一、Activity Results API介绍
Activity Results API 是 Google官方推荐的Activity、Fragment获取数据的方式。Activity Results API 中两个重要的组件：ActivityResultContract和ActivityResultLauncher。
① ActivityResultContract: 协议，它定义了如何传递数据和如何处理返回的数据。ActivityResultContract是一个抽象类，你需要继承它来创建自己的协议，每个 ActivityResultContract 都需要定义输入和输出类型，如果您不需要任何输入，可使用 Void（在 Kotlin 中，使用 Void? 或 Unit）作为输入类型。
②ActivityResultLauncher: 启动器，调用ActivityResultLauncher的launch方法来启动页面跳转，作用相当于原来的startActivity()
二、调用预定义的Contract
在Activity和Fragment中调用内置的Contract的简单使用。
引入库
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3implementation 'androidx.activity:activity:1.4.0' implementation 'androidx.fragment:fragment:1.4.1'
1、预定义Contract介绍
| 预定义Contract | 释义 |
|---|---|
| StartActivityForResult() | 通用的Contract,不做任何转换，Intent作为输入，ActivityResult作为输出，这也是最常用的一个协定。 |
| RequestMultiplePermissions() | 用于请求一组权限 |
| RequestPermission() | 用于请求单个权限 |
| TakePicturePreview() | 调用MediaStore.ACTION_IMAGE_CAPTURE拍照，返回值为Bitmap图片 |
| TakePicture() | 调用MediaStore.ACTION_IMAGE_CAPTURE拍照，并将图片保存到给定的Uri地址，返回true表示保存成功。 |
| TakeVideo() | 调用MediaStore.ACTION_VIDEO_CAPTURE 拍摄视频，保存到给定的Uri地址，返回一张缩略图。 |
| PickContact() | 从通讯录APP获取联系人 |
| CreateDocument() | 提示用户选择一个文档，返回一个(file:/http:/content:)开头的Uri。 |
| OpenDocumentTree() | 提示用户选择一个目录，并返回用户选择的作为一个Uri返回，应用程序可以完全管理返回目录中的文档。 |
| OpenMultipleDocuments() | 提示用户选择文档（可以选择多个），分别返回它们的Uri，以List的形式。 |
| OpenDocument() | 提示用户选择文档，返回它的Uri |
| GetContent() | 提示用选择一条内容，返回一个通过ContentResolver#openInputStream(Uri)访问原生数据的Uri地址（content://形式） 。默认情况下，它增加了 Intent#CATEGORY_OPENABLE, 返回可以表示流的内容。 |
上面这些预定义的Contract中，除了StartActivityForResult和RequestMultiplePermissions之外，基本都是处理的与其他APP交互，返回数据的场景，比如，拍照，选择图片，选择联系人，打开文档等等。使用最多的就是StartActivityForResult和RequestMultiplePermissions了。
2、简单使用
ActivityResultLauncher必需在activity的onCreate()方法或fragment的onCreate()、onAttach()前先注册，然后在需要调用的地方调用launch方法
1)示例一：页面跳转
从MainActivity跳转到TwoActicity
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39public class MainActivity extends AppCompatActivity { private ActivityResultLauncher<Intent> mIntentActivityResultLauncher; private Context mContext; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mContext = this; //只能在onCreate、onAttach方法中注册 mIntentActivityResultLauncher = registerForActivityResult(new ActivityResultContracts.StartActivityForResult(), new ActivityResultCallback<ActivityResult>() { @Override public void onActivityResult(ActivityResult result) { //回传的数据处理 String answer = result.getData().getStringExtra("message"); Toast.makeText(mContext, answer, Toast.LENGTH_LONG).show(); } }); //按钮点击事件 findViewById(R.id.bt).setOnClickListener(v -> { //执行跳转的方法 jumpToTwoActivity(); }); } private void jumpToTwoActivity() { //封装Intent Intent intent = new Intent(mContext,TwoActivity.class); intent.putExtra("message", "问:吃饭了吗?"); //跳转 mIntentActivityResultLauncher.launch(intent); } }
从TwoActivity返回数据
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23public class TwoActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); //页面传递过来的数据 String askMsg = getIntent().getStringExtra("message"); Toast.makeText(this, askMsg, Toast.LENGTH_LONG).show(); //点击事件 findViewById(R.id.bt).setOnClickListener(v -> { //回传数据 Intent intent = new Intent(); intent.putExtra("message", "答:我吃过了"); setResult(RESULT_OK, intent); finish(); }); } }
2)示例二：申请单个或多个权限
推荐用第三方请求权限的库，不推荐这样写
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28//申请单个权限 registerForActivityResult(new ActivityResultContracts.RequestPermission(), new ActivityResultCallback<Boolean>() { @Override public void onActivityResult(Boolean result) { if(result){ Log.d(TAG,"获取权限成功"); }else{ Log.d(TAG,"获取权限失败"); } } }).launch(Manifest.permission.READ_CONTACTS); //申请多个权限 String[] permissions = {Manifest.permission.CAMERA,Manifest.permission.WRITE_EXTERNAL_STORAGE,Manifest.permission.READ_EXTERNAL_STORAGE}; registerForActivityResult(new ActivityResultContracts.RequestMultiplePermissions(), new ActivityResultCallback<Map<String, Boolean>>() { @Override public void onActivityResult(Map<String, Boolean> result) { //result的key为权限,value为权限是否申请通过 //是否请求权限前弹窗询问? //第一次用户用户点击拒绝权限shouldShowRequestPermissionRationale返回false,如果用户拒绝了权限并且勾选了不再询问shouldShowRequestPermissionRationale返回true //通过这个特性可以判断哪些权限被永久拒绝 ActivityCompat.shouldShowRequestPermissionRationale(MainActivity.this,Manifest.permission.CAMERA); } }).launch(permissions);
3)示例三：获取联系人信息
获取联系人信息前需要申请权限Manifest.permission.READ_CONTACTS。代码如下：
