ViewAllProducts
package com.example.venkateshbm.myapplication;
import android.app.Activity;
import android.os.Bundle;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import java.util.ArrayList;
import java.util.List;
/**
* Created by VenkateshBM on 08/01/18.
*/
public class ViewAllProducts extends Activity{
DBHelper database;
RecyclerView recyclerView;
RecycleProductAdapter recycler;
List<ProductDataModel> productDataModels;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.displaybillproduct);
productDataModels =new ArrayList<ProductDataModel>();
recyclerView = (RecyclerView) findViewById (R.id.recycler);
database = new DBHelper(ViewAllProducts.this);
productDataModels = database.getdata();
recycler =new RecycleProductAdapter(productDataModels);
RecyclerView.LayoutManager reLayoutManager =new LinearLayoutManager(getApplicationContext());
recyclerView.setLayoutManager(reLayoutManager);
recyclerView.setItemAnimator(new DefaultItemAnimator());
recyclerView.setAdapter(recycler);
}
}
BillingFragment Code
package com.example.venkateshbm.myapplication;
import android.content.Context;
import android.content.Intent;
import android.database.sqlite.SQLiteDatabase;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.AutoCompleteTextView;
import android.widget.Toast;
public class BillingFragment extends Fragment {
AutoCompleteTextView fracproductname;
public BillingFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
DBHelper dbHelper = new DBHelper(getActivity());
View rootview = inflater.inflate(R.layout.fragment_billing,container,false);
fracproductname = (AutoCompleteTextView)rootview.findViewById(R.id.fr_ac_product_name);
DBHelper mydb = new DBHelper(getActivity());
SQLiteDatabase db = mydb.getReadableDatabase();
String myproduct [] = mydb.SelectAllData(DBHelper.ITEM_TABLE,DBHelper.ITEM_NAME,DBHelper.ITEM_CODE);
ArrayAdapter<String> aaprodut = new ArrayAdapter<String>(getActivity(),android.R.layout.simple_dropdown_item_1line,myproduct);
fracproductname.setAdapter(aaprodut);
fracproductname.setThreshold(1);
Intent intent = new Intent(getActivity(),ViewAllProducts.class);
startActivity(intent);
// Inflate the layout for this fragment
fracproductname.setOnFocusChangeListener(new View.OnFocusChangeListener() {
@Override
public void onFocusChange(View view, boolean b) {
if (fracproductname.getText() == null || fracproductname.length()<=0 ){
fracproductname.setError("Invalid Selection Data");
}
else
{
Toast.makeText(getActivity(),"The Data Found",Toast.LENGTH_LONG).show();
}
}
});
return rootview;
}
}
DBHelper - getdata -
public List<ProductDataModel> getdata(){
// DataModel dataModel = new DataModel();
List<ProductDataModel> data=new ArrayList<>();
SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery("select * from item_mst " ,null);
StringBuffer stringBuffer = new StringBuffer();
ProductDataModel productDataModel = null;
while (cursor.moveToNext()) {
productDataModel= new ProductDataModel();
String name = cursor.getString(cursor.getColumnIndexOrThrow("item_name"));
// String country = cursor.getString(cursor.getColumnIndexOrThrow("country"));
// String city = cursor.getString(cursor.getColumnIndexOrThrow("city"));
productDataModel.setProduct_name(name);
stringBuffer.append(productDataModel);
// stringBuffer.append(dataModel);
data.add(productDataModel);
}
for (ProductDataModel mo:data ) {
Log.i("Hellomo",""+mo.getProduct_name());
}
//
return data;
}
应用程序崩溃 - 某些数据正在获取并显示在Logcat中
01-08 15:42:13.617 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: HIBRID 228.5MG DRY SYP
01-08 15:42:13.617 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: DEWSOFT PREMIA CREAM
01-08 15:42:13.617 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: KESH KING
01-08 15:42:13.618 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: HUMAN MIXTARD
01-08 15:42:13.618 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: NOSIKIND P NASAL DROPS
01-08 15:42:13.618 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: SAKUNTHALA HERBAL HAIR OIL
01-08 15:42:13.618 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: RUSHIKESH BRING HAIR OIL
01-08 15:42:13.618 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: ROOP NISARGA FACE GEL
01-08 15:42:13.618 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: ASCORIL PLUS TAB
01-08 15:42:13.618 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: COTTON CREPE BANDEG
01-08 15:42:13.618 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: GLIWILL M2
01-08 15:42:13.618 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: RAYPLEX FORT (PSYCO)
01-08 15:42:13.618 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: TEST CROCIN TAB
01-08 15:42:13.618 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.619 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.619 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.619 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.619 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.619 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.619 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.619 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.619 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.619 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.619 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.619 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.619 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.620 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.620 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.620 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.620 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.620 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.620 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.620 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.620 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.620 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.620 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.621 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.621 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.621 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.621 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.621 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.621 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.621 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.621 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.621 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.622 3365-3365/com.example.venkateshbm.myapplication I/Hellomo: null
01-08 15:42:13.637 3365-3365/com.example.venkateshbm.myapplication D/AndroidRuntime: Shutting down VM
beginning of crash
01-08 15:42:13.638 3365-3365/com.example.venkateshbm.myapplication E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.venkateshbm.myapplication, PID: 3365
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.venkateshbm.myapplication/com.example.venkateshbm.myapplication.ViewAllProducts}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.RecyclerView.setLayoutManager(android.support.v7.widget.RecyclerView$LayoutManager)' on a null object reference
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2325)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.support.v7.widget.RecyclerView.setLayoutManager(android.support.v7.widget.RecyclerView$LayoutManager)' on a null object reference
at com.example.venkateshbm.myapplication.ViewAllProducts.onCreate(ViewAllProducts.java:42)
at android.app.Activity.performCreate(Activity.java:5990)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1106)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2278)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2387)
at android.app.ActivityThread.access$800(ActivityThread.java:151)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1303)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
我正在附加recycler xml标签
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context="com.example.venkateshbm.myapplication.BillingFragment">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<android.support.v7.widget.CardView
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:cardMaxElevation="2dp"
app:cardElevation="5dp">
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<AutoCompleteTextView
android:id="@+id/fr_ac_product_name"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:maxLength="60"
android:maxLines="1"
android:hint="Enter Patient Name"
/>
</android.support.design.widget.TextInputLayout>
<android.support.design.widget.TextInputLayout
android:layout_width="match_parent"
android:layout_height="wrap_content" >
<android.support.v7.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="50dp"
android:id="@+id/recycler">
</android.support.v7.widget.RecyclerView>
</android.support.design.widget.TextInputLayout>
</android.support.v7.widget.CardView>
</LinearLayout>
</ScrollView>
答案 0 :(得分：0)
recyclerView =（RecyclerView）findViewById（R.id.recycler）;
您的应用崩溃的原因是因为对象＆＃39; recyclerView＆＃39;是空的。
您确定＆＃39;回收商＆＃39;是recyclerView的正确XML标记吗？