Java tutorial
/* * Copyright 2016 czy1121 * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.github.czy1121.view; import android.annotation.TargetApi; import android.content.Context; import android.content.res.TypedArray; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.Path; import android.graphics.PorterDuff; import android.graphics.PorterDuffXfermode; import android.graphics.Rect; import android.os.Build; import android.support.annotation.ColorInt; import android.support.annotation.ColorRes; import android.support.v4.content.ContextCompat; import android.text.TextPaint; import android.util.AttributeSet; import android.view.View; import com.github.czy1121.cornerlabelview.R; public class CornerLabelView extends View { private static final float SQRT2 = (float) Math.sqrt(2); private Paint mPaint; private final Painter mText1 = new Painter(); private final Painter mText2 = new Painter(); private float mPaddingTop = 0; private float mPaddingCenter = 0; private float mPaddingBottom = 0; private boolean mIsLeft = true; private boolean mIsTop = true; private boolean mIsTriangle = true; private int mHeight; public CornerLabelView(Context context) { this(context, null); } public CornerLabelView(Context context, AttributeSet attrs) { this(context, attrs, -1); } public CornerLabelView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); init(context, attrs); } @TargetApi(Build.VERSION_CODES.LOLLIPOP) public CornerLabelView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { super(context, attrs, defStyleAttr, defStyleRes); init(context, attrs); } public void init(Context context, AttributeSet attrs) { TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.CornerLabelView); mPaddingTop = ta.getDimension(R.styleable.CornerLabelView_clvPaddingTop, dp2px(10)); mPaddingCenter = ta.getDimension(R.styleable.CornerLabelView_clvPaddingCenter, dp2px(0)); mPaddingBottom = ta.getDimension(R.styleable.CornerLabelView_clvPaddingBottom, dp2px(3)); mText1.text = ta.getString(R.styleable.CornerLabelView_clvText1); mText1.height = ta.getDimension(R.styleable.CornerLabelView_clvText1Height, dp2px(12)); mText1.color = ta.getColor(R.styleable.CornerLabelView_clvText1Color, 0xffffffff); mText1.init(); mText1.reset(); mText2.text = ta.getString(R.styleable.CornerLabelView_clvText2); mText2.height = ta.getDimension(R.styleable.CornerLabelView_clvText2Height, dp2px(8)); mText2.color = ta.getColor(R.styleable.CornerLabelView_clvText2Color, 0x66ffffff); mText2.init(); mText2.reset(); int fillColor = ta.getColor(R.styleable.CornerLabelView_clvFillColor, 0x66000000); int flags = ta.getInteger(R.styleable.CornerLabelView_clvFlags, 0); ta.recycle(); mIsLeft = (flags & 1) == 0; mIsTop = (flags & 2) == 0; mIsTriangle = (flags & 4) > 0; mPaint = new Paint(); mPaint.setStyle(Paint.Style.FILL); mPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_OVER)); mPaint.setAntiAlias(true); mPaint.setColor(fillColor); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, heightMeasureSpec); mHeight = (int) (mPaddingTop + mPaddingCenter + mPaddingBottom + mText1.height + mText2.height); int size = (int) (mHeight * SQRT2); setMeasuredDimension(size, size); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); float xy = mHeight / SQRT2; canvas.save(); canvas.translate(xy, xy); canvas.rotate((mIsTop ? 1 : -1) * (mIsLeft ? -45 : 45)); canvas.drawPath(calcPath(), mPaint); mText1.draw(canvas, mPaddingBottom, mIsTop); if (mIsTriangle) { mText2.draw(canvas, mPaddingBottom + mPaddingCenter + mText1.height, mIsTop); } canvas.restore(); } private int dp2px(float dp) { final float scale = getContext().getResources().getDisplayMetrics().density; return (int) (dp * scale + 0.5f); } private Path calcPath() { Path path = new Path(); path.moveTo(-mHeight, 0); path.lineTo(mHeight, 0); int factor = mIsTop ? -1 : 1; if (mIsTriangle) { path.lineTo(0, factor * mHeight); } else { int lineHeight = factor * (int) (mPaddingCenter + mPaddingBottom + mText1.height); path.lineTo(mHeight + lineHeight, lineHeight); path.lineTo(-mHeight + lineHeight, lineHeight); } path.close(); return path; } public CornerLabelView setPaddingTop(float dp) { mPaddingTop = dp2px(dp); requestLayout(); return this; } public CornerLabelView setPaddingCenter(float dp) { mPaddingCenter = dp2px(dp); requestLayout(); return this; } public CornerLabelView setPaddingBottom(float dp) { mPaddingBottom = dp2px(dp); requestLayout(); return this; } public CornerLabelView setText1(String text) { mText1.text = text; mText1.init(); requestLayout(); return this; } public CornerLabelView setText1Height(float dp) { mText1.height = dp2px(dp); mText1.init(); requestLayout(); return this; } public CornerLabelView setText1Color(@ColorInt int color) { mText1.color = color; mText1.init(); invalidate(); return this; } public CornerLabelView setText1ColorResource(@ColorRes int resource) { mText1.color = ContextCompat.getColor(getContext(), resource); mText1.init(); invalidate(); return this; } public CornerLabelView setText2(String text) { mText2.text = text; mText2.init(); requestLayout(); return this; } public CornerLabelView setText2Height(float dp) { mText2.height = dp2px(dp); mText2.init(); requestLayout(); return this; } public CornerLabelView setText2Color(@ColorInt int color) { mText2.color = color; mText2.init(); invalidate(); return this; } public CornerLabelView setText2ColorResource(@ColorRes int resource) { mText2.color = ContextCompat.getColor(getContext(), resource); mText2.init(); invalidate(); return this; } public CornerLabelView setFillColor(@ColorInt int color) { mPaint.setColor(color); invalidate(); return this; } public CornerLabelView setFillColorResource(@ColorRes int resource) { return setFillColor(ContextCompat.getColor(getContext(), resource)); } public CornerLabelView left() { mIsLeft = true; invalidate(); return this; } public CornerLabelView right() { mIsLeft = false; invalidate(); return this; } public CornerLabelView top() { mIsTop = true; invalidate(); return this; } public CornerLabelView bottom() { mIsTop = false; invalidate(); return this; } public CornerLabelView triangle(boolean value) { mIsTriangle = value; invalidate(); return this; } static class Painter { private final TextPaint paint = new TextPaint(Paint.ANTI_ALIAS_FLAG); String text = ""; int color = Color.WHITE; float height = 0; private float offset = 0; void init() { paint.setTextAlign(Paint.Align.CENTER); paint.setTextSize(height); paint.setColor(color); reset(); } void draw(Canvas canvas, float y, boolean isTop) { canvas.drawText(text, 0, (isTop ? -1 : 1) * (y + height / 2) + offset, paint); } void reset() { if (text == null) { text = ""; } Rect rect = new Rect(); paint.getTextBounds(text, 0, text.length(), rect); offset = rect.height() / 2; } } }