一种TextView插入图片的途径(图片的显示高度和文字高度一致)

最新推荐文章于 2021-05-27 08:57:34 发布

原创最新推荐文章于 2021-05-27 08:57:34 发布 · 1.3k 阅读

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本文介绍了一种自定义的Android图片Span——AdaptiveImageSpan。该Span可根据文本的高度自适应调整图片大小，确保图片与文本行高一致。文章提供了完整的源码实现及关键步骤解析。

实现效果：

控件代码：

import java.lang.ref.WeakReference;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.Paint.FontMetricsInt;
import android.graphics.drawable.Drawable;
import android.text.style.ReplacementSpan;
import android.util.Log;

public class AdaptiveImageSpan extends ReplacementSpan {

  private final static String LOG_TAG = "AdaptiveImageSpan";

  private Context mContext;

  private int mResourceId;

  private int mHeight;

  private int mLeading;

  private WeakReference<Drawable> mDrawableRef;

  public AdaptiveImageSpan(Context context, int resourceId) {

    mResourceId = resourceId;

    mContext = context;
  }

  @Override
  public int getSize(Paint paint, CharSequence text, int start, int end, FontMetricsInt fm) {

    FontMetricsInt tempTm = fm;

    if (tempTm == null) {

      tempTm = new FontMetricsInt();

      paint.getFontMetricsInt(tempTm);
    }

    if (tempTm != null) {

      Log.i(LOG_TAG, LOG_TAG + " --> getSize - fm.bottom:" + tempTm.bottom + " - fm.top: "
          + tempTm.top);

      mLeading = (tempTm.bottom - tempTm.descent) - (tempTm.top - tempTm.ascent);

      Log.i(LOG_TAG, LOG_TAG + " --> getSize - fm.ascent:" + tempTm.ascent + " - fm.descent: "
          + tempTm.descent + " - fm.leading: " + tempTm.leading + " - leading: " + mLeading);

      mHeight = tempTm.descent - tempTm.ascent - mLeading;

      // mHeight = tempTm.bottom - tempTm.top;
      
      if(tempTm.top * tempTm.bottom == 0){
        return 0;
      }
    }
    
    Drawable d = getCachedDrawable();

    Rect rect = d.getBounds();

    Log.i(LOG_TAG, LOG_TAG + " --> getSize size:" + rect.right + " - height: " + mHeight);

    return rect.right;
  }

  @Override
  public void draw(Canvas canvas, CharSequence text, int start, int end, float x, int top, int y,
      int bottom, Paint paint) {

    Log.i(LOG_TAG, LOG_TAG + " --> draw - text:" + text + " - height: " + (bottom - top));

    Drawable b = getCachedDrawable();

    canvas.save();

    int transY = bottom - b.getBounds().bottom;

    transY -= mLeading;

    canvas.translate(x, transY);

    b.draw(canvas);

    canvas.restore();
  }

  private Drawable getCachedDrawable() {
    WeakReference<Drawable> wr = mDrawableRef;
    Drawable d = null;

    if (wr != null) d = wr.get();

    if (d == null) {
      d = getDrawable();
      mDrawableRef = new WeakReference<Drawable>(d);
    }

    return d;
  }


  public Drawable getDrawable() {

    Drawable drawable = null;

    drawable = mContext.getResources().getDrawable(mResourceId);

    int width = 0;

    if (drawable.getIntrinsicHeight() > 0 && mHeight > 0) {

      width =
          (int) ((drawable.getIntrinsicWidth() / (drawable.getIntrinsicHeight() * 1.0f)) * mHeight);
    }

    Log.i(LOG_TAG, LOG_TAG + " --> getDrawable - mHeight:" + mHeight + " - width: " + width);

    if (width > 0) {

      drawable.setBounds(0, 0, width, mHeight);
    } else {

      drawable.setBounds(0, 0, drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight());
    }

    return drawable;
  }

}

参考：FLAVIEN LAURENT