安卓：如何改变复选框的大小？

我找到了一种方法，可以在不创建自己的图像的情况下完成操作。换句话说，系统图像被缩放了。我并不是说这个解决方案完美无缺；如果有人知道如何缩短其中的一些步骤，那么我会很高兴地了解如何做到。

首先，在项目（WonActivity）的主活动类中放置以下内容。这直接来自于Stack Overflow - 谢谢你们！

/** get the default drawable for the check box */
Drawable getDefaultCheckBoxDrawable()
{
  int resID = 0;

  if (Build.VERSION.SDK_INT <= 10)
  {
    // pre-Honeycomb has a different way of setting the CheckBox button drawable
    resID = Resources.getSystem().getIdentifier("btn_check", "drawable", "android");
  }
  else
  {
    // starting with Honeycomb, retrieve the theme-based indicator as CheckBox button drawable
    TypedValue value = new TypedValue();
    getApplicationContext().getTheme().resolveAttribute(android.R.attr.listChoiceIndicatorMultiple, value, true);
    resID = value.resourceId;
  }

  return getResources().getDrawable(resID);
}

其次，我创建了一个用于“缩放可绘制对象”的类。请注意，它与标准的ScaleDrawable完全不同。

import android.graphics.drawable.*;

/** The drawable that scales the contained drawable */

public class ScalingDrawable extends LayerDrawable
{
  /** X scale */
  float scaleX;

  /** Y scale */
  float scaleY;

  ScalingDrawable(Drawable d, float scaleX, float scaleY)
  {
    super(new Drawable[] { d });
    setScale(scaleX, scaleY);
  }

  ScalingDrawable(Drawable d, float scale)
  {
    this(d, scale, scale);
  }

  /** set the scales */
  void setScale(float scaleX, float scaleY)
  {
    this.scaleX = scaleX;
    this.scaleY = scaleY;
  }

  /** set the scale -- proportional scaling */
  void setScale(float scale)
  {
    setScale(scale, scale);
  }

  // The following is what I wrote this for!

  @Override
  public int getIntrinsicWidth()
  {
    return (int)(super.getIntrinsicWidth() * scaleX);
  }

  @Override
  public int getIntrinsicHeight()
  {
    return (int)(super.getIntrinsicHeight() * scaleY);
  }
}

最后，我定义了一个复选框类。

import android.graphics.*;
import android.graphics.drawable.Drawable;
import android.widget.*;

/** A check box that resizes itself */

public class WonCheckBox extends CheckBox
{
  /** the check image */
  private ScalingDrawable checkImg;

  /** original height of the check-box image */
  private int origHeight;

  /** original padding-left */
  private int origPadLeft;

  /** height set by the user directly */
  private float height;

  WonCheckBox()
  {
    super(WonActivity.W.getApplicationContext());
    setBackgroundColor(Color.TRANSPARENT);

    // get the original drawable and get its height
    Drawable origImg = WonActivity.W.getDefaultCheckBoxDrawable();
    origHeight = height = origImg.getIntrinsicHeight();
    origPadLeft = getPaddingLeft();

    // I tried origImg.mutate(), but that fails on Android 2.1 (NullPointerException)
    checkImg = new ScalingDrawable(origImg, 1);
    setButtonDrawable(checkImg);
  }

  /** set checkbox height in pixels directly */
  public void setHeight(int height)
  {
    this.height = height;
    float scale = (float)height / origHeight;
    checkImg.setScale(scale);

    // Make sure the text is not overlapping with the image.
    // This is unnecessary on Android 4.2.2, but very important on previous versions.
    setPadding((int)(scale * origPadLeft), 0, 0, 0);

    // call the checkbox's internal setHeight()
    //   (may be unnecessary in your case)
    super.setHeight(height);
  }
}

就这样。如果您在视图中放置一个 WonCheckBox 并应用 setHeight()，则复选框图像的大小将是正确的。

假设您的原始XML如下：

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_checked="true"
        android:drawable="@drawable/tick_img" />
    <item android:state_checked="false"
        android:drawable="@drawable/untick_img" />
</selector>

然后在您的复选框xml中简单地删除android:button="@drawable/xml_above"，并在Java中以编程方式进行可绘制缩放（将150大尺寸减小到所需的dp大小）：

CheckBox tickRememberPasswd = findViewById(R.id.remember_tick);

//custom selector size
Drawable drawableTick = ContextCompat.getDrawable(this, R.drawable.tick_img);
Drawable drawableUntick = ContextCompat.getDrawable(this, R.drawable.untick_img);
Bitmap bitmapTick = null;
if (drawableTick != null && drawableUntick != null) {
    int desiredPixels = Math.round(convertDpToPixel(150, this));

    bitmapTick = ((BitmapDrawable) drawableTick).getBitmap();
    Drawable dTick = new BitmapDrawable(getResources()
            , Bitmap.createScaledBitmap(bitmapTick, desiredPixels, desiredPixels, true));

    Bitmap bitmapUntick = ((BitmapDrawable) drawableUntick).getBitmap();
    Drawable dUntick = new BitmapDrawable(getResources()
            , Bitmap.createScaledBitmap(bitmapUntick, desiredPixels, desiredPixels, true));

    final StateListDrawable statesTick = new StateListDrawable();
    statesTick.addState(new int[] {android.R.attr.state_checked},
            dTick);
    statesTick.addState(new int[] { }, //else state_checked false
            dUntick);
    tickRememberPasswd.setButtonDrawable(statesTick);
}

convertDpToPixel方法：

public static float convertDpToPixel(float dp, Context context) {
    Resources resources = context.getResources();
    DisplayMetrics metrics = resources.getDisplayMetrics();
    float px = dp * (metrics.densityDpi / 160f);
    return px;
}

如果您想将自定义图像添加到复选框中， 请将按钮设置为 null，然后将背景添加到复选框即可解决问题。

 <CheckBox
    android:layout_width="22dp"
    android:layout_height="22dp"
    android:layout_marginLeft="-10dp"
    android:button="@null"
    android:background="@drawable/memory_selector"/>