在渲染到布局之前获取文本视图的高度

Question

找不到任何好的解决方案计算 textview 高度其中设置了文本 在渲染之前 textview 到布局。请帮忙

Answer 1

2 个解决方案

最初使用解决方案 1，后来找到解决方案 2。两者都有效，这确实是您喜欢的。

重要的是确保所有尺寸都正确，因为在 sp 或 px 中混合字体大小会产生很大差异，具体取决于您在哪个屏幕上进行测试。

https://github.com/hanscappelle/SO-3654321 上提供了一个非常基本的示例项目

使用 TextView 和 MeasureSpec 的解决方案 1

原始问题的主要问题是下面方法中的 TextView 应该配置为我们的 TextView 应该呈现到布局。我认为这个解决方案对许多面临这个问题的人来说很有价值。

public static int getHeight(Context context, CharSequence text, int textSize, int deviceWidth, Typeface typeface,int padding) {
            TextView textView = new TextView(context);
            textView.setPadding(padding,0,padding,padding);
            textView.setTypeface(typeface);
            textView.setText(text, TextView.BufferType.SPANNABLE);
            textView.setTextSize(TypedValue.COMPLEX_UNIT_SP, textSize);
            int widthMeasureSpec = View.MeasureSpec.makeMeasureSpec(deviceWidth, View.MeasureSpec.AT_MOST);
            int heightMeasureSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
            textView.measure(widthMeasureSpec, heightMeasureSpec);
            return textView.getMeasuredHeight();
        }

以及如何使用它的示例：

// retrieve deviceWidth
int deviceWidth;
WindowManager wm = (WindowManager) textView.getContext().getSystemService(Context.WINDOW_SERVICE);
Display display = wm.getDefaultDisplay();
if(android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB_MR2){
    Point size = new Point();
    display.getSize(size);
    deviceWidth = size.x;
} else {
    deviceWidth = display.getWidth();
}
// the text to check for
String exampleTextToMeasure = "some example text that will be long enough to make this example split over multiple lines so we can't easily predict the final height";
//  some dimensions from dimes resources to take into account
int textSize = getContext().getResources().getDimensionPixelSize(R.dimen.text_size);
int padding = getContext().getResources().getDimensionPixelSize(R.dimen.text_padding);

// final calculation of textView height
int measuredTextHeight = getHeight(getContext(), exampleTextToMeasure, textSize, deviceWidth, TypeFace.DEFAULT, padding); 

使用 TextPaint 和 StaticLayout 的解决方案 2

此方法依赖于 TextPaint 和 StaticLayout，它还可以在我迄今为止测试的所有 API 级别上提供可靠的结果。注意尺寸单位；一切都应该以像素为单位！

来源：Measuring text height to be drawn on Canvas ( Android )

    public static int method1UsingTextPaintAndStaticLayout(
            final CharSequence text,
            final int textSize, // in pixels
            final int deviceWidth, // in pixels
            final int padding // in pixels
    ) {

        TextPaint myTextPaint = new TextPaint();
        myTextPaint.setAntiAlias(true);
        // this is how you would convert sp to pixels based on screen density
        //myTextPaint.setTextSize(16 * context.getResources().getDisplayMetrics().density);
        myTextPaint.setTextSize(textSize);
        Layout.Alignment alignment = Layout.Alignment.ALIGN_NORMAL;
        float spacingMultiplier = 1;
        float spacingAddition = padding; // optionally apply padding here
        boolean includePadding = padding != 0;
        StaticLayout myStaticLayout = new StaticLayout(text, myTextPaint, deviceWidth, alignment, spacingMultiplier, spacingAddition, includePadding);
        return myStaticLayout.getHeight();
    }

Answer 2

从 support_ms 的回答中，有一个更简单的方法，它只接受一个 TextView 作为参数。

/**
 * Get the TextView height before the TextView will render
 * @param textView the TextView to measure
 * @return the height of the textView
 */
public static int getTextViewHeight(TextView textView) {
    WindowManager wm =
            (WindowManager) textView.getContext().getSystemService(Context.WINDOW_SERVICE);
    Display display = wm.getDefaultDisplay();

    int deviceWidth;

    if(android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB_MR2){
        Point size = new Point();
        display.getSize(size);
        deviceWidth = size.x;
    } else {
        deviceWidth = display.getWidth();
    }

    int widthMeasureSpec = View.MeasureSpec.makeMeasureSpec(deviceWidth, View.MeasureSpec.AT_MOST);
    int heightMeasureSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
    textView.measure(widthMeasureSpec, heightMeasureSpec);
    return textView.getMeasuredHeight();
}

