【AndroidX】Activity Result API使用示例

本文主要是介绍【AndroidX】Activity Result API使用示例，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

参考官方链接：获取Activity的结果

    implementation 'androidx.activity:activity:1.2.0-beta01'implementation 'androidx.fragment:fragment:1.3.0-beta01'

本示例演示了从系统相册中获取图片uri并进行显示的功能。

Activity文件：

public class MainActivity extends AppCompatActivity {public static final String TAG = "ActivityTest";private static final int GET_IMAGE_REQUEST_CODE = 1;private ImageView imageView;// Activity返回结果private final ActivityResultLauncher<String> mGetContent = registerForActivityResult(new ActivityResultContracts.GetContent(),result -> {displayImage(parseImageUri(result));});@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);findViewById(R.id.get_content).setOnClickListener(v -> checkPermission());imageView = findViewById(R.id.img);}@Overridepublic void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {super.onRequestPermissionsResult(requestCode, permissions, grantResults);if (requestCode == GET_IMAGE_REQUEST_CODE) {if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {mGetContent.launch("image/*");} else {Toast.makeText(this, "You denied the permission.", Toast.LENGTH_SHORT).show();}}}// 检查读外部存储权限private void checkPermission() {if (ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE)!= PackageManager.PERMISSION_GRANTED) {ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, GET_IMAGE_REQUEST_CODE);} else {mGetContent.launch("image/*");  // 根据返回结果}}// 解析uri，获取图片真实地址private String parseImageUri(Uri uri) {String imagePath = null;if (DocumentsContract.isDocumentUri(this, uri)) {String docId = DocumentsContract.getDocumentId(uri);Log.d(TAG, "docId: " + docId);if ("com.android.providers.media.documents".equals(uri.getAuthority())) {String id = docId.split(":")[1];String selection = MediaStore.Images.Media._ID + "=" + id;imagePath = getImagePath(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, selection);} else if ("com.android.providers.downloads.documents".equals(uri.getAuthority())) {Uri contentUri = ContentUris.withAppendedId(Uri.parse("content://downloads/public_downloads"), Long.parseLong(docId));imagePath = getImagePath(contentUri, null);}} else if ("content".equalsIgnoreCase(uri.getScheme())) {   // content://com.miui.gallery.open/raw/%2Fstorage%2Femulated%2F0%2FDCIM%2FScreenshots%2FScreenshot_2020-10-25-14-43-57-798_com.miui.home.jpgLog.d(TAG, "is content.");imagePath = getImagePath(uri, null);} else if ("file".equalsIgnoreCase(uri.getScheme())) {Log.d(TAG, "is file.");imagePath = uri.getPath();}Log.d(TAG, "imagePath: " + imagePath);return imagePath;}// 获取真实图片地址private String getImagePath(Uri uri, String selection) {String path = null;Cursor cursor = getContentResolver().query(uri, null, selection, null, null);if (cursor != null) {if (cursor.moveToFirst()) {path = cursor.getString(cursor.getColumnIndex(MediaStore.Images.Media.DATA));}cursor.close();}return path;}// 显示图片private void displayImage(String imagePath) {if (imagePath != null) {Bitmap bitmap = BitmapFactory.decodeFile(imagePath);imageView.setImageBitmap(bitmap);} else {Toast.makeText(this, "Failed to get image.", Toast.LENGTH_SHORT).show();}}
}

使用权限：

    <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />

布局文件：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical"tools:context=".MainActivity"><Buttonandroid:id="@+id/get_content"android:layout_width="match_parent"android:layout_height="wrap_content"android:text="Get Content" /><ImageViewandroid:id="@+id/img"android:layout_gravity="center_horizontal"android:layout_width="wrap_content"android:layout_height="wrap_content"/></LinearLayout>

 

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