我是Android编程的新手，但我有一些以前的java经验。我正在从一个大书呆子牧场指南到android编程的项目。因为我缺乏使用android的经验，所以我在学习的同时复制代码，而不是试图用它来创造。但是我已经达到犯罪意图应用程序中的一个点，我的应用程序每次单击我的RecyclerView中的项目时都会崩溃。我在网上搜索过，发现其他问题有点像这样但是他们没有帮我解决这个问题。正如我所说，我是新手Android和额外，意图和所有这些。任何人都可以帮助我找出原因以及如何解决它？我发布了一些代码以及Exceptions堆栈跟踪。这是包含回收站视图的列表片段：
package com.bignerdranch.android.criminalintent;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.NavUtils;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.view.menu.ExpandedMenuView;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.IllegalFormatCodePointException;
import java.util.List;
public class CrimeListFragment extends Fragment{
private RecyclerView mCrimeRecyclerView;
private CrimeAdapter mAdapter;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState){
View view = inflater.inflate(R.layout.fragment_crime_list, container, false);
mCrimeRecyclerView = (RecyclerView) view.findViewById(R.id.crime_recycler_view);
mCrimeRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
updateUI();
return view;
}//end onCreate
private void updateUI(){
CrimeLab crimeLab = CrimeLab.get(getActivity());
List<Crime> crimes = crimeLab.getCrimes();
if (mAdapter == null){
mAdapter = new CrimeAdapter(crimes);
mCrimeRecyclerView.setAdapter(mAdapter);
}else {
mAdapter.notifyDataSetChanged();
}
}//end updateUI()
private class CrimeHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
private TextView mTitleTextView;
private TextView mDateTextView;
private Crime mCrime;
private ImageView mSolvedImageView;
public CrimeHolder(LayoutInflater inflater, ViewGroup parent){
super(inflater.inflate(R.layout.list_item_crime, parent, false));
itemView.setOnClickListener(this);
mTitleTextView = (TextView) itemView.findViewById(R.id.crime_title);
mDateTextView = (TextView) itemView.findViewById(R.id.crime_date);
mSolvedImageView = (ImageView) itemView.findViewById(R.id.crime_solved);
}//end constructor
@Override
public void onClick(View view){
try {
Intent intent = CrimePagerActivity.newIntent(getActivity(), mCrime.getId());
startActivity(intent); // something wrong with the activity starting when clicked!
}catch(Exception e){
Log.d("ONCLICK", e.toString());
}
}//end onCLick()
public void bind(Crime crime){
mCrime = crime;
mTitleTextView.setText(crime.getTitle());
mDateTextView.setText(mCrime.getDate().toString());
mSolvedImageView.setVisibility(crime.isSolved() ? View.VISIBLE : View.GONE);
}//end bind()
}//end CrimeHolder inner Class
private class CrimeAdapter extends RecyclerView.Adapter<CrimeHolder>{
private List<Crime> mCrimes;
public CrimeAdapter(List<Crime> crimes){
mCrimes = crimes;
}//end constructor
@Override
public CrimeHolder onCreateViewHolder(ViewGroup parent, int viewType){
LayoutInflater layoutInflater = LayoutInflater.from(getActivity());
return new CrimeHolder(layoutInflater, parent);
}// end onCreateViewHolder
@Override
public void onBindViewHolder(CrimeHolder holder, int position){
Crime crime = mCrimes.get(position);
holder.bind(crime);
}
@Override
public int getItemCount(){
return mCrimes.size();
}
}//end CrimeAdapter inner Class
}//end CrimeListFragment class