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2<uses-permission android:name="android.permission.READ_CONTACTS"/>
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66public class MainActivity extends AppCompatActivity { private static final String TAG = MainActivity.class.getSimpleName(); private ActivityResultLauncher<Void> mIntentActivityResultLauncher; private Context mContext; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mContext = this; //申请读取通讯录权限 registerForActivityResult(new ActivityResultContracts.RequestPermission(), new ActivityResultCallback<Boolean>() { @Override public void onActivityResult(Boolean result) { if(result){ Log.d(TAG,"获取权限成功"); //跳转读取联系人信息 mIntentActivityResultLauncher.launch(null); }else{ Log.d(TAG,"获取权限失败"); } } }).launch(Manifest.permission.READ_CONTACTS); //只能在onCreate、onAttach方法中注册 mIntentActivityResultLauncher = registerForActivityResult(new ActivityResultContracts.PickContact(), new ActivityResultCallback<Uri>() { @SuppressLint("Range") @RequiresApi(api = Build.VERSION_CODES.O) @Override public void onActivityResult(Uri result) { if (result != null) { StringBuilder builder = new StringBuilder(); Cursor cursor = getContentResolver().query(result, null, null, null); while (cursor.moveToNext()) { //联系人ID String id = cursor.getString(cursor.getColumnIndex(ContactsContract.Contacts._ID)); builder.append("用户ID:" + id + ","); //联系人姓名 String name = cursor.getString(cursor.getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME)); builder.append("用户姓名:" + name + ","); Cursor query = getContentResolver().query( ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null, ContactsContract.CommonDataKinds.Phone.CONTACT_ID + "=" + id, null, null); builder.append("用户手机号:"); while (query.moveToNext()) { String phoneNum = query.getString(query.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER)); builder.append(phoneNum + " | "); } query.close(); } cursor.close(); //打印 Log.d(TAG, builder.toString()); } } }); } }
弹出权限申请窗口时点击了同意权限。日志打印结果为：
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3D/MainActivity: 获取权限成功 D/MainActivity: 用户ID:1,用户姓名:张三,用户手机号:130 1234 5678 | 131 1234 5678 |
4)示例四：调用相机拍照
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18//申请多个权限 String[] permissions = {Manifest.permission.CAMERA, Manifest.permission.WRITE_EXTERNAL_STORAGE, Manifest.permission.READ_EXTERNAL_STORAGE}; registerForActivityResult(new ActivityResultContracts.RequestMultiplePermissions(), new ActivityResultCallback<Map<String, Boolean>>() { @Override public void onActivityResult(Map<String, Boolean> result) { //申请权限成功后申请调用相机拍照 mIntentActivityResultLauncher.launch(null); } }).launch(permissions); //申请调用相机拍照 mIntentActivityResultLauncher = registerForActivityResult(new ActivityResultContracts.TakePicturePreview(), new ActivityResultCallback<Bitmap>() { @Override public void onActivityResult(Bitmap bitmap) { Glide.with(mContext).load(bitmap).format(PREFER_ARGB_8888).into(iv); } });
5)示例五：获取文件
在Android Q以上获取文件比较困难，存在适配的问题，解决办法：
①mainfest 文件配置
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12<provider android:name="androidx.core.content.FileProvider" //模块中需要继承FileProvider创建新的 android:authorities="你的包名.fileprovider" android:exported="false" android:grantUriPermissions="true" tools:replace="android:authorities"> <meta-data android:name="android.support.FILE_PROVIDER_PATHS" android:resource="@xml/file_paths" /> </provider>
②file_paths.xml指定文件类型
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28<?xml version="1.0" encoding="utf-8"?> <resources> <paths> <root-path name="root" path="" /> <files-path name="files" path="" /> <cache-path name="cache" path="" /> <external-path name="external" path="" /> <external-files-path name="external_file_path" path="" /> <external-cache-path name="external_cache_path" path="" /> </paths> </resources>
③工具类
