我收到一个java.lang.NullPointerException：当我在我的android marshmallow手机上加载我的应用程序时，尝试在空对象引用错误上调用虚拟方法'int android.view.View.getVisibility（）'但它没有在avd模拟器上 这个问题是不同的，因为错误似乎只发生在Android 6.1或更低版本。
AlarmReceiver.java
package com.example.ersch.noschoolcalculator;
public class MainActivity extends AppCompatActivity {
private String htmlContentInStringFormat;
private TextView Day1a;
private TextView Day1b;
private TextView Day1c;
private TextView Day2a;
private TextView Day2b;
private TextView Day2c;
private Boolean weather_gov_error;
private TextView ERROR_LOG;
private String first;
public Boolean fatal_error;
private String second;
private String day1a;
private String[] day1b;
private String day1c;
private String day2c;
private String day2a;
private String[] day2b;
private PendingIntent pendingIntent;
private AlarmManager manager;
private String[] months = {"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};
private StringBuilder sb = new StringBuilder(14);
private Map<String, String> firstlist = new HashMap<>();
private Map<String, String> secondlist = new HashMap<>();
public static void longInfo(String str) {
if(str.length() > 4000) {
Log.i("Message:", str.substring(0, 4000));
longInfo(str.substring(4000));
} else
Log.i("Message:", str);
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//executes jsoup
JsoupAsyncTask jsoupAsyncTask = new JsoupAsyncTask();
jsoupAsyncTask.execute();
//initializes layout
setContentView(R.layout.activity_main);
Day1a = (TextView)findViewById(R.id.Day1a);
Day1b = (TextView)findViewById(R.id.Day1b);
Day1c = (TextView)findViewById(R.id.Day1c);
Day2a = (TextView)findViewById(R.id.Day2a);
Day2b = (TextView)findViewById(R.id.Day2b);
Day2c = (TextView)findViewById(R.id.Day2c);
ERROR_LOG = (TextView)findViewById(R.id.ERROR_LOG);
ERROR_LOG.setVisibility(View.INVISIBLE);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
//button click
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Snackbar.make(view, "Refreshing", Snackbar.LENGTH_SHORT)
.setAction("Action", null).show();
longInfo("Refreshing");
JsoupAsyncTask jsoupAsyncTask = new JsoupAsyncTask();
jsoupAsyncTask.execute();
}
});
}
@Override
public void onResume(){
super.onResume();
Intent alarmIntent = new Intent(this, AlarmReceiver.class);
pendingIntent = PendingIntent.getBroadcast(this, 0, alarmIntent, 0);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
public void startAlarm(View view) {
manager = (AlarmManager)getSystemService(Context.ALARM_SERVICE);
int interval = 10000;
manager.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), interval, pendingIntent);
Toast.makeText(this, "Alarm Set", Toast.LENGTH_SHORT).show();
longInfo("Alarm Set");
}
public void cancelAlarm(View view) {
if (manager != null) {
manager.cancel(pendingIntent);
Toast.makeText(this, "Alarm Canceled", Toast.LENGTH_SHORT).show();
longInfo("Alarm Canceled");
}
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public static boolean isListContainMethod(List<String> arraylist,String value) {
for (String str : arraylist) {
if (!str.toLowerCase().contains(value)) {
return false;
}
}
return true;
}
public class JsoupAsyncTask extends AsyncTask<Void, Void, Void> {
@Override
protected void onPreExecute() {
super.onPreExecute();
}
@Override
protected Void doInBackground(Void... params) {
try {
String loginFormUrl = "https://www.snowdaycalculator.com/Account/login.php";
String loginActionUrl = "https://www.snowdaycalculator.com/prediction.php?zipcode=10562&snowdays=0&extra=0&";
String email = "erschmny@gmail.com";
String passinstr = "email";
String password = "ltlake66";
HashMap<String, String> cookies = new HashMap<>();
HashMap<String, String> formData = new HashMap<>();
Connection.Response loginForm = Jsoup.connect(loginFormUrl).method(Connection.Method.GET).execute();
Document loginDoc = loginForm.parse(); // this is the document that contains response html
cookies.putAll(loginForm.cookies());
formData.put("passInstr", "password");
formData.put("email", email);
formData.put("password", password);
formData.put("back", "");
Connection.Response homePage = Jsoup.connect(loginActionUrl)
.cookies(cookies)
.data(formData)
.method(Connection.Method.POST)
.execute();
htmlContentInStringFormat = homePage.parse().html();
//longInfo(htmlContentInStringFormat);
String[] lines = htmlContentInStringFormat.split("\\r?\\n");
Pattern p = Pattern.compile("(theChance\\[)[0-9]{5,11}] = -?\\d*\\.?\\d+E*\\+*\\d*;");
int x = 0;
for( int i = 0; i < lines.length - 1; i++) {
Matcher m = p.matcher(lines[i]);
if (m.find()) {
if (x == 0) {
first = lines[i];
x += 1;
}
else{
second = lines[i];
}
}
}
longInfo(first);
if (first != null & second != null){
String regex = "[0-9]{8,11}";
Matcher m = Pattern.compile(regex).matcher(first);
if (m.find()) {
firstlist.put("date",Long.toString(Math.round(Double.parseDouble(m.group()))));
}
String regex2 = "-?\\d*\\.?\\d*;";
Matcher m2 = Pattern.compile(regex2).matcher(first);
if (m2.find()) {
firstlist.put("chance",Long.toString(Math.round(Double.parseDouble(m2.group().substring(0, m2.group().length()-1)))));
}
String regex3 = "[0-9]{8,11}";
Matcher m3 = Pattern.compile(regex3).matcher(second);
if (m3.find()) {
secondlist.put("date",Long.toString(Math.round(Double.parseDouble(m3.group()))));
}
String regex4 = "-?\\d*\\.?\\d*;";
Matcher m4 = Pattern.compile(regex4).matcher(second);
if (m4.find()) {
secondlist.put("chance",Long.toString(Math.round(Double.parseDouble(m4.group().substring(0, m2.group().length()-1)))));
}
sb.setLength(0);
day1a = firstlist.get("date");
day1b = day1a.split("(?!^)");
sb.append(day1b[0]).append(day1b[1]).append(day1b[2]).append(day1b[3]);
firstlist.put("year", sb.toString());
sb.setLength(0);
sb.append(day1b[4]).append(day1b[5]);
firstlist.put("month", sb.toString());
sb.setLength(0);
sb.append(day1b[6]).append(day1b[7]);
firstlist.put("day", sb.toString());
longInfo(firstlist.toString());
day2a = secondlist.get("date");
day2b = day2a.split("(?!^)");
sb.setLength(0);
sb.append(day2b[0]).append(day2b[1]).append(day2b[2]).append(day2b[3]);
secondlist.put("year", sb.toString());
sb.setLength(0);
sb.append(day2b[4]).append(day2b[5]);
secondlist.put("month", sb.toString());
sb.setLength(0);
sb.append(day2b[6]).append(day2b[7]);
secondlist.put("day", sb.toString());
longInfo(secondlist.toString());
htmlContentInStringFormat = homePage.parse().html();
lines = htmlContentInStringFormat.split("\\r?\\n");
p = Pattern.compile("(1.5em\">)|(0.85em\")");
x = 0;
for( int i = 0; i < lines.length - 1; i++) {
m = p.matcher(lines[i]);
if (m.find()) {
if (x == 0) {
first = lines[i];
longInfo(first);
x += 1;
}
else{
second = lines[i];
longInfo(second);
}
}
}
regex = ">[A-z0-9, %]{2,1000}";
m = Pattern.compile(regex).matcher(first);
sb.setLength(0);
while (m.find()) {
sb.append(m.group());
}
String temp = sb.toString();
temp = temp.replaceAll(">","");
temp = temp.replaceAll("T","t");
firstlist.put("message",temp);
longInfo(firstlist.get("message"));
regex = ">[A-z0-9, %]{2,1000}";
m = Pattern.compile(regex).matcher(second);
sb.setLength(0);
while (m.find()) {
sb.append(m.group());
}
temp = sb.toString();
temp = temp.replaceAll(">","");
temp = temp.replaceAll("T","t");
secondlist.put("message",temp);
longInfo(secondlist.get("message"));
}
else{
p = Pattern.compile("<b>Fatal error<\\/b>[A-z :()<>/.0-9]*");
x = 0;
for( int i = 0; i < lines.length - 1; i++) {
Matcher m = p.matcher(lines[i]);
if (m.find()) {
if (x == 0) {
fatal_error = Boolean.TRUE;
x += 1;
longInfo(fatal_error.toString());
}
else{
longInfo("Extra fatal error data received");
}
}
}
p = Pattern.compile("\\/\\*\\*\\/\\/\\*Error[\\*={'\"#!;}A-z :()<>/.0-9]*");
//not verified working
x = 0;
for( int i = 0; i < lines.length - 1; i++) {
Matcher m = p.matcher(lines[i]);
if (m.find()) {
if (x == 0) {
weather_gov_error = Boolean.TRUE;
x += 1;
longInfo(weather_gov_error.toString());
}
else{
longInfo("Extra weather.gov error data received");
}
}
}
}
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Void result) {
if (first != null & second != null){
Day1a.setText(months[Integer.parseInt(firstlist.get("month")) - 1] + " " + firstlist.get("day") + ", " + firstlist.get("year"));
if (Integer.parseInt(firstlist.get("chance")) <= 0) {
Day1b.setText("Low");
}
else{
Day1b.setText(firstlist.get("chance") + "%");
}
Day1c.setText(firstlist.get("message") + ".");
Day2a.setText(months[Integer.parseInt(secondlist.get("month")) - 1] + " " + secondlist.get("day") + ", " + secondlist.get("year"));
if (Integer.parseInt(secondlist.get("chance")) <= 0) {
Day2b.setText("Low");
}
else{
Day2b.setText(secondlist.get("chance") + "%");
}
Day2c.setText(secondlist.get("message") + ".");
}
else {
Day1a.setText("Error");
