notifyDataSetInvalidated()…

本文详细解析了Android中notifyDataSetChanged()和notifyDataSetInvalidated()两个方法的区别,前者用于强制刷新所有Item,后者则用于在数据集监控改变时触发事件,帮助开发者更好地理解适配器更新机制。

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notifyDataSetChanged方法通过一个外部的方法控制如果适配器的内容改变时需要强制调用getView来刷新每个Item的内容。

public void notifyDataSetChanged ()

该方法内部实现了在每个观察者上面调用onChanged事件。每当发现数据集有改变的情况,或者读取到数据的新状态时,就会调用此方法。

public void notifyDataSetInvalidated ()

该方法内部实现了在每个观察者上面调用onInvalidated事件。每当发现数据集监控有改变的情况,比如该数据集不再有效,就会调用此方法。

 

notifyDataSetInvalidated(),会重绘控件(还原到初始状态)
notifyDataSetChanged(),重绘当前可见区域

// 优化后的 FilterableAdapter 类 public static abstract class FilterableAdapter<T> extends ArrayAdapter<T> implements Filterable { private static final String TAG = "FilterableAdapter"; private final LayoutInflater inflater; private List<T> originalList; private List<T> filteredList; private final ItemFilter filter = new ItemFilter(); public FilterableAdapter(Context context, int resource, List<T> objects) { super(context, resource, objects); this.inflater = LayoutInflater.from(context); this.originalList = new ArrayList<>(objects); this.filteredList = new ArrayList<>(objects); } @Override public int getCount() { return filteredList.size(); } @Override public T getItem(int position) { return filteredList.get(position); } // 核心优化:统一的格式化方法 protected abstract String formatItemText(T item); @NonNull @Override public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) { if (convertView == null) { convertView = inflater.inflate(android.R.layout.simple_dropdown_item_1line, parent, false); } TextView textView = convertView.findViewById(android.R.id.text1); T item = getItem(position); textView.setText(item != null ? formatItemText(item) : ""); return convertView; } @Override public View getDropDownView(int position, @Nullable View convertView, @NonNull ViewGroup parent) { if (convertView == null) { convertView = inflater.inflate(android.R.layout.simple_dropdown_item_1line, parent, false); } TextView textView = convertView.findViewById(android.R.id.text1); T item = getItem(position); textView.setText(item != null ? formatItemText(item) : ""); return convertView; } public void updateList(List<T> newList) { this.originalList = new ArrayList<>(newList); this.filteredList = new ArrayList<>(newList); notifyDataSetChanged(); } @Override public Filter getFilter() { return filter; } private class ItemFilter extends Filter { @Override protected FilterResults performFiltering(CharSequence constraint) { FilterResults results = new FilterResults(); List<T> filtered = new ArrayList<>(); if (constraint == null || constraint.length() == 0) { filtered.addAll(originalList); } else { String filterPattern = constraint.toString().toLowerCase().trim(); for (T item : originalList) { if (formatItemText(item).toLowerCase().contains(filterPattern)) { filtered.add(item); } } } results.values = filtered; results.count = filtered.size(); return results; } @Override @SuppressWarnings("unchecked") protected void publishResults(CharSequence constraint, FilterResults results) { filteredList = (List<T>) results.values; if (results.count > 0 || constraint == null || constraint.length() == 0) { notifyDataSetChanged(); } else { notifyDataSetInvalidated(); } } } } 选择之后显示的还是内存地址
最新发布
07-01
package com.example.kucun2.function; import android.content.Context; import android.util.Log; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.ArrayAdapter; import android.widget.Filter; import android.widget.Filterable; import android.widget.Spinner; import android.widget.TextView; import androidx.annotation.NonNull; import androidx.annotation.Nullable; import com.example.kucun2.entity.Bancai; import com.example.kucun2.entity.Caizhi; import com.example.kucun2.entity.Chanpin; import com.example.kucun2.entity.Dingdan; import com.example.kucun2.entity.Mupi; import com.example.kucun2.entity.Zujian; import java.util.ArrayList; import java.util.List; public class Adapter { // 安全适配器基类,处理公共逻辑 // 安全适配器基类,处理公共逻辑 private static abstract class SafeSpinnerAdapter<T> extends ArrayAdapter<T> { private static final String TAG = "SafeSpinnerAdapter"; private final LayoutInflater inflater; private final String defaultText; public SafeSpinnerAdapter(Context context, int resource, List<T> objects, String defaultText) { super(context, resource, objects); this.inflater = LayoutInflater.from(context); this.defaultText = defaultText != null ? defaultText : "请选择"; } @Override public int getCount() { return super.getCount() + 1; // 增加一个默认项 } @Override public T getItem(int position) { return position == 0 ? null : super.getItem(position - 1); } @Override public View getDropDownView(int position, @Nullable View convertView, @NonNull ViewGroup parent) { if (parent == null) { Log.w(TAG, "Parent is null in getDropDownView"); return new TextView(getContext()); } if (convertView == null) { convertView = inflater.inflate(android.R.layout.simple_spinner_dropdown_item, parent, false); } TextView textView = convertView.findViewById(android.R.id.text1); if (position == 0) { textView.setText(defaultText); } else { T item = getItem(position); textView.setText(item != null ? formatDropdownText(item) : ""); } return convertView; } @NonNull @Override public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) { if (parent == null) { Log.w(TAG, "Parent is null in getView"); return new TextView(getContext()); } if (convertView == null) { convertView = inflater.inflate(android.R.layout.simple_spinner_item, parent, false); } TextView textView = convertView.findViewById(android.R.id.text1); if (position == 0) { textView.setText(defaultText); } else { T item = getItem(position); textView.setText(item != null ? formatDisplayText(item) : ""); } return convertView; } protected abstract String formatDisplayText(T item); protected abstract String formatDropdownText(T item); } // 1. 材质适配器 public static ArrayAdapter<Caizhi> setupCaizhiSpinner(Spinner spinner, List<Caizhi> data, Context context) { ArrayAdapter<Caizhi> adapter = new SafeSpinnerAdapter<Caizhi>( context, android.R.layout.simple_spinner_item, data, "请选择材质" ) { @Override protected String formatDisplayText(Caizhi item) { return item != null ? item.getName() : ""; } @Override protected String formatDropdownText(Caizhi item) { return item != null ? item.getName() : ""; } }; adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); spinner.setAdapter(adapter); spinner.setSelection(0); // 默认选中"请选择" return adapter; } // 2. 木皮适配器 public static void setupMupiSpinner(Spinner spinner, List<Mupi> data, Context context) { ArrayAdapter<Mupi> adapter = new SafeSpinnerAdapter<Mupi>( context, android.R.layout.simple_spinner_item, data, "请选择木皮" ) { @Override protected String formatDisplayText(Mupi item) { return item != null ? item.formatMupiDisplay() : ""; } @Override protected String formatDropdownText(Mupi item) { return item != null ? item.formatMupiDisplay() : ""; } }; adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); spinner.setAdapter(adapter); spinner.setSelection(0); // 默认选中"请选择" } // 3. 板材适配器 public static void setupBancaiSpinners(Spinner spinner, List<Bancai> data, Context context) { ArrayAdapter<Bancai> adapter = new SafeSpinnerAdapter<Bancai>( context, android.R.layout.simple_spinner_item, data, "请选择板材" ) { @Override protected String formatDisplayText(Bancai item) { return item != null ? item.TableText() : ""; } @Override protected String formatDropdownText(Bancai item) { return item != null ? item.TableText() : ""; } }; adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); spinner.setAdapter(adapter); spinner.setSelection(0); // 默认选中"请选择" } // 4. 订单适配器 public static void setupDingdanSpinner(Spinner spinner, List<Dingdan> data, Context context) { ArrayAdapter<Dingdan> adapter = new SafeSpinnerAdapter<Dingdan>( context, android.R.layout.simple_spinner_item, data, "请选择订单" ) { @Override protected String formatDisplayText(Dingdan item) { return item != null ? item.getNumber() : ""; } @Override protected String formatDropdownText(Dingdan item) { return item != null ? item.getNumber() : ""; } }; adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); spinner.setAdapter(adapter); spinner.setSelection(0); // 默认选中"请选择" } // 5. 产品适配器 public static void setupChanpinSpinner(Spinner spinner, List<Chanpin> data, Context context) { ArrayAdapter<Chanpin> adapter = new SafeSpinnerAdapter<Chanpin>( context, android.R.layout.simple_spinner_item, data, "请选择产品" ) { @Override protected String formatDisplayText(Chanpin item) { return item != null ? item.getBianhao() : ""; } @Override protected String formatDropdownText(Chanpin item) { return item != null ? item.getBianhao() : ""; } }; adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); spinner.setAdapter(adapter); spinner.setSelection(0); // 默认选中"请选择" } // 6. 组件适配器 public static void setupZujianSpinner(Spinner spinner, List<Zujian> data, Context context) { ArrayAdapter<Zujian> adapter = new SafeSpinnerAdapter<Zujian>( context, android.R.layout.simple_spinner_item, data, "请选择组件" ) { @Override protected String formatDisplayText(Zujian item) { return item != null ? item.getName() : ""; } @Override protected String formatDropdownText(Zujian item) { return item != null ? item.getName() : ""; } }; adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item); spinner.setAdapter(adapter); spinner.setSelection(0); // 默认选中"请选择" } // 1. 新增支持筛选的适配器基类 /** * 新增支持筛选的适配器基类 * @param <T> */ public static abstract class FilterableAdapter<T> extends ArrayAdapter<T> implements Filterable { private static final String TAG = "FilterableAdapter"; private final LayoutInflater inflater; private List<T> originalList; private List<T> filteredList; private final String defaultText; private final ItemFilter filter = new ItemFilter(); public FilterableAdapter(Context context, int resource, List<T> objects, String defaultText) { super(context, resource, objects); this.inflater = LayoutInflater.from(context); this.originalList = new ArrayList<>(objects); this.filteredList = new ArrayList<>(objects); this.defaultText = defaultText != null ? defaultText : "请选择"; } public FilterableAdapter(Context context, int resource, List<T> objects) { super(context, resource, objects); this.inflater = LayoutInflater.from(context); this.originalList = new ArrayList<>(objects); this.filteredList = new ArrayList<>(objects); this.defaultText = "请选择"; } @Override public int getCount() { return filteredList.size() + 1; // 增加默认项 } @Override public T getItem(int position) { return position == 0 ? null : filteredList.get(position - 1); // 位置偏移处理 } @NonNull @Override public View getView(int position, @Nullable View convertView, @NonNull ViewGroup parent) { if (convertView == null) { convertView = inflater.inflate(android.R.layout.simple_spinner_item, parent, false); } TextView textView = convertView.findViewById(android.R.id.text1); if (position == 0) { textView.setText(defaultText); // 默认提示文本 } else { T item = getItem(position); textView.setText(item != null ? formatDisplayText(item) : ""); } return convertView; } @Override public View getDropDownView(int position, @Nullable View convertView, @NonNull ViewGroup parent) { if (convertView == null) { convertView = inflater.inflate(android.R.layout.simple_spinner_dropdown_item, parent, false); } TextView textView = convertView.findViewById(android.R.id.text1); if (position == 0) { textView.setText(defaultText); // 下拉框中的默认提示 } else { T item = getItem(position); textView.setText(item != null ? formatDropdownText(item) : ""); } return convertView; } public void updateList(List<T> newList) { this.originalList = new ArrayList<>(newList); this.filteredList = new ArrayList<>(newList); notifyDataSetChanged(); } @Override public Filter getFilter() { return filter; } // 必须实现的抽象方法 protected abstract String formatDisplayText(T item); protected abstract String formatDropdownText(T item); private class ItemFilter extends Filter { @Override protected FilterResults performFiltering(CharSequence constraint) { FilterResults results = new FilterResults(); List<T> filtered = new ArrayList<>(); if (constraint == null || constraint.length() == 0) { // 无筛选条件时包含所有项 filtered.addAll(originalList); } else { String filterPattern = constraint.toString().toLowerCase().trim(); for (T item : originalList) { if (formatDisplayText(item).toLowerCase().contains(filterPattern)) { filtered.add(item); } } } results.values = filtered; results.count = filtered.size(); return results; } @Override @SuppressWarnings("unchecked") protected void publishResults(CharSequence constraint, FilterResults results) { filteredList = (List<T>) results.values; if (results.count > 0 || constraint == null || constraint.length() == 0) { notifyDataSetChanged(); } else { notifyDataSetInvalidated(); } } } } // /** * 为订单创建筛选适配器 * @param context * @param data * @return */ public static FilterableAdapter<Dingdan> createDingdanFilterableAdapter( Context context, List<Dingdan> data) { return new FilterableAdapter<Dingdan>(context, android.R.layout.simple_spinner_item, data) { @Override protected String formatDisplayText(Dingdan item) { return item != null ? item.getNumber() : ""; } @Override protected String formatDropdownText(Dingdan item) { return item != null ? item.getNumber() : ""; } }; } // 为产品创建筛选适配器 public static FilterableAdapter<Chanpin> createChanpinFilterableAdapter( Context context, List<Chanpin> data) { return new FilterableAdapter<Chanpin>(context, android.R.layout.simple_spinner_item, data) { @Override protected String formatDisplayText(Chanpin item) { return item != null ? item.getBianhao() : ""; } @Override protected String formatDropdownText(Chanpin item) { return item != null ? item.getBianhao() : ""; } }; } // 为组件创建筛选适配器 public static FilterableAdapter<Zujian> createZujianFilterableAdapter( Context context, List<Zujian> data) { return new FilterableAdapter<Zujian>(context, android.R.layout.simple_spinner_item, data) { @Override protected String formatDisplayText(Zujian item) { return item != null ? item.getName() : ""; } @Override protected String formatDropdownText(Zujian item) { return item != null ? item.getName() : ""; } }; } // 为板材创建筛选适配器 public static FilterableAdapter<Bancai> createBancaiFilterableAdapter( Context context, List<Bancai> data) { return new FilterableAdapter<Bancai>(context, android.R.layout.simple_spinner_item, data) { @Override protected String formatDisplayText(Bancai item) { return item != null ? item.TableText() : ""; } @Override protected String formatDropdownText(Bancai item) { return item != null ? item.TableText() : ""; } }; } } 在FilterableAdapter中直接输出标准格式文字
07-01
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