Android APIs
public class

JSONArray

extends Object
java.lang.Object
   ↳ org.json.JSONArray

Class Overview

A dense indexed sequence of values. Values may be any mix of JSONObjects, other JSONArrays, Strings, Booleans, Integers, Longs, Doubles, null or NULL. Values may not be NaNs, infinities, or of any type not listed here.

JSONArray has the same type coercion behavior and optional/mandatory accessors as JSONObject. See that class' documentation for details.

Warning: this class represents null in two incompatible ways: the standard Java null reference, and the sentinel value NULL. In particular, get fails if the requested index holds the null reference, but succeeds if it holds JSONObject.NULL.

Instances of this class are not thread safe. Although this class is nonfinal, it was not designed for inheritance and should not be subclassed. In particular, self-use by overridable methods is not specified. See Effective Java Item 17, "Design and Document or inheritance or else prohibit it" for further information.

Summary

Public Constructors
JSONArray()
Creates a JSONArray with no values.
JSONArray(Collection copyFrom)
Creates a new JSONArray by copying all values from the given collection.
JSONArray(JSONTokener readFrom)
Creates a new JSONArray with values from the next array in the tokener.
JSONArray(String json)
Creates a new JSONArray with values from the JSON string.
JSONArray(Object array)
Creates a new JSONArray with values from the given primitive array.
Public Methods
boolean equals(Object o)
Compares this instance with the specified object and indicates if they are equal.
Object get(int index)
Returns the value at index.
boolean getBoolean(int index)
Returns the value at index if it exists and is a boolean or can be coerced to a boolean.
double getDouble(int index)
Returns the value at index if it exists and is a double or can be coerced to a double.
int getInt(int index)
Returns the value at index if it exists and is an int or can be coerced to an int.
JSONArray getJSONArray(int index)
Returns the value at index if it exists and is a JSONArray.
JSONObject getJSONObject(int index)
Returns the value at index if it exists and is a JSONObject.
long getLong(int index)
Returns the value at index if it exists and is a long or can be coerced to a long.
String getString(int index)
Returns the value at index if it exists, coercing it if necessary.
int hashCode()
Returns an integer hash code for this object.
boolean isNull(int index)
Returns true if this array has no value at index, or if its value is the null reference or NULL.
String join(String separator)
Returns a new string by alternating this array's values with separator.
int length()
Returns the number of values in this array.
Object opt(int index)
Returns the value at index, or null if the array has no value at index.
boolean optBoolean(int index)
Returns the value at index if it exists and is a boolean or can be coerced to a boolean.
boolean optBoolean(int index, boolean fallback)
Returns the value at index if it exists and is a boolean or can be coerced to a boolean.
double optDouble(int index, double fallback)
Returns the value at index if it exists and is a double or can be coerced to a double.
double optDouble(int index)
Returns the value at index if it exists and is a double or can be coerced to a double.
int optInt(int index)
Returns the value at index if it exists and is an int or can be coerced to an int.
int optInt(int index, int fallback)
Returns the value at index if it exists and is an int or can be coerced to an int.
JSONArray optJSONArray(int index)
Returns the value at index if it exists and is a JSONArray.
JSONObject optJSONObject(int index)
Returns the value at index if it exists and is a JSONObject.
long optLong(int index, long fallback)
Returns the value at index if it exists and is a long or can be coerced to a long.
long optLong(int index)
Returns the value at index if it exists and is a long or can be coerced to a long.
String optString(int index)
Returns the value at index if it exists, coercing it if necessary.
String optString(int index, String fallback)
Returns the value at index if it exists, coercing it if necessary.
JSONArray put(Object value)
Appends value to the end of this array.
JSONArray put(int index, int value)
Sets the value at index to value, null padding this array to the required length if necessary.
JSONArray put(int index, boolean value)
Sets the value at index to value, null padding this array to the required length if necessary.
JSONArray put(int index, long value)
Sets the value at index to value, null padding this array to the required length if necessary.
JSONArray put(int index, Object value)
Sets the value at index to value, null padding this array to the required length if necessary.
JSONArray put(boolean value)
Appends value to the end of this array.
JSONArray put(int index, double value)
Sets the value at index to value, null padding this array to the required length if necessary.
JSONArray put(int value)
Appends value to the end of this array.
JSONArray put(long value)
Appends value to the end of this array.
JSONArray put(double value)
Appends value to the end of this array.
Object remove(int index)
Removes and returns the value at index, or null if the array has no value at index.
JSONObject toJSONObject(JSONArray names)
Returns a new object whose values are the values in this array, and whose names are the values in names.
String toString()
Encodes this array as a compact JSON string, such as: 
[94043,90210]
String toString(int indentSpaces)
Encodes this array as a human readable JSON string for debugging, such as: 
 [
     94043,
     90210
 ]
[Expand]
Inherited Methods
From class java.lang.Object

Public Constructors

public JSONArray ()

Added in API level 1

Creates a JSONArray with no values.

public JSONArray (Collection copyFrom)

Added in API level 1

Creates a new JSONArray by copying all values from the given collection.

