Question

下面的代码将图片加载到我的应用程序中的全屏活动中。它们来自listview，然后加载到details_activity中，因此我将它们打开到全屏活动中。

我注意到只有当我全屏打开它们时才会存储到SD卡存储中。那么，有人可以告诉我，在返回details_activity或关闭应用程序后删除图像的最佳方法是什么？

public class FullScreenActivity extends Activity {

PhotoViewAttacher mAttacher;
ShareActionProvider mShareActionProvider;
private static final String TAG_ARQUIVO = "arquivo";
String path;
File file;
Intent shareIntent;
ImageView fullImg;

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

    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, 
            WindowManager.LayoutParams.FLAG_FULLSCREEN);

    fullImg = (ImageView) findViewById(R.id.fullImage);

    Intent i = getIntent();
    path = i.getStringExtra(TAG_ARQUIVO);

    Picasso.with(FullScreenActivity.this).load(path).into(fullImg);

    mAttacher = new PhotoViewAttacher(fullImg);

    Uri bmpUri = getLocalBitmapUri(fullImg);

    shareIntent = new Intent();
    shareIntent.setAction(Intent.ACTION_SEND);
    shareIntent.setType("image/*");
    shareIntent.putExtra(Intent.EXTRA_STREAM, bmpUri);

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    getMenuInflater().inflate(R.menu.full_screen, menu);

    MenuItem item = menu.findItem(R.id.menu_item_share);
    mShareActionProvider = (ShareActionProvider) item.getActionProvider();
    if (mShareActionProvider != null) {
        mShareActionProvider.setShareIntent(shareIntent);
    }
    return true;
}

// Returns the URI path to the Bitmap displayed in specified ImageView
public Uri getLocalBitmapUri(ImageView imageView) {
    // Extract Bitmap from ImageView drawable
    Drawable drawable = imageView.getDrawable();
    Bitmap bmp = null;
    if (drawable instanceof BitmapDrawable){
       bmp = ((BitmapDrawable) imageView.getDrawable()).getBitmap();
    } else {
       return null;
    }
    // Store image to default external storage directory
    Uri bmpUri = null;
    try {
        File file =  new File(Environment.getExternalStoragePublicDirectory(  
            Environment.DIRECTORY_DOWNLOADS), "share_image_" + System.currentTimeMillis() + ".png");
        file.getParentFile().mkdirs();
        FileOutputStream out = new FileOutputStream(file);
        bmp.compress(Bitmap.CompressFormat.PNG, 90, out);
        out.close();
        bmpUri = Uri.fromFile(file);
    } catch (IOException e) {
        e.printStackTrace();
    }
    return bmpUri;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    int id = item.getItemId();
    if (id == R.id.action_settings) {
        return true;
    }
    return super.onOptionsItemSelected(item);
  }
}

修改

当我按下android native back按钮时，我尝试使用下面的代码来删除图像，但它不起作用：

PicassoTools.java

public class PicassoTools {

  public static void clearCache(Picasso p) {
    p.cache.clear();
  }

}

FullScreen.java：

@Override
public void onBackPressed() {
    PicassoTools.clearCache(Picasso.with(FullScreenActivity.this));
    super.onBackPressed();
}

Answer 1

我将clearCache更改为deleteDirectoryTree（file）：

public class FullScreenActivity extends Activity {

PhotoViewAttacher mAttacher;
ShareActionProvider mShareActionProvider;
private static final String TAG_ARQUIVO = "arquivo";
String path;
File file;
Intent shareIntent;
ImageView fullImg;

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

getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, 
        WindowManager.LayoutParams.FLAG_FULLSCREEN);

fullImg = (ImageView) findViewById(R.id.fullImage);

Intent i = getIntent();
path = i.getStringExtra(TAG_ARQUIVO);

Picasso.with(FullScreenActivity.this).load(path).into(fullImg);

mAttacher = new PhotoViewAttacher(fullImg);

Uri bmpUri = getLocalBitmapUri(fullImg);

shareIntent = new Intent();
shareIntent.setAction(Intent.ACTION_SEND);
shareIntent.setType("image/*");
shareIntent.putExtra(Intent.EXTRA_STREAM, bmpUri);

}

@Override
public void onBackPressed() {
    deleteDirectoryTree(file);
    super.onBackPressed();
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.full_screen, menu);

MenuItem item = menu.findItem(R.id.menu_item_share);
mShareActionProvider = (ShareActionProvider) item.getActionProvider();
if (mShareActionProvider != null) {
    mShareActionProvider.setShareIntent(shareIntent);
}
return true;
}

public Uri getLocalBitmapUri(ImageView imageView) {
Drawable drawable = imageView.getDrawable();
Bitmap bmp = null;
if (drawable instanceof BitmapDrawable){
   bmp = ((BitmapDrawable) imageView.getDrawable()).getBitmap();
} else {
   return null;
}

Uri bmpUri = null;
try {
    File file =  new File(Environment.getExternalStoragePublicDirectory(  
        Environment.DIRECTORY_DOWNLOADS), "share_image_" + System.currentTimeMillis() + ".png");
    file.getParentFile().mkdirs();
    FileOutputStream out = new FileOutputStream(file);
    bmp.compress(Bitmap.CompressFormat.PNG, 90, out);
    out.close();
    bmpUri = Uri.fromFile(file);
} catch (IOException e) {
    e.printStackTrace();
}
return bmpUri;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
int id = item.getItemId();
if (id == R.id.action_settings) {
    return true;
 }
 return super.onOptionsItemSelected(item);
 }

    public static void deleteDirectoryTree(File fileOrDirectory) {
    if (fileOrDirectory.isDirectory()) {
        for (File child : fileOrDirectory.listFiles()) {
            deleteDirectoryTree(child);
        }
    }

    fileOrDirectory.delete();
}    

}

已经做了一些测试，现在它正在运行。

来自存储的Android清晰图像缓存

1 个答案: