尝试从Parse中检索信息时，如字符串，数字和图像，我收到以下错误： 特别是，我从ParseImageView接收错误，其中字符串和数字被很好地检索。 logcat消息
08-23 13:25:28.269: E/AndroidRuntime(1377): FATAL EXCEPTION: main
08-23 13:25:28.269: E/AndroidRuntime(1377): Process: com.dooba.beta, PID: 1377
08-23 13:25:28.269: E/AndroidRuntime(1377): java.lang.NullPointerException
08-23 13:25:28.269: E/AndroidRuntime(1377): at com.dooba.beta.Fragment1$1$1.done(Fragment1.java:184)
08-23 13:25:28.269: E/AndroidRuntime(1377): at com.parse.ParseImageView$1.done(ParseImageView.java:157)
08-23 13:25:28.269: E/AndroidRuntime(1377): at com.parse.GetDataCallback.internalDone(GetDataCallback.java:20)
08-23 13:25:28.269: E/AndroidRuntime(1377): at com.parse.GetDataCallback.internalDone(GetDataCallback.java:1)
08-23 13:25:28.269: E/AndroidRuntime(1377): at com.parse.Parse$6$1.run(Parse.java:888)
08-23 13:25:28.269: E/AndroidRuntime(1377): at android.os.Handler.handleCallback(Handler.java:733)
08-23 13:25:28.269: E/AndroidRuntime(1377): at android.os.Handler.dispatchMessage(Handler.java:95)
08-23 13:25:28.269: E/AndroidRuntime(1377): at android.os.Looper.loop(Looper.java:136)
XML布局
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="@drawable/bac_blue"
android:orientation="vertical" >
<Button
android:id="@+id/button1"
android:layout_width="100dp"
android:layout_height="50dp"
android:layout_below="@+id/userlistactivityname"
android:layout_centerHorizontal="true"
android:layout_marginTop="28dp"
android:alpha="0.7"
android:background="#ADD8E6"
android:text="Confirm"
android:textColor="#000000"
android:textSize="22sp"
android:typeface="serif" />
<ListView
android:id="@+id/userlistage"
android:layout_width="220dp"
android:layout_height="50dp"
android:layout_below="@+id/profilePictureresult"
android:layout_marginTop="19dp"
android:layout_toLeftOf="@+id/imageView2"
android:divider="@null" >
</ListView>
<com.parse.ParseImageView
android:id="@+id/profilePictureresult"
android:layout_width="132dp"
android:layout_height="120dp"
android:layout_below="@+id/userlistheadline"
android:layout_centerHorizontal="true"
android:layout_marginTop="17dp"
android:alpha="1"
android:background="@drawable/border_image"
android:cropToPadding="true"
android:padding="3dp"
android:scaleType="centerCrop" />
<ListView
android:id="@+id/userlistname"
android:layout_width="220dp"
android:layout_height="50dp"
android:layout_alignParentTop="true"
android:layout_marginTop="25dp"
android:layout_toRightOf="@+id/imageView1"
android:divider="@null" >
</ListView>
<ImageView
android:id="@+id/imageView2"
android:layout_width="70dp"
android:layout_height="50dp"
android:layout_alignParentRight="true"
android:layout_alignTop="@+id/profilePictureresult"
android:layout_marginTop="16dp"
android:alpha="0.7"
android:src="@drawable/left_right" />
<ImageView
android:id="@+id/imageView1"
android:layout_width="70dp"
android:layout_height="50dp"
android:layout_alignParentLeft="true"
android:layout_alignTop="@+id/imageView2"
android:alpha="0.7"
android:src="@drawable/left_arrow2" />
<ListView
android:id="@+id/userlistheadline"
android:layout_width="220dp"
android:layout_height="50dp"
android:layout_below="@+id/userlistname"
android:layout_marginTop="17dp"
android:layout_toRightOf="@+id/imageView1"
android:divider="@null" >
</ListView>
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/userlistage"
android:layout_centerHorizontal="true"
android:text="Activity Name"
