57 lines
2.0 KiB
Java
57 lines
2.0 KiB
Java
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import android.graphics.Canvas;
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import android.graphics.Color;
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import android.graphics.LinearGradient;
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import android.graphics.Paint;
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import android.graphics.PorterDuff;
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import android.graphics.PorterDuffXfermode;
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import android.graphics.Shader;
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import android.graphics.Xfermode;
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import androidx.recyclerview.widget.RecyclerView;
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/**
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* RecyclerView右側渐变的itemDecoration
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* 渐变参考文档：https://blog.csdn.net/u010126792/article/details/85237085
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* 半透明则是由0→黑的渐变效果
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* 使用方法： RecyclerView.addItemDecoration(new RightGradual());
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*/
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public class RightGradual extends RecyclerView.ItemDecoration {
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private Paint mPaint;
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private Xfermode mXfermode;
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private LinearGradient mLinearGradient;
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private int mLayerId;
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public RightGradual() {
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mPaint = new Paint();
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mXfermode = new PorterDuffXfermode(PorterDuff.Mode.DST_IN);
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mLinearGradient = null;
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}
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@Override
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public void onDrawOver(Canvas canvas, RecyclerView parent, RecyclerView.State state) {
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super.onDrawOver(canvas, parent, state);
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float left=parent.getRight()-parent.getRight()/0.1f;
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float top=0f;
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float right=parent.getRight();
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float bottom=parent.getBottom();
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if(mLinearGradient==null){
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mLinearGradient=new LinearGradient(parent.getMeasuredWidth(), 0.0f, 0.0f, 0.0f, new int[]{0, Color.BLACK}, new float[]{0.0f,0.2f}, Shader.TileMode.CLAMP);
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}
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mPaint.setXfermode(mXfermode);
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mPaint.setShader(mLinearGradient);
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//mPaint.setColor(Color.BLUE);
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canvas.drawRect(left, top,right, bottom, mPaint);
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mPaint.setXfermode(null);
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canvas.restoreToCount(mLayerId);
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}
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@Override
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public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
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super.onDraw(c, parent, state);
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mLayerId = c.saveLayer(0.0f, 0.0f, (float) parent.getWidth(), (float) parent.getHeight(), mPaint, Canvas.ALL_SAVE_FLAG);
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}
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}
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