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230/** * 包含Uri转path * 包含path转uri * 兼容Android 10 */ public class FileProviderUtils { /** * 根据Uri获取文件绝对路径，解决Android4.4以上版本Uri转换 兼容Android 10 * * @param context * @param imageUri */ public static String getFileAbsolutePath(Context context, Uri imageUri) { if (context == null || imageUri == null) { return null; } if (android.os.Build.VERSION.SDK_INT < android.os.Build.VERSION_CODES.KITKAT) { return getRealFilePath(context, imageUri); } if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.KITKAT && android.os.Build.VERSION.SDK_INT < Build.VERSION_CODES.Q && DocumentsContract.isDocumentUri(context, imageUri)) { if (isExternalStorageDocument(imageUri)) { String docId = DocumentsContract.getDocumentId(imageUri); String[] split = docId.split(":"); String type = split[0]; if ("primary".equalsIgnoreCase(type)) { return Environment.getExternalStorageDirectory() + "/" + split[1]; } } else if (isDownloadsDocument(imageUri)) { String id = DocumentsContract.getDocumentId(imageUri); Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.valueOf(id)); return getDataColumn(context, contentUri, null, null); } else if (isMediaDocument(imageUri)) { String docId = DocumentsContract.getDocumentId(imageUri); String[] split = docId.split(":"); String type = split[0]; Uri contentUri = null; if ("image".equals(type)) { contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI; } else if ("video".equals(type)) { contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI; } else if ("audio".equals(type)) { contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI; } String selection = MediaStore.Images.Media._ID + "=?"; String[] selectionArgs = new String[]{split[1]}; return getDataColumn(context, contentUri, selection, selectionArgs); } } // MediaStore (and general) if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q){ return uriToFileApiQ(context,imageUri); } else if ("content".equalsIgnoreCase(imageUri.getScheme())) { // Return the remote address if (isGooglePhotosUri(imageUri)) { return imageUri.getLastPathSegment(); } return getDataColumn(context, imageUri, null, null); } // File else if ("file".equalsIgnoreCase(imageUri.getScheme())) { return imageUri.getPath(); } return null; } //此方法 只能用于4.4以下的版本 private static String getRealFilePath(final Context context, final Uri uri) { if (null == uri) { return null; } final String scheme = uri.getScheme(); String data = null; if (scheme == null) { data = uri.getPath(); } else if (ContentResolver.SCHEME_FILE.equals(scheme)) { data = uri.getPath(); } else if (ContentResolver.SCHEME_CONTENT.equals(scheme)) { String[] projection = {MediaStore.Images.ImageColumns.DATA}; Cursor cursor = context.getContentResolver().query(uri, projection, null, null, null); // Cursor cursor = context.getContentResolver().query(uri, new String[]{MediaStore.Images.ImageColumns.DATA}, null, null, null); if (null != cursor) { if (cursor.moveToFirst()) { int index = cursor.getColumnIndex(MediaStore.Images.ImageColumns.DATA); if (index > -1) { data = cursor.getString(index); } } cursor.close(); } } return data; } /** * @param uri The Uri to check. * @return Whether the Uri authority is ExternalStorageProvider. */ private static boolean isExternalStorageDocument(Uri uri) { return "com.android.externalstorage.documents".equals(uri.getAuthority()); } /** * @param uri The Uri to check. * @return Whether the Uri authority is DownloadsProvider. */ private static boolean isDownloadsDocument(Uri uri) { return "com.android.providers.downloads.documents".equals(uri.getAuthority()); } private static String getDataColumn(Context context, Uri uri, String selection, String[] selectionArgs) { Cursor cursor = null; String column = MediaStore.Images.Media.DATA; String[] projection = {column}; try { cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs, null); if (cursor != null && cursor.moveToFirst()) { int index = cursor.getColumnIndexOrThrow(column); return cursor.getString(index); } } finally { if (cursor != null) { cursor.close(); } } return null; } /** * @param uri The Uri to check. * @return Whether the Uri authority is MediaProvider. */ private static boolean isMediaDocument(Uri uri) { return "com.android.providers.media.documents".equals(uri.getAuthority()); } /** * @param uri The Uri to check. * @return Whether the Uri authority is Google Photos. */ private static boolean isGooglePhotosUri(Uri uri) { return "com.google.android.apps.photos.content".equals(uri.getAuthority()); } /** * Android 10 以上适配 另一种写法 * @param context * @param uri * @return */ @SuppressLint("Range") private static String getFileFromContentUri(Context context, Uri uri) { if (uri == null) { return null; } String filePath; String[] filePathColumn = {MediaStore.MediaColumns.DATA, MediaStore.MediaColumns.DISPLAY_NAME}; ContentResolver contentResolver = context.getContentResolver(); Cursor cursor = contentResolver.query(uri, filePathColumn, null, null, null); if (cursor != null) { cursor.moveToFirst(); try { filePath = cursor.getString(cursor.getColumnIndex(filePathColumn[0])); return filePath; } catch (Exception e) { } finally { cursor.close(); } } return ""; } /** * Android 10 以上适配 * @param context * @param uri * @return */ @SuppressLint("Range") @RequiresApi(api = Build.VERSION_CODES.Q) private static String uriToFileApiQ(Context context, Uri uri) { File file = null; //android10以上转换 if (uri.getScheme().equals(ContentResolver.SCHEME_FILE)) { file = new File(uri.getPath()); } else if (uri.getScheme().equals(ContentResolver.SCHEME_CONTENT)) { //把文件复制到沙盒目录 ContentResolver contentResolver = context.getContentResolver(); Cursor cursor = contentResolver.query(uri, null, null, null, null); if (cursor.moveToFirst()) { String displayName = cursor.getString(cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME)); try { InputStream is = contentResolver.openInputStream(uri); File cache = new File(context.getExternalCacheDir().getAbsolutePath(), Math.round((Math.random() + 1) * 1000) + displayName); FileOutputStream fos = new FileOutputStream(cache); FileUtils.copy(is, fos); file = cache; fos.close(); is.close(); } catch (IOException e) { e.printStackTrace(); } } } return file.getAbsolutePath(); } /** * path转uri * @param context * @param filePath * @return */ public static Uri toUri(Context context,String filePath) { if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) { return FileProvider.getUriForFile(context, context.getApplicationInfo().packageName + ".fileprovider", new File(filePath)); } return Uri.fromFile(new File(filePath)); } }
解决了适配问题，看如何获取文件：
获取单类型单文件
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16//获取单类型单文件 registerForActivityResult(new ActivityResultContracts.GetContent(), new ActivityResultCallback<Uri>() { @Override public void onActivityResult(Uri uri) { if (uri != null) { //获取文件真实路径 String path = FileProviderUtils.getFileAbsolutePath(mContext, uri); Log.d(TAG, "文件真实路径:" + path); } } }).launch("text/plain"); //具体多少中文件类型可以看MediaFile这个类 //打印日志 D/MainActivity: 文件真实路径:/storage/emulated/0/Android/data/com.cad/files/tbslog/tbslog.txt
获取多种文件类型，可以使用OpenDocument。
三、自定义ActivityResultContract
新建一个Contract类，继承自ActivityResultContract<I,O>，其中，I是输入的类型，O是输出的类型。需要实现2个方法，createIntent和parseResult,输入类型I作为createIntent的参数，输出类型O作为parseResult方法的返回值。
自定义ActivityResultContract<I,O>
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24/** * 自定义ActivityResultContract */ public class CustomActivityResultContract extends ActivityResultContract<Integer, String> { //input为输入值,然后包装成Intent传递 @NotNull @Override public Intent createIntent(@NotNull Context context, Integer input) { //Intent包装了跳转到SecondActivity Intent intent = new Intent(context, SecondActivity.class); intent.putExtra("in", input); return intent; } //返回的Intent拆解,变换成String作为返回值 @Override public String parseResult(int result, @Nullable Intent intent) { //拿到SecondActivity返回的Intent,拆解出需要的数据并返回 return intent.getStringExtra("out"); } }
SecondActivity的代码
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6Intent intent = new Intent(); intent.putExtra("out","2"); setResult(1001,intent); finish();
在MainActivity中使用
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8registerForActivityResult(new CustomActivityResultContract(), new ActivityResultCallback<String>() { @Override public void onActivityResult(String result) { //参数就是返回值 Log.d(TAG, "out:" + result); } }).launch(1); //输入值就是在这里传入
日志
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38058-8058/com.abc.rxjava3 D/MainActivity: out:2
四、初级封装
1、在Activity/Fragment中自动注册
Activity生命周期监听，有个接口类Application.ActivityLifecycleCallbacks，先看下面的简单示例：
示例的目录:
首先看AppLifeCallback类，实现Application.ActivityLifecycleCallbacks接口:
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29class AppLifeCallback : Application.ActivityLifecycleCallbacks { companion object { const val TAG = "AppHelper" } override fun onActivityCreated(activity: Activity, savedInstanceState: Bundle?) { //打印调用此方法的Activity的类的名称 Log.d(TAG, "onActivityCreated:${activity.localClassName}") } override fun onActivityDestroyed(activity: Activity) { //打印调用此方法的Activity的类的名称 Log.d(TAG, "onActivityDestroyed:${activity.localClassName}") } override fun onActivityStarted(activity: Activity) {} override fun onActivityResumed(activity: Activity) {} override fun onActivityPaused(activity: Activity) {} override fun onActivityStopped(activity: Activity) {} override fun onActivitySaveInstanceState(activity: Activity, outState: Bundle) {} }
