绘制多行居中文字

DrawTextDemo/app/src/main/java/com/yl/drawtext/CustomTextView.java

@@ -5,6 +5,9 @@
 import android.graphics.Color;
 import android.graphics.Paint;
 import android.support.annotation.Nullable;
+import android.text.Layout;
+import android.text.StaticLayout;
+import android.text.TextPaint;
 import android.util.AttributeSet;
 import android.util.TypedValue;
 import android.view.View;
@@ -37,6 +40,7 @@ private void init() {
         paint = new Paint();
         paint.setAntiAlias(true);
         paint.setColor(Color.GRAY);
+        paint.setTextSize(sp2px(50));
         paint.setStyle(Paint.Style.STROKE);
     }
 
@@ -50,8 +54,26 @@ public void draw(Canvas canvas) {
         // y轴
         canvas.drawLine(0, -getHeight() / 2, 0, getHeight() / 2, paint);
 
+        // 绘制坐标
+        drawCoordinate(canvas);
+
+        // 绘制居中文字
+        //drawCenterText(canvas);
+
+        // 绘制多行居中文字（方式1）
+        //drawCenterMultiText1(canvas);
+
+        // 绘制多行居中文字（方式2）
+        //drawCenterMultiText2(canvas);
+    }
+
+    /**
+     * 绘制坐标
+     *
+     * @param canvas 画布
+     */
+    private void drawCoordinate(Canvas canvas) {
         // 绘制文字
-        paint.setTextSize(sp2px(50));
         canvas.drawText("YangLe", 0, 0, paint);
 
         // top-红
@@ -74,15 +96,82 @@ public void draw(Canvas canvas) {
         float bottom = fontMetrics.bottom;
         paint.setColor(Color.BLUE);
         canvas.drawLine(-getWidth() / 2, bottom, getWidth() / 2, bottom, paint);
+    }
 
-        // 绘制居中文字
-        /*paint.setTextSize(sp2px(50));
-        paint.setColor(Color.GRAY);
+    /**
+     * 绘制居中文字
+     *
+     * @param canvas 画布
+     */
+    private void drawCenterText(Canvas canvas) {
         // 文字宽
         float textWidth = paint.measureText("YangLe");
         // 文字baseline在y轴方向的位置
         float baseLineY = Math.abs(paint.ascent() + paint.descent()) / 2;
-        canvas.drawText("YangLe", -textWidth / 2, baseLineY, paint);*/
+        canvas.drawText("YangLe", -textWidth / 2, baseLineY, paint);
+    }
+
+    /**
+     * 绘制多行居中文字（方式1）
+     *
+     * @param canvas 画布
+     */
+    private void drawCenterMultiText1(Canvas canvas) {
+        String text = "ABC";
+
+        // 画笔
+        TextPaint textPaint = new TextPaint();
+        textPaint.setAntiAlias(true);
+        textPaint.setColor(Color.GRAY);
+
+        // 设置宽度超过50dp时换行
+        StaticLayout staticLayout = new StaticLayout(text, textPaint, dp2px(50),
+                Layout.Alignment.ALIGN_CENTER, 1, 0, false);
+        canvas.save();
+        canvas.translate(-staticLayout.getWidth() / 2, -staticLayout.getHeight() / 2);
+        staticLayout.draw(canvas);
+        canvas.restore();
+    }
+
+    /**
+     * 绘制多行居中文字（方式2）
+     *
+     * @param canvas 画布
+     */
+    private void drawCenterMultiText2(Canvas canvas) {
+        String[] texts = {"A", "B", "C"};
+        Paint.FontMetrics fontMetrics = paint.getFontMetrics();
+        float top = Math.abs(fontMetrics.top);
+        float ascent = Math.abs(fontMetrics.ascent);
+        float descent = fontMetrics.descent;
+        float bottom = fontMetrics.bottom;
+        // 行数
+        int textLines = texts.length;
+        // 文字高度
+        float textHeight = top + bottom;
+        // 文字总高度
+        float textTotalHeight = textHeight * textLines;
+        // 基数
+        float basePosition = (textLines - 1) / 2f;
+
+        for (int i = 0; i < textLines; i++) {
+            // 文字宽度
+            float textWidth = paint.measureText(texts[i]);
+            // 文字baseline在y轴方向的位置
+            float baselineY;
+
+            if (i < basePosition) { // 上
+                baselineY = -(textTotalHeight / 2 - textHeight * i - top);
+
+            } else if (i > basePosition) { // 下
+                baselineY = textTotalHeight / 2 - textHeight * (textLines - i - 1) - bottom;
+
+            } else { // 中
+                baselineY = (ascent - descent) / 2;
+            }
+
+            canvas.drawText(texts[i], -textWidth / 2, baselineY, paint);
+        }
     }
 
     /**