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        UriMatcher：

        当我们在使用ContentProvide进行进程间通信时，那我们就必然会用到UriMatcher这个类，这个类的功能可以这样去理解，就是一段字符串与一个数值对应起来，只不过这段字符串是分段存储的，比如"path/csdn"，那么在存的时候会先“/”对这个字符串进行分割然后在存起来，先来一段代码：

private static final String AUTHORITY = "com.zzq.uri";matcher = new UriMatcher(UriMatcher.NO_MATCH);matcher.addURI(AUTHORITY,"path1/zzq1",1);matcher.addURI(AUTHORITY,"path1/zzq2",2);matcher.addURI(AUTHORITY,"path2/zzq3/*",3);matcher.addURI(AUTHORITY,"path2/zzq4/#",4);matcher.match(Uri.parse("content://com.zzq.uri/path1/zzq2"));

它的存储图形：

我们先来说它是如何匹配的，如果是我们自己定义的字符串匹配，那么这个协议头content：//是可以随意取的，实际在这个匹配过程中，这个协议头实际是没有用到的，接下来就是看“com.zzq.uri/path1/zzq2”，内部匹配的时候实际也是讲这个字符串分成了三段，com.zzq.uri、path1、zzq2，分成三段后，先是第一段com.zzq.uri去匹配，匹配到的就只有一个，接下来在这个路径去匹配第二段，匹配到path1，再在path1路径下去匹配第三段，匹配到的结果就是zzq2，zzq2里面有记录添加时对应的数字，到这返回就是2了，对于添加时含有符号是#或*，那么在匹配时，#号对应的位置只要是数字就都可以匹配，而*号对应的位置只要是字符串就都可以匹配。这个类的作用有点像map集合，键是字符串，值是数字。如果还是不太清楚的可以去看源码。

UriMatcher的源码比较短。这里就直接贴出来了：

public class UriMatcher{    public static final int NO_MATCH = -1;    /**     * Creates the root node of the URI tree.     *     * @param code the code to match for the root URI     */    public UriMatcher(int code)    {        mCode = code;        mWhich = -1;        mChildren = new ArrayList
   
    ();        mText = null;    }    private UriMatcher()    {        mCode = NO_MATCH;        mWhich = -1;        mChildren = new ArrayList
    
     ();        mText = null;    }    /**     * Add a URI to match, and the code to return when this URI is     * matched. URI nodes may be exact match string, the token "*"     * that matches any text, or the token "#" that matches only     * numbers.     * 
     
     * Starting from API level {
   @link android.os.Build.VERSION_CODES#JELLY_BEAN_MR2},     * this method will accept a leading slash in the path.     *     * @param authority the authority to match     * @param path the path to match. * may be used as a wild card for     * any text, and # may be used as a wild card for numbers.     * @param code the code that is returned when a URI is matched     * against the given components. Must be positive.     */    public void addURI(String authority, String path, int code)    {        if (code < 0) {            throw new IllegalArgumentException("code " + code + " is invalid: it must be positive");        }        String[] tokens = null;        if (path != null) {            String newPath = path;            // Strip leading slash if present.            if (path.length() > 0 && path.charAt(0) == '/') {                newPath = path.substring(1);            }            tokens = newPath.split("/");        }        int numTokens = tokens != null ? tokens.length : 0;        UriMatcher node = this;        for (int i = -1; i < numTokens; i++) {            String token = i < 0 ? authority : tokens[i];            ArrayList
      
        children = node.mChildren;            int numChildren = children.size();            UriMatcher child;            int j;            for (j = 0; j < numChildren; j++) {                child = children.get(j);                if (token.equals(child.mText)) {                    node = child;                    break;                }            }            if (j == numChildren) {                // Child not found, create it                child = new UriMatcher();                if (token.equals("#")) {                    child.mWhich = NUMBER;                } else if (token.equals("*")) {                    child.mWhich = TEXT;                } else {                    child.mWhich = EXACT;                }                child.mText = token;                node.mChildren.add(child);                node = child;            }        }        node.mCode = code;    }    /**     * Try to match against the path in a url.     *     * @param uri       The url whose path we will match against.     *     * @return  The code for the matched node (added using addURI),      * or -1 if there is no matched node.     */    public int match(Uri uri)    {        final List
       
         pathSegments = uri.getPathSegments();        final int li = pathSegments.size();        UriMatcher node = this;        if (li == 0 && uri.getAuthority() == null) {            return this.mCode;        }        for (int i=-1; i
        