再看AppHelper类，重点在init方法:
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11object AppHelper { /** * 注冊Application的生命周期 */ fun init(application: Application) { //注册自定义的生命周期 application.registerActivityLifecycleCallbacks(AppLifeCallback()) } }
在App中完成init初始化操作：
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9class App :Application() { override fun onCreate() { super.onCreate() //注册生命周期 AppHelper.init(this) } }
MainActivity和SecondActivity的代码比较简单：
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12class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) registerForActivityResult(ActivityResultContracts.StartActivityForResult(), ActivityResultCallback { //JUST STARTACTIVITY DO NOTHING }).launch(Intent(this, SecondActivity::class.java)); } }
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10class SecondActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_second) //finish finish() } }
打印日志：
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5D/AppHelper: onActivityCreated:MainActivity D/AppHelper: onActivityCreated:SecondActivity D/AppHelper: onActivityDestroyed:SecondActivity
可以发现实现了Application.ActivityLifecycleCallbacks，所有Activity的生命周期都会在这里回调，那么就可以在这里完成Activity跳转前的注册。
2、初级封装
以下代码来自于DeMon-ARA，详细注释都写在代码里
目录结构：
DemoActivityCallbacks类代码：
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54object DemoActivityCallbacks : Application.ActivityLifecycleCallbacks { private val TAG = "DemoActivityCallbacks" const val DEMON_ACTIVITY_KEY = "Demo_Activity_Key" val DEMON_FRAGMENT_KEY = "Demo_Fragment_Key" //临时存储FragmentCallbacks val callbackMap = mutableMapOf<String, DemoFragmentCallbacks>() //临时存储DeMonActivityResult val resultMap = mutableMapOf<String, DemoActivityResult<Intent, ActivityResult>>() override fun onActivityCreated(activity: Activity, p1: Bundle?) { if (activity is FragmentActivity) { val mapKey: String = activity.javaClass.simpleName + System.currentTimeMillis() Log.i(TAG, "onActivityCreated: mapKey=$mapKey") //Fragment生命周期的自定义实现类 val fragmentCallbacks = DemoFragmentCallbacks() callbackMap[mapKey] = fragmentCallbacks //注册Fragment的生命周期 activity.supportFragmentManager.registerFragmentLifecycleCallbacks(fragmentCallbacks, false) //Activity注册获取ActivityResult对象 val result = DemoActivityResult(activity, ActivityResultContracts.StartActivityForResult()) //Activity生命周期持有Intent(getIntent),通过往Intent注入Key来获取ActivityResult对象(HashMap) //ActivityResult可以用于跳转 activity.intent.putExtra(DEMON_ACTIVITY_KEY, mapKey) resultMap[mapKey] = result } } override fun onActivityDestroyed(activity: Activity) { if (activity is FragmentActivity) { val mapKey = activity.intent.getStringExtra(DEMON_ACTIVITY_KEY) Log.i(TAG, "onActivityDestroyed: mapKey=$mapKey") if (!mapKey.isNullOrEmpty()) { //反注册Fragment的生命周期 callbackMap[mapKey]?.let { activity.supportFragmentManager.unregisterFragmentLifecycleCallbacks(it) } //移除Fragment的生命周期的回调 callbackMap.remove(mapKey) //移除ActivityResult resultMap.remove(mapKey) } } } override fun onActivityStarted(p0: Activity) {} override fun onActivitySaveInstanceState(p0: Activity, p1: Bundle) {} override fun onActivityResumed(p0: Activity) {} override fun onActivityPaused(p0: Activity) {} override fun onActivityStopped(p0: Activity) {} }
DemoFragmentCallbacks类代码：
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26class DemoFragmentCallbacks : FragmentManager.FragmentLifecycleCallbacks() { private val TAG = "DeMonFragmentCallbacks" override fun onFragmentAttached(fm: FragmentManager, fragment: Fragment, context: Context) { super.onFragmentAttached(fm, fragment, context) val mapKey: String = fragment.javaClass.simpleName + System.currentTimeMillis() Log.i(TAG, "onFragmentAttached: mapKey=$mapKey") //Fragment注册 val result = DemoActivityResult(fragment, ActivityResultContracts.StartActivityForResult()) //Activity生命周期持有Intent(getIntent),通过往Intent注入Key来获取ActivityResult对象(HashMap) //ActivityResult可以用于跳转 fragment.requireActivity().intent.putExtra(DEMON_FRAGMENT_KEY, mapKey) DemoActivityCallbacks.resultMap[mapKey] = result } override fun onFragmentDetached(fm: FragmentManager, fragment: Fragment) { super.onFragmentDetached(fm, fragment) val mapKey = fragment.requireActivity().intent.getStringExtra(DEMON_FRAGMENT_KEY) Log.i(TAG, "onFragmentDetached: mapKey=$mapKey") if (!mapKey.isNullOrEmpty()) { DemoActivityCallbacks.resultMap.remove(mapKey) } } }
