Intent.java分析

　　代码位于frameworks/base/core/java/anroid/Content/Intent.java

Intent是对要进行操作的一种抽象描述。用action抽象操作，用data(android.net.Uri)抽象操作参数。

除此之外，category用来描述action所属的类别（添加action对应的component的额外属性）来指导系相应的component如何被匹配与被处理，type用来指定data的MIME类型；component指定用来执行action的组件，如果指定了这个，其他参数被忽略；extra用来给component相应方法附加额外的所需参数。

先打成package android.content，并import这些类

 1 17package android.content;
 2 18
 3 19import android.annotation.AnyRes;
 4 20import android.annotation.IntDef;
 5 21import android.annotation.SdkConstant;
 6 22import android.annotation.SdkConstant.SdkConstantType;
 7 23import android.annotation.SystemApi;
 8 24import android.content.pm.ActivityInfo;
 9 25import android.content.pm.ApplicationInfo;
10 26import android.content.pm.ComponentInfo;
11 27import android.content.pm.PackageManager;
12 28import android.content.pm.ResolveInfo;
13 29import android.content.res.Resources;
14 30import android.content.res.TypedArray;
15 31import android.graphics.Rect;
16 32import android.net.Uri;
17 33import android.os.Build;
18 34import android.os.Bundle;
19 35import android.os.IBinder;
20 36import android.os.Parcel;
21 37import android.os.Parcelable;
22 38import android.os.Process;
23 39import android.os.ResultReceiver;
24 40import android.os.ShellCommand;
25 41import android.os.StrictMode;
26 42import android.os.UserHandle;
27 43import android.provider.DocumentsContract;
28 44import android.provider.DocumentsProvider;
29 45import android.provider.MediaStore;
30 46import android.provider.OpenableColumns;
31 47import android.util.ArraySet;
32 48import android.util.AttributeSet;
33 49import android.util.Log;
34 50import com.android.internal.util.XmlUtils;
35 51import org.xmlpull.v1.XmlPullParser;
36 52import org.xmlpull.v1.XmlPullParserException;
37 53import org.xmlpull.v1.XmlSerializer;
38 54
39 55import java.io.IOException;
40 56import java.io.PrintWriter;
41 57import java.io.Serializable;
42 58import java.lang.annotation.Retention;
43 59import java.lang.annotation.RetentionPolicy;
44 60import java.net.URISyntaxException;
45 61import java.util.ArrayList;
46 62import java.util.HashSet;
47 63import java.util.List;
48 64import java.util.Locale;
49 65import java.util.Objects;
50 66import java.util.Set;
51 67
52 68import static android.content.ContentProvider.maybeAddUserId;

这个类实现了Parcelable和Cloneable接口

1 619public class Intent implements Parcelable, Cloneable {

定义了的attr字符串有action，category，type，component，data，flags

1 620    private static final String ATTR_ACTION = "action";
2 622    private static final String ATTR_CATEGORY = "category";
3 624    private static final String ATTR_TYPE = "type";
4 625    private static final String ATTR_COMPONENT = "component";
5 626    private static final String ATTR_DATA = "data";
6 627    private static final String ATTR_FLAGS = "flags";

tag字符串有categories，extra

1 621    private static final String TAG_CATEGORIES = "categories";
2 623    private static final String TAG_EXTRA = "extra";