将图像 Uri 从图库转换为位图 Android 的问题

Question

我是 android 新手，我在从图像 uri 转换为位图然后在图像视图中显示时遇到问题，但在转换为位图时遇到未处理的异常，这是代码：

public class MainActivity extends AppCompatActivity {
public static final int PICK_IMAGE = 1;
Image picture = new Image();
Context context = getApplicationContext();

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Button btnGallery = (Button) findViewById(R.id.btnGallery);
    final ImageView imageView = (ImageView) findViewById(R.id.imageView);

    btnGallery.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            Intent intent = new Intent();
            intent.setType("image/*");
            intent.setAction(Intent.ACTION_GET_CONTENT);
            startActivityForResult(Intent.createChooser(intent, "Select Picture"), PICK_IMAGE);
            Uri imageUri = intent.getData();
            Bitmap bitmap= MediaStore.Images.Media.getBitmap(context.getContentResolver(), imageUri);
            imageView.setImageBitmap(bitmap);
        }});

有什么建议么？ 先谢谢了！

Answer 1

您没有以正确的方式选择图像。 从您的onClick方法中删除这三行代码，您会将它们移动到onActivityResult ：

Uri imageUri = intent.getData();
Bitmap bitmap = 
    MediaStore.Images.Media.getBitmap(context.getContentResolver(), imageUri);
imageView.setImageBitmap(bitmap);

然后在你的（可能） Activity覆盖onActivityResult并在里面做这样的事情：

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);

    if (requestCode == PICK_IMAGE && resultCode == RESULT_OK && data != null) {

        Uri imageUri = data.getData();
        try {
            Bitmap bitmap = 
                MediaStore.Images.Media.getBitmap(getContentResolver(), imageUri);
            imageView.setImageBitmap(bitmap);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

Answer 2

请尝试此代码，这适用于我的应用程序。

 public void choosePhotoFromGallary() {
    Intent galleryIntent = new Intent(Intent.ACTION_PICK,
            MediaStore.Images.Media.EXTERNAL_CONTENT_URI);

    startActivityForResult(galleryIntent, GALLERY);
}

private void takePhotoFromCamera() {
    Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    startActivityForResult(intent, CAMERA);
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {

    super.onActivityResult(requestCode, resultCode, data);
    if (resultCode == RESULT_CANCELED) {
        return;
    }
    if (requestCode == GALLERY) {
        if (data != null) {
            Uri contentURI = data.getData();
            try {
                ByteArrayOutputStream bytes = new ByteArrayOutputStream();
                Bitmap bitmap = MediaStore.Images.Media.getBitmap(this.getContentResolver(), contentURI);
                bitmap.compress(Bitmap.CompressFormat.JPEG, 90, bytes);
                // path = saveImage(bitmap);

                imageView.setImageBitmap(bitmap);
            } catch (IOException e) {
                e.printStackTrace();
                Toast.makeText(MainActivity.this, "Failed!", Toast.LENGTH_SHORT).show();
            }
        }
    } else if (requestCode == CAMERA) {
        Bitmap thumbnail = (Bitmap) data.getExtras().get("data");
        imageView.setImageBitmap(thumbnail);
        path = saveImage(thumbnail);

    }
}

public String saveImage(Bitmap myBitmap) {
    ByteArrayOutputStream bytes = new ByteArrayOutputStream();
    myBitmap.compress(Bitmap.CompressFormat.JPEG, 90, bytes);
    File wallpaperDirectory = new File(
            Environment.getExternalStorageDirectory() + IMAGE_DIRECTORY);
    // have the object build the directory structure, if needed.
    if (!wallpaperDirectory.exists()) {
        wallpaperDirectory.mkdirs();
    }

    try {
        File f = new File(wallpaperDirectory, Calendar.getInstance()
                .getTimeInMillis() + ".jpg");
        f.createNewFile();
        FileOutputStream fo = new FileOutputStream(f);
        fo.write(bytes.toByteArray());
        MediaScannerConnection.scanFile(this,
                new String[]{f.getPath()},
                new String[]{"image/jpeg"}, null);
        fo.close();
        Log.d("TAG", "File Saved::--->" + f.getAbsolutePath());

        return f.getAbsolutePath();
    } catch (IOException e1) {
        e1.printStackTrace();
    }
    return "";
}