DemoActivityResult类的代码：
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43/** * 注册和跳转的具体实现 * @author DeMon * Created on 2022/3/1. * E-mail idemon_liu@qq.com * Desc: */ class DemoActivityResult<I, O>(caller: ActivityResultCaller, contract: ActivityResultContract<I, O>) { /** * 直接点击返回键或者直接finish是否会触发回调 * 用于处理一些特殊情况：如只要返回就刷新等 * 注意此时回调返回的值或者{ActivityResult#getData()}应该为空，需要做好判空处理 */ private var isNeedBack = false private var launcher: ActivityResultLauncher<I>? = caller.registerForActivityResult(contract) { if (isNeedBack) { callback?.onActivityResult(it) } else { if (it != null) { if (it is ActivityResult) { if (it.resultCode == Activity.RESULT_OK) callback?.onActivityResult(it) } else { callback?.onActivityResult(it) } } } //回收单次的callback callback = null } private var callback: ActivityResultCallback<O>? = null @JvmOverloads fun launch(input: I, isNeedBack: Boolean = false, callback: ActivityResultCallback<O>?) { this.callback = callback this.isNeedBack = isNeedBack launcher?.launch(input) } }
DemoResultHelper类的代码：
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55/** * 注册和具体跳转的调用处 * @author DeMon * Created on 2022/3/2. * E-mail idemon_liu@qq.com * Desc: Activity Results API */ object DemoResultHelper { /** * 初始化，注册ActivityLifecycleCallbacks */ @JvmStatic fun init(@NonNull application: Application) { application.registerActivityLifecycleCallbacks(DemoActivityCallbacks) } /** * 跳转使用的方法 * 获取在Activity生命周期自动注册的ActivityResult * Activity中请使用此方法 */ @JvmStatic fun getActivityResult(@NonNull activity: FragmentActivity): DemoActivityResult<Intent, ActivityResult>? { activity.run { val mapKey = intent.getStringExtra(DemoActivityCallbacks.DEMON_ACTIVITY_KEY) return if (!mapKey.isNullOrEmpty()) { DemoActivityCallbacks.resultMap[mapKey] } else { null } } } /** * 跳转使用的方法 * 获取在Fragment生命周期自动注册的ActivityResult * Fragment中请使用此方法 */ @JvmStatic fun getActivityResult(@NonNull fragment: Fragment): DemoActivityResult<Intent, ActivityResult>? { fragment.requireActivity().run { val mapKey = intent.getStringExtra(DemoActivityCallbacks.DEMON_FRAGMENT_KEY) return if (!mapKey.isNullOrEmpty()) { DemoActivityCallbacks.resultMap[mapKey] } else { null } } } }
测试以上代码的跳转：
先在Application中注册
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8class App : Application() { override fun onCreate() { super.onCreate() DemoResultHelper.init(this) } }
在MainActivity中点击按钮跳转：
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25class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) var text = findViewById<TextView>(R.id.tv) //点击事件 text.setOnClickListener { //获取提前注册好的ActivityResult var result: DemoActivityResult<Intent, ActivityResult>? = DemoResultHelper.getActivityResult(this@MainActivity) //跳转 result?.launch(Intent(this, SecondActivity::class.java), true) { //解析回调的数据 it?.data?.getStringExtra("value")?.let { value -> Log.d("MainActivity", value) } } } } }
在SecondActivity直接SetResult后finish：
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13class SecondActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_second) var intent = Intent().putExtra("value", "我是SecondActivity") setResult(RESULT_OK, intent) finish() } }
打印结果：
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3D/MainActivity: 我是SecondActivity
成功跳转并带回了数据。
五、基于Kotlin进一步的封装
以下代码来自于DeMon-ARA
增加了二个Kotlin的扩展类：
ActivityResultApi是个ktx大杂烩，需要有点耐心才能完全看明白，代码如下：
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165/** * @author DeMon * Created on 2021/10/20. * E-mail idemon_liu@qq.com * Desc: ktx扩展 */ /** * Activity中获取DeMonActivityResult */ fun FragmentActivity.getActivityResult(): DeMonActivityResult<Intent, ActivityResult>? { val mapKey = intent.getStringExtra(DeMonActivityCallbacks.DEMON_ACTIVITY_KEY) return if (!mapKey.isNullOrEmpty()) { DeMonActivityCallbacks.resultMap[mapKey] } else { null } } /** * Fragment中获取DeMonActivityResult */ fun Fragment.getActivityResult(): DeMonActivityResult<Intent, ActivityResult>? { val mapKey = requireActivity().intent.getStringExtra(DeMonActivityCallbacks.DEMON_FRAGMENT_KEY) return if (!mapKey.isNullOrEmpty()) { DeMonActivityCallbacks.resultMap[mapKey] } else { null } } /** * Activity跳转并在回调用获取返回结果 * <pre> * val intent = Intent(this@MainActivity,JavaActivity::class.java) * forActivityResult(intent) { * val str = it?.getStringExtra("tag") ?: "" * text.text = "跳转页面返回值：$str" * } * </pre> * * @param