• 作者:Mr.Egg
• 狀態:未完成
• 轉載請註明，雖然寫的不好但是最少讓我知道下

簡單的商品打折控制元件實現

首先，上效果圖

那麼問題來了，怎麼實現

首先分析，這個肯定要自定義View實現。與這個最像的肯定是TextView。
繼承於TextView(同樣可用於ImageView，這裡只是測試使用不然應該用ImageView，因為內容應該是圖片)
接著是繪製介面(陰影是用來顯示倒計時的，暫時沒用到所以不做解釋)
要實現斜著的長條，首先繪製一條橫向矩形

然後沿著白色矩形左下角頂點逆時針旋轉(設為335°)

顯然左上角過小，向右平移最後繪上文字(記得計算距離長度，用於適配)

最後，附上程式碼：

  package microcloud.org.cn.testhelloworld;

import android.annotation.TargetApi;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.os.Build;
import android.util.AttributeSet;
import
 
 android.util.Log;
import android.widget.TextView;

/**
 * Created by Mr.Egg on 2016/11/19.
 */
public class FuckView extends TextView {

    private int defaultRotate = 315;
    private String labelText = "default";
    private int labelColor = Color.WHITE;
    private int textColor = Color.BLACK;

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

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

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

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

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        int width = getMeasuredWidth();
        int height = getMeasuredHeight();


        //draw a translucent in top
        Paint timPaint = new Paint();
        timPaint.setColor(Color.parseColor("#30000000"));
        timPaint.setStyle(Paint.Style.FILL);
        canvas.drawRect(0f, 0f, width, height / 2f, timPaint);

        //draw a left mark
        Paint discountPaint = new Paint();
        discountPaint.setColor(labelColor);
        discountPaint.setStyle(Paint.Style.FILL);
        canvas.rotate(defaultRotate, 0, height / 2 + height / 8);
        canvas.translate(0, height / 8);
        Rect rect = new Rect(0, height / 4, width, height / 2);
        canvas.drawRect(rect, discountPaint);

        //draw the left mark text
        Paint textPaint = new Paint();
        textPaint.setColor(textColor);
        textPaint.setTextAlign(Paint.Align.LEFT);
        textPaint.setTextSize(rect.height() / 2);
        canvas.drawText(labelText, rect.left + height / 7, height / 2 - rect.bottom / 7, textPaint);

    }

    public FuckView retateView(int rotate) {
        this.defaultRotate = rotate;
        return this;
    }

    public FuckView setLabelText(String str) {
        this.labelText = str;
        return this;
    }

    public FuckView setLabelColor(int labelColor) {
        this.labelColor = labelColor;
        return this;
    }
    public FuckView setLabelTextColor(int textColor) {
        this.textColor = textColor;
        return this;
    }
}