         < 0 ? uri.getAuthority() : pathSegments.get(i); ArrayList
         
           list = node.mChildren; if (list == null) { break; } node = null; int lj = list.size(); for (int j=0; j
          
            '9') { break which_switch; } } node = n; break; case TEXT: node = n; break; } if (node != null) { break; } } if (node == null) { return NO_MATCH; } } return node.mCode; } private static final int EXACT = 0; private static final int NUMBER = 1; private static final int TEXT = 2; private int mCode; private int mWhich; private String mText; private ArrayList
           
             mChildren;}
           
          
         
        
       
      
    
   

        ContentProvide：

public class MyCOntentProvide extends ContentProvider {    private static final String TAG = "MyCOntentProvide";    private static final String authority = "com.example.zzq";    private static UriMatcher matcher = new UriMatcher(UriMatcher.NO_MATCH);    private static final String path1 = "path1";    private static final String path2 = "path2";    private static final String path3 = "path3";    private static final String path4 = "path4";    private static final String path5 = "path5";    private static final int code1 = 1;    private static final int code2 = 2;    private static final int code3 = 3;    private static final int code4 = 4;    private static final int code5 = 5;    static{        matcher.addURI(authority,path1,code1);        matcher.addURI(authority,path2,code2);        matcher.addURI(authority,path3,code3);        matcher.addURI(authority,path4,code4);        matcher.addURI(authority,path5,code5);    }    @Override    public boolean onCreate() {        return false;    }    @Nullable    @Override    public Cursor query(@NonNull Uri uri, @Nullable String[] projection, @Nullable String selection, @Nullable String[] selectionArgs, @Nullable String sortOrder) {        int match = matcher.match(uri);        switch (match){            case code1:                //你的处理                break;            case code2:                //你的处理                break;            case code3:                //你的处理                break;            case code4:                //你的处理                break;            case code5:                //你的处理                break;        }        MatrixCursor cursor = new MatrixCursor(new String[]{
  "name","age"});        cursor.addRow(new String[]{
  "zzq","12"});        return cursor;    }    @Nullable    @Override    public String getType(@NonNull Uri uri) {        return "根据需要返回，也可以不做处理";    }    @Nullable    @Override    public Uri insert(@NonNull Uri uri, @Nullable ContentValues values) {        int match = matcher.match(uri);        switch (match){            case code1:                //你的处理                break;            case code2:                //你的处理                break;            case code3:                //你的处理                break;            case code4:                //你的处理                break;            case code5:                //你的处理                break;        }        return uri;    }    @Override    public int delete(@NonNull Uri uri, @Nullable String selection, @Nullable String[] selectionArgs) {        return 1;    }    @Override    public int update(@NonNull Uri uri, @Nullable ContentValues values, @Nullable String selection, @Nullable String[] selectionArgs) {        return 2;    }}

getContentResolver().query(uri,null,null,null,null);

        对于ContentProvider的使用，这里可以分为两个步骤，一是ContentProvider的注册，二是uri解析：

        1、对于ContentProvider的注册，其主要目的是对外提供访问这个ContentProvider的路径，也就是它的基路径，一般都是content://authorities的值，这个authorities就是注册这个ContentProvider的时候里面的一个属性。

        2、有了基路径content://authoritie后，后面可以在加一些其他的路径content://authorities/...，这样访问到的也是你定义的这个ContentProvider，后面加的参数是什么参数，要做什么处理，那就是你自己定义了，Android为我们提供了对这个路径的处理，那就是UriMatcher。