我有一个包含edittext字段的recyclerviewholder。
在edittext字段中，我正在尝试使用TextChangedListener更新特定的SQLite值，以便它可以自动更新SQLite值而无需按任何按钮。但它会抛出NullPointerException
我的OnCreateView
SQLiteCBLCAdapter sqliteCBLCAdapter;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
view = inflater.inflate(R.layout.fragment_tab_cart, container, false);
ButterKnife.setDebug(true);
ButterKnife.bind(this, view);
sqliteCBLCAdapter = new SQLiteCBLCAdapter(getContext());
return view;
}
这是我的onTextChangedListener方法
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
try {
if (!s.equals("")) {
String newQuantity = s.toString();
sqliteCBLCAdapter.updateQuantity(orderName, newQuantity);
} else {
// irrelevant to the question
}
} catch (NumberFormatException e) {
holder.tv_currentPrice_atc.setText("0");
}
}
这是我的updateQuantity方法。
public void updateQuantity(String orderName, String newQuantity) {
SQLiteDatabase sqLiteDatabase = sqLiteCBLC.getWritableDatabase();
String updateQuery = "UPDATE "+SQLiteCBLC.TABLE_NAME+" SET "+SQLiteCBLC.COL_QUANTITY+" = "+newQuantity+" WHERE "+SQLiteCBLC.COL_ORDNAME+" = '"+orderName+"'";
sqLiteDatabase.execSQL(updateQuery);
}
这是我的日志
java.lang.NullPointerException: Attempt to invoke virtual method 'void com.steven.frio.systemanalysisanddesign.sqlite.SQLiteCBLCAdapter.updateQuantity(java.lang.String, java.lang.String)' on a null object reference
at com.steven.frio.systemanalysisanddesign.FragmentTabCart$2.onTextChanged(FragmentTabCart.java:204)
at android.widget.TextView.sendOnTextChanged(TextView.java:8189)
at android.widget.TextView.setText(TextView.java:4485)
at android.widget.TextView.setText(TextView.java:4339)
at android.widget.EditText.setText(EditText.java:89)
at android.widget.TextView.setText(TextView.java:4314)
at com.steven.frio.systemanalysisanddesign.FragmentTabCart$1.addButtonClick(FragmentTabCart.java:138)
at com.steven.frio.systemanalysisanddesign.recycleradapters.RAdapterAddToCart$1.onClick(RAdapterAddToCart.java:80)
at android.view.View.performClick(View.java:5620)
at android.view.View$PerformClick.run(View.java:22300)
at android.os.Handler.handleCallback(Handler.java:754)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:160)
at android.app.ActivityThread.main(ActivityThread.java:6237)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:877)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)
在监听器的textchangedlistener / parent方法中初始化sqliteCBLCAdapter时，它会抛出此异常
Process: com.steven.frio.systemanalysisanddesign, PID: 22921
java.lang.NullPointerException: Attempt to invoke virtual method 'android.database.sqlite.SQLiteDatabase android.content.Context.openOrCreateDatabase(java.lang.String, int, android.database.sqlite.SQLiteDatabase$CursorFactory, android.database.DatabaseErrorHandler)' on a null object reference
at android.database.sqlite.SQLiteOpenHelper.getDatabaseLocked(SQLiteOpenHelper.java:223)
at android.database.sqlite.SQLiteOpenHelper.getWritableDatabase(SQLiteOpenHelper.java:163)
at com.steven.frio.systemanalysisanddesign.sqlite.SQLiteCBLCAdapter$SQLiteCBLC.<init>(SQLiteCBLCAdapter.java:115)
at com.steven.frio.systemanalysisanddesign.sqlite.SQLiteCBLCAdapter.<init>(SQLiteCBLCAdapter.java:21)
at com.steven.frio.systemanalysisanddesign.FragmentTabCart.editTextWatchers(FragmentTabCart.java:189)
at com.steven.frio.systemanalysisanddesign.recycleradapters.RAdapterAddToCart.onBindViewHolder(RAdapterAddToCart.java:75)
at com.steven.frio.systemanalysisanddesign.recycleradapters.RAdapterAddToCart.onBindViewHolder(RAdapterAddToCart.java:30)
at android.support.v7.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:6356)
答案 0 :(得分：0)
确保正确初始化数据库。
SQLiteCBLCAdapter sqliteCBLCAdapter = new SQLiteCBLCAdapter (context);