我正在编写一个Android应用程序，它使用我使用RecyclerView制作的自定义适配器。适配器工作正常但是当我离开正在使用它的活动时，应用程序崩溃并给我这个错误：
07-22 14:30:41.037 11083-11083/com.epicodus.parkr E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.epicodus.parkr, PID: 11083
java.lang.NoClassDefFoundError: android.support.v7.widget.RecyclerView$SavedState
at android.support.v7.widget.RecyclerView.onSaveInstanceState(RecyclerView.java:1078)
at android.view.View.dispatchSaveInstanceState(View.java:14641)
at android.view.ViewGroup.dispatchFreezeSelfOnly(ViewGroup.java:3175)
at android.support.v7.widget.RecyclerView.dispatchSaveInstanceState(RecyclerView.java:1109)
at android.view.ViewGroup.dispatchSaveInstanceState(ViewGroup.java:3161)
at android.view.ViewGroup.dispatchSaveInstanceState(ViewGroup.java:3161)
at android.view.ViewGroup.dispatchSaveInstanceState(ViewGroup.java:3161)
at android.view.ViewGroup.dispatchSaveInstanceState(ViewGroup.java:3161)
at android.view.ViewGroup.dispatchSaveInstanceState(ViewGroup.java:3161)
at android.view.View.saveHierarchyState(View.java:14624)
at com.android.internal.policy.impl.PhoneWindow.saveHierarchyState(PhoneWindow.java:2126)
at android.app.Activity.onSaveInstanceState(Activity.java:1456)
at android.support.v4.app.FragmentActivity.onSaveInstanceState(FragmentActivity.java:564)
at android.support.v7.app.AppCompatActivity.onSaveInstanceState(AppCompatActivity.java:502)
at android.app.Activity.performSaveInstanceState(Activity.java:1383)
at android.app.Instrumentation.callActivityOnSaveInstanceState(Instrumentation.java:1286)
at android.app.ActivityThread.callCallActivityOnSaveInstanceState(ActivityThread.java:4473)
at android.app.ActivityThread.performStopActivityInner(ActivityThread.java:3845)
at android.app.ActivityThread.handleStopActivity(ActivityThread.java:3908)
at android.app.ActivityThread.access$1200(ActivityThread.java:177)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1477)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:145)
at android.app.ActivityThread.main(ActivityThread.java:5942)
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:1399)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1194)
以下是使用适配器的活动的代码：
package com.epicodus.parkr.ui;
import android.content.Intent;
import android.graphics.Typeface;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import com.epicodus.parkr.Constants;
import com.epicodus.parkr.R;
import com.epicodus.parkr.adapters.RentedSpotsAdapter;
import com.epicodus.parkr.models.Spot;
import com.google.android.gms.maps.model.LatLng;
import com.google.firebase.auth.FirebaseAuth;
import com.google.firebase.database.DataSnapshot;
import com.google.firebase.database.DatabaseError;
import com.google.firebase.database.DatabaseReference;
import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.database.ValueEventListener;
import java.util.ArrayList;
import butterknife.Bind;
import butterknife.ButterKnife;
public class AccountActivity extends AppCompatActivity implements View.OnClickListener {
private FirebaseAuth mAuth;
private String uid;
private DatabaseReference mSpecificUserReference;
private DatabaseReference mAllSpotsReference;
private RentedSpotsAdapter mAdapter;
@Bind(R.id.rentedSpotRecyclerView) RecyclerView mRecyclerView;
@Bind(R.id.userNameDisplay) TextView mUserNameDisplay;
@Bind(R.id.headline) TextView mHeadline;
@Bind(R.id.logOutButton) Button mLogOutButton;
@Bind(R.id.postSpotButton) Button mPostSpotButton;
@Bind(R.id.findSpotsButton) Button mFindSpotsButton;
@Override
protected void onCreate(Bundle savedInstanceState) {
mAuth = FirebaseAuth.getInstance();
uid = mAuth.getCurrentUser().getUid();
mSpecificUserReference = FirebaseDatabase.getInstance().getReference().child(Constants.FIREBASE_CHILD_USER).child(uid);
mAllSpotsReference = FirebaseDatabase.getInstance().getReference().child("spots");
mSpecificUserReference.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
String userName = dataSnapshot.child("fullName").getValue().toString();
mUserNameDisplay.setText(userName);
}
@Override
public void onCancelled(DatabaseError databaseError) {
}
});
mSpecificUserReference.child("rentedSpots").addValueEventListener(new ValueEventListener() {
ArrayList<Spot> mSpots = new ArrayList<>();
ArrayList<String> spotKeys = new ArrayList<>();
@Override
public void onDataChange(DataSnapshot dataSnapshot) {
for(DataSnapshot spotKeySnapshot : dataSnapshot.getChildren()){
String spotKey = spotKeySnapshot.getValue().toString();
spotKeys.add(spotKey);
}
mAllSpotsReference.addValueEventListener(new ValueEventListener() {
@Override
public void onDataChange(DataSnapshot AllSpotsDataSnapshot) {
for(DataSnapshot eachSpotSnapshot : AllSpotsDataSnapshot.getChildren()){
String compareSpotId = eachSpotSnapshot.getKey();
for(String eachSpotKey : spotKeys)
if(compareSpotId.equals(eachSpotKey)){
String ownerId = eachSpotSnapshot.child("ownerID").getValue().toString();
String address = eachSpotSnapshot.child("address").getValue().toString();
String description = eachSpotSnapshot.child("description").getValue().toString();
Double lat = Double.parseDouble(eachSpotSnapshot.child("latLng").child("latitude").getValue().toString());
