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<?xml version="1.0" encoding="utf-8"?> | |
<!-- | |
Copyright 2016 Farbod Salamat-Zadeh | |
Licensed under the Apache License, Version 2.0 (the "License"); | |
you may not use this file except in compliance with the License. | |
You may obtain a copy of the License at | |
http://www.apache.org/licenses/LICENSE-2.0 | |
Unless required by applicable law or agreed to in writing, software | |
distributed under the License is distributed on an "AS IS" BASIS, | |
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
See the License for the specific language governing permissions and | |
limitations under the License. | |
--> | |
<LinearLayout | |
xmlns:android="http://schemas.android.com/apk/res/android" | |
xmlns:app="http://schemas.android.com/apk/res-auto" | |
android:orientation="vertical" | |
android:layout_width="match_parent" | |
android:layout_height="match_parent"> | |
<android.support.design.widget.AppBarLayout | |
android:layout_width="match_parent" | |
android:layout_height="wrap_content"> | |
<android.support.v7.widget.Toolbar | |
android:id="@+id/toolbar" | |
style="@style/AppStyle.Toolbar" | |
android:layout_width="match_parent" | |
android:layout_height="wrap_content"/> | |
</android.support.design.widget.AppBarLayout> | |
<android.support.v7.widget.RecyclerView | |
android:id="@+id/recyclerView" | |
android:layout_width="match_parent" | |
android:layout_height="wrap_content"/> | |
</LinearLayout> |
/* | |
* Copyright 2016 Farbod Salamat-Zadeh | |
* | |
* Licensed under the Apache License, Version 2.0 (the "License"); | |
* you may not use this file except in compliance with the License. | |
* You may obtain a copy of the License at | |
* | |
* http://www.apache.org/licenses/LICENSE-2.0 | |
* | |
* Unless required by applicable law or agreed to in writing, software | |
* distributed under the License is distributed on an "AS IS" BASIS, | |
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
* See the License for the specific language governing permissions and | |
* limitations under the License. | |
*/ | |
package com.yourcompany.yourapp; | |
import android.support.v7.widget.RecyclerView; | |
import android.view.LayoutInflater; | |
import android.view.View; | |
import android.view.ViewGroup; | |
import android.widget.TextView; | |
import java.util.ArrayList; | |
public class ExampleAdapter extends RecyclerView.Adapter<ExampleAdapter.ExampleViewHolder> { | |
public class ExampleViewHolder extends RecyclerView.ViewHolder { | |
TextView text1, text2; | |
ExampleViewHolder(View itemView) { | |
super(itemView); | |
text1 = (TextView) itemView.findViewById(R.id.text1); | |
text2 = (TextView) itemView.findViewById(R.id.text2); | |
} | |
} | |
private ArrayList<CustomClass> mCustomObjects; | |
public ExampleAdapter(ArrayList<CustomClass> arrayList) { | |
mCustomObjects = arrayList; | |
} | |
@Override | |
public int getItemCount() { | |
return mCustomObjects.size(); | |
} | |
@Override | |
public ExampleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { | |
View view = LayoutInflater.from(parent.getContext()).inflate(android.R.layout.simple_list_item_2, parent, false); | |
return new ExampleViewHolder(view); | |
} | |
@Override | |
public void onBindViewHolder(ExampleViewHolder holder, int position) { | |
CustomClass object = mCustomObjects.get(position); | |
// My example assumes CustomClass objects have getFirstText() and getSecondText() methods | |
String firstText = object.getFirstText() | |
String secondText = object.getSecondText() | |
holder.text1.setText(firstText); | |
holder.text2.setText(secondText); | |
} | |
@Override | |
public void onAttachedToRecyclerView(RecyclerView recyclerView) { | |
super.onAttachedToRecyclerView(recyclerView); | |
} | |
} |
/* | |
* Copyright 2016 Farbod Salamat-Zadeh | |
* | |
* Licensed under the Apache License, Version 2.0 (the "License"); | |
* you may not use this file except in compliance with the License. | |
* You may obtain a copy of the License at | |
* | |
* http://www.apache.org/licenses/LICENSE-2.0 | |
* | |
* Unless required by applicable law or agreed to in writing, software | |
* distributed under the License is distributed on an "AS IS" BASIS, | |
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
* See the License for the specific language governing permissions and | |
* limitations under the License. | |
*/ | |
package com.yourcompany.yourapp; | |
import android.support.v7.widget.RecyclerView; | |
import android.view.LayoutInflater; | |
import android.view.View; | |
import android.view.ViewGroup; | |
import android.widget.TextView; | |
import java.util.ArrayList; | |
public class ExampleClickAdapter extends RecyclerView.Adapter<ExampleClickAdapter.ExampleClickViewHolder> { | |
public class ExampleClickViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener { | |
TextView text1, text2; | |
ExampleClickViewHolder(View itemView) { | |
super(itemView); | |
itemView.setOnClickListener(this); | |
title = (TextView) itemView.findViewById(android.R.id.text1); | |
subtitle = (TextView) itemView.findViewById(android.R.id.text2); | |
} | |
@Override | |
public void onClick(View v) { | |
// The user may not set a click listener for list items, in which case our listener | |
// will be null, so we need to check for this | |
if (mOnEntryClickListener != null) { | |
mOnEntryClickListener.onEntryClick(v, getLayoutPosition()); | |
} | |
} | |
} | |
private ArrayList<CustomClass> mCustomObjects; | |
