Android中自定义TextView文字循环渐变_android 换行文本横向渐变-优快云博客

本文介绍了一个自定义的MyTextView类，它继承自Android的TextView。这个自定义视图通过使用LinearGradient和Matrix实现了文字内容的循环渐变效果，为UI增加了动态视觉体验。在onSizeChanged方法中初始化了渐变颜色和矩阵，在onDraw方法中更新并重绘视图，以实现平滑的滚动效果。

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参考网址：https://blog.youkuaiyun.com/ll741237952/article/details/50900730

package com.view;

import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.LinearGradient;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.graphics.Shader;
import android.util.AttributeSet;
import android.widget.TextView;
/**
*文字内容循环渐变，动态效果
*
**/
@SuppressLint("AppCompatCustomView")
public class MyTextView extends TextView {

    private LinearGradient mLinearGradient;
    private Matrix mGradientMatrix;
    private Paint mPaint;
    private int mViewWidth = 0;
    private int mTranslate = 0;
    private boolean mAnimating = true;

    public MyTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }
    @Override
    protected void onSizeChanged(int w, int h, int oldw, int oldh) {
        super.onSizeChanged(w, h, oldw, oldh);
        if (mViewWidth == 0) {
            mViewWidth = getMeasuredWidth();
            if (mViewWidth > 0) {
                mPaint = getPaint();
                mLinearGradient = new LinearGradient(-mViewWidth, 0, 0, 0,
                        new int[] { 0x33ffffff, 0xffffffff, 0x33ffffff },
                        new float[] { 0, 0.5f, 1 }, Shader.TileMode.CLAMP);
                mPaint.setShader(mLinearGradient);
                mGradientMatrix = new Matrix();
            }
        }
    }
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        if (mAnimating && mGradientMatrix != null) {
            mTranslate += mViewWidth / 10;
            if (mTranslate > 2 * mViewWidth) {
                mTranslate = -mViewWidth;
            }
            mGradientMatrix.setTranslate(mTranslate, 0);
            mLinearGradient.setLocalMatrix(mGradientMatrix);
            postInvalidateDelayed(50);
        }
    }
}