论怎么点击，button会一直被触发...
仅仅须要在item的root-layout中 加入 一个属性： android:descendantFocusability="blocksDescendants"
关于item-view复用后。显示混乱：
有时条目过多，滑动到下一屏数据时。有些view复用后，view的状态(比方CheckBox的选种状态。ImageView的图片反复出现)会变乱。
一般处理呢。须要有一个机制，来管理一种相应关系： 当前position相应哪种状态
比方说checkBox选中状态混乱：
class MyAdapter extends StoneListAdapter {
private SparseBooleanArray mCheckStateArray;
public MyAdapter(Context context, int layoutID, List data) {
super(context, layoutID, data);
this.mCheckStateArray = new SparseBooleanArray();
}
public void setChecked(int position, boolean isChecked) {
mCheckStateArray.put(position, isChecked);
}
public boolean isChecked(int position) {
return mCheckStateArray.get(position);
}
@Override
protected void getView(Context context, final StoneViewHolder holder, final int position) {
CheckBox cb = holder.getView(R.id.cb_check);
cb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked) {
setChecked(position, isChecked);//记录状态。防缓存显示
}
});
cb.setChecked(isChecked(position));
}
}
关于SparseArray
SparseArray 内部实现是Array数组。当长度不够时，会调用System.arrayCopy
内部有 keys和values两个数组。
put(key, value); 二分法查找key应该存放的位置 由于key是Integer类型
put、get时 两个数组都是操作的同一个位置上的数据
SparseArray 用于替代形如 HashMap
SparseBooleanArray 用于替代形如 HashMap
SparseIntArray 用于替代形如 HashMap
SparseLongArray 用于替代形如 HashMap
support.v4.util.SparseArrayCompat 提供了v4包相应平台的 SparseArray实现