isCanBack 直接点击返回键或者直接finish是否会触发回调 */ inline fun FragmentActivity.forActivityResult( data: Intent, isCanBack: Boolean = false, crossinline callback: ((result: Intent?) -> Unit) ) { getActivityResult()?.launch(data, isCanBack) { callback(it.data) } } /** * Activity跳转并在回调用获取返回结果 * <pre> * forActivityResult<TestJumpActivity>( * "tag" to TAG, * "timestamp" to System.currentTimeMillis(), * isCanBack = false * ) { * val str = it?.getStringExtra("tag") ?: "" * text.text = "跳转页面返回值：$str" * } * </pre> * * @param extras 可变参数Pair键值对 * @param isCanBack 直接点击返回键或者直接finish是否会触发回调 */ inline fun <reified T : FragmentActivity> FragmentActivity.forActivityResult( vararg extras: Pair<String, Any?>, isCanBack: Boolean = false, crossinline callback: ((result: Intent?) -> Unit) ) { val intent = pairIntent<T>(*extras) forActivityResult(intent, isCanBack, callback) } /** * Fragment中使用 * Activity跳转并在回调用获取返回结果 * * @param isCanBack 直接点击返回键或者直接finish是否会触发回调 */ inline fun Fragment.forActivityResult( data: Intent, isCanBack: Boolean = false, crossinline callback: ((result: Intent?) -> Unit) ) { getActivityResult()?.launch(data, isCanBack) { callback(it.data) } } /** * Fragment中使用 * Activity跳转并在回调用获取返回结果 * * @param extras 可变参数Pair键值对 * @param isCanBack 直接点击返回键或者直接finish是否会触发回调 */ inline fun <reified T : FragmentActivity> Fragment.forActivityResult( vararg extras: Pair<String, Any?>, isCanBack: Boolean = false, crossinline callback: ((result: Intent?) -> Unit) ) { val intent = pairIntent<T>(*extras) forActivityResult(intent, isCanBack, callback) } /** * 作用同[Activity.finish] * <pre> * finish(this, "Key" to "Value") * </pre> * * @param params 可变参数Pair键值对 */ fun FragmentActivity.finishResult(vararg params: Pair<String, Any?>) = run { setResult(Activity.RESULT_OK, Intent().putExtras(*params)) finish() } fun FragmentActivity.finishResult(intent: Intent) = run { setResult(Activity.RESULT_OK, intent) finish() } /** * 普通跳转 */ fun Context.toActivity(intent: Intent, vararg extras: Pair<String, Any?>) { startActivity(intent.putExtras(*extras)) } fun Fragment.toActivity(intent: Intent, vararg extras: Pair<String, Any?>) { requireActivity().startActivity(intent.putExtras(*extras)) } inline fun <reified T : FragmentActivity> Context.toActivity(vararg extras: Pair<String, Any?>) { startActivity(Intent(this, T::class.java).putExtras(*extras)) } inline fun <reified T : FragmentActivity> Fragment.toActivity(vararg extras: Pair<String, Any?>) { requireActivity().run { startActivity(Intent(this, T::class.java).putExtras(*extras)) } } /** * 泛型Activity获取一个Intent实例的扩展 * <pre> * pairIntent<ActResultActivity>( * "tag" to TAG, * "timestamp" to System.currentTimeMillis() * ) * </pre> */ inline fun <reified T : FragmentActivity> Context.pairIntent(vararg extras: Pair<String, Any?>) = Intent(this, T::class.java).putExtras(*extras) inline fun <reified T : FragmentActivity> Fragment.pairIntent(vararg extras: Pair<String, Any?>) = requireActivity().pairIntent<T>(*extras)
IntentExt是Intent的扩展，主要是存取值，代码如下：
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174/** * @author DeMon * Created on 2020/7/22. * E-mail idemon_liu@qq.com * Desc: */ fun Intent.putExtras(vararg extras: Pair<String, Any?>): Intent { if (extras.isEmpty()) return this extras.forEach { (key, value) -> value ?: return@forEach when (value) { is Bundle -> this.putExtra(key, value) is Boolean -> this.putExtra(key, value) is BooleanArray -> this.putExtra(key, value) is Byte -> this.putExtra(key, value) is ByteArray -> this.putExtra(key, value) is Char -> this.putExtra(key, value) is CharArray -> this.putExtra(key, value) is String -> this.putExtra(key, value) is CharSequence -> this.putExtra(key, value) is Double -> this.putExtra(key, value) is DoubleArray -> this.putExtra(key, value) is Float -> this.putExtra(key, value) is FloatArray -> this.putExtra(key, value) is Int -> this.putExtra(key, value) is IntArray -> this.putExtra(key, value) is Long -> this.putExtra(key, value) is LongArray -> this.putExtra(key, value) is Short -> this.putExtra(key, value) is ShortArray -> this.putExtra(key, value) is Parcelable -> this.putExtra(key, value) is Serializable -> this.putExtra(key, value) is Array<*> -> { @Suppress("UNCHECKED_CAST") when { value.isArrayOf<String>() -> { this.putStringArrayListExtra(key, value as ArrayList<String?>) } value.isArrayOf<CharSequence>() -> { this.putCharSequenceArrayListExtra(key, value as ArrayList<CharSequence?