public ExampleClickAdapter(ArrayList<CustomClass> arrayList) { | |
mCustomObjects = arrayList; | |
} | |
@Override | |
public int getItemCount() { | |
return mCustomObjects.size(); | |
} | |
@Override | |
public ExampleClickViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { | |
View view = LayoutInflater.from(parent.getContext()).inflate(android.R.layout.simple_list_item_2, parent, false); | |
return new ExampleClickViewHolder(view); | |
} | |
@Override | |
public void onBindViewHolder(ExampleClickViewHolder holder, int position) { | |
CustomClass object = mCustomObjects.get(position); | |
// My example assumes CustomClass objects have getFirstText() and getSecondText() methods | |
String firstText = object.getFirstText() | |
String secondText = object.getSecondText() | |
holder.text1.setText(firstText); | |
holder.text2.setText(secondText); | |
} | |
@Override | |
public void onAttachedToRecyclerView(RecyclerView recyclerView) { | |
super.onAttachedToRecyclerView(recyclerView); | |
} | |
private OnEntryClickListener mOnEntryClickListener; | |
public interface OnEntryClickListener { | |
void onEntryClick(View view, int position); | |
} | |
public void setOnEntryClickListener(OnEntryClickListener onEntryClickListener) { | |
mOnEntryClickListener = onEntryClickListener; | |
} | |
} |
/* | |
* Copyright 2016 Farbod Salamat-Zadeh | |
* | |
* Licensed under the Apache License, Version 2.0 (the "License"); | |
* you may not use this file except in compliance with the License. | |
* You may obtain a copy of the License at | |
* | |
* http://www.apache.org/licenses/LICENSE-2.0 | |
* | |
* Unless required by applicable law or agreed to in writing, software | |
* distributed under the License is distributed on an "AS IS" BASIS, | |
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |
* See the License for the specific language governing permissions and | |
* limitations under the License. | |
*/ | |
package com.yourcompany.yourapp; | |
import android.support.v7.app.AppCompatActivity; | |
import android.support.v7.widget.LinearLayoutManager; | |
import android.support.v7.widget.RecyclerView; | |
import android.support.v7.widget.Toolbar; | |
import android.view.View; | |
import java.util.ArrayList; | |
public class RecyclerViewActivity extends AppCompatActivity { | |
@Override | |
protected void onCreate(Bundle savedInstanceState) { | |
super.onCreate(savedInstanceState); | |
setContentView(R.layout.activity_main); | |
// Setting up the Toolbar | |
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); | |
setSupportActionBar(toolbar); | |
assert getSupportActionBar() != null; | |
getSupportActionBar().setDisplayHomeAsUpEnabled(true); | |
// Setting up the RecyclerView | |
RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerView); | |
assert recyclerView != null; | |
recyclerView.setLayoutManager(new LinearLayoutManager(this)); | |
// Getting your ArrayList - this will be up to you | |
ArrayList<CustomClass> yourObjects = getMyObjects(); | |
// Standard RecyclerView implementation | |
ExampleAdapter adapter = new ExampleAdapter(yourObjects); | |
recyclerView.setAdapter(adapter); | |
// OR RecyclerView with a click listener | |
ExampleClickAdapter clickAdapter = new ExampleClickAdapter(yourObjects); | |
clickAdapter.setOnEntryClickListener(new ExampleClickAdapter.OnEntryClickListener() { | |
@Override | |
public void onEntryClick(View view, int position) { | |
// stuff that will happen when a list item is clicked | |
} | |
}); | |
recyclerView.setAdapter(clickAdapter); | |
} | |
private ArrayList<CustomClass> getMyObjects() { | |
// This will return the ArrayList of your CustomClass objects | |
} | |
} |
I implemented everything but i got an error on loading the screen.
java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.TextView.setText(java.lang.CharSequence)' on a null object reference
at com.example.alaincheng.loginapp.ExampleClickAdapter.onBindViewHolder(ExampleClickAdapter.java:77)
at com.example.alaincheng.loginapp.ExampleClickAdapter.onBindViewHolder(ExampleClickAdapter.java:29)
at android.support.v7.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:6673)
at android.support.v7.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:6714)
at android.support.v7.widget.RecyclerView$Recycler.tryBindViewHolderByDeadline(RecyclerView.java:5647)
at android.support.v7.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:5913)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:5752)
at android.support.v7.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:
I just followed all the source code, any suggestions?
Kind regards
Hey,
The form of this code that won't throw the NullPointerException that @alaincheng is talking about requires a change to line 36 and 37;
Instead of
title = (TextView) itemView.findViewById(R.id.text1);
subtitle = (TextView) itemView.findViewById(R.id.text2);
you need to write
title = (TextView) itemView.findViewById(android.R.id.text1);
subtitle = (TextView) itemView.findViewById(android.R.id.text2);
Hope this helps
Hey,
The form of this code that won't throw the NullPointerException that @alaincheng is talking about requires a change to line 36 and 37;
Instead of
title = (TextView) itemView.findViewById(R.id.text1);
subtitle = (TextView) itemView.findViewById(R.id.text2);you need to write
title = (TextView) itemView.findViewById(android.R.id.text1);
subtitle = (TextView) itemView.findViewById(android.R.id.text2);Hope this helps
Good point. I've updated the file now so it should be ok.
By changing this its not working
It is good.