中英文混排对齐的TextView

src/com/zftlive/android/view/AlignTextView.java

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+package com.zftlive.android.view;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import android.content.Context;
+import android.graphics.Canvas;
+import android.graphics.Paint;
+import android.text.Layout;
+import android.text.TextPaint;
+import android.util.AttributeSet;
+import android.widget.TextView;
+
+/**
+ * 两端对齐的textview，可以设置最后一行靠左，靠右，居中对齐
+ * 
+ * @author 曾繁添
+ * @version 1.0
+ * 
+ */
+public class AlignTextView extends TextView {
+	
+	private float textHeight; // 单行文字高度
+	private int width; // textview宽度
+	private List<String> lines = new ArrayList<String>(); // 分割后的行
+	private List<Integer> tailLines = new ArrayList<Integer>(); // 尾行
+	private Align align = Align.ALIGN_LEFT; // 默认最后一行左对齐
+
+	// 尾行对齐方式
+	public enum Align {
+		ALIGN_LEFT, ALIGN_CENTER, ALIGN_RIGHT; // 居中，居左，居右,针对段落最后一行
+	}
+
+	public AlignTextView(Context context, AttributeSet attrs) {
+		super(context, attrs);
+	}
+
+	@Override
+	protected void onDraw(Canvas canvas) {
+		TextPaint paint = getPaint();
+		paint.setColor(getCurrentTextColor());
+		paint.drawableState = getDrawableState();
+		width = getMeasuredWidth();
+		String text = getText().toString();
+
+		Paint.FontMetrics fm = paint.getFontMetrics();
+		// 计算行高
+		Layout layout = getLayout();
+
+		// layout.getLayout()在4.4.3出现NullPointerException
+		if (layout == null) {
+			return;
+		}
+
+		textHeight = fm.descent - fm.ascent;
+
+		textHeight = textHeight * layout.getSpacingMultiplier()
+				+ layout.getSpacingAdd();
+
+		float firstHeight = getTextSize();
+
+		int gravity = getGravity();
+		if ((gravity & 0x1000) == 0) { // 是否垂直居中
+			firstHeight = firstHeight + (textHeight - firstHeight) / 2;
+		}
+
+		int paddingLeft = getPaddingLeft();
+		int paddingRight = getPaddingRight();
+		width = width - paddingLeft - paddingRight;
+
+		lines.clear();
+		tailLines.clear();
+
+		// 文本含有换行符时，分割单独处理
+		String[] items = text.split("\\n");
+		for (String item : items) {
+			calc(paint, item);
+		}
+
+		for (int i = 0; i < lines.size(); i++) {
+			float drawY = i * textHeight + firstHeight;
+			String line = lines.get(i);
+			// 绘画起始x坐标
+			float drawSpacingX = paddingLeft;
+			float gap = (width - paint.measureText(line));
+			float interval = gap / (line.length() - 1);
+
+			// 绘制最后一行
+			if (tailLines.contains(i)) {
+				interval = 0;
+				if (align == Align.ALIGN_CENTER)
+					drawSpacingX += gap / 2;
+				else if (align == Align.ALIGN_RIGHT)
+					drawSpacingX += gap;
+			}
+
+			for (int j = 0; j < line.length(); j++) {
+				float drawX = paint.measureText(line.substring(0, j))
+						+ interval * j;
+				canvas.drawText(line.substring(j, j + 1), drawX + drawSpacingX,
+						drawY, paint);
+			}
+		}
+	}
+
+	/**
+	 * 设置尾行对齐方式
+	 * 
+	 * @param align
+	 */
+	public void setAlign(Align align) {
+		this.align = align;
+		invalidate();
+	}
+
+	/**
+	 * 计算每行应显示的文本数
+	 * 
+	 * @param text
+	 * @return
+	 */
+	private void calc(Paint paint, String text) {
+		if (text.length() == 0) {
+			lines.add("\n");
+			return;
+		}
+		StringBuffer sb = new StringBuffer("");
+		int startPosition = 0; // 起始位置
+		for (int i = 0; i < text.length(); i++) {
+			if (paint.measureText(text.substring(startPosition, i + 1)) > width) {
+				startPosition = i;
+				lines.add(sb.toString());
+				sb = new StringBuffer();
+			}
+			sb.append(text.charAt(i));
+		}
+		if (sb.length() > 0)
+			lines.add(sb.toString());
+
+		tailLines.add(lines.size() - 1);
+	}
+}