对于同一个位图,位图有时保存为黑色图像
Bitmap saved as black image sometimes for same bitmap
我知道这是一个常见问题,但我尝试了不同的建议,但仍然没有解决方案。
我的问题是位图显示正确,但有时它保存为黑色位图,而其他时候保存正确。
谁能看到我做了什么并告诉我哪里可能出错了?
我已经查看了大多数其他 Whosebug 问题。
以下是我的代码,将剪贴板文本编码成二维码,并尝试保存生成的二维码。
谢谢!
import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.text.ClipboardManager;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;
import java.io.File;
import java.io.FileOutputStream;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
//import android.content.ClipboardManager;
public class BarcodeWriter extends AppCompatActivity {
ImageLoader imgLoader;
ImageView qrImg;
String copiedStr;
TextView qrTxt;
ClipboardManager clipboard;
String BASE_QR_URL = "http://chart.apis.google.com/chart?cht=qr&chs=400x400&chld=M&choe=UTF-8&chl=";
String fullUrl = BASE_QR_URL;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.barcode_writer);
DisplayImageOptions defaultOptions = new DisplayImageOptions.Builder()
.cacheInMemory(true)
.cacheOnDisk(true)
.build();
ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(getApplicationContext())
.defaultDisplayImageOptions(defaultOptions)
.build();
imgLoader = ImageLoader.getInstance(); // Do it on Application start
imgLoader.init(config);
qrImg = (ImageView)findViewById(R.id.qrImg);
qrTxt = (TextView)findViewById(R.id.qrTxt);
clipboard = (ClipboardManager)getSystemService(Context.CLIPBOARD_SERVICE);
/*
* clipboard.getText() is now deprecated. But I am going to use it here
* because the new way of doing the same thing only works on API lvl 11+
* Since I want this application to support API lvl 4+ we have to use
* the old method.
*/
CharSequence clipTxt = clipboard.getText();
//This is the new, non-deprecated way of getting text from the Clipboard.
//CharSequence clipTxt = clipboard.getPrimaryClip().getItemAt(0).getText();
//If the clipboard has text, and it is more than 0 characters.
if((null != clipTxt) && (clipTxt.length() > 0)){
try {
qrTxt.setText(clipTxt);
copiedStr = clipTxt.toString();
fullUrl += URLEncoder.encode(copiedStr, "UTF-8");
//imgLoader.displayImage(fullUrl, qrImg);
ImageLoader.getInstance().displayImage(fullUrl, qrImg, defaultOptions); // Incoming options will be used
qrImg.setDrawingCacheEnabled(true);
qrImg.measure(View.MeasureSpec.makeMeasureSpec(100, View.MeasureSpec.EXACTLY),
View.MeasureSpec.makeMeasureSpec(100, View.MeasureSpec.EXACTLY));
qrImg.layout(0, 0, qrImg.getMeasuredWidth(), qrImg.getMeasuredHeight());
qrImg.buildDrawingCache();
Bitmap bm = Bitmap.createBitmap(qrImg.getDrawingCache());
qrImg.setDrawingCacheEnabled(false); // clear drawing cache
try {
String root = Environment.getExternalStorageDirectory().toString();
File myDir = new File(root + "/DCIM/QR codes");
myDir.mkdirs();
String fname = clipTxt+".png";
File file = new File (myDir, fname);
if (file.exists ()) file.delete ();
try {
FileOutputStream out = new FileOutputStream(file);
bm.compress(Bitmap.CompressFormat.PNG, 100, out);
Toast.makeText(BarcodeWriter.this, "Image Saved", Toast.LENGTH_SHORT).show();
out.flush();
out.close();
} catch (Exception e) {
e.printStackTrace();
}
Intent mediaScanIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
Uri contentUri = Uri.fromFile(file);
mediaScanIntent.setData(contentUri);
getApplicationContext().sendBroadcast(mediaScanIntent);
Toast.makeText(this,"QR Code showing "+clipTxt,Toast.LENGTH_SHORT).show();
} catch (Exception e) {
Toast.makeText(this, "Error occurred. Please try again later.",
Toast.LENGTH_SHORT).show();
}
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}else{ //If no text display a dialog.
Toast.makeText(this,"No text in clipboard",Toast.LENGTH_SHORT).show();
}
}
}
您的代码似乎没问题,我唯一看到的是您在调用 displayImage
后立即使用 Universal Image Loader 从外部 URL 获取位图。因此,由于网络延迟,有时您的 ImageView
仍然没有完整的图像,因此可能会使您的位图保存为黑色。
请尝试将下面 ImageLoader.getInstance().displayImage
中的所有代码移动到 onLoadingComplete
中,如下所示:
ImageLoader.getInstance().displayImage(fullUrl, qrImg, defaultOptions, new SimpleImageLoadingListener()
{
@Override
public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
ImageLoader.getInstance().displayImage(fullUrl, qrImg, defaultOptions,null);
qrImg.setDrawingCacheEnabled(true);
...
catch (Exception e) {
Toast.makeText(this, "Error occurred. Please try again later.",
Toast.LENGTH_SHORT).show();
}
}
});
希望对您有所帮助!!
我知道这是一个常见问题,但我尝试了不同的建议,但仍然没有解决方案。
我的问题是位图显示正确,但有时它保存为黑色位图,而其他时候保存正确。
谁能看到我做了什么并告诉我哪里可能出错了?
我已经查看了大多数其他 Whosebug 问题。
以下是我的代码,将剪贴板文本编码成二维码,并尝试保存生成的二维码。
谢谢!
import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.text.ClipboardManager;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;
import java.io.File;
import java.io.FileOutputStream;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
//import android.content.ClipboardManager;
public class BarcodeWriter extends AppCompatActivity {
ImageLoader imgLoader;
ImageView qrImg;
String copiedStr;
TextView qrTxt;
ClipboardManager clipboard;
String BASE_QR_URL = "http://chart.apis.google.com/chart?cht=qr&chs=400x400&chld=M&choe=UTF-8&chl=";
String fullUrl = BASE_QR_URL;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.barcode_writer);
DisplayImageOptions defaultOptions = new DisplayImageOptions.Builder()
.cacheInMemory(true)
.cacheOnDisk(true)
.build();
ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(getApplicationContext())
.defaultDisplayImageOptions(defaultOptions)
.build();
imgLoader = ImageLoader.getInstance(); // Do it on Application start
imgLoader.init(config);
qrImg = (ImageView)findViewById(R.id.qrImg);
qrTxt = (TextView)findViewById(R.id.qrTxt);
clipboard = (ClipboardManager)getSystemService(Context.CLIPBOARD_SERVICE);
/*
* clipboard.getText() is now deprecated. But I am going to use it here
* because the new way of doing the same thing only works on API lvl 11+
* Since I want this application to support API lvl 4+ we have to use
* the old method.
*/
CharSequence clipTxt = clipboard.getText();
//This is the new, non-deprecated way of getting text from the Clipboard.
//CharSequence clipTxt = clipboard.getPrimaryClip().getItemAt(0).getText();
//If the clipboard has text, and it is more than 0 characters.
if((null != clipTxt) && (clipTxt.length() > 0)){
try {
qrTxt.setText(clipTxt);
copiedStr = clipTxt.toString();
fullUrl += URLEncoder.encode(copiedStr, "UTF-8");
//imgLoader.displayImage(fullUrl, qrImg);
ImageLoader.getInstance().displayImage(fullUrl, qrImg, defaultOptions); // Incoming options will be used
qrImg.setDrawingCacheEnabled(true);
qrImg.measure(View.MeasureSpec.makeMeasureSpec(100, View.MeasureSpec.EXACTLY),
View.MeasureSpec.makeMeasureSpec(100, View.MeasureSpec.EXACTLY));
qrImg.layout(0, 0, qrImg.getMeasuredWidth(), qrImg.getMeasuredHeight());
qrImg.buildDrawingCache();
Bitmap bm = Bitmap.createBitmap(qrImg.getDrawingCache());
qrImg.setDrawingCacheEnabled(false); // clear drawing cache
try {
String root = Environment.getExternalStorageDirectory().toString();
File myDir = new File(root + "/DCIM/QR codes");
myDir.mkdirs();
String fname = clipTxt+".png";
File file = new File (myDir, fname);
if (file.exists ()) file.delete ();
try {
FileOutputStream out = new FileOutputStream(file);
bm.compress(Bitmap.CompressFormat.PNG, 100, out);
Toast.makeText(BarcodeWriter.this, "Image Saved", Toast.LENGTH_SHORT).show();
out.flush();
out.close();
} catch (Exception e) {
e.printStackTrace();
}
Intent mediaScanIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
Uri contentUri = Uri.fromFile(file);
mediaScanIntent.setData(contentUri);
getApplicationContext().sendBroadcast(mediaScanIntent);
Toast.makeText(this,"QR Code showing "+clipTxt,Toast.LENGTH_SHORT).show();
} catch (Exception e) {
Toast.makeText(this, "Error occurred. Please try again later.",
Toast.LENGTH_SHORT).show();
}
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}else{ //If no text display a dialog.
Toast.makeText(this,"No text in clipboard",Toast.LENGTH_SHORT).show();
}
}
}
您的代码似乎没问题,我唯一看到的是您在调用 displayImage
后立即使用 Universal Image Loader 从外部 URL 获取位图。因此,由于网络延迟,有时您的 ImageView
仍然没有完整的图像,因此可能会使您的位图保存为黑色。
请尝试将下面 ImageLoader.getInstance().displayImage
中的所有代码移动到 onLoadingComplete
中,如下所示:
ImageLoader.getInstance().displayImage(fullUrl, qrImg, defaultOptions, new SimpleImageLoadingListener()
{
@Override
public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
ImageLoader.getInstance().displayImage(fullUrl, qrImg, defaultOptions,null);
qrImg.setDrawingCacheEnabled(true);
...
catch (Exception e) {
Toast.makeText(this, "Error occurred. Please try again later.",
Toast.LENGTH_SHORT).show();
}
}
});
希望对您有所帮助!!