android:textColor="#a2a2a2"
android:textSize="22sp" />
<ListView
android:id="@+id/userlistactivityname"
android:layout_width="220dp"
android:layout_height="50dp"
android:layout_below="@+id/textView1"
android:layout_marginTop="7dp"
android:layout_toLeftOf="@+id/imageView2"
android:divider="@null" >
</ListView>
</RelativeLayout>
活动代码
public class Fragment1 extends Fragment {
public interface Constants {
String LOG = "com.dooba.beta";
}
private String currentUserId;
private ArrayAdapter<String> namesArrayAdapter;
private ArrayList<String> names;
private ArrayList<String> age;
private ArrayList<String> headline;
private ArrayList<String> activityname;
private ArrayList<Images> alProfilePicture;
private ListView usersListView;
private Button logoutButton;
String userGender = ParseUser.getCurrentUser().getString("Gender");
String activityName = ParseUser.getCurrentUser().getString("ActivityName");
Number maxDistance = ParseUser.getCurrentUser().getNumber(
"Maximum_Distance");
String userLookingGender = ParseUser.getCurrentUser().getString(
"Looking_Gender");
Number minimumAge = ParseUser.getCurrentUser().getNumber("Minimum_Age");
Number maximumAge = ParseUser.getCurrentUser().getNumber("Maximum_Age");
Number userage = ParseUser.getCurrentUser().getNumber("Age");
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
setConversationsList();
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment1_layout, container,
false);
return view;
}
private void setConversationsList() {
currentUserId = ParseUser.getCurrentUser().getObjectId();
names = new ArrayList<String>();
age = new ArrayList<String>();
headline = new ArrayList<String>();
activityname = new ArrayList<String>();
alProfilePicture = new ArrayList<Images>();
// String userActivitySelectionName = null;
ParseQuery<ParseUser> query = ParseUser.getQuery();
// query.whereEqualTo("ActivityName",userActivitySelectionName);
query.whereNotEqualTo("objectId", ParseUser.getCurrentUser()
.getObjectId());
// users with Gender = currentUser.Looking_Gender
query.whereEqualTo("Gender", userLookingGender);
// users with Looking_Gender = currentUser.Gender
query.whereEqualTo("Looking_Gender", userGender);
query.setLimit(1);
query.whereEqualTo("ActivityName", activityName);
// query.whereGreaterThanOrEqualTo("Age", minimumAge);
// query.whereLessThanOrEqualTo("Age", maximumAge);
query.orderByDescending("Name");
ParseQuery<ParseUser> query1 = ParseUser.getQuery();
// query.whereEqualTo("ActivityName",userActivitySelectionName);
query1.whereNotEqualTo("objectId", ParseUser.getCurrentUser()
.getObjectId());
// users with Gender = currentUser.Looking_Gender
query1.whereEqualTo("Gender", userLookingGender);
// users with Looking_Gender = currentUser.Gender
query1.whereEqualTo("Looking_Gender", userGender);
query1.setLimit(1);
query1.whereEqualTo("ActivityName", activityName);
// query.whereGreaterThanOrEqualTo("Age", minimumAge);
// query.whereLessThanOrEqualTo("Age", maximumAge);
query1.orderByDescending("Name");
ParseQuery<ParseUser> query11 = ParseUser.getQuery();
// query.whereEqualTo("ActivityName",userActivitySelectionName);
query11.whereNotEqualTo("objectId", ParseUser.getCurrentUser()
.getObjectId());
// users with Gender = currentUser.Looking_Gender
query11.whereEqualTo("Gender", userLookingGender);
// users with Looking_Gender = currentUser.Gender
query11.whereEqualTo("Looking_Gender", userGender);