这是应该在点击时启动的活动的类：
package com.bignerdranch.android.criminalintent;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.view.ViewPropertyAnimatorCompatSet;
import java.util.List;
import java.util.UUID;
public class CrimePagerActivity extends AppCompatActivity {
private static final String EXTRA_CRIME_ID = "com.bignerdranch.android.criminalintent.crime_id";
private ViewPager mViewPager;
private List<Crime> mCrimes;
public static Intent newIntent(Context packageContext, UUID crimeId){
Intent intent = new Intent(packageContext, CrimePagerActivity.class);
intent.putExtra(EXTRA_CRIME_ID, crimeId);
return intent;
}
@Override
protected void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_crime_pager);
UUID crimeId = (UUID) getIntent().getSerializableExtra(EXTRA_CRIME_ID);
mViewPager = (ViewPager) findViewById(R.id.crime_view_pager);
mCrimes = CrimeLab.get(this).getCrimes();
FragmentManager fragmentManager = getSupportFragmentManager();
mViewPager.setAdapter(new FragmentStatePagerAdapter(fragmentManager) {
@Override
public Fragment getItem(int position) {
Crime crime = mCrimes.get(position);
return CrimeFragment.newInstance(crime.getId());
}
@Override
public int getCount() {
return mCrimes.size();
}
});
}// end onCreate()
}//end crimePagerAtivity class
这里是CrimeLab类的代码：
package com.bignerdranch.android.criminalintent;
import android.content.Context;
import java.util.ArrayList;
import java.util.List;
import java.util.UUID;
public class CrimeLab {
private static CrimeLab sCrimeLab;
private List<Crime> mCrimes;
public static CrimeLab get(Context context){
if(sCrimeLab == null){
sCrimeLab = new CrimeLab(context);
}
return sCrimeLab;
}//end get()
private CrimeLab(Context context){
}//end constructor
public List<Crime> getCrimes(){
mCrimes = new ArrayList<>();
for (int i = 0; i < 100; i++){
Crime crime = new Crime();
crime.setTitle("Crime #" + i);
crime.setSolved(i % 2 == 0); //every other crime will be checked!
mCrimes.add(crime);
}
return mCrimes;
}//end getCrimes
public Crime getCrime(UUID id){
for (Crime crime : mCrimes){
if (crime.getId().equals(id)){
return crime;
}
}
return null;
}//end getCrime()
}//end CrimeLab class
这是我的Exeptions堆栈跟踪，它是从CrimeHolders onClick（）中的try / catch块记录的：
04-30 09:11:33.090 2526-14527/com.google.android.googlequicksearchbox:search W/ErrorProcessor: onFatalError, processing error from engine(4)
com.google.android.apps.gsa.shared.speech.a.g: Error reading from input stream
at com.google.android.apps.gsa.staticplugins.recognizer.i.a.a(SourceFile:342)
at com.google.android.apps.gsa.staticplugins.recognizer.i.a$1.run(SourceFile:1367)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:428)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at com.google.android.apps.gsa.shared.util.concurrent.a.ak.run(SourceFile:66)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
at java.lang.Thread.run(Thread.java:761)
at com.google.android.apps.gsa.shared.util.concurrent.a.ad$1.run(SourceFile:85)
Caused by: com.google.android.apps.gsa.shared.exception.GsaIOException: Error code: 393238 | Buffer overflow, no available space.