Answer 3

@support_ms 给出了很好的答案，但是当您可以先格式化 TextView 然后只使用一个参数调用静态方法时，我不确定创建新 TextView 并计算所有这些输入参数的意义， TextView 本身！

我也不确定为什么一个参数被标记为deviceWidth 我只是使用Textview 本身的宽度。我的是match_parent，我想任何TextView 和wrap_content 都可能根本不起作用。但这就是你得到的。

public static int getHeight(TextView t) {
    int widthMeasureSpec = View.MeasureSpec.makeMeasureSpec(screenWidth(t.getContext()), View.MeasureSpec.AT_MOST);
    int heightMeasureSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
    t.measure(widthMeasureSpec, heightMeasureSpec);
    return t.getMeasuredHeight();
}

public static int screenWidth(Context context)
{
    WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
    Display display = wm.getDefaultDisplay();
    return display.getWidth();
}

Answer 4

这是我的简单解决方案，它在绘制之前获取尺寸

https://stackoverflow.com/a/40133275/1240672

Answer 5

渲染前获取TextView的一行

这是我基于上述想法的代码。它对我有用。

private int widthMeasureSpec;
private int heightMeasureSpec;
private int heightOfEachLine;
private int paddingFirstLine;
private void calculateHeightOfEachLine() {
    WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
    Display display = wm.getDefaultDisplay();
    Point size = new Point();
    display.getSize(size);
    int deviceWidth = size.x;
    widthMeasureSpec = View.MeasureSpec.makeMeasureSpec(deviceWidth, View.MeasureSpec.AT_MOST);
    heightMeasureSpec = View.MeasureSpec.makeMeasureSpec(0, View.MeasureSpec.UNSPECIFIED);
    //1 line = 76; 2 lines = 76 + 66; 3 lines = 76 + 66 + 66
    //=> height of first line = 76 pixel; height of second line = third line =... n line = 66 pixel
    int heightOfFirstLine = getHeightOfTextView("A");
    int heightOfSecondLine = getHeightOfTextView("A\nA") - heightOfFirstLine;
    paddingFirstLine = heightOfFirstLine - heightOfSecondLine;
    heightOfEachLine = heightOfSecondLine;
}

private int getHeightOfTextView(String text) {
    // Getting height of text view before rendering to layout
    TextView textView = new TextView(context);
    textView.setPadding(10, 0, 10, 0);
    //textView.setTypeface(typeface);
    textView.setTextSize(TypedValue.COMPLEX_UNIT_PX, context.getResources().getDimension(R.dimen.tv_size_14sp));
    textView.setText(text, TextView.BufferType.SPANNABLE);
    textView.measure(widthMeasureSpec, heightMeasureSpec);
    return textView.getMeasuredHeight();
}

private int getLineCountOfTextViewBeforeRendering(String text) {
    return (getHeightOfTextView(text) - paddingFirstLine) / heightOfEachLine;
}

注意：此代码也必须为屏幕上的真实文本视图设置

textView.setTextSize(TypedValue.COMPLEX_UNIT_PX, context.getResources().getDimension(R.dimen.tv_size_14sp));

Answer 6

Kotlin 扩展

fun TextView.calculateHeight(text: CharSequence = getText()): Int {
    val alignment = when(gravity) {
        Gravity.CENTER -> Layout.Alignment.ALIGN_CENTER
        Gravity.RIGHT -> Layout.Alignment.ALIGN_OPPOSITE
        else -> Layout.Alignment.ALIGN_NORMAL
    }
    return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        StaticLayout.Builder.obtain(text, 0, text.length, TextPaint(paint), width)
            .setLineSpacing(lineSpacingExtra, lineSpacingMultiplier)
            .setAlignment(alignment)
            .setIncludePad(true).build()
    } else {
        @Suppress("DEPRECATION")
        StaticLayout(
            text, TextPaint(paint), width, alignment,
            lineSpacingMultiplier, lineSpacingExtra, true
        )
    }.height
}