[英]Android - Saving a downloaded image from URL onto SD card
我在单击按钮时从 URL 加载图像,并将其存储为 Bitmap。 现在我想知道如何将下载的图像保存到 SD 卡以及系统中。
我试图通过以下方式做到这一点:
package com.v3.thread.fetchImage;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.Toast;
public class MainThreadActivity extends Activity {
ImageView imView;
EditText ed1;
Bitmap bmImg;
Button bt, btSave;
String imageUrl = "";
int visibilty = 0;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.main);
ed1 = (EditText) findViewById(R.id.edURL);
btSave = (Button) findViewById(R.id.btnSave);
bt = (Button) findViewById(R.id.btnLoad);
bt.setOnClickListener(getImgListener);
imView = (ImageView) findViewById(R.id.imview);
Log.i("img already downloaded", "img");
btSave.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
Log.i("img url", "Under Save");
saveImage();
}
});
}
View.OnClickListener getImgListener = new View.OnClickListener() {
public void onClick(View view) {
// TODO Auto-generated method stub
imageUrl = ed1.getText().toString();
if (imageUrl.equals(""))
Toast.makeText(getApplicationContext(), "Enter an URL first", 1000).show();
downloadFile(imageUrl);
Log.i("im url", imageUrl);
btSave.setVisibility(visibilty);
}
};
void downloadFile(String fileUrl) {
URL myFileUrl = null;
try {
myFileUrl = new URL(fileUrl);
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
try {
HttpURLConnection conn = (HttpURLConnection) myFileUrl
.openConnection();
conn.setDoInput(true);
conn.connect();
InputStream is = conn.getInputStream();
Log.i("im connected", "Download");
bmImg = BitmapFactory.decodeStream(is);
imView.setImageBitmap(bmImg);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
void saveImage() {
File filename;
try {
String path = Environment.getExternalStorageDirectory().toString();
Log.i("in save()", "after mkdir");
new File(path + "/mvc/mvc").mkdir();
filename = new File(path + "/mvc/mvc/var3.jpg");
Log.i("in save()", "after file");
FileOutputStream out = new FileOutputStream(filename);
Log.i("in save()", "after outputstream");
bmImg.compress(Bitmap.CompressFormat.JPEG, 90, out);
out.flush();
out.close();
Log.i("in save()", "after outputstream closed");
MediaStore.Images.Media.insertImage(getContentResolver(),
filename.getAbsolutePath(), filename.getName(),
filename.getName());
bt.setText("Saved...");
Toast.makeText(getApplicationContext(),
"File is Saved in " + filename, 1000).show();
} catch (Exception e) {
e.printStackTrace();
}
}
}
从 URL 加载图像正在工作,但是当我按下保存按钮保存它时,它会引发异常
java.io.FileNotFoundException:/mnt/sdcard/mvc/mvc/var3.image(没有这样的文件或目录)
那么如何正确地将图像保存到 SD 卡中呢?
您需要首先创建要在其中创建文件的目录和子目录。 我看到您使用了 mkdir() 方法。 试试 mkdirs(),它应该可以工作。
在您的清单中添加 WRITE_EXTERNAL_STORAGE android 权限:
然后
BitmapDrawable drawable = (BitmapDrawable) mImageView.getDrawable();
Bitmap bitmap = drawable.getBitmap();
从 SD 卡获取目录(文件对象),例如:
File sdCardDirectory = Environment.getExternalStorageDirectory();
创建用于图像存储的特定文件:
File image = new File(sdCardDirectory, "download.png");
然后,
boolean success = false;
// Encode the file as a PNG image.
FileOutputStream outStream;
try {
outStream = new FileOutputStream(image);
bitmap.compress(Bitmap.CompressFormat.PNG, 100, outStream);
/* 100 to keep full quality of the image */
outStream.flush();
outStream.close();
success = true;
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
if (success) {
//Display Downloaded
} else {
// display Error in Downloading
}
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