at com.google.android.apps.gsa.speech.audio.Tee.g(SourceFile:2531)
at com.google.android.apps.gsa.speech.audio.ap.read(SourceFile:555)
at java.io.InputStream.read(InputStream.java:101)
at com.google.android.apps.gsa.speech.audio.al.run(SourceFile:362)
at com.google.android.apps.gsa.speech.audio.ak$1.run(SourceFile:471)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:428)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at com.google.android.apps.gsa.shared.util.concurrent.a.ak.run(SourceFile:66)
at com.google.android.apps.gsa.shared.util.concurrent.a.ax.run(SourceFile:139)
at com.google.android.apps.gsa.shared.util.concurrent.a.ax.run(SourceFile:139)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607)
at java.lang.Thread.run(Thread.java:761)
at com.google.android.apps.gsa.shared.util.concurrent.a.ad$1.run(SourceFile:85)
提前感谢您的帮助。
这里是仅限应用程序的日志。不确定这是否有帮助：
04-30 09:11:34.042 14542-14542/? I/art: Not late-enabling -Xcheck:jni
(already on)
04-30 09:11:34.043 14542-14542/? W/art: Unexpected CPU variant for X86 using
defaults: x86
04-30 09:11:34.187 14542-14542/com.bignerdranch.android.criminalintent
W/System: ClassLoader referenced unknown path:
/data/app/com.bignerdranch.android.criminalintent-1/lib/x86
04-30 09:11:34.203 14542-14542/com.bignerdranch.android.criminalintent
I/InstantRun: starting instant run server: is main process
04-30 09:11:34.298 14542-14542/com.bignerdranch.android.criminalintent
04-30 09:11:34.298 14542-14542/com.bignerdranch.android.criminalintent
W/art: Before Android 4.1, method android.graphics.PorterDuffColorFilter
04-30 09:11:34.298 14542-14542/com.bignerdranch.android.criminalintent W/art: Before Android 4.1, method android.graphics.PorterDuffColorFilter android.support.graphics.drawable.VectorDrawableCompat.updateTintFilter(android.graphics.PorterDuffColorFilter, android.content.res.ColorStateList, android.graphics.PorterDuff$Mode) would have incorrectly overridden the package-private method in android.graphics.drawable.Drawable
04-30 09:11:34.623 14542-14572/com.bignerdranch.android.criminalintent I/OpenGLRenderer: Initialized EGL, version 1.4
04-30 09:11:34.623 14542-14572/com.bignerdranch.android.criminalintent D/OpenGLRenderer: Swap behavior 1
04-30 09:11:34.624 14542-14572/com.bignerdranch.android.criminalintent W/OpenGLRenderer: Failed to choose config with EGL_SWAP_BEHAVIOR_PRESERVED, retrying without...
04-30 09:11:34.624 14542-14572/com.bignerdranch.android.criminalintent D/OpenGLRenderer: Swap behavior 0
04-30 09:11:34.802 14542-14542/com.bignerdranch.android.criminalintent W/art: Before Android 4.1, method int android.support.v7.widget.ListViewCompat.lookForSelectablePosition(int, boolean) would have incorrectly overridden the package-private method in android.widget.ListView
好的，所以这就是我现在的堆栈跟踪：
[ 04-30 13:21:32.818 5236: 5236 D/ ]
HostConnection::get() New Host
Connection established 0x92014100, tid 5236
04-30 13:29:45.065 5236-5236/com.bignerdranch.android.criminalintent
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.bignerdranch.android.criminalintent, PID: 5236
java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.bignerdranch.android.criminalintent.Crime.getTitle()' on a null object reference
at com.bignerdranch.android.criminalintent.CrimeFragment.onCreateView(CrimeFragment.java:50)
at android.support.v4.app.Fragment.performCreateView(Fragment.java:2192)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1299)
at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1528)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1595)
at android.support.v4.app.BackStackRecord.executeOps(BackStackRecord.java:758)
at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2363)
at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2149)
at android.support.v4.app.FragmentManagerImpl.optimizeAndExecuteOps(FragmentManager.java:2103)
at android.support.v4.app.FragmentManagerImpl.execSingleAction(FragmentManager.java:1984)
at android.support.v4.app.BackStackRecord.commitNowAllowingStateLoss(BackStackRecord.java:626)
at android.support.v4.app.FragmentStatePagerAdapter.finishUpdate(FragmentStatePagerAdapter.java:166)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1268)
at android.support.v4.view.ViewPager.populate(ViewPager.java:1116)
at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1642)
at android.view.View.measure(View.java:19857)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6083)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:139)
at android.view.View.measure(View.java:19857)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6083)
at android.support.v7.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:393)
at android.view.View.measure(View.java:19857)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6083)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
at android.view.View.measure(View.java:19857)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6083)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1464)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:758)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:640)
at android.view.View.measure(View.java:19857)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6083)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
at com.android.internal.policy.DecorView.onMeasure(DecorView.java:689)
at android.view.View.measure(View.java:19857)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2275)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1366)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1619)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1254)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6337)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:874)
at android.view.Choreographer.doCallbacks(Choreographer.java:686)
at android.view.Choreographer.doFrame(Choreographer.java:621)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:860)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6119)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)