Parameters
copyFrom a collection whose values are of supported types. Unsupported values are not permitted and will yield an array in an inconsistent state.

public JSONArray (JSONTokener readFrom)

Added in API level 1

Creates a new JSONArray with values from the next array in the tokener.

Parameters
readFrom a tokener whose nextValue() method will yield a JSONArray.
Throws
JSONException if the parse fails or doesn't yield a JSONArray.

public JSONArray (String json)

Added in API level 1

Creates a new JSONArray with values from the JSON string.

Parameters
json a JSON-encoded string containing an array.
Throws
JSONException if the parse fails or doesn't yield a JSONArray.

public JSONArray (Object array)

Added in API level 19

Creates a new JSONArray with values from the given primitive array.

Throws
JSONException

Public Methods

public boolean equals (Object o)

Added in API level 1

Compares this instance with the specified object and indicates if they are equal. In order to be equal, o must represent the same object as this instance using a class-specific comparison. The general contract is that this comparison should be reflexive, symmetric, and transitive. Also, no object reference other than null is equal to null.

The default implementation returns true only if this == o. See Writing a correct equals method if you intend implementing your own equals method.

The general contract for the equals and hashCode() methods is that if equals returns true for any two objects, then hashCode() must return the same value for these objects. This means that subclasses of Object usually override either both methods or neither of them.

Parameters
o the object to compare this instance with.
Returns
  • true if the specified object is equal to this Object; false otherwise.

public Object get (int index)

Added in API level 1

Returns the value at index.

Throws
JSONException if this array has no value at index, or if that value is the null reference. This method returns normally if the value is JSONObject#NULL.

public boolean getBoolean (int index)

Added in API level 1

Returns the value at index if it exists and is a boolean or can be coerced to a boolean.

Throws
JSONException if the value at index doesn't exist or cannot be coerced to a boolean.

public double getDouble (int index)

Added in API level 1

Returns the value at index if it exists and is a double or can be coerced to a double.

Throws
JSONException if the value at index doesn't exist or cannot be coerced to a double.

public int getInt (int index)

Added in API level 1

Returns the value at index if it exists and is an int or can be coerced to an int.

Throws
JSONException if the value at index doesn't exist or cannot be coerced to a int.

public JSONArray getJSONArray (int index)

Added in API level 1

Returns the value at index if it exists and is a JSONArray.

Throws
JSONException if the value doesn't exist or is not a JSONArray.

public JSONObject getJSONObject (int index)

Added in API level 1

Returns the value at index if it exists and is a JSONObject.

Throws
JSONException if the value doesn't exist or is not a JSONObject.

public long getLong (int index)

Added in API level 1

Returns the value at index if it exists and is a long or can be coerced to a long.

Throws
JSONException if the value at index doesn't exist or cannot be coerced to a long.

public String getString (int index)

Added in API level 1

Returns the value at index if it exists, coercing it if necessary.

Throws
JSONException if no such value exists.

public int hashCode ()

Added in API level 1

Returns an integer hash code for this object. By contract, any two objects for which equals(Object) returns true must return the same hash code value. This means that subclasses of Object usually override both methods or neither method.

Note that hash values must not change over time unless information used in equals comparisons also changes.

See Writing a correct hashCode method if you intend implementing your own hashCode method.

Returns
  • this object's hash code.

public boolean isNull (int index)

Added in API level 1

Returns true if this array has no value at index, or if its value is the null reference or NULL.

public String join (String separator)

Added in API level 1

Returns a new string by alternating this array's values with separator. This array's string values are quoted and have their special characters escaped. For example, the array containing the strings '12" pizza', 'taco' and 'soda' joined on '+' returns this: 

"12\" pizza"+"taco"+"soda"

Throws
JSONException

public int length ()

Added in API level 1

Returns the number of values in this array.

public Object opt (int index)

Added in API level 1

Returns the value at index, or null if the array has no value at index.

public boolean optBoolean (int index)

Added in API level 1

Returns the value at index if it exists and is a boolean or can be coerced to a boolean. Returns false otherwise.

