【AndroidX】Activity Result API使用示例_resultsuccess = (imageview) findviewbyid(r.id.veri

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));
        }
    );
 
    @Override
    protected 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);
    }
 
    @Override
    public 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.jpg
            Log.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">
 
    <Button
        android:id="@+id/get_content"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Get Content" />
 
    <ImageView
        android:id="@+id/img"
        android:layout_gravity="center_horizontal"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>
 
</LinearLayout>