我正在学习如何在天气预报中按预期运行所有天气预报，因为在代码的每一行中都没有发现任何错误，但是当我尝试执行代码时，我的应用程序强制关闭
错误看起来像这样：
01-22 16:14:45.114 11085-11085/? I/art: Late-enabling -Xcheck:jni
01-22 16:14:45.136 11085-11085/? D/TidaProvider: TidaProvider()
01-22 16:14:45.159 11085-11085/? W/ActivityThread: Application info.landingcasts.myapplication is waiting for the debugger on port 8100...
01-22 16:14:45.159 11085-11085/? I/System.out: Sending WAIT chunk
01-22 16:14:45.338 11085-11091/info.landingcasts.myapplication I/art: Debugger is active
01-22 16:14:45.360 11085-11085/info.landingcasts.myapplication I/System.out: Debugger has connected
01-22 16:14:45.360 11085-11085/info.landingcasts.myapplication I/System.out: waiting for debugger to settle...
01-22 16:14:45.560 11085-11085/info.landingcasts.myapplication I/System.out: waiting for debugger to settle...
01-22 16:14:45.760 11085-11085/info.landingcasts.myapplication I/System.out: waiting for debugger to settle...
01-22 16:14:45.961 11085-11085/info.landingcasts.myapplication I/System.out: waiting for debugger to settle...
01-22 16:14:46.161 11085-11085/info.landingcasts.myapplication I/System.out: waiting for debugger to settle...
01-22 16:14:46.361 11085-11085/info.landingcasts.myapplication I/System.out: waiting for debugger to settle...
01-22 16:14:46.562 11085-11085/info.landingcasts.myapplication I/System.out: waiting for debugger to settle...
01-22 16:14:46.762 11085-11085/info.landingcasts.myapplication I/System.out: waiting for debugger to settle...
01-22 16:14:46.963 11085-11085/info.landingcasts.myapplication I/System.out: debugger has settled (1457)
01-22 16:14:46.969 11085-11085/info.landingcasts.myapplication W/System: ClassLoader referenced unknown path: /data/app/info.landingcasts.myapplication-2/lib/arm64
01-22 16:14:46.994 11085-11085/info.landingcasts.myapplication 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$Mode) would have incorrectly overridden the package-private method in android.graphics.drawable.Drawable
01-22 16:14:47.027 11085-11085/info.landingcasts.myapplication V/BoostFramework: mAcquireFunc method = public int com.qualcomm.qti.Performance.perfLockAcquire(int,int[])
01-22 16:14:47.028 11085-11085/info.landingcasts.myapplication V/BoostFramework: mReleaseFunc method = public int com.qualcomm.qti.Performance.perfLockRelease()
01-22 16:14:47.028 11085-11085/info.landingcasts.myapplication V/BoostFramework: mAcquireTouchFunc method = public int com.qualcomm.qti.Performance.perfLockAcquireTouch(android.view.MotionEvent,android.util.DisplayMetrics,int,int[])
01-22 16:14:47.028 11085-11085/info.landingcasts.myapplication V/BoostFramework: mIOPStart method = public int com.qualcomm.qti.Performance.perfIOPrefetchStart(int,java.lang.String)
01-22 16:14:47.028 11085-11085/info.landingcasts.myapplication V/BoostFramework: mIOPStop method = public int com.qualcomm.qti.Performance.perfIOPrefetchStop()
01-22 16:14:47.031 11085-11085/info.landingcasts.myapplication V/BoostFramework: BoostFramework() : mPerf = com.qualcomm.qti.Performance@b391908
01-22 16:14:47.031 11085-11085/info.landingcasts.myapplication V/BoostFramework: BoostFramework() : mPerf = com.qualcomm.qti.Performance@12048a1
01-22 16:14:47.037 11085-11085/info.landingcasts.myapplication I/art: Rejecting re-init on previously-failed class java.lang.Class<android.support.v4.view.ViewCompat$OnUnhandledKeyEventListenerWrapper>
01-22 16:14:47.037 11085-11085/info.landingcasts.myapplication I/art: Rejecting re-init on previously-failed class java.lang.Class<android.support.v4.view.ViewCompat$OnUnhandledKeyEventListenerWrapper>