public boolean optBoolean (int index, boolean fallback)

Added in API level 1

Returns the value at index if it exists and is a boolean or can be coerced to a boolean. Returns fallback otherwise.

public double optDouble (int index, double fallback)

Added in API level 1

Returns the value at index if it exists and is a double or can be coerced to a double. Returns fallback otherwise.

public double optDouble (int index)

Added in API level 1

Returns the value at index if it exists and is a double or can be coerced to a double. Returns NaN otherwise.

public int optInt (int index)

Added in API level 1

Returns the value at index if it exists and is an int or can be coerced to an int. Returns 0 otherwise.

public int optInt (int index, int fallback)

Added in API level 1

Returns the value at index if it exists and is an int or can be coerced to an int. Returns fallback otherwise.

public JSONArray optJSONArray (int index)

Added in API level 1

Returns the value at index if it exists and is a JSONArray. Returns null otherwise.

public JSONObject optJSONObject (int index)

Added in API level 1

Returns the value at index if it exists and is a JSONObject. Returns null otherwise.

public long optLong (int index, long fallback)

Added in API level 1

Returns the value at index if it exists and is a long or can be coerced to a long. Returns fallback otherwise.

public long optLong (int index)

Added in API level 1

Returns the value at index if it exists and is a long or can be coerced to a long. Returns 0 otherwise.

public String optString (int index)

Added in API level 1

Returns the value at index if it exists, coercing it if necessary. Returns the empty string if no such value exists.

public String optString (int index, String fallback)

Added in API level 1

Returns the value at index if it exists, coercing it if necessary. Returns fallback if no such value exists.

public JSONArray put (Object value)

Added in API level 1

Appends value to the end of this array.

Parameters
value a JSONObject, JSONArray, String, Boolean, Integer, Long, Double, NULL, or null. May not be NaNs or infinities. Unsupported values are not permitted and will cause the array to be in an inconsistent state.
Returns
  • this array.

public JSONArray put (int index, int value)

Added in API level 1

Sets the value at index to value, null padding this array to the required length if necessary. If a value already exists at index, it will be replaced.

Returns
  • this array.
Throws
JSONException

public JSONArray put (int index, boolean value)

Added in API level 1

Sets the value at index to value, null padding this array to the required length if necessary. If a value already exists at index, it will be replaced.

Returns
  • this array.
Throws
JSONException

public JSONArray put (int index, long value)

Added in API level 1

Sets the value at index to value, null padding this array to the required length if necessary. If a value already exists at index, it will be replaced.

Returns
  • this array.
Throws
JSONException

public JSONArray put (int index, Object value)

Added in API level 1

Sets the value at index to value, null padding this array to the required length if necessary. If a value already exists at index, it will be replaced.

Parameters
value a JSONObject, JSONArray, String, Boolean, Integer, Long, Double, NULL, or null. May not be NaNs or infinities.
Returns
  • this array.
Throws
JSONException

public JSONArray put (boolean value)

Added in API level 1

Appends value to the end of this array.

Returns
  • this array.

public JSONArray put (int index, double value)

Added in API level 1

Sets the value at index to value, null padding this array to the required length if necessary. If a value already exists at index, it will be replaced.

Parameters
value a finite value. May not be NaNs or infinities.
Returns
  • this array.
Throws
JSONException

public JSONArray put (int value)

Added in API level 1

Appends value to the end of this array.

Returns
  • this array.

public JSONArray put (long value)

Added in API level 1

Appends value to the end of this array.

Returns
  • this array.

public JSONArray put (double value)

Added in API level 1

Appends value to the end of this array.

Parameters
value a finite value. May not be NaNs or infinities.
Returns
  • this array.
Throws
JSONException

public Object remove (int index)

Added in API level 19

Removes and returns the value at index, or null if the array has no value at index.

public JSONObject toJSONObject (JSONArray names)

Added in API level 1

Returns a new object whose values are the values in this array, and whose names are the values in names. Names and values are paired up by index from 0 through to the shorter array's length. Names that are not strings will be coerced to strings. This method returns null if either array is empty.

Throws
JSONException

public String toString ()

Added in API level 1

Encodes this array as a compact JSON string, such as: 

[94043,90210]

Returns
  • a printable representation of this object.

public String toString (int indentSpaces)

Added in API level 1

Encodes this array as a human readable JSON string for debugging, such as: 

 [
     94043,
     90210
 ]

Parameters
indentSpaces the number of spaces to indent for each level of nesting.
Throws
JSONException