我遇到一个问题，我已尝试过几种不同的失败解决方案。
我有一个AutoCompleteTextView，其SimpleCursorAdaptor绑定到我的数据库以提取产品名称。当用户搜索产品时，名称显示正常。当他们点击产品时，会出现NullPointerException并导致应用程序崩溃。有趣的是，它只发生在HTC Devices上。我的三星工作，我的好友摩托罗拉工作，模拟器工作。只是不是HTC。
以下是来自Android Market提交的用户的堆栈跟踪。
java.lang.NullPointerException
at enders.pos.test.PointOfSale$8.onItemClick(PointOfSale.java:571)
at android.widget.AutoCompleteTextView.onCommitCompletion(AutoCompleteTextView.java:921)
at com.android.internal.widget.EditableInputConnection.commitCompletion(EditableInputConnection.java:78)
at com.android.internal.view.IInputConnectionWrapper.executeMessage(IInputConnectionWrapper.java:309)
at com.android.internal.view.IInputConnectionWrapper$MyHandler.handleMessage(IInputConnectionWrapper.java:75)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:130)
at android.app.ActivityThread.main(ActivityThread.java:3835)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:507)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:847)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:605)
at dalvik.system.NativeStart.main(Native Method)
第571行是：
Cursor c = shop.getProdByName(text.getText().toString());
我相信TextView文本返回null。但我不确定为什么。
以下是PointOfsale类的一部分：
final int[] to = new int[] { android.R.id.text1 };
final String[] from = new String[] { "name" };
SimpleCursorAdapter Autoadapter =
new SimpleCursorAdapter(this,
android.R.layout.simple_dropdown_item_1line, null,
from, to);
textView = (AutoCompleteTextView) findViewById(R.id.autoproduct);
textView.setAdapter(Autoadapter);
textView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> listView, View view, int position, long id) {
TextView text = (TextView) view;
Cursor c = shop.getProdByName(text.getText().toString());
if(c != null){
if(c.getColumnIndex("_id") >= 0){
Product product = new Product();
product.setId(c.getInt(c.getColumnIndex("_id")));
product.setBarcode(c.getString(c.getColumnIndex("barcode")));
product.setName(c.getString(c.getColumnIndex("name")));
product.setDesc(c.getString(c.getColumnIndex("desc")));
product.setPrice(c.getFloat(c.getColumnIndex("price")));
product.setCat(c.getInt(c.getColumnIndex("catid")));
cart.AddProduct(product);
c.close();
}else{
alertbox("Not Found", "Product not found");
}
}else{
alertbox("Not Found", "Product not found");
}
textView.setText("");
((ProductAdapter) inventoryList.getAdapter()).notifyDataSetChanged();
}
});
Autoadapter.setCursorToStringConverter(new CursorToStringConverter() {
public String convertToString(android.database.Cursor cursor) {
// Get the label for this row out of the "state" column
final int columnIndex = cursor.getColumnIndexOrThrow("name");
final String str = cursor.getString(columnIndex);
return str;
}
});
// Set the FilterQueryProvider, to run queries for choices
// that match the specified input.
Autoadapter.setFilterQueryProvider(new FilterQueryProvider() {
public Cursor runQuery(CharSequence constraint) {
// Search for states whose names begin with the specified letters.
Cursor cursor = ProductDatabase.helper.fetchItemsByName(
(constraint != null ? constraint.toString() : null));
return cursor;
}
});
答案 0 :(得分：0)
在您收到错误的代码中添加一个日志，看看它是否从HTC设备的Logcat返回一个值。处理该设备的文本视图可能存在差异。请在某个系统中检查它们是否为空。
System.out.println(text,text.getText().toString());
如果它只为HTC设备返回一个null，那么你需要找到一个解决方法，因为你的视图层次结构逻辑是错误的（这里似乎没问题）或HTC设备有一个错误。如果是这样的话很难解决然后好运。
答案 1 :(得分：0)
我找到了解决问题的好方法！我已经摆脱了SimpleCursorAdaptor并实现了我自己的方法。我还确定了几个设备以不同的方式处理UI。所以我实现了一种强力方法来从4种不同的方法中获取数据。如果一个失败，它将继续下一个。但是一种方法应该始终获取数据。这是代码：
Autoadapter = new ArrayAdapter<String>(this,
android.R.layout.simple_dropdown_item_1line);
Autoadapter.setNotifyOnChange(true);
textView = (AutoCompleteTextView) findViewById(R.id.autoproduct);
textView.setAdapter(Autoadapter);
textView.setOnItemClickListener(new OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> listView, View view, int position, long id) {
boolean isAGo = false;
String item = null;
Cursor c = null;
if(listView != null){
item = listView.getItemAtPosition(position).toString();
c = shop.getProdByName(item);
isAGo = true;
}
if(isAGo == false){
if(view != null){
TextView text = (TextView) view;
c = shop.getProdByName(text.getText().toString());
isAGo = true;
}
}
if(isAGo == false){
if(textView.getText() != null){
item = textView.getText().toString();
c = shop.getProdByName(item);
isAGo = true;
}
}
if(isAGo == false){
if(prodList.length > 0){
item = prodList[0];
c = shop.getProdByName(item);
isAGo = true;
}
}
if(c != null){
if(c.getColumnIndex("_id") >= 0){
Product product = new Product();
product.setId(c.getInt(c.getColumnIndex("_id")));
product.setBarcode(c.getString(c.getColumnIndex("barcode")));
product.setName(c.getString(c.getColumnIndex("name")));
product.setDesc(c.getString(c.getColumnIndex("desc")));
product.setPrice(c.getFloat(c.getColumnIndex("price")));
product.setCat(c.getInt(c.getColumnIndex("catid")));
cart.AddProduct(product);
}else{
alertbox("Not Found", "Product not found");
}
}else{
alertbox("Error", "Unable to retrieve product.");
}
textView.setText("");
((ProductAdapter) inventoryList.getAdapter()).notifyDataSetChanged();
}
});
textView.addTextChangedListener(new TextWatcher() {
public void afterTextChanged(Editable s) {}
public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
public void onTextChanged(CharSequence s, int start, int before, int count)
{
prodList = ProductDatabase.helper.fetchItemsByName(s.toString());
if(prodList != null){
Autoadapter.clear();
for (int i = 0; i < prodList.length; i++)
{
Log.v("Items", "Item: " + prodList[i]);
Autoadapter.add(prodList[i]);
}
}else{
Autoadapter.clear();
}
}
});