query11.setLimit(1);
query11.whereEqualTo("ActivityName", activityName);
// query.whereGreaterThanOrEqualTo("Age", minimumAge);
// query.whereLessThanOrEqualTo("Age", maximumAge);
query11.orderByDescending("Name");
Log.d(Constants.LOG, "");
query.findInBackground(new FindCallback<ParseUser>() {
@Override
public void done(List<ParseUser> objects,ParseException e) {
for(int i=0;i<objects.size();i++){
// Do whatever you need to extract object from "users"
ParseQuery<ParseObject> query = ParseQuery.getQuery("User");
query.whereNotEqualTo("objectId", ParseUser.getCurrentUser()
.getObjectId());
// users with Gender = currentUser.Looking_Gender
query.whereEqualTo("Gender", userLookingGender);
// users with Looking_Gender = currentUser.Gender
query.whereEqualTo("Looking_Gender", userGender);
query.setLimit(1);
query.whereEqualTo("ActivityName", activityName);
// query.whereGreaterThanOrEqualTo("Age", minimumAge);
// query.whereLessThanOrEqualTo("Age", maximumAge);
query.orderByDescending("Name");
ParseFile image = objects.get(i).getParseFile("ProfilePicture");
ParseImageView imageView = (ParseImageView) getView().findViewById(R.id.profilePictureresult);
// The placeholder will be used before and during the fetch, to be replaced by the fetched image
// data.
imageView.setPlaceholder(getResources().getDrawable(R.drawable.profile_pict));
imageView.setParseFile(image);
imageView.loadInBackground(new GetDataCallback() {
@Override
public void done(byte[] data, ParseException e) {
Log.i("ParseImageView",
"Fetched! Data length: " + data.length + ", or exception: " + e.getMessage());
}
});
}
}//for loop
});
query1.findInBackground(new FindCallback<ParseUser>() {
public void done(List<ParseUser> userlistname, ParseException e) {
if (e == null) {
for (int i = 0; i < userlistname.size(); i++) {
names.add(userlistname.get(i).get("Name").toString());
}
usersListView = (ListView) getActivity().findViewById(
R.id.userlistname);
namesArrayAdapter = new ArrayAdapter<String>(getActivity()
.getApplicationContext(), R.layout.user_list_item,
names);
usersListView.setAdapter(namesArrayAdapter);
usersListView
.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> a,
View v, int i, long l) {
openConversation(names, i);
}
});
} else {
Toast.makeText(getActivity().getApplicationContext(),
"Error loading user list", Toast.LENGTH_LONG)
.show();
}
}
});
query11.findInBackground(new FindCallback<ParseUser>() {
public void done(List<ParseUser> userlistheadline, ParseException e) {
if (e == null) {
for (int i = 0; i < userlistheadline.size(); i++) {
headline.add(userlistheadline.get(i).get("Headline")
.toString());
}
usersListView = (ListView) getActivity().findViewById(
R.id.userlistheadline);
namesArrayAdapter = new ArrayAdapter<String>(getActivity()
.getApplicationContext(), R.layout.user_list_all,
headline);
usersListView.setAdapter(namesArrayAdapter);
usersListView
.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> a,
View v, int i, long l) {
openConversation(names, i);
}
});
} else {
Toast.makeText(getActivity().getApplicationContext(),
"Error loading user list", Toast.LENGTH_LONG)
.show();
}
}
});
}
public void openConversation(ArrayList<String> names, int pos) {
ParseQuery<ParseUser> query = ParseUser.getQuery();
query.whereEqualTo("Name", names.get(pos));
query.findInBackground(new FindCallback<ParseUser>() {
public void done(List<ParseUser> user, ParseException e) {