Double lng = Double.parseDouble(eachSpotSnapshot.child("latLng").child("longitude").getValue().toString());
LatLng newLatLng = new LatLng(lat, lng);
String startDate = eachSpotSnapshot.child("startDate").getValue().toString();
String startTime = eachSpotSnapshot.child("startTime").getValue().toString();
String endDate = eachSpotSnapshot.child("endDate").getValue().toString();
String endTime = eachSpotSnapshot.child("endTime").getValue().toString();
Spot newSpot = new Spot(eachSpotKey, ownerId, address, description, newLatLng, startDate, startTime, endDate, endTime);
mSpots.add(newSpot);
}
}
mAdapter = new RentedSpotsAdapter(getApplicationContext(), mSpots);
mRecyclerView.setAdapter(mAdapter);
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(AccountActivity.this);
mRecyclerView.setLayoutManager(layoutManager);
mRecyclerView.setHasFixedSize(true);
}
@Override
public void onCancelled(DatabaseError databaseError) {
finish();
}
});
}
@Override
public void onCancelled(DatabaseError databaseError) {
finish();
}
});
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_account);
ButterKnife.bind(this);
Typeface newFont = Typeface.createFromAsset(getAssets(), "fonts/Lobster-Regular.ttf");
mHeadline.setTypeface(newFont);
Intent infoIntent = getIntent();
String userName = infoIntent.getStringExtra("user");
mUserNameDisplay.setText(userName);
mPostSpotButton.setOnClickListener(this);
mLogOutButton.setOnClickListener(this);
mFindSpotsButton.setOnClickListener(this);
}
private void logout() {
FirebaseAuth.getInstance().signOut();
Intent intent = new Intent(AccountActivity.this, MainActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(intent);
finish();
}
@Override
public void onClick(View view) {
if(view == mLogOutButton){
logout();
} else if (view == mPostSpotButton){
Intent postSpotIntent = new Intent (AccountActivity.this, NewSpotActivity.class);
startActivity(postSpotIntent);
} else if (view == mFindSpotsButton){
Intent findSpotsIntent = new Intent(AccountActivity.this, FindSpotsActivity.class);
startActivity(findSpotsIntent);
}
}
}
以下是适配器本身的代码：
package com.epicodus.parkr.adapters;
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import com.epicodus.parkr.R;
import com.epicodus.parkr.models.Spot;
import java.util.ArrayList;
import butterknife.Bind;
import butterknife.ButterKnife;
public class RentedSpotsAdapter extends RecyclerView.Adapter<RentedSpotsAdapter.RentedSpotViewHolder> {
private ArrayList<Spot> mSpots;
private Context mContext;
public RentedSpotsAdapter(Context context, ArrayList<Spot> spots){
mSpots = spots;
mContext = context;
}
@Override
public RentedSpotsAdapter.RentedSpotViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.rented_spot_list_item, parent, false);
RentedSpotViewHolder viewHolder = new RentedSpotViewHolder(view);
return viewHolder;
}
@Override
public void onBindViewHolder(RentedSpotsAdapter.RentedSpotViewHolder holder, int position) {
holder.bindSpot(mSpots.get(position));
}
@Override
public int getItemCount() {
return mSpots.size();
}
public class RentedSpotViewHolder extends RecyclerView.ViewHolder {
@Bind(R.id.rentedSpotAddressDisplay) TextView mRentedSpotAddressDisplay;
@Bind(R.id.rentedSpotEndDateDisplay) TextView mRentedSpotEndDateDisplay;
@Bind(R.id.rentedSpotEndTimeDisplay) TextView mRentedSpotEndTimeDisplay;
private Context mContext;
public RentedSpotViewHolder(View itemView) {
super(itemView);
ButterKnife.bind(this, itemView);
mContext = itemView.getContext();
}
public void bindSpot(Spot spot){
mRentedSpotAddressDisplay.setText(spot.getAddress());
mRentedSpotEndDateDisplay.setText(spot.getEndDate());
mRentedSpotEndTimeDisplay.setText(spot.getEndTime());
}
}
}
以下是app level build.gradle文件：
apply plugin: 'com.android.application'
android {
compileSdkVersion 24
buildToolsVersion "24.0.0"
defaultConfig {
applicationId "com.epicodus.parkr"
minSdkVersion 15
targetSdkVersion 24
versionCode 1
versionName "1.0"
}
packagingOptions {
exclude 'META-INF/DEPENDENCIES.txt'
exclude 'META-INF/DEPENDENCIES'
exclude 'META-INF/dependencies.txt'
exclude 'META-INF/LICENSE.txt'
exclude 'META-INF/LICENSE'
exclude 'META-INF/license.txt'
exclude 'META-INF/LGPL2.1'
exclude 'META-INF/NOTICE.txt'
exclude 'META-INF/NOTICE'
exclude 'META-INF/notice.txt'
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:24.0.0'
compile 'com.jakewharton:butterknife:7.0.1'
compile 'com.google.firebase:firebase-database:9.0.2'
compile 'com.firebaseui:firebase-ui-database:0.4.1'
compile 'com.google.firebase:firebase-auth:9.0.2'
compile 'com.google.android.gms:play-services:9.0.2'
compile 'com.android.support:recyclerview-v7:+'
compile 'com.google.android.gms:play-services-appindexing:9.0.2'
}
configurations.all {
resolutionStrategy {
force 'com.android.support:design:23.4.0'
force 'com.android.support:support-v4:23.4.0'
force 'com.android.support:appcompat-v7:23.4.0'
}
}
apply plugin: 'com.google.gms.google-services'
更新
我得到了它的工作。看起来我只需要覆盖onSaveInstanceState方法并让它为空。
答案 0 :(得分：0)
我只是在这里猜测..你可以移动代码并在oncreate（）方法之后立即放置它并再试一次。
super.onCreate（savedInstanceState）;
的setContentView（R.layout.activity_account）;