用相机拍照并在图像视图中查看答案

【问题标题】：Taking a Picture With Camera and Viewing in Image View用相机拍照并在图像视图中查看
【发布时间】：2016-11-19 21:41:50
【问题描述】：

我不知道为什么我的代码刚刚运行并突然停止了？我想通过我的图像按钮拍照，然后将其显示在图像视图中。这是我的代码，不会显示在图像视图中：

public class UserInterface extends AppCompatActivity {
    private static final int REQUEST_IMAGE_CAPTURE= 1;
    private ImageView imageView;
    ImageButton cap;
    Bundle extras;
    Bitmap imageBitmap;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_user_interface);
        imageView = (ImageView)this.findViewById(R.id.imageView1);
        cap = (ImageButton) this.findViewById(R.id.cap);
        cap.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
                if (takePictureIntent.resolveActivity(getPackageManager()) != null) {
                    startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE);
                }
            }

        });
    }
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
             extras = data.getExtras();
             imageBitmap = (Bitmap) extras.get("data");
            imageView.setImageBitmap(imageBitmap);
        }

    }
}

【问题讨论】：

代码对我来说看起来不错。有错误吗？或者相机打开但捕获的图像没有进入图像视图？还是什么都没有发生？
捕获的图像不会进入图像视图。相机出现，并将图像保存在我的手机上，但它没有出现在图像视图中。
你确定 imageView id 是 imageView1 吗？
是的，我刚刚检查过了。
是否调用了 onActivityResult() 方法？放置一些日志消息并检查。

标签： android android-camera android-imageview android-bitmap

【解决方案1】：

Uri imageUri;

在您的按钮点击监听器上：

cap.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        imageUri = Uri.fromFile(new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DCIM), "IMG_" + String.valueOf(System.currentTimeMillis()) + ".jpg"));
        takePictureIntent.putExtra(android.provider.MediaStore.EXTRA_OUTPUT, imageUri);
        startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE);
    }
});

关于活动结果：

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
        imageView.setImageURI(imageUri);
    }
}

【讨论】：

【解决方案2】：

我之前遇到过这个问题，这是因为图像在完全保存到设备之前就显示出来了，所以尝试将其包装在延迟处理程序中：

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
        new Handler().postDelayed(new Runnable() {          
           @Override
           public void run() {
              extras = data.getExtras();
              imageBitmap = (Bitmap) extras.get("data");
              imageView.setImageBitmap(imageBitmap);
           }
        }, 750);
    }
}

如果它也不起作用，请尝试先将其保存到 sdcard 并直接从那里获取：

cap.setOnClickListener(new View.OnClickListener() {
  @Override
  public void onClick(View v) {
    Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
    File file = new File(Environment.getExternalStorageDirectory()+File.separator + "image.jpg");
    intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(file));
    startActivityForResult(intent, REQUEST_IMAGE_CAPTURE);
  }
});

然后得到它：

File file = new File(Environment.getExternalStorageDirectory()+File.separator + "image.jpg");
Bitmap image = decodeSampledBitmapFromFile(file.getAbsolutePath(), 1000, 700);


public static Bitmap decodeSampledBitmapFromFile(String path, int reqWidth, int reqHeight) 
{ // BEST QUALITY MATCH

    //First decode with inJustDecodeBounds=true to check dimensions
    final BitmapFactory.Options options = new BitmapFactory.Options();
    options.inJustDecodeBounds = true;
    BitmapFactory.decodeFile(path, options);

    // Calculate inSampleSize, Raw height and width of image
    final int height = options.outHeight;
    final int width = options.outWidth;
    options.inPreferredConfig = Bitmap.Config.RGB_565;
    int inSampleSize = 1;

    if (height > reqHeight) 
    {
        inSampleSize = Math.round((float)height / (float)reqHeight);
    }
    int expectedWidth = width / inSampleSize;

    if (expectedWidth > reqWidth) 
    {
        //if(Math.round((float)width / (float)reqWidth) > inSampleSize) // If bigger SampSize..
        inSampleSize = Math.round((float)width / (float)reqWidth);
    }

    options.inSampleSize = inSampleSize;

    // Decode bitmap with inSampleSize set
    options.inJustDecodeBounds = false;

    return BitmapFactory.decodeFile(path, options);
}

【讨论】：