01-22 16:14:47.108 11085-11102/info.landingcasts.myapplication I/System.out: filename : city.list.json
01-22 16:14:47.109 11085-11102/info.landingcasts.myapplication W/System.err: java.io.FileNotFoundException: city.list.json
01-22 16:14:47.110 11085-11102/info.landingcasts.myapplication W/System.err: at android.content.res.AssetManager.openAsset(Native Method)
01-22 16:14:47.110 11085-11102/info.landingcasts.myapplication W/System.err: at android.content.res.AssetManager.open(AssetManager.java:317)
01-22 16:14:47.110 11085-11102/info.landingcasts.myapplication W/System.err: at info.landingcasts.myapplication.helpers.CustomApplication.getJsonStream(CustomApplication.java:29)
01-22 16:14:47.110 11085-11102/info.landingcasts.myapplication W/System.err: at info.landingcasts.myapplication.MainActivity$PrepareDataSource.doInBackground(MainActivity.java:72)
01-22 16:14:47.110 11085-11102/info.landingcasts.myapplication W/System.err: at info.landingcasts.myapplication.MainActivity$PrepareDataSource.doInBackground(MainActivity.java:62)
01-22 16:14:47.111 11085-11102/info.landingcasts.myapplication W/System.err: at android.os.AsyncTask$2.call(AsyncTask.java:295)
01-22 16:14:47.111 11085-11102/info.landingcasts.myapplication W/System.err: at java.util.concurrent.FutureTask.run(FutureTask.java:237)
01-22 16:14:47.111 11085-11102/info.landingcasts.myapplication W/System.err: at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:234)
01-22 16:14:47.111 11085-11102/info.landingcasts.myapplication W/System.err: at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
01-22 16:14:47.111 11085-11102/info.landingcasts.myapplication W/System.err: at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
01-22 16:14:47.111 11085-11102/info.landingcasts.myapplication W/System.err: at java.lang.Thread.run(Thread.java:818)
01-22 16:14:47.116 11085-11102/info.landingcasts.myapplication E/AndroidRuntime: FATAL EXCEPTION: AsyncTask #1
Process: info.landingcasts.myapplication, PID: 11085
java.lang.RuntimeException: An error occurred while executing doInBackground()
at android.os.AsyncTask$3.done(AsyncTask.java:309)
at java.util.concurrent.FutureTask.finishCompletion(FutureTask.java:354)
at java.util.concurrent.FutureTask.setException(FutureTask.java:223)
at java.util.concurrent.FutureTask.run(FutureTask.java:242)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:234)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
at java.lang.Thread.run(Thread.java:818)
Caused by: java.lang.NullPointerException: lock == null
at java.io.Reader.<init>(Reader.java:64)
at java.io.InputStreamReader.<init>(InputStreamReader.java:77)
at info.landingcasts.myapplication.helpers.CustomApplication.readStream(CustomApplication.java:40)
at info.landingcasts.myapplication.MainActivity$PrepareDataSource.doInBackground(MainActivity.java:73)
at info.landingcasts.myapplication.MainActivity$PrepareDataSource.doInBackground(MainActivity.java:62)
at android.os.AsyncTask$2.call(AsyncTask.java:295)
at java.util.concurrent.FutureTask.run(FutureTask.java:237)
at android.os.AsyncTask$SerialExecutor$1.run(AsyncTask.java:234)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1113)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:588)
at java.lang.Thread.run(Thread.java:818)
01-22 16:14:47.142 11085-11105/info.landingcasts.myapplication D/OpenGLRenderer: Use EGL_SWAP_BEHAVIOR_PRESERVED: true
01-22 16:14:47.187 11085-11085/info.landingcasts.myapplication D/ActivityThreadInjector: clearCachedDrawables.
