Android计算字体宽度和Textview宽度

为了下次方便搜查，贴一下代码

 isGo=true;
    final Paint paint = new Paint();
    paint.setTextSize(tv_detail.getTextSize());
    Rect rect = new Rect();
    //精确计算文字宽度
    tv_detail.post(new Runnable() {
        @Override
        public void run() {
            tvWidth = tv_detail.getWidth();
            textWidth = getTextWidth(paint, test);
            if (textWidth>tvWidth * 4 - tvWidth / 2){
                img_detail_more.setVisibility(View.VISIBLE);
                showText = test.substring(0, subInex(paint, test));
                tv_detail.setText(showText + "...");
            }else {
                img_detail_more.setVisibility(View.GONE);
            }

        }
    });
    img_detail_more.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            isGo = !isGo;
            if(isGo){
                tv_detail.setText(test);
            }else {
                tv_detail.setText(showText + "...");
            }

        }
    });
}


public static int getTextWidth(Paint paint, String str) {
    int iRet = 0;
    if (str != null && str.length() > 0) {
        int len = str.length();
        float[] widths = new float[len];
        paint.getTextWidths(str, widths);
        for (int j = 0; j < len; j++) {
            iRet += (int) Math.ceil(widths[j]);
        }
    }
    return iRet;
}

//需要截取的位置
public int subInex(Paint paint, String str) {
    int iRet = 0;
    int j = 0;
    if (str != null && str.length() > 0) {
        int len = str.length();
        float[] widths = new float[len];
        paint.getTextWidths(str, widths);
        for (j = 0; j < len; j++) {
            iRet += (int) Math.ceil(widths[j]);
            if (iRet > tvWidth * 4 - tvWidth / 2) {
                break;
            }
        }
    }
    return j;
}