Question

我无法将图像保存到设备上的内存中。我已经查看了其他主题并实现了它们，但没有任何对我有用。如果有人能指出我正确的方向，我们将不胜感激。我也无法将图像保存到SD卡，因为我的平板电脑没有。这是我的代码

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.Locale;

import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.app.Activity;
import android.content.Context;
import android.content.ContextWrapper;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.BitmapFactory.Options;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.Toast;

public class MainActivity extends Activity 
{
// Request codes for Activities
private static final int CAPTURE_IMAGE_REQUEST = 100;
private static final int MEDIA_TYPE_IMAGE = 1;
private static final int LINK_TO_DROPBOX = 150;

// Directory name to store captured images
private static String IMAGE_DIRECTORY_NAME = "Android to Dropbox";

// Uri to store images
private Uri fileUri;

private ImageView imagePreview; // To preview image
private Button captureImage;    // To launch camera intent
private Button linkDropbox;     // Link users Dropbox account

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

    imagePreview = (ImageView)findViewById(R.id.imagePrview);
    captureImage = (Button)findViewById(R.id.imageCapture);
    linkDropbox = (Button)findViewById(R.id.linkToDropbox);

    // Go to method to start camera intent to capture image
    captureImage.setOnClickListener(new View.OnClickListener() 
    {

        @Override
        public void onClick(View v) 
        {
            captureImage();
        }
    });

    // Check if user is connected to their Dropbox account
    linkDropbox.setOnClickListener(new View.OnClickListener()
    {

        @Override
        public void onClick(View v) 
        {
            linkToDropbox();
        }
    });
}// End onCreate

@Override
protected void onSaveInstanceState(Bundle outState)
{
    super.onSaveInstanceState(outState);
    outState.putParcelable("file_uri", fileUri);
}// End onSavedInstanceState

// Restore fileUri
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState)
{
    super.onRestoreInstanceState(savedInstanceState);
    fileUri = savedInstanceState.getParcelable("file_uri");
}// End onRestoreInstanceState

@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;
}// End onCreateOptionsMenu

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data)
{
    if(requestCode == CAPTURE_IMAGE_REQUEST)
    {
        if(resultCode == RESULT_OK) // Successfully captured image
            previewCapturedImage();
        else if(resultCode == RESULT_CANCELED)  // User cancelled image capture
            Toast.makeText(getApplicationContext(), "User cancelled image capture", Toast.LENGTH_SHORT).show();
        else    // Failed to capture image
            Toast.makeText(getApplicationContext(), "Failed to capture image", Toast.LENGTH_SHORT).show();
    }
}// End onActivityResult

// Method to launch camera within app
private void captureImage()
{
    Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    fileUri = getOutputMediaFileUri(MEDIA_TYPE_IMAGE);
    intent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri);
    startActivityForResult(intent, CAPTURE_IMAGE_REQUEST);
}// End captureImage

// Check if user has linked to their Dropbox account
private void linkToDropbox()
{

}// End linkToDropbox

// Preview captured image
private void previewCapturedImage()
{
    try
    {
        imagePreview.setVisibility(View.VISIBLE);   // Show ImageView

        BitmapFactory.Options options = new BitmapFactory.Options();
        options.inSampleSize = 8;

        final Bitmap image = BitmapFactory.decodeFile(fileUri.getPath(), options);
        imagePreview.setImageBitmap(image);
        saveToInternalMemory(image); // TRY TO SAVE IMAGE IN INTERNAL MEMORY
    }
    catch(NullPointerException e)
    {
        e.printStackTrace();
    }
}// End previewCapturedImage

// Method to save image to inernal memory
public void saveToInternalMemory(Bitmap image)
{
    boolean ableToSave = true;
    File pictureFile = getOutputMediaFile(MEDIA_TYPE_IMAGE);
    if(pictureFile == null)
    {
        Toast.makeText(getApplicationContext(), "Failed to save image", Toast.LENGTH_SHORT).show();
        ableToSave = false;
    }

    if(ableToSave)
    {
        try
        {
            FileOutputStream stream = new FileOutputStream(pictureFile);
            image.compress(Bitmap.CompressFormat.PNG, 100, stream);
            stream.close();
        }
        catch(FileNotFoundException e)
        {
            Toast.makeText(getApplicationContext(), "File not found", Toast.LENGTH_SHORT).show();
        }
        catch(IOException e)
        {
            Toast.makeText(getApplicationContext(), "Error accessing file", Toast.LENGTH_SHORT).show();
        }
    }
}// End saveToInternalMemory

// Create file uri to store image
public Uri getOutputMediaFileUri(int type)
{
    return Uri.fromFile(getOutputMediaFile(type));
}// End getOutputMediaFileUri

// Return image
private static File getOutputMediaFile(int type)
{
    File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES), IMAGE_DIRECTORY_NAME);
    File mediaFile;

    if(!mediaStorageDir.exists())
    {
        if(!mediaStorageDir.mkdirs())
        {
            Log.d(IMAGE_DIRECTORY_NAME, "Failed to create " + IMAGE_DIRECTORY_NAME + " directory");
            mediaFile = null;
        }
    }

    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss", Locale.getDefault()).format(new Date()); // Image name

    if(type == MEDIA_TYPE_IMAGE)
    {
        mediaFile = new File(mediaStorageDir.getPath() + File.separator + "IMG_" + timeStamp + ".jpg");
    }
    else
        mediaFile = null;

    return mediaFile;
}// End getOutputMediaFile

}// End MainActivity

编辑：看起来这段代码对我有用。除非我重新启动它们，否则这些图片不会显示在我的设备上，然后它们会显示在我的照片应用程序中。

Answer 1

保存：

FileOutputStream outStream = null;
File sdCard = Environment.getExternalStorageDirectory();
File dir = new File(sdCard.getAbsolutePath() + "/YourFolderName");
dir.mkdirs();
String fileName = String.format("%d.jpg", System.currentTimeMillis());
File outFile = new File(dir, fileName);
outStream = new FileOutputStream(outFile);
bitmap.compress(Bitmap.CompressFormat.JPEG, 100, outStream);
outStream.flush();
outStream.close();

提供清单权限，还可以转到设备设置＆gt;设备＆gt;应用程序＆gt;应用程序管理器＆gt;＆＃34;您的应用＆＃34;＆gt;权限＆gt;启用存储权限！

Answer 2

在保存方法中，尝试执行以下操作：

String FILENAME = "hello_file";

FileOutputStream fos = openFileOutput(FILENAME, Context.MODE_PRIVATE);
image.compress(Bitmap.CompressFormat.PNG, 100, fos);
fos.close();

有关详细信息，请参阅开发人员文档。 http://developer.android.com/guide/topics/data/data-storage.html#filesInternal

您当前代码可能无法正常工作的另一个注意事项 - 在getOutputMediaFile方法中，您正在使用外部存储目录创建新文件：

Environment.getExternalStoragePublicDirectory

保存到内存android

2 个答案: