要保存ImageView布尔值的ListView项列表的状态,您可以使用一个列表来存储每个项的状态,并在每个项的状态更改时更新列表。然后,您可以使用SharedPreferences将此列表保存到设备上,以便在应用程序重新启动时恢复列表的状态。
以下是一个示例代码:
public class MyAdapter extends BaseAdapter {
private List itemStates;
private Context context;
public MyAdapter(Context context, List itemStates) {
this.context = context;
this.itemStates = itemStates;
}
@Override
public int getCount() {
return itemStates.size();
}
@Override
public Object getItem(int position) {
return itemStates.get(position);
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
convertView = LayoutInflater.from(context).inflate(R.layout.list_item, parent, false);
holder = new ViewHolder();
holder.imageView = convertView.findViewById(R.id.imageView);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
// 设置ImageView的可见性根据项的状态
if (itemStates.get(position)) {
holder.imageView.setVisibility(View.VISIBLE);
} else {
holder.imageView.setVisibility(View.GONE);
}
// 添加点击事件来切换项的状态
convertView.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
boolean currentState = itemStates.get(position);
itemStates.set(position, !currentState);
notifyDataSetChanged();
}
});
return convertView;
}
private static class ViewHolder {
ImageView imageView;
}
}
public class MainActivity extends AppCompatActivity {
private List itemStates;
private MyAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ListView listView = findViewById(R.id.listView);
// 初始化itemStates列表
itemStates = new ArrayList<>();
itemStates.add(false);
itemStates.add(false);
// 添加更多项...
// 从SharedPreferences中加载保存的状态
SharedPreferences preferences = getSharedPreferences("MyPrefs", MODE_PRIVATE);
for (int i = 0; i < itemStates.size(); i++) {
boolean state = preferences.getBoolean("state_" + i, false);
itemStates.set(i, state);
}
// 创建适配器并设置给ListView
adapter = new MyAdapter(this, itemStates);
listView.setAdapter(adapter);
}
@Override
protected void onDestroy() {
super.onDestroy();
// 保存状态到SharedPreferences
SharedPreferences.Editor editor = getSharedPreferences("MyPrefs", MODE_PRIVATE).edit();
for (int i = 0; i < itemStates.size(); i++) {
editor.putBoolean("state_" + i, itemStates.get(i));
}
editor.apply();
}
}
在上述代码中,每当用户点击ListView的某个项时,项的状态会在itemStates列表中进行更改,并通过调用adapter.notifyDataSetChanged()来刷新ListView。当Activity被销毁时,状态会保存到SharedPreferences中,并在Activity重新创建时恢复。