Question

在我的应用程序中，我有一个调用摄像头的button1，捕获图像后，必须将其保存到设备库中。当我点击button2时，它必须打开图库，并要求选择图片。选择后，它必须显示在这些按钮下方的imageView上。

这是我的代码：

package com.android.imageuploading;

import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

public class ImageUploadingActivity extends Activity {
    private static final int REQUEST_CODE = 1;
    private Bitmap bitmap;
    private ImageView imageView;
    private Button button_1;
    public int TAKE_PICTURE = 1;
    private Button button_2;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        imageView = (ImageView) findViewById(R.id.image);
        button_1 = (Button) findViewById(R.id.button1);
        button_1.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {

                Intent intent = new Intent("android.media.action.IMAGE_CAPTURE");
                startActivityForResult(intent, TAKE_PICTURE);

            }
        });
        button_2 = (Button) findViewById(R.id.button2);
        button_2.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {

                pickImage(getCurrentFocus());
            }
        });
    }

    public void pickImage(View view) {
        Intent intent = new Intent();
        intent.setType("image/*");
        intent.setAction(Intent.ACTION_GET_CONTENT);
        intent.addCategory(Intent.CATEGORY_OPENABLE);
        startActivityForResult(intent, REQUEST_CODE);
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == REQUEST_CODE && resultCode == Activity.RESULT_OK)
            try {
                // We need to recyle unused bitmaps
                if (bitmap != null) {
                    bitmap.recycle();
                }
                InputStream stream = getContentResolver().openInputStream(
                        data.getData());
                bitmap = BitmapFactory.decodeStream(stream);
                stream.close();
                imageView.setImageBitmap(bitmap);
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }
        super.onActivityResult(requestCode, resultCode, data);
    }

    public static boolean isIntentAvailable(Context context, String action) {
        final PackageManager packageManager = context.getPackageManager();
        final Intent intent = new Intent(action);
        List<ResolveInfo> list = packageManager.queryIntentActivities(intent,
                PackageManager.MATCH_DEFAULT_ONLY);
        return list.size() > 0;
    }
}

问题是，当我捕获图像时，它会要求保存或丢弃。当我点击保存时，我的应用程序崩溃，说：

java.lang.RuntimeException：将结果ResultInfo {who = null，request = 1，result = -1，data = Intent {act = inline-data（has extras）}}传递给activity {com.android.imageuploading /com.android.imageuploading.ImageUploadingActivity}：java.lang.NullPointerException

我需要在哪里更改代码？

Answer 1

在我的情况下，我使用这个：当我点击保存按钮pic保存并返回我在filePath变量中的路径。

String filePath =
        Environment.getExternalStorageDirectory() +"/your_image_name.jpeg";
File file = new File(filePath);
Uri output = Uri.fromFile(file);
Intent cameraIntent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
cameraIntent.putExtra(MediaStore.EXTRA_OUTPUT, output);

并且在onactivityresult（）中我使用这个“filePath”。

Answer 2

捕获图片

  public class Camera extends Activity 
  {
 private static final int CAMERA_REQUEST = 1888;
 private String selectedImagePath;
 WebView webview;
 String fileName = "capturedImage.jpg";
 private static Uri mCapturedImageURI; 

@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    Intent cameraIntent = new Intent(ACTION_IMAGE_CAPTURE);
    startActivityForResult(cameraIntent, CAMERA_REQUEST);
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data)
{
    if (resultCode == RESULT_OK) {
        if (requestCode == CAMERA_REQUEST) 
        { 
            Bitmap photo = (Bitmap) data.getExtras().get("data"); 
            ByteArrayOutputStream bytes = new ByteArrayOutputStream();
            photo.compress(Bitmap.CompressFormat.JPEG, 40, bytes);
            Random randomGenerator = new Random();randomGenerator.nextInt();
            String newimagename=randomGenerator.toString()+".jpg";
            File f = new File(Environment.getExternalStorageDirectory()
                                    + File.separator + newimagename);
            try {
                f.createNewFile();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            //write the bytes in file

            try {
                fo = new FileOutputStream(f.getAbsoluteFile());
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            try {
                fo.write(bytes.toByteArray());
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
                uri=f.getAbsolutePath(); 
    //this is the url that where you are saved the image
      }



  }

选择图片：

   public class ChoosePicture extends Activity 
   {
      private static final int SELECT_PICTURE = 1;
      private String  selectedImagePath;

      @Override
      public void onCreate(Bundle savedInstanceState)
      {
          super.onCreate(savedInstanceState);
          webview=(WebView)findViewById(R.id.webView1);
          Intent intent = new Intent();
          intent.setType("image/*");
          intent.setAction(Intent.ACTION_GET_CONTENT);
          intent.addCategory(Intent.CATEGORY_OPENABLE);
          startActivityForResult(intent, SELECT_PICTURE);
      }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data)
    {
        if (resultCode == RESULT_OK) {
            if (requestCode == SELECT_PICTURE)
            {
                Uri selectedImageUri = data.getData();
                selectedImagePath = getPath(selectedImageUri);
                try {
                    FileInputStream fileis=new FileInputStream(selectedImagePath);
                    BufferedInputStream bufferedstream=new BufferedInputStream(fileis);
                    byte[] bMapArray= new byte[bufferedstream.available()];
                    bufferedstream.read(bMapArray);
                    Bitmap bMap = BitmapFactory.decodeByteArray(bMapArray, 0, bMapArray.length);
  //this is the image that you are choosen

                    if (fileis != null) 
                    {
                        fileis.close();
                    }
                    if (bufferedstream != null) 
                    {
                        bufferedstream.close();
                    }
                } catch (FileNotFoundException e) {                 
                    e.printStackTrace();
                } catch (IOException e) {                   
                    e.printStackTrace();
                }               
            }
        }
    }


public String getPath(Uri uri) {
        String[] projection = { MediaStore.Images.Media.DATA };
        Cursor cursor = managedQuery(uri, projection, null, null, null);
        int column_index = cursor
                .getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
        cursor.moveToFirst();
        return cursor.getString(column_index);
    }
}

从活动中调用摄像头，捕获图像并上载到服务器

2 个答案: