java 自定义TextView实现，允许VectorDrawableCompat使用复合Drawables

Posted 2021-05-08

<?xml version="1.0" encoding="utf-8"?>
<resources>
	<declare-styleable name="CompatTextView">
		<attr name="drawableStart" format="reference"/>
		<attr name="drawableTop" format="reference"/>
		<attr name="drawableEnd" format="reference"/>
		<attr name="drawableBottom" format="reference"/>
	</declare-styleable>
</resources>

import android.annotation.TargetApi;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.drawable.Drawable;
import android.os.Build;
import android.support.annotation.Nullable;
import android.support.v4.view.ViewCompat;
import android.support.v7.widget.AppCompatDrawableManager;
import android.support.v7.widget.AppCompatTextView;
import android.util.AttributeSet;
import android.widget.TextView;

public class CompatTextView extends AppCompatTextView {
	public CompatTextView(Context context) {
		super(context);
		init(null);
	}

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

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

	@TargetApi(Build.VERSION_CODES.LOLLIPOP)
	public CompatTextView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
		super(context, attrs, defStyleAttr, defStyleRes);
		init(attrs);
	}

	private void init(@Nullable AttributeSet attrs) {
		if (attrs != null) {
			Context context = getContext();
			TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CompatTextView);

			// Obtain DrawableManager used to pull Drawables safely, and check if we're in RTL
			AppCompatDrawableManager dm = AppCompatDrawableManager.get();
			boolean rtl = ViewCompat.getLayoutDirection(this) == ViewCompat.LAYOUT_DIRECTION_RTL;

			// Grab the compat drawable resources from the XML
			int startDrawableRes = a.getResourceId(R.styleable.CompatTextView_drawableStart, 0);
			int topDrawableRes = a.getResourceId(R.styleable.CompatTextView_drawableTop, 0);
			int endDrawableRes = a.getResourceId(R.styleable.CompatTextView_drawableEnd, 0);
			int bottomDrawableRes = a.getResourceId(R.styleable.CompatTextView_drawableBottom, 0);

			// Load the used drawables, falling back to whatever may be set in an "android:" namespace attribute
			Drawable[] currentDrawables = getCompoundDrawables();
			Drawable left = startDrawableRes != 0 ? dm.getDrawable(context, startDrawableRes) : currentDrawables[0];
			Drawable right = endDrawableRes != 0 ? dm.getDrawable(context, endDrawableRes) : currentDrawables[1];
			Drawable top = topDrawableRes != 0 ? dm.getDrawable(context, topDrawableRes) : currentDrawables[2];
			Drawable bottom = bottomDrawableRes != 0 ? dm.getDrawable(context, bottomDrawableRes) : currentDrawables[3];

			// Account for RTL and apply the compound Drawables
			Drawable start = rtl ? right : left;
			Drawable end = rtl ? left : right;
			setCompoundDrawablesWithIntrinsicBounds(start, top, end, bottom);

			a.recycle();
		}
	}
}