>) } value.isArrayOf<Parcelable>() -> { this.putParcelableArrayListExtra(key, value as ArrayList<out Parcelable?>) } } } else -> { throw IllegalArgumentException("Not support $value type ${value.javaClass}..") } } } return this } class ActivityExtras<T>(private val extraName: String, private val defaultValue: T) : ReadWriteProperty<Activity, T> { /** * getExtras字段对应的值 */ private var extra: T? = null override fun getValue(thisRef: Activity, property: KProperty<*>): T { // 如果extra不为空则返回extra // 如果extra是空的，则判断intent的参数的值，如果值不为空，则将值赋予extra，并且返回 // 如果intent参数的值也为空，则返回defaultValue，并且将值赋予extra return extra ?: thisRef.intent?.get<T>(extraName)?.also { extra = it } ?: defaultValue.also { extra = it } } override fun setValue(thisRef: Activity, property: KProperty<*>, value: T) { extra = value } } /** * 获取Intent参数，Fragment * 示例同[ActivityExtras] */ class FragmentExtras<T>(private val extraName: String, private val defaultValue: T) : ReadWriteProperty<Fragment, T> { /** * getExtras字段对应的值 */ private var extra: T? = null override fun getValue(thisRef: Fragment, property: KProperty<*>): T { // 如果extra不为空则返回extra // 如果extra是空的，则判断intent的参数的值，如果值不为空，则将值赋予extra，并且返回 // 如果intent参数的值也为空，则返回defaultValue，并且将值赋予extra return extra ?: thisRef.arguments?.get<T>(extraName)?.also { extra = it } ?: defaultValue.also { extra = it } } override fun setValue(thisRef: Fragment, property: KProperty<*>, value: T) { extra = value } } fun <T> extraFrag(extraName: String): FragmentExtras<T?> = FragmentExtras(extraName, null) fun <T> extraFrag(extraName: String, defaultValue: T): FragmentExtras<T> = FragmentExtras(extraName, defaultValue) fun <T> extraAct(extraName: String): ActivityExtras<T?> = ActivityExtras(extraName, null) fun <T> extraAct(extraName: String, defaultValue: T): ActivityExtras<T> = ActivityExtras(extraName, defaultValue) /** * [Intent]的扩展方法，此方法可无视类型直接获取到对应值 * 如getStringExtra()、getIntExtra()、getSerializableExtra()等方法通通不用 * 可以直接通过此方法来获取到对应的值，例如： * <pre> * var mData: List<String>? = null * mData = intent.get("Data") * </pre> * 而不用显式强制转型 * * @param key 对应的Key * @return 对应的Value */ fun <O> Intent?.get(key: String, defaultValue: O? = null) = this?.internalMap()?.get(key) as? O ?: defaultValue /** * 作用同Intent.[get] */ fun <O> Bundle?.get(key: String, defaultValue: O? = null) = this?.internalMap()?.get(key) as? O ?: defaultValue /** * 不报错执行 */ inline fun <T, R> T.runSafely(block: (T) -> R) = try { block(this) } catch (e: Exception) { e.printStackTrace() null } internal object IntentFieldMethod { private val bundleClass = (if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) BaseBundle::class else Bundle::class).java private val mExtras: Field? by lazy { Intent::class.java.getDeclaredField("mExtras").also { it.isAccessible = true } } private val mMap: Field? by lazy { runSafely { bundleClass.getDeclaredField("mMap").also { it.isAccessible = true } } } private val unparcel: Method? by lazy { runSafely { bundleClass.getDeclaredMethod("unparcel").also { it.isAccessible = true } } } internal fun Intent.internalMap() = runSafely { mMap?.get((mExtras?.get(this) as? Bundle).also { it?.run { unparcel?.invoke(this) } }) as? Map<String, Any?> } internal fun Bundle.internalMap() = runSafely { unparcel?.invoke(it) mMap?.get(it) as? Map<String, Any?> } }
进一步封装后的使用，还是上例中的二个Activity：
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23class MainActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_main) var text = findViewById<TextView>(R.id.tv) //点击事件 text.setOnClickListener { //跳转 forActivityResult(Intent(this@MainActivity, SecondActivity::class.java)) { //解析回调的数据 it?.getStringExtra("value")?.let { value -> Log.d("MainActivity", value) } } } } }
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12class SecondActivity : AppCompatActivity() { override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContentView(R.layout.activity_second) //回传数据 finishResult("value" to "我是SecondActivity") } }
打印的日志：
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3D/MainActivity: 我是SecondActivity
跳转后成功拿到了回调数据。
参考了以下文章,表示感谢：
Android ActivityResultContract使用_xiangxiongfly-程序员ITS301
Android ActivityResultContract使用
registerForActivityResult()
再见！onActivityResult！你好，Activity Results API！
Uri与真实路径转换File-全适配
丢掉onActivityResult，探索Activity Results API极简方案
DeMon-ARA
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