Android 三角形自定义按钮

Question

我想制作 2 个对角三角形按钮，例如 this question。

我怎样才能做到这一点？我应该用矩形制作一个可绘制的 xml 并以某种方式旋转它吗？我应该在数学的帮助下制作一个图像并使其只能在三角形部分上点击吗？

Answer 1

    package com.example.buttonsView;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.graphics.Path.FillType;
import android.graphics.Point;
import android.graphics.RectF;
import android.graphics.Region;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

public class TwoButtons extends View {

    private Path path;
    private Path path1;
    private Region region;
    private Region region1;
    private static int GAP=10;

    private ButtonClickEvents buttonClickEvent;

    public interface ButtonClickEvents{
        public void redButtonClick();
        public void blueButtonClick();
    }

    public void setOnButtonClickEvent(ButtonClickEvents buttonClickEvent) {
        this.buttonClickEvent=buttonClickEvent;
    }

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

    private void init() {

    }


    @Override
    protected void onDraw(Canvas canvas) {
        // TODO Auto-generated method stub
        super.onDraw(canvas);
        canvas.drawColor(Color.GRAY);
        Paint paint = new Paint();
        paint.setColor(android.graphics.Color.BLACK);
        canvas.drawPaint(paint);

        paint.setStrokeWidth(0);

        paint.setColor(android.graphics.Color.RED);
        paint.setStyle(Paint.Style.FILL_AND_STROKE);
        paint.setAntiAlias(true);

        Point a = new Point(GAP, GAP);
        Point b = new Point(GAP, getHeight()-2*GAP);
        Point c = new Point(getWidth()-2*GAP, GAP);

        path = new Path();
        path.setFillType(FillType.EVEN_ODD);
        path.moveTo(a.x, a.y);
        path.lineTo(b.x, b.y);
        path.lineTo(c.x, c.y);
        path.close();

        canvas.drawPath(path, paint);

        RectF rectF = new RectF();
        path.computeBounds(rectF, true);
        region = new Region();
        region.setPath(path, new Region((int) rectF.left, (int) rectF.top, (int) rectF.right, (int) rectF.bottom));

        paint.setColor(Color.BLUE);
        Point a1 = new Point(getWidth()-GAP, getHeight()-GAP);
        Point b1 = new Point(getWidth()-GAP, 2*GAP);
        Point c1 = new Point(2*GAP, getHeight()-GAP);

        path1 = new Path();
        path1.setFillType(FillType.EVEN_ODD);
        path1.moveTo(a1.x, a1.y);
        path1.lineTo(b1.x, b1.y);
        path1.lineTo(c1.x, c1.y);

        path1.close();
        canvas.drawPath(path1, paint);

        RectF rectF1 = new RectF();
        path1.computeBounds(rectF1, true);
        region1 = new Region();
        region1.setPath(path1, new Region((int) rectF1.left, (int) rectF1.top, (int) rectF1.right, (int) rectF1.bottom));


    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        // TODO Auto-generated method stub
        switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:

            Point point = new Point();
            point.x = (int) event.getX();
            point.y = (int) event.getY();

            invalidate();


            if(region.contains((int)point.x,(int) point.y))
            {
                if(buttonClickEvent!=null)
                    buttonClickEvent.redButtonClick();
            }else if(region1.contains((int)point.x,(int) point.y))
            {
                if(buttonClickEvent!=null)
                    buttonClickEvent.blueButtonClick();
            }

        return true;
        }

        return false;
    }

}

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.buttonsView.MainActivity" >

    <com.example.buttonsView.TwoButtons
        android:id="@+id/twoButtons1"
        android:layout_width="200dp"
        android:layout_height="200dp"
        android:layout_alignParentLeft="true"
        android:layout_alignParentTop="true" />

</RelativeLayout>

MainActivity.java

package com.example.buttonsView;

import android.app.Activity;
import android.os.Bundle;
import android.widget.Toast;

import com.afbb.preferencessample.R;
import com.example.buttonsView.TwoButtons.ButtonClickEvents;

public class MainActivity extends Activity {

    TwoButtons buttons;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        buttons = (TwoButtons) findViewById(R.id.twoButtons1);
        buttons.setOnButtonClickEvent(new ButtonClickEvents() {

            @Override
            public void redButtonClick() {
                // TODO Auto-generated method stub
                Toast.makeText(getApplicationContext(), "red",
                        Toast.LENGTH_SHORT).show();

            }

            @Override
            public void blueButtonClick() {
                // TODO Auto-generated method stub
                Toast.makeText(getApplicationContext(), "blue",
                        Toast.LENGTH_SHORT).show();

            }
        });

    }

}

输出：