问题
I am scaling a Bitmap by using a seekbar. Whenever i increase the progress of seekbar, image scaling fails by giving error "Bitmap size exceeds 32bits". If i scale the image with default seekbar value. it gives an error "Illegal argument exception: Width and height must be > 0".
Log Report
07-26 05:20:23.189: E/AndroidRuntime(1145): FATAL EXCEPTION: main
07-26 05:20:23.189: E/AndroidRuntime(1145): java.lang.IllegalArgumentException: bitmap size exceeds 32bits
07-26 05:20:23.189: E/AndroidRuntime(1145): at android.graphics.Bitmap.nativeCreate(Native Method)
07-26 05:20:23.189: E/AndroidRuntime(1145): at android.graphics.Bitmap.createBitmap(Bitmap.java:697)
07-26 05:20:23.189: E/AndroidRuntime(1145): at android.graphics.Bitmap.createBitmap(Bitmap.java:674)
07-26 05:20:23.189: E/AndroidRuntime(1145): at android.graphics.Bitmap.createBitmap(Bitmap.java:607)
07-26 05:20:23.189: E/AndroidRuntime(1145): at com.example.navigationexample.QRCodeGenerator.scaleImage(QRCodeGenerator.java:127)
07-26 05:20:23.189: E/AndroidRuntime(1145): at com.example.navigationexample.MainActivity$3.onClick(MainActivity.java:356)
07-26 05:20:23.189: E/AndroidRuntime(1145): at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:166)
07-26 05:20:23.189: E/AndroidRuntime(1145): at android.os.Handler.dispatchMessage(Handler.java:99)
07-26 05:20:23.189: E/AndroidRuntime(1145): at android.os.Looper.loop(Looper.java:137)
07-26 05:20:23.189: E/AndroidRuntime(1145): at android.app.ActivityThread.main(ActivityThread.java:5103)
07-26 05:20:23.189: E/AndroidRuntime(1145): at java.lang.reflect.Method.invokeNative(Native Method)
07-26 05:20:23.189: E/AndroidRuntime(1145): at java.lang.reflect.Method.invoke(Method.java:525)
07-26 05:20:23.189: E/AndroidRuntime(1145): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
07-26 05:20:23.189: E/AndroidRuntime(1145): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
07-26 05:20:23.189: E/AndroidRuntime(1145): at dalvik.system.NativeStart.main(Native Method)
07-26 05:20:25.857: I/Process(1145): Sending signal. PID: 1145 SIG: 9
Code snippet
public void showSaveDialog() {
LayoutInflater inflater = getLayoutInflater();
dialog = null;
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Save QR Image");
View v = inflater.inflate(R.layout.save_dialog, null);
builder.setView(v);
final EditText et = (EditText) v.findViewById(R.id.qrName);
et.setMaxLines(1);
final TextView widthText = (TextView) v.findViewById(R.id.widthSize);
final TextView heightText = (TextView) v.findViewById(R.id.heightSize);
SeekBar seekBar = (SeekBar) v.findViewById(R.id.seekBar1);
seekBar.setMax(16);
// To set minimum value of seekbar
seekMin = seekBar.getProgress();
if (seekMin < 128) {
seekBar.setProgress(1);
widthText.setText("128");
heightText.setText("128");
}
seekBar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
@Override
public void onStopTrackingTouch(SeekBar arg0) {
// TODO Auto-generated method stub
}
@Override
public void onStartTrackingTouch(SeekBar arg0) {
// TODO Auto-generated method stub
}
@Override
public void onProgressChanged(SeekBar seekBar, int progresValue,
boolean fromUser) {
// TODO Auto-generated method stub
val = progresValue * 128;
String size = String.valueOf(val);
widthText.setText(size);
heightText.setText(size);
}
});
builder.setPositiveButton("Save", new OnClickListener() {
@Override
public void onClick(DialogInterface arg0, int arg1) {
// TODO Auto-generated method stub
qrName = et.getText().toString();
if (qrName.isEmpty()) {
Toast.makeText(getApplicationContext(),
"Please enter name", Toast.LENGTH_SHORT).show();
} else {
Bitmap sImg = classB.scaleImage(image, val, density);
saveImage(sImg);
}
}
});
dialog = builder.create();
dialog.show();
}
Function to scale image in Class B
public Bitmap scaleImage(Bitmap bitmap, int bound, int density) {
int w = bitmap.getWidth();
int h = bitmap.getHeight();
// Get current dimensions AND the desired bounding box
int bounding = dpToPx(bound, density);
Log.i("Test", "original width = " + Integer.toString(w));
Log.i("Test", "original height = " + Integer.toString(h));
Log.i("Test", "bounding = " + Integer.toString(bounding));
// Determine how much to scale: the dimension requiring less scaling is
// closer to the its side. This way the image always stays inside your
// bounding box AND either x/y axis touches it.
float xScale = ((float) bounding) / w;
float yScale = ((float) bounding) / h;
float scale = (xScale <= yScale) ? xScale : yScale;
Log.i("Test", "xScale = " + Float.toString(xScale));
Log.i("Test", "yScale = " + Float.toString(yScale));
Log.i("Test", "scale = " + Float.toString(scale));
// Create a matrix for the scaling and add the scaling data
Matrix matrix = new Matrix();
matrix.postScale(scale, scale);
// Create a new bitmap and convert it to a format understood by the
// ImageView
Bitmap scaledBitmap = Bitmap.createBitmap(bitmap, 0, 0, w, h, matrix,
true);
sWidth = scaledBitmap.getWidth(); // re-use
sHeight = scaledBitmap.getHeight(); // re-use
@SuppressWarnings("deprecation")
BitmapDrawable result = new BitmapDrawable(scaledBitmap);
Log.i("Test", "scaled width = " + Integer.toString(sWidth));
Log.i("Test", "scaled height = " + Integer.toString(sHeight));
return scaledBitmap;
}
Function to get bounding value in scaleImage() function
private int dpToPx(int dp, int density) {
int result = Math.round((float) dp * density);
return result;
}
回答1:
Which value are you passing into the density argument of your dpToPx(int,int) method?
Your method declares density as int, which leads me to believe you may be passing in DisplayMetrics.densityDpi, a three-digit int number. What you meant to use DisplayMetrics.density, a single digit float number. This will have pushed your image dimension outside 32 bits:
threshold 32 bits signed int = 2^31 -1 = 2147483647
progressValue = 16
bitmap edge = 16 * 128 = 2048
bitmap size = 2048^2 = 4194304
at 32 bpp = 4194304 * 32 = 134217728
multiplied by densityDpi = 134217728 * 460 = 61740154880 // kaboom
multiplied by density = 134217728 * 3 = 402653184 // ok
来源：https://stackoverflow.com/questions/24969579/bitmap-size-exceeds-32bits