以编程方式将文本添加到android中的图像

Question

我想制作一个应用程序，就像 android 的打开屏幕一样。我正在动态地将图像添加到 tableLayout 的行中。我只在 xml 文件中定义了 tableLayout，其余代码在 java 中。我已成功添加图像，但在设置该图像的文本（我想在图像下显示文本）和图像设置为特定填充方面没有任何帮助。如何做到这一点？提前致谢。

Answer 1

使用以下函数在图像上写入文本：

private BitmapDrawable writeTextOnDrawable(int drawableId, String text) {

    Bitmap bm = BitmapFactory.decodeResource(getResources(), drawableId)
            .copy(Bitmap.Config.ARGB_8888, true);

    Typeface tf = Typeface.create("Helvetica", Typeface.BOLD);

    Paint paint = new Paint();
    paint.setStyle(Style.FILL);
    paint.setColor(Color.WHITE);
    paint.setTypeface(tf);
    paint.setTextAlign(Align.CENTER);
    paint.setTextSize(convertToPixels(mContext, 11));

    Rect textRect = new Rect();
    paint.getTextBounds(text, 0, text.length(), textRect);

    Canvas canvas = new Canvas(bm);

    //If the text is bigger than the canvas , reduce the font size
    if(textRect.width() >= (canvas.getWidth() - 4))     //the padding on either sides is considered as 4, so as to appropriately fit in the text
        paint.setTextSize(convertToPixels(mContext, 7));        //Scaling needs to be used for different dpi's

    //Calculate the positions
    int xPos = (canvas.getWidth() / 2) - 2;     //-2 is for regulating the x position offset

    //"- ((paint.descent() + paint.ascent()) / 2)" is the distance from the baseline to the center.
    int yPos = (int) ((canvas.getHeight() / 2) - ((paint.descent() + paint.ascent()) / 2)) ;  

    canvas.drawText(text, xPos, yPos, paint);

    return new BitmapDrawable(getResources(), bm);
}



public static int convertToPixels(Context context, int nDP)
{
    final float conversionScale = context.getResources().getDisplayMetrics().density;

    return (int) ((nDP * conversionScale) + 0.5f) ;

}

Answer 2

您可以改为使用 RelativeLayout 将 TextView 叠加到 ImageView :)

Answer 3

这是 Kotlin 版本 Arun 的 solution：

import org.jetbrains.anko.dip

fun Context.writeTextOnDrawable(drawableId: Int, text: String) =
        DrawableUtil.writeTextOnDrawableInternal(this, drawableId, text, 25, -2, 0)

object DrawableUtil {

    fun writeTextOnDrawableInternal(context: Context, drawableId: Int, text: String,
            textSizeDp: Int, horizontalOffset: Int, verticalOffset: Int): BitmapDrawable {

        val bm = BitmapFactory.decodeResource(context.resources, drawableId)
                .copy(Bitmap.Config.ARGB_8888, true)

        val tf = Typeface.create("Helvetica", Typeface.BOLD)

        val paint = Paint()
        paint.style = Paint.Style.FILL
        paint.color = Color.WHITE
        paint.typeface = tf
        paint.textAlign = Paint.Align.LEFT
        paint.textSize = context.dip(textSizeDp).toFloat()

        val textRect = Rect()
        paint.getTextBounds(text, 0, text.length, textRect)

        val canvas = Canvas(bm)

        //If the text is bigger than the canvas , reduce the font size
        if (textRect.width() >= canvas.getWidth() - 4)
            //the padding on either sides is considered as 4, so as to appropriately fit in the text
            paint.textSize = context.dip(12).toFloat()

        //Calculate the positions
        val xPos = canvas.width.toFloat()/2 + horizontalOffset  

        //"- ((paint.descent() + paint.ascent()) / 2)" is the distance from the baseline to the center.
        val yPos = (canvas.height / 2 - (paint.descent() + paint.ascent()) / 2) + verticalOffset

        canvas.drawText(text, xPos, yPos, paint)

        return BitmapDrawable(context.resources, bm)
    }
}

Answer 4

我成功实现了在图像上添加文本的问题。看看下面的代码。首先将一个视图作为该布局中的相对布局在该 EditText 和该按钮之后获取 ImageView。给每个人一个id。下面写一个loadBitmapFromView函数。

public Bitmap loadBitmapFromView(View v) {
        Bitmap b = Bitmap.createBitmap(v.getWidth(), v.getHeight(), Config.ARGB_8888);
        Canvas c = new Canvas(b);
        v.layout(v.getLeft(), v.getTop(), v.getRight(), v.getBottom());
        v.draw(c);
        return b;
    }

点击按钮。

               Bitmap bitmap = loadBitmapFromView(relativeLayout);
                File dir = new File(Environment.getExternalStorageDirectory().getAbsolutePath(),         "folderName");
                if (!dir.exists())
                    dir.mkdirs();

                File file = new File(dir, "capture.jpg");
                try {
                    FileOutputStream fos = new FileOutputStream(file);
                    bitmap.compress(Bitmap.CompressFormat.JPEG, 100, fos);
                    imageView.setImageBitmap(bitmap);    
                } catch (Exception e) {
                    Log.e("ExpressionEditImageActivity", "Error, " + e);
                }

享受...

更多参考，请参考以下截图：