if (e == null) {
Intent intent = new Intent(getActivity()
.getApplicationContext(), MessagingActivity.class);
intent.putExtra("RECIPIENT_ID", user.get(0).getObjectId());
startActivity(intent);
} else {
Toast.makeText(getActivity().getApplicationContext(),
"Error finding that user", Toast.LENGTH_SHORT)
.show();
}
}
});
}
}
提前致谢
更新
08-23 11:42:32.291: E/AndroidRuntime(1283): FATAL EXCEPTION: main
08-23 11:42:32.291: E/AndroidRuntime(1283): Process: com.dooba.beta, PID: 1283
08-23 11:42:32.291: E/AndroidRuntime(1283): java.lang.ClassCastException: android.widget.ImageView cannot be cast to com.parse.ParseImageView
08-23 11:42:32.291: E/AndroidRuntime(1283): at com.dooba.beta.Fragment1$1.done(Fragment1.java:174)
08-23 11:42:32.291: E/AndroidRuntime(1283): at com.parse.FindCallback.internalDone(FindCallback.java:45)
08-23 11:42:32.291: E/AndroidRuntime(1283): at com.parse.FindCallback.internalDone(FindCallback.java:1)
08-23 11:42:32.291: E/AndroidRuntime(1283): at com.parse.Parse$6$1.run(Parse.java:888)
08-23 11:42:32.291: E/AndroidRuntime(1283): at android.os.Handler.handleCallback(Handler.java:733)
08-23 11:42:32.291: E/AndroidRuntime(1283): at android.os.Handler.dispatchMessage(Handler.java:95)
08-23 11:42:32.291: E/AndroidRuntime(1283): at android.os.Looper.loop(Looper.java:136)
08-23 11:42:32.291: E/AndroidRuntime(1283): at android.app.ActivityThread.main(ActivityThread.java:5017)
08-23 11:42:32.291: E/AndroidRuntime(1283): at java.lang.reflect.Method.invokeNative(Native Method)
08-23 11:42:32.291: E/AndroidRuntime(1283): at java.lang.reflect.Method.invoke(Method.java:515)
08-23 11:42:32.291: E/AndroidRuntime(1283): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
08-23 11:42:32.291: E/AndroidRuntime(1283): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
08-23 11:42:32.291: E/AndroidRuntime(1283): at dalvik.system.NativeStart.main(Native Method)
08-23 13:25:28.269: E/AndroidRuntime(1377): FATAL EXCEPTION: main
08-23 13:25:28.269: E/AndroidRuntime(1377): Process: com.dooba.beta, PID: 1377
08-23 13:25:28.269: E/AndroidRuntime(1377): java.lang.NullPointerException
08-23 13:25:28.269: E/AndroidRuntime(1377): at com.dooba.beta.Fragment1$1$1.done(Fragment1.java:184)
08-23 13:25:28.269: E/AndroidRuntime(1377): at com.parse.ParseImageView$1.done(ParseImageView.java:157)
08-23 13:25:28.269: E/AndroidRuntime(1377): at com.parse.GetDataCallback.internalDone(GetDataCallback.java:20)
08-23 13:25:28.269: E/AndroidRuntime(1377): at com.parse.GetDataCallback.internalDone(GetDataCallback.java:1)
08-23 13:25:28.269: E/AndroidRuntime(1377): at com.parse.Parse$6$1.run(Parse.java:888)
08-23 13:25:28.269: E/AndroidRuntime(1377): at android.os.Handler.handleCallback(Handler.java:733)
08-23 13:25:28.269: E/AndroidRuntime(1377): at android.os.Handler.dispatchMessage(Handler.java:95)
08-23 13:25:28.269: E/AndroidRuntime(1377): at android.os.Looper.loop(Looper.java:136)
答案 0 :(得分：1)
异常位于Fragment1.java类的第184行，可能就是那行：
Log.i("ParseImageView", "Fetched! Data length: " + data.length + ", or exception: " + e.getMessage());
这将始终抛出NullPointerException：
如果图片正确加载，data将是有效byte[]，e将是null。因此e.getMessage()会抛出NullPointerException
如果图片未正确加载，则data将为null，而e将为有效Exception，因此data.length会投放NullPointerException
你可能想要做的是：
if (data != null) {
Log.i("ParseImageView", "Fetched: " + data.length);
} else {
Log.e("ParseImageView", "Error fetching: " + e.getMessage());
}