Android自定义TextView实现文字图片居中显示的方法

int vspace = bottom - top - compoundPaddingBottom - compoundPaddingTop;
int hspace = right - left - compoundPaddingRight - compoundPaddingLeft;
// IMPORTANT: The coordinates computed are also used in invalidateDrawable()
// Make sure to update invalidateDrawable() when changing this code.
if (dr.mShowing[Drawables.LEFT] != null) {
  canvas.save();
  canvas.translate(scrollX + mPaddingLeft + leftOffset,
           scrollY + compoundPaddingTop +
           (vspace - dr.mDrawableHeightLeft) / 2);
  dr.mShowing[Drawables.LEFT].draw(canvas);
  canvas.restore();
}
// IMPORTANT: The coordinates computed are also used in invalidateDrawable()
// Make sure to update invalidateDrawable() when changing this code.
if (dr.mShowing[Drawables.RIGHT] != null) {
  canvas.save();
  canvas.translate(scrollX + right - left - mPaddingRight
      - dr.mDrawableSizeRight - rightOffset,
       scrollY + compoundPaddingTop + (vspace - dr.mDrawableHeightRight) / 2);
  dr.mShowing[Drawables.RIGHT].draw(canvas);
  canvas.restore();
}

package com.chaoxing.email.view;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.Gravity;
import android.widget.TextView;
/**
 * use in xml
 * use in code
 */
public class EmailCenterTextView extends TextView {
  public EmailCenterTextView(Context context) {
    super(context);
  }
  public EmailCenterTextView(Context context, AttributeSet attrs) {
    super(context, attrs);
  }
  public EmailCenterTextView(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
  }
  @Override
  protected void onDraw(Canvas canvas) {
    Drawable[] drawables = getCompoundDrawables();
    if (null != drawables) {
      Drawable drawableLeft = drawables[0];
      Drawable drawableRight = drawables[2];
      float textWidth = getPaint().measureText(getText().toString());
      if (null != drawableLeft) {
        setGravity(Gravity.START | Gravity.CENTER_VERTICAL);
        float cOntentWidth= textWidth + getCompoundDrawablePadding() + drawableLeft.getIntrinsicWidth();
        if (getWidth() - contentWidth > 0) {
          canvas.translate((getWidth() - contentWidth - getPaddingRight() - getPaddingLeft()) / 2, 0);
        }
      }
      if (null != drawableRight) {
        setGravity(Gravity.END | Gravity.CENTER_VERTICAL);
        float cOntentWidth= textWidth + getCompoundDrawablePadding() + drawableRight.getIntrinsicWidth();
        if (getWidth() - contentWidth > 0) {
          canvas.translate(-(getWidth() - contentWidth - getPaddingRight() - getPaddingLeft()) / 2, 0);
        }
      }
      if (null == drawableRight && null == drawableLeft) {
        setGravity(Gravity.CENTER);
      }
    }
    super.onDraw(canvas);
  }
}