01-22 16:14:47.249 11085-11105/info.landingcasts.myapplication I/Adreno: QUALCOMM build : 3689ef7, Ibb8f3faafb
Build Date : 07/15/16
OpenGL ES Shader Compiler Version: XE031.08.00.00
Local Branch :
Remote Branch :
Remote Branch :
Reconstruct Branch :
01-22 16:14:47.269 11085-11105/info.landingcasts.myapplication I/OpenGLRenderer: Initialized EGL, version 1.4
01-22 16:14:51.492 11085-11102/info.landingcasts.myapplication I/Process: Sending signal. PID: 11085 SIG: 9
这是我的代码类：
import android.app.Application;
import android.content.res.AssetManager;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.stream.JsonReader;
import info.landingcasts.myapplication.entity.ListJsonObject;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;
import java.util.List;
public class CustomApplication extends Application {
public InputStream getJsonStream(){
AssetManager mgr = getAssets();
String filename = null;
InputStream stream = null;
try {
filename = "city.list.json";
System.out.println("filename : " + filename);
stream = mgr.open(filename, AssetManager.ACCESS_BUFFER);
} catch (IOException e) {
e.printStackTrace();
}
return stream;
}
public List<ListJsonObject> readStream(InputStream stream) {
JsonReader reader = null;
List<ListJsonObject> messages = new ArrayList<ListJsonObject>();
try {
reader = new JsonReader(new InputStreamReader(stream, "UTF-8"));
Gson gson = new GsonBuilder().create();
reader.beginArray();
while (reader.hasNext()) {
ListJsonObject message = gson.fromJson(reader, ListJsonObject.class);
messages.add(message);
}
reader.endArray();
reader.close();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}catch (IOException ex) {
}
Collections.sort(messages, new Comparator<ListJsonObject>() {
@Override
public int compare(ListJsonObject listJsonObject, ListJsonObject nextListJsonObject) {
return listJsonObject.getName().compareToIgnoreCase(nextListJsonObject.getName());
}
});
return messages;
}
}
import android.content.Intent;
import android.content.pm.ActivityInfo;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.Handler;
import android.support.v7.app.ActionBar;
import android.support.v7.app.AppCompatActivity;
import android.view.Window;
import android.view.WindowManager;
import com.google.common.collect.Lists;
import com.google.common.math.IntMath;
import info.landingcasts.myapplication.entity.ListJsonObject;
import info.landingcasts.myapplication.helpers.CustomApplication;
import info.landingcasts.myapplication.helpers.CustomSharedPreference;
import info.landingcasts.myapplication.helpers.Helper;
import java.io.InputStream;
import java.math.RoundingMode;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private static final String TAG = MainActivity.class.getSimpleName();
private final int SPLASH_DISPLAY_LENGTH = 5000;
private CustomSharedPreference customSharedPreference;
@Override
protected void onCreate(Bundle savedInstanceState) {
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
ActionBar actionBar = getSupportActionBar();
if(actionBar != null){
actionBar.hide();
}
customSharedPreference = new CustomSharedPreference(MainActivity.this);
if(!customSharedPreference.getDataSourceIfPresent()){
PrepareDataSource mDataSource = new PrepareDataSource();
mDataSource.execute();
}
new Handler().postDelayed(new Runnable(){
@Override
public void run(){
Intent startActivityIntent = new Intent(MainActivity.this, WeatherActivity.class);
startActivity(startActivityIntent);
MainActivity.this.finish();
}
}, SPLASH_DISPLAY_LENGTH);
}
private class PrepareDataSource extends AsyncTask<Void, Void, Void> {
protected void onProgressUpdate() {
}
protected void onPostExecute() {
}
@Override
protected Void doInBackground(Void... voids) {
InputStream stream = ((CustomApplication)getApplication()).getJsonStream();
List<ListJsonObject> storeSourceData = ((CustomApplication)getApplication()).readStream(stream);
// store data in shared reference
int partitionSize = IntMath.divide(storeSourceData.size(), 2, RoundingMode.UP);
List<List<ListJsonObject>> partitions = Lists.partition(storeSourceData, partitionSize);
List<ListJsonObject> firstListObject = partitions.get(0);
List<ListJsonObject> secondListObject = partitions.get(1);
customSharedPreference.setDataFromSharedPreferences(Helper.STORED_DATA_FIRST, firstListObject);
customSharedPreference.setDataFromSharedPreferences(Helper.STORED_DATA_SECOND, secondListObject);
customSharedPreference.setDataSourceIfPresent(true);
return null;
}
}
}
答案是：是的，我忘了包括资产