@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

    int desiredWidth = 100;
    int desiredHeight = 100;

    int widthMode = MeasureSpec.getMode(widthMeasureSpec);
    int widthSize = MeasureSpec.getSize(widthMeasureSpec);
    int heightMode = MeasureSpec.getMode(heightMeasureSpec);
    int heightSize = MeasureSpec.getSize(heightMeasureSpec);

    int width;
    int height;

    //Measure Width
    if (widthMode == MeasureSpec.EXACTLY) {
        //Must be this size
        width = widthSize;
    } else if (widthMode == MeasureSpec.AT_MOST) {
        //Can't be bigger than...
        width = Math.min(desiredWidth, widthSize);
    } else {
        //Be whatever you want
        width = desiredWidth;
    }

    //Measure Height
    if (heightMode == MeasureSpec.EXACTLY) {
        //Must be this size
        height = heightSize;
    } else if (heightMode == MeasureSpec.AT_MOST) {
        //Can't be bigger than...
        height = Math.min(desiredHeight, heightSize);
    } else {
        //Be whatever you want
        height = desiredHeight;
    }

    //MUST CALL THIS
    setMeasuredDimension(width, height);
}

解決的方法總結(jié)：

• 1。指定一個默認的內(nèi)部寬高，例如本方法中的desiredWidth = 100。
• 2。判斷當(dāng)MeasureSpec的模式為AT_MOST(對應(yīng)于wrap_content)時，設(shè)置結(jié)果為設(shè)置的值（最大為我們設(shè)置的值，如果小于設(shè)置值就設(shè)置為specSize）。
• 3。判斷當(dāng)MeasureSpec的模式為非AT_MOST時，直接設(shè)置為系統(tǒng)的測量值即可。
• 4。設(shè)置值沒有特定的標(biāo)準(zhǔn)，以實際情況為準(zhǔn)。