如何 select 从设备的图库中获取图像并将其显示在图像视图上

Question

I currently have three buttons on the home page of my android application. One opens the camera, one detects text from the image, but I want the third button to open the gallery for users to select images from their device.

MainActivity.java

package com.mvsolutions.snap;

import android.os.Bundle;

import com.google.android.material.floatingactionbutton.FloatingActionButton;
import com.google.android.material.snackbar.Snackbar;

import android.view.View;

import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.navigation.ui.AppBarConfiguration;
import androidx.navigation.ui.NavigationUI;

import com.google.android.material.navigation.NavigationView;

import androidx.drawerlayout.widget.DrawerLayout;

import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;

import android.view.Menu;

public class MainActivity extends AppCompatActivity {

    private AppBarConfiguration mAppBarConfiguration;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);
        FloatingActionButton fab = findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });
        DrawerLayout drawer = findViewById(R.id.drawer_layout);
        NavigationView navigationView = findViewById(R.id.nav_view);
        // Passing each menu ID as a set of Ids because each menu should be considered as top level destinations.
        mAppBarConfiguration = new AppBarConfiguration.Builder(
                R.id.nav_home, R.id.nav_gallery, R.id.nav_slideshow, R.id.nav_tools, R.id.nav_share, R.id.nav_send)
                .setDrawerLayout(drawer)
                .build();
        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment);
        NavigationUI.setupActionBarWithNavController(this, navController, mAppBarConfiguration);
        NavigationUI.setupWithNavController(navigationView, navController);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onSupportNavigateUp() {
        NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment);
        return NavigationUI.navigateUp(navController, mAppBarConfiguration) || super.onSupportNavigateUp();
    }
}

HomeFragment.java

package com.mvsolutions.snap.ui.home;

import android.content.Intent;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.provider.MediaStore;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;

import androidx.annotation.Nullable;
import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.lifecycle.Observer;
import androidx.lifecycle.ViewModelProviders;

import com.google.android.gms.tasks.OnFailureListener;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.firebase.ml.vision.FirebaseVision;
import com.google.firebase.ml.vision.common.FirebaseVisionImage;
import com.google.firebase.ml.vision.text.FirebaseVisionText;
import com.google.firebase.ml.vision.text.FirebaseVisionTextDetector;
import com.mvsolutions.snap.R;

import java.util.List;

import static android.app.Activity.RESULT_OK;

public class HomeFragment extends Fragment {

    private HomeViewModel homeViewModel;

    private ImageView imageView;
    private Button captureImageButton, detectButton;
    private Bitmap imageBitmap;
    private TextView capturedTextView;
    static final int REQUEST_IMAGE_CAPTURE = 1;

    public View onCreateView(@NonNull LayoutInflater inflater,
                             ViewGroup container, Bundle savedInstanceState) {
        homeViewModel = ViewModelProviders.of(this).get(HomeViewModel.class);
        View root = inflater.inflate(R.layout.fragment_home, container, false);
        imageView = root.findViewById(R.id.home_image_view_img);
        capturedTextView = root.findViewById(R.id.home_text_view_txt);
        captureImageButton = root.findViewById(R.id.button_capture_image_btn);
        detectButton = root.findViewById(R.id.button_detect_text_btn);


        captureImageButton.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                dispatchTakePictureIntent();
            }
        });
        detectButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                detectTextFromImage();
            }
        });
        return root;
    }

    private void placeholder() {
         //ignore this
    }

    private void detectTextFromImage() {

        capturedTextView.setText("");
        FirebaseVisionImage firebaseVisionImage = FirebaseVisionImage.fromBitmap(imageBitmap);
        FirebaseVisionTextDetector visionTextDetector = FirebaseVision.getInstance().getVisionTextDetector();
        visionTextDetector.detectInImage(firebaseVisionImage).addOnSuccessListener(new OnSuccessListener<FirebaseVisionText>() {
            @Override
            public void onSuccess(FirebaseVisionText firebaseVisionText) {
                List<FirebaseVisionText.Block> textBlocks = firebaseVisionText.getBlocks();
                if(textBlocks.size() == 0){
                    Toast.makeText(getContext(), "No Text Found", Toast.LENGTH_SHORT).show();
                }else{
                    for(FirebaseVisionText.Block block : textBlocks){
                        String text = block.getText();
                        capturedTextView.setText(capturedTextView.getText() + " " + text);
                    }
                }
            }
        }).addOnFailureListener(new OnFailureListener() {
            @Override
            public void onFailure(@NonNull Exception e) {
                Toast.makeText(getContext(), "Something went wrong", Toast.LENGTH_SHORT).show();
                Log.d("Error", e.getMessage());
            }
        });
    }

    private void pickImage() {

    }

    private void dispatchTakePictureIntent() {
        Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        if (takePictureIntent.resolveActivity(getActivity().getPackageManager()) != null) {
            startActivityForResult(takePictureIntent, REQUEST_IMAGE_CAPTURE);
        }
    }


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

I want the method to go in the HomeFragment.java file. My final goal is to use the button to select an image from the gallery on the device and display it on the imageview in HomeFragment.java

Answer 1

For Android P (api 28) and later versions, you need to reference the data to be decoded using ImageDecoder.Source . To decode just use ImageDecoder.decodeBitmap (source) .

To recover and decode an image in previous versions, you must use MediaStore .

Your onActivityResult should look like this

  @Override
  public void onActivityResult(int requestCode, int resultCode, Intent data) {
  super.onActivityResult(requestCode, resultCode, data);
  
    if (requestCode == REQUEST_IMAGE_CAPTURE && resultCode == RESULT_OK) {
      Uri uri = data.getData();
      
      try {
          assert uri != null;
          if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
          
              ImageDecoder.Source source = ImageDecoder.createSource(this.getContentResolver(), uri);
              imageBitmap = ImageDecoder.decodeBitmap(source);
              
          } else {
              imageBitmap = MediaStore.Images.Media.getBitmap(getContentResolver(), uri);
          }
          imageView.setImageBitmap(imageBitmap);
      } catch (IOException e) {
          e.printStackTrace();
      }
    }
  }

I hope this helps you in some way ^ - ^

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For more information, see ImageDecoder MediaStore

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