Day1b.setText("Error");
Day1c.setText("Error");
Day2a.setText("Error");
Day2b.setText("Error");
Day2c.setText("Error");
if (fatal_error) {
ERROR_LOG.setVisibility(View.VISIBLE);
ERROR_LOG.setText("Website: Fatal Error");
}
else {
ERROR_LOG.setVisibility(View.INVISIBLE);
}
if (weather_gov_error) {
ERROR_LOG.setVisibility(View.VISIBLE);
ERROR_LOG.setText("Website: Weather Error");
}
else {
ERROR_LOG.setVisibility(View.INVISIBLE);
}
}
}
}
}
cell_shape.xml
<?xml version="1.0" encoding="utf-8"?>
<shape
xmlns:android="http://schemas.android.com/apk/res/android"
android:shape= "rectangle" >
<solid android:color="#ffffff"/>
<stroke android:width="1dp" android:color="#000000"/>
activity_main.xml中
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="com.example.ersch.noschoolcalculator.MainActivity">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="@style/AppTheme.AppBarOverlay">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:popupTheme="@style/AppTheme.PopupOverlay" />
</android.support.design.widget.AppBarLayout>
<include layout="@layout/content_main" />
<android.support.design.widget.FloatingActionButton
android:id="@+id/fab"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom|end"
android:layout_margin="@dimen/fab_margin"
app:srcCompat="@android:drawable/ic_popup_sync"
app:backgroundTint="@android:color/holo_green_dark"
app:rippleColor="@android:color/holo_red_dark" />
contnt_main.xml
<?xml version="1.0" encoding="utf-8"?>
<TableLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:gravity="center_horizontal"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/content_main"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
tools:context="com.example.ersch.noschoolcalculator.MainActivity"
tools:showIn="@layout/activity_main">
<TableRow
android:gravity="center_horizontal">
<TextView
android:background="@drawable/cell_shape"
android:layout_column="1"
android:text="Date"
android:gravity="center_horizontal"
android:padding="3dip"
android:paddingStart="10dip"
android:paddingEnd="10dip"
android:textColor="@android:color/black"
android:textSize="18sp" />
<TextView
android:background="@drawable/cell_shape"
android:text="Chance"
android:gravity="center_horizontal"
android:padding="3dip"
android:paddingStart="10dip"
android:paddingEnd="10dip"
android:textColor="@android:color/black"
android:textSize="18sp" />
<TextView
android:background="@drawable/cell_shape"
android:text="Message"
android:gravity="center_horizontal"
android:padding="3dip"
android:paddingStart="10dip"
android:layout_weight="1"
android:paddingEnd="10dip"
android:textColor="@android:color/black"
android:textSize="18sp" />
</TableRow>
<TableRow android:gravity="center_horizontal"
android:layout_height="match_parent"
android:layout_width="match_parent">
<TextView
android:background="@drawable/cell_shape"
android:gravity="center_horizontal"
android:layout_column="1"
android:padding="3dip"
android:paddingStart="10dip"
android:paddingEnd="10dip"
android:id="@+id/Day1a"
android:textSize="18sp"
android:layout_height="match_parent" />
<TextView
android:background="@drawable/cell_shape"
android:gravity="center_horizontal"
android:padding="3dip"
android:paddingStart="10dip"
android:paddingEnd="10dip"
android:id="@+id/Day1b"
android:textSize="18sp"
android:layout_height="match_parent" />
<TextView
android:background="@drawable/cell_shape"
android:gravity="center_horizontal"
android:padding="3dip"
android:paddingStart="10dip"
android:paddingEnd="10dip"
android:id="@+id/Day1c"
android:textSize="12sp"
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</TableRow>
<TableRow android:gravity="center_horizontal">
<TextView
android:background="@drawable/cell_shape"
android:layout_column="1"
android:padding="3dip"
android:paddingStart="10dip"
android:paddingEnd="10dip"
android:gravity="center_horizontal"
android:id="@+id/Day2a"
android:textSize="18sp"
android:layout_height="match_parent" />
<TextView
android:background="@drawable/cell_shape"
android:gravity="center_horizontal"
android:padding="3dip"
android:paddingStart="10dip"
android:paddingEnd="10dip"
android:id="@+id/Day2b"
android:textSize="18sp"
android:layout_height="match_parent" />
<TextView
android:background="@drawable/cell_shape"
android:gravity="center_horizontal"
android:padding="3dip"
android:paddingStart="10dip"
android:paddingEnd="10dip"
