item.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:id="@+id/textView"
android:layout_width="match_parent"
android:layout_height="48dp"
android:gravity="center"
android:text="万能适配器测试"
android:textSize="18sp" />
</LinearLayout>
listview加载数据
private void commonAdapterTest() {
ListView listView = (ListView) findViewById(R.id.listview);
List<String> datas = new ArrayList<>();
for (int i = 0; i < 18; i++) {
datas.add("万能适配器测试" + i);
}
listView.setAdapter(new CommonAdapter<String>(this, datas, R.layout.item) {
@Override
protected void convertView(View item, String s) {
TextView textView = CommonViewHolder.get(item, R.id.textView);
textView.setText(s);
}
});
}
两个工具类优化listview
public abstract class CommonAdapter<T> extends BaseAdapter {
private Context context;
private List<T> datas;
private int layoutId;
public CommonAdapter(Context context, List<T> datas, int layoutId) {
this.context = context;
this.datas = datas;
this.layoutId = layoutId;
}
@Override
public int getCount() {
return datas == null ? 0 : datas.size();
}
@Override
public T getItem(int position) {
return datas.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
if (convertView == null) {
Log.d("listview", "---------LayoutInflater()-----------" + position);
convertView = LayoutInflater.from(context).inflate(layoutId, null);
}else{
}
// Log.d("listview", "---------getView()-----------" + position);
T t = getItem(position);
convertView(convertView, t);
return convertView;
}
/**
* 局部更新数据,调用一次getView()方法;Google推荐的做法
*
* @param listView 要更新的listview
* @param position 要更新的位置
*/
public void notifyDataSetChanged(ListView listView, int position) {
/**第一个可见的位置**/
int firstVisiblePosition = listView.getFirstVisiblePosition();
/**最后一个可见的位置**/
int lastVisiblePosition = listView.getLastVisiblePosition();
/**在看见范围内才更新,不可见的滑动后自动会调用getView方法更新**/
if (position >= firstVisiblePosition && position <= lastVisiblePosition) {
/**获取指定位置view对象**/
View view = listView.getChildAt(position - firstVisiblePosition);
getView(position, view, listView);
}
}
/**
* 需要去实现的对item中的view的设置操作
*
* @param item
* @param t
*/
protected abstract void convertView(View item, T t);
}
2222222222222222222222222222
public class CommonViewHolder {
/**
* @param view 所有缓存View的根View
* @param id 缓存View的唯一标识
* @return
*/
public static <T extends View> T get(View view, int id) {
SparseArray<View> viewHolder = (SparseArray<View>) view.getTag();
//如果根view没有用来缓存View的集合
if (viewHolder == null) {
viewHolder = new SparseArray<View>();
view.setTag(viewHolder);//创建集合和根View关联
}
View chidlView = viewHolder.get(id);//获取根View储存在集合中的孩纸
if (chidlView == null) {//如果没有改孩纸
//找到该孩纸
chidlView = view.findViewById(id);
viewHolder.put(id, chidlView);//保存到集合
}
return (T) chidlView;
}
}
2、BaseAdapter使用
public class SampleAdapter extends BaseAdapter {
private List<AreaEntity> mDataSet;
private Context context;
public SampleAdapter(Context context, List<AreaEntity> dataSet) {
this.mDataSet = dataSet;
this.context = context;
}
@Override
public int getCount() {
return mDataSet.size();
}
@Override
public Object getItem(int position) {
return position;
}
@Override
public long getItemId(int position) {
return position;
}
// 删除 打勾 全选
public void cleckAll(int is_checked) { //全选 删除多少那里要删除全部
for (int a = 0; a < mDataSet.size(); a++) {
if (is_checked == a) {
mDataSet.get(a).setIfsecect(true);
} else {
mDataSet.get(a).setIfsecect(false);
}
}
notifyDataSetChanged();
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
convertView = View.inflate(context, R.layout.item_popup_car, null);
TextView textView = (TextView) convertView.findViewById(R.id.text);
textView.setText(mDataSet.get(position).getName());
if (position == 1) {
textView.setTextColor(context.getResources().getColor(R.color.derder));
}
if (mDataSet.get(position).isIfsecect()) {
textView.setBackgroundColor(context.getResources().getColor(R.color.topbgokc));
} else {
textView.setBackgroundColor(context.getResources().getColor(R.color.xianlanbgc));
}
return convertView;
}
}
3、ArrayAdapter使用
item_view
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="wrap_content" android:orientation="vertical"> <TextView android:id="@+id/tv_items" android:layout_width="wrap_content" android:layout_height="wrap_content" android:padding="20dp" android:textSize="25sp"/> </LinearLayout>
实现
private String[] mTitle = new String[]{"开启蓝牙", "关闭蓝牙", "设备列表", "接收数据", "已配对设备"};
mList.setAdapter(new ArrayAdapter<>(this, R.layout.item_list, R.id.tv_items, mTitle));