Android应用性能优化之使用SparseArray

最近在看一些Android应用性能优化的文章时，发现提到了SparseArray替代HashMap可以优化app性能，就对SparseArray做了一番了解，并记录使用心得。

我们来看看SparseArray点击进去包含了那些方法

 // // Source code recreated from a .class file by IntelliJ IDEA // (powered by Fernflower decompiler) //  package android.util;  public class SparseArray<E> implements Cloneable {     public SparseArray() {         throw new RuntimeException("Stub!");     }      public SparseArray(int initialCapacity) {         throw new RuntimeException("Stub!");     }      public SparseArray<E> clone() {         throw new RuntimeException("Stub!");     }      public E get(int key) {         throw new RuntimeException("Stub!");     }      public E get(int key, E valueIfKeyNotFound) {         throw new RuntimeException("Stub!");     }      public void delete(int key) {         throw new RuntimeException("Stub!");     }      public void remove(int key) {         throw new RuntimeException("Stub!");     }      public void removeAt(int index) {         throw new RuntimeException("Stub!");     }      public void removeAtRange(int index, int size) {         throw new RuntimeException("Stub!");     }      public void put(int key, E value) {         throw new RuntimeException("Stub!");     }      public int size() {         throw new RuntimeException("Stub!");     }      public int keyAt(int index) {         throw new RuntimeException("Stub!");     }      public E valueAt(int index) {         throw new RuntimeException("Stub!");     }      public void setValueAt(int index, E value) {         throw new RuntimeException("Stub!");     }      public int indexOfKey(int key) {         throw new RuntimeException("Stub!");     }      public int indexOfValue(E value) {         throw new RuntimeException("Stub!");     }      public void clear() {         throw new RuntimeException("Stub!");     }      public void append(int key, E value) {         throw new RuntimeException("Stub!");     }      public String toString() {         throw new RuntimeException("Stub!");     } } 

增加

   public void put(int key, E value) {         throw new RuntimeException("Stub!");     }   public void append(int key, E value) {         throw new RuntimeException("Stub!");     }

通过键值对方式存储。

删除

  public void delete(int key) {         throw new RuntimeException("Stub!");     }   public void remove(int key) {         throw new RuntimeException("Stub!");     }   public void removeAt(int index) {         throw new RuntimeException("Stub!");     }   public void removeAtRange(int index, int size) {         throw new RuntimeException("Stub!");     }  public void clear() {         throw new RuntimeException("Stub!");     }

delete，remove根据key来删除，removeAt根据下标删除，removeAtRange根据下标范围删除。

改变

  public void setValueAt(int index, E value) {         throw new RuntimeException("Stub!");     }  public void put(int key, E value) {         throw new RuntimeException("Stub!");     }

setValueAt根据下标来重新赋值，put通过key来重新赋值，有就重新赋值，没有就添加。

查找

  public E get(int key) {         throw new RuntimeException("Stub!");     }  //设置没有查找到的返回信息  public E get(int key, E valueIfKeyNotFound) {         throw new RuntimeException("Stub!");     }  public int keyAt(int index) {         throw new RuntimeException("Stub!");     }   public E valueAt(int index) {         throw new RuntimeException("Stub!");     }  public int indexOfKey(int key) {         throw new RuntimeException("Stub!");     }   public int indexOfValue(E value) {         throw new RuntimeException("Stub!");     } 

get根据key来查找。keyAt根据下标查找key值，valueAt通过下标查找value，indexOfKey通过key查询下标，indexOfValue通过value查找下标。

构造方法

     public SparseArray(int initialCapacity) {         throw new RuntimeException("Stub!");     }

可以初始化长度，SparseArray array=new SparseArray<>(5);

 SparseIntArray intArray=new SparseIntArray(); SparseBooleanArray booleanArray=new SparseBooleanArray(); SparseLongArray longArray=new SparseLongArray();

来取代相应的HashMap

来自： http://blog.csdn.net/qq_16131393/article/details/51821210