Question

我希望你们中的一个能帮我解决这个问题。我有2个活动。一个带有一个按钮，当你点击打开相机时，应该保存图片，然后在第二个活动的imageview中显示它。我可以打开应用程序点击按钮保存照片点击确定然后进入第二个活动，但它没有显示图像。但是，如果我在图像视图src中添加ic launche图标，它会显示绿色的android徽标，但是当我删除它只是一个空白页面时：S

我的MainActivity.java文件

package com.MYAPP.apk;

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

import java.io.File;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;

public class MainActivity extends Activity {

private File mFileUri;
private final Context mContext = this;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);

Button btnbutton1 = (Button) findViewById(R.id.button1);
btnbutton1.setOnClickListener(new OnClickListener() {

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        Intent intent = new  Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
        startActivityForResult(intent, 100);
    }});


// start the image capture Intent
startActivityForResult(getIntent(), 100);

Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);

mFileUri = getOutputMediaFile(1);

intent.putExtra(MediaStore.EXTRA_OUTPUT, mFileUri);


}  

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

if (resultCode == RESULT_OK) {
    if (mFileUri != null) {
        String mFilePath = mFileUri.toString();
        if (mFilePath != null) {
            Intent intent = new Intent(mContext, SecondActivity.class);
            intent.putExtra("filepath", mFilePath);
            startActivity(intent);



      }
    }
  }               
}


// Return image / video
private static File getOutputMediaFile(int type) {

// External sdcard location
File mediaStorageDir = new   File(Environment.getExternalStorageDirectory(),  "DCIM/Camera");

// Create the storage directory if it does not exist
if (!mediaStorageDir.exists()) {
    if (!mediaStorageDir.mkdirs()) {
        return null;
    }
 }

// Create a media file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss",  Locale.getDefault()).format(new Date());
File mediaFile;
if (type == 1) { // image
    mediaFile = new File(mediaStorageDir.getPath() + File.separator + "IMG_"  + timeStamp + ".jpg");
} else if (type == 2) { // video
    mediaFile = new File(mediaStorageDir.getPath() + File.separator + "VID_" + timeStamp + ".mp4");
} else {
    return null;
}

return mediaFile;
}
}

我的activity_main.xml文件

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.MYAPP.apk.MainActivity" >

<Button
    android:id="@+id/button1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_centerVertical="true"
    android:text="Let&apos;s Start Here!" />

</RelativeLayout>

我的SecondActivity.java文件

package com.MYAPP.apk;

import android.app.Activity;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.widget.ImageView;

import java.io.File;

public class SecondActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);

Intent intent = getIntent();
String filepath = intent.getStringExtra("filepath");
BitmapFactory.Options options = new BitmapFactory.Options();
options.inSampleSize = 8; // down sizing image as it throws OutOfMemory    Exception for larger images
filepath = filepath.replace("file://", ""); // remove to avoid   BitmapFactory.decodeFile return null
File imgFile = new File(filepath);
if (imgFile.exists()) {
    ImageView imageView = (ImageView) findViewById(R.id.imageView1);
    Bitmap bitmap = BitmapFactory.decodeFile(imgFile.getAbsolutePath(),  options);
    imageView.setImageBitmap(bitmap);
  }
 }


}

我的activity_second.xml文件

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.MYAPP.apk.SecondActivity" >

<ImageView
    android:id="@+id/imageView1"
    android:layout_width="200dp"
    android:layout_height="200dp"
    android:layout_centerHorizontal="true"
    android:layout_centerVertical="true" />

</RelativeLayout>

Answer 1

我认为你同时做了太多事情而不知道失败了。首先尝试在第一个活动中显示图像。一旦知道如何正确显示图像，就可以将文件路径传递给第二个活动。我试图使用你的代码，但它甚至没有进入第二个活动，因为mFileUri总是为null。同样在onActivityResult方法中，您应该过滤请求代码，而不仅仅是结果代码。

我编辑了你的代码，删除了未使用过的东西，但它确实有效。

MainActivity

public class MainActivity extends Activity {

private String mFileUri;
private final Context mContext = this;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    Button btnbutton1 = (Button) findViewById(R.id.button1);
    btnbutton1.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            Uri uri = createPictureFile();
            mFileUri = uri.getEncodedPath();
            Intent intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
            intent.putExtra(MediaStore.EXTRA_OUTPUT, uri);
            startActivityForResult(intent, 100);
        }
    });
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == 100 && resultCode == RESULT_OK) {
        if (mFileUri != null) {
            Intent intent = new Intent(mContext, SecondActivity.class);
            intent.putExtra("filepath", mFileUri);
            startActivity(intent);
        }
    }
}

private static File getOutputMediaFile(int type) {

    File mediaStorageDir = new File(Environment.getExternalStorageDirectory(), "DCIM/Camera");

    if (!mediaStorageDir.exists()) {
        if (!mediaStorageDir.mkdirs()) {
            return null;
        }
    }

