RadioButton设置图片无法居中问题
像下面这样的布局只能让文字居中，文字左边的圆圈图标还是靠左显示。

<RadioGroup
        android:id="@+id/group"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center_horizontal"
        android:orientation="horizontal" >
        <RadioButton
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:checked="false"
            android:gravity="center"
            android:text="1asdf"
            android:textColor="#000000" />
        <RadioButton
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:checked="false"
            android:gravity="center"
            android:text="2asdf"
            android:textColor="#000000" />
</RadioGroup>

1.png

解决思路：根据设置的gravity来重新设定图片的位置：自定义一个view:CustomRadioButton继承RadioButton,需要重写onDraw()方法：

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.Gravity;
import android.widget.RadioButton;

public class CustomRadioButton extends RadioButton {
    private static final String TAG = CustomRadioButton.class.getSimpleName();

    public CustomRadioButton(Context context) {
        super(context);
    }

    public CustomRadioButton(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public CustomRadioButton(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        Drawable[] drawables = getCompoundDrawables();
        Drawable drawable = drawables[0];
        int gravity = getGravity();
        int left = 0;
        if (gravity == Gravity.CENTER) {
            left = ((int) (getWidth() - drawable.getIntrinsicWidth() - getPaint().measureText(getText().toString()))
                    / 2);
        }
        drawable.setBounds(left, 0, left + drawable.getIntrinsicWidth(), drawable.getIntrinsicHeight());
    }
}

新的view要设置android:button="@null",然后设置一个android:drawableStart="@drawable/radiobutton_selector"

radiobutton_selector:

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">

    <item android:drawable="@drawable/ic_radio_button_checked" android:state_checked="true"></item>
    <item android:drawable="@drawable/ic_radio_button_not_checked"></item>

</selector>

图片资源需要自己找，推荐一个网站：阿里巴巴矢量图标库
新的布局：

<RadioGroup
        android:id="@+id/group"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center_horizontal"
        android:orientation="horizontal" >

        <RadioButton
            android:layout_width="0dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:checked="false"
            android:gravity="center"
            android:text="1asdf"
            android:textColor="#000000" />

        <com.example.lifecycle.CustomRadioButton
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:background="#aabbcc"
            android:button="@null"
            android:checked="false"
            android:drawableStart="@drawable/radiobutton_selector"
            android:gravity="center"
            android:text="2asdf"
            android:textColor="#000000" />
</RadioGroup>

2.png

PS：才知道简书上传图片形成的链接最后的数字代表宽度，而且是可以更改的。。。。。。