android:id="@+id/Day2c"
android:textSize="12sp"
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</TableRow>
<TextView
android:background="@drawable/cell_shape"
android:gravity="center_horizontal"
android:padding="3dip"
android:paddingStart="10dip"
android:paddingEnd="10dip"
android:id="@+id/ERROR_LOG"
android:textSize="12sp"
android:layout_weight="1"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<Button
android:id="@+id/button1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Start Alarm"
android:onClick="startAlarm" />
<Button
android:id="@+id/button2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Cancel Alarm"
android:onClick="cancelAlarm" />
Android清单
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.ersch.noschoolcalculator">
<uses-permission android:name="android.permission.INTERNET" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<receiver android:name=".AlarmReceiver"></receiver>
<activity
android:name=".MainActivity"
android:label="@string/app_name"
android:theme="@style/AppTheme.NoActionBar">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
错误消息
--------- beginning of crash
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.ersch.noschoolcalculator, PID: 2203
java.lang.NullPointerException: Attempt to invoke virtual method 'int android.view.View.getVisibility()' on a null object reference
at android.widget.LinearLayout.forceUniformHeight(LinearLayout.java:1380)
at android.widget.LinearLayout.measureHorizontal(LinearLayout.java:1368)
at android.widget.TableRow.onMeasure(TableRow.java:114)
at android.view.View.measure(View.java:17547)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436)
at android.widget.TableLayout.measureChildBeforeLayout(TableLayout.java:464)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:722)
at android.widget.TableLayout.measureVertical(TableLayout.java:476)
at android.widget.TableLayout.onMeasure(TableLayout.java:439)
at android.view.View.measure(View.java:17547)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535)
at android.support.design.widget.CoordinatorLayout.onMeasureChild(CoordinatorLayout.java:703)
at android.support.design.widget.HeaderScrollingViewBehavior.onMeasureChild(HeaderScrollingViewBehavior.java:90)
at android.support.design.widget.AppBarLayout$ScrollingViewBehavior.onMeasureChild(AppBarLayout.java:1367)
at android.support.design.widget.CoordinatorLayout.onMeasure(CoordinatorLayout.java:768)
at android.view.View.measure(View.java:17547)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:139)
at android.view.View.measure(View.java:17547)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:722)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:613)
at android.view.View.measure(View.java:17547)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
at android.view.View.measure(View.java:17547)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535)
at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1436)
at android.widget.LinearLayout.measureVertical(LinearLayout.java:722)
at android.widget.LinearLayout.onMeasure(LinearLayout.java:613)
at android.view.View.measure(View.java:17547)
at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5535)
at android.widget.FrameLayout.onMeasure(FrameLayout.java:436)
at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2615)
at android.view.View.measure(View.java:17547)
at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2015)
at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1173)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1379)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1061)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5885)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:767)
at android.view.Choreographer.doCallbacks(Choreographer.java:580)
at android.view.Choreographer.doFrame(Choreographer.java:550)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:753)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
I/Message:: theChance[20170219] = -1; //PREDICTION
I/Message:: {day=19, date=20170219, month=02, chance=-1, year=2017}
I/Message:: {day=20, date=20170220, month=02, chance=-1, year=2017}
Application terminated.
答案 0 :(得分：1)
这只是意味着视图没有膨胀。从本质上讲，您已经设置了一个条件，您可以在调用回调之前依赖于View来获取膨胀（例如在onCreate方法中）。你不能这样做，一般来说，你不能在真实的手机上预测会发生哪种情况。甚至可能发生在同一部手机上，您的代码可以在50％的时间内工作。基本上你需要延迟调用回调，直到创建完所有内容。