    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss", Locale.getDefault()).format(new Date());
    File mediaFile;
    if (type == 1) { // image
        mediaFile = new File(mediaStorageDir.getPath() + File.separator + "IMG_" + timeStamp + ".jpg");
    } else if (type == 2) { // video
        mediaFile = new File(mediaStorageDir.getPath() + File.separator + "VID_" + timeStamp + ".mp4");
    } else {
        return null;
    }

    return mediaFile;
}

public Uri createPictureFile() {
    String storageState = Environment.getExternalStorageState();
    if (storageState.equals(Environment.MEDIA_MOUNTED)) {
        File pictureDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES);
        pictureDir = new File(pictureDir, "MyApp");

        // Create the storage directory if it does not exist
        if (!pictureDir.exists()) {
            if (!pictureDir.mkdirs()) {
                Log.d("user", "failed to create directory");
                return null;
            }
        }

        //Create a media file name
        String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
        String fileName = pictureDir.getPath() + File.separator + "IMG_" + timeStamp + ".jpg";
        File imageFile = new File(fileName);

        // Convert to URI and return
        return Uri.fromFile(imageFile);
    } else {
        Log.d("user", "No media mounted");
        return null;
    }
}
}

SecondActivity

public class SecondActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_second);

    Intent intent = getIntent();
    String filepath = intent.getStringExtra("filepath");

    ImageView imageView = (ImageView) findViewById(R.id.imageView1);

    BitmapFactory.Options opts = new BitmapFactory.Options();
    opts.inSampleSize = 6;
    Bitmap bm = BitmapFactory.decodeFile(filepath, opts);
    imageView.setImageBitmap(bm);
}
}

可用于旋转位图的ExifUtil类

public class ExifUtil {
/**
 * @see http://sylvana.net/jpegcrop/exif_orientation.html
 */
public static Bitmap rotateBitmap(String src, Bitmap bitmap) {
    try {
        int orientation = getExifOrientation(src);

        if (orientation == 1) {
            return bitmap;
        }

        Matrix matrix = new Matrix();
        switch (orientation) {
            case 2:
                matrix.setScale(-1, 1);
                break;
            case 3:
                matrix.setRotate(180);
                break;
            case 4:
                matrix.setRotate(180);
                matrix.postScale(-1, 1);
                break;
            case 5:
                matrix.setRotate(90);
                matrix.postScale(-1, 1);
                break;
            case 6:
                matrix.setRotate(90);
                break;
            case 7:
                matrix.setRotate(-90);
                matrix.postScale(-1, 1);
                break;
            case 8:
                matrix.setRotate(-90);
                break;
            default:
                return bitmap;
        }

        try {
            Bitmap oriented = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
            bitmap.recycle();
            return oriented;
        } catch (OutOfMemoryError e) {
            e.printStackTrace();
            return bitmap;
        }
    } catch (IOException e) {
        e.printStackTrace();
    }

    return bitmap;
}

private static int getExifOrientation(String src) throws IOException {
    int orientation = 1;

    try {
        /**
         * if your are targeting only api level >= 5
         * ExifInterface exif = new ExifInterface(src);
         * orientation = exif.getAttributeInt(ExifInterface.TAG_ORIENTATION, 1);
         */
        if (Build.VERSION.SDK_INT >= 5) {
            Class<?> exifClass = Class.forName("android.media.ExifInterface");
            Constructor<?> exifConstructor = exifClass.getConstructor(new Class[] { String.class });
            Object exifInstance = exifConstructor.newInstance(new Object[] { src });
            Method getAttributeInt = exifClass.getMethod("getAttributeInt", new Class[] { String.class, int.class });
            Field tagOrientationField = exifClass.getField("TAG_ORIENTATION");
            String tagOrientation = (String) tagOrientationField.get(null);
            orientation = (Integer) getAttributeInt.invoke(exifInstance, new Object[] { tagOrientation, 1});
        }
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
    } catch (SecurityException e) {
        e.printStackTrace();
    } catch (NoSuchMethodException e) {
        e.printStackTrace();
    } catch (IllegalArgumentException e) {
        e.printStackTrace();
    } catch (InstantiationException e) {
        e.printStackTrace();
    } catch (IllegalAccessException e) {
        e.printStackTrace();
    } catch (InvocationTargetException e) {
        e.printStackTrace();
    } catch (NoSuchFieldException e) {
        e.printStackTrace();
    }

    return orientation;
}

}

Imageview不在活动中显示来自Camera的图像

1 个答案: