java - How to correctly draw text in an extended class for TextView? -
i'm working on extending textview, adding outline around text. far, problem i've been having inability position "outline" correctly behind text. if code extended class 1 portrayed below, label looks this:
note: in above screenshot, set fill color white, , stroke color black.
what doing wrong?
public class outlinedtextview extends textview { /* =========================================================== * constants * =========================================================== */ private static final float outline_proportion = 0.1f; /* =========================================================== * members * =========================================================== */ private final paint mstrokepaint = new paint(); private int moutlinecolor = color.transparent; /* =========================================================== * constructors * =========================================================== */ public outlinedtextview(context context) { super(context); this.setuppaint(); } public outlinedtextview(context context, attributeset attrs) { super(context, attrs); this.setuppaint(); this.setupattributes(context, attrs); } public outlinedtextview(context context, attributeset attrs, int defstyle) { super(context, attrs, defstyle); this.setuppaint(); this.setupattributes(context, attrs); } /* =========================================================== * overrides * =========================================================== */ @override protected void ondraw(canvas canvas) { // text print final float textsize = super.gettextsize(); final string text = super.gettext().tostring(); // setup stroke mstrokepaint.setcolor(moutlinecolor); mstrokepaint.setstrokewidth(textsize * outline_proportion); mstrokepaint.settextsize(textsize); mstrokepaint.setflags(super.getpaintflags()); mstrokepaint.settypeface(super.gettypeface()); // figure out drawing coordinates //mstrokepaint.gettextbounds(text, 0, text.length(), mtextbounds); // draw canvas.drawtext(text, super.getwidth() * 0.5f, super.getbottom() * 0.5f, mstrokepaint); super.ondraw(canvas); } /* =========================================================== * private/protected methods * =========================================================== */ private final void setuppaint() { mstrokepaint.setantialias(true); mstrokepaint.setstyle(paint.style.stroke); mstrokepaint.settextalign(paint.align.center); } private final void setupattributes(context context, attributeset attrs) { final typedarray array = context.obtainstyledattributes(attrs, r.styleable.outlinedtextview); moutlinecolor = array.getcolor( r.styleable.outlinedtextview_outlinecolor, 0x00000000); array.recycle(); // force text label centered super.setgravity(gravity.center_horizontal); } }
bah, stupid of me. needed change-up commented-out line:
super.getpaint().gettextbounds(text, 0, text.length(), mtextbounds); in addition, rendering text, need average view's height , text's height:
// draw canvas.drawtext(text, super.getwidth() * 0.5f, (super.getheight() + mtextbounds.height()) * 0.5f, mstrokepaint); the entire code reads follows:
public class outlinedtextview extends textview { /* =========================================================== * constants * =========================================================== */ private static final float outline_proportion = 0.1f; /* =========================================================== * members * =========================================================== */ private final paint mstrokepaint = new paint(); private final rect mtextbounds = new rect(); private int moutlinecolor = color.transparent; /* =========================================================== * constructors * =========================================================== */ public outlinedtextview(context context) { super(context); this.setuppaint(); } public outlinedtextview(context context, attributeset attrs) { super(context, attrs); this.setuppaint(); this.setupattributes(context, attrs); } public outlinedtextview(context context, attributeset attrs, int defstyle) { super(context, attrs, defstyle); this.setuppaint(); this.setupattributes(context, attrs); } /* =========================================================== * overrides * =========================================================== */ @override protected void ondraw(canvas canvas) { // text print final float textsize = super.gettextsize(); final string text = super.gettext().tostring(); // setup stroke mstrokepaint.setcolor(moutlinecolor); mstrokepaint.setstrokewidth(textsize * outline_proportion); mstrokepaint.settextsize(textsize); mstrokepaint.setflags(super.getpaintflags()); mstrokepaint.settypeface(super.gettypeface()); // figure out drawing coordinates super.getpaint().gettextbounds(text, 0, text.length(), mtextbounds); // draw canvas.drawtext(text, super.getwidth() * 0.5f, (super.getheight() + mtextbounds.height()) * 0.5f, mstrokepaint); super.ondraw(canvas); } /* =========================================================== * private/protected methods * =========================================================== */ private final void setuppaint() { mstrokepaint.setantialias(true); mstrokepaint.setstyle(paint.style.stroke); mstrokepaint.settextalign(paint.align.center); } private final void setupattributes(context context, attributeset attrs) { final typedarray array = context.obtainstyledattributes(attrs, r.styleable.outlinedtextview); moutlinecolor = array.getcolor( r.styleable.outlinedtextview_outlinecolor, 0x00000000); array.recycle(); // force text label centered super.setgravity(gravity.center_horizontal); } }
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