Android - 自定义按钮，带有形状可绘制对象和渐变，以编程方式

我想制作一个自定义按钮，就像这个程序所做的那样，也许是径向渐变。

我对视图进行了子分类，绘制了三个形状可绘制对象，然后绘制文本。文本似乎偏离了中心，所以我试图为文本绘制一个边界矩形，但没有运气。并计划添加一个点击监听器来获取按钮的行为。

也许我应该子类按钮，但是在哪里绘制我的可绘制对象，这样它们就不会被按钮的文本弄乱。

任何指示将不胜感激。

谢谢

编辑2：请参阅下面的第二次尝试。

Edit3：赏金的原因是弄清楚为什么子类化可绘制不起作用。梯度不是那么重要。

edit4：在 DrawableView：：OnDraw（） 中发现 drawRect 之前 getTextBounds（）。

package acme.drawables;
import android.content.*;
import android.content.pm.*;
import android.graphics.*;
import android.graphics.drawable.*;
import android.graphics.drawable.shapes.*;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.*;
import android.view.Menu;
import android.view.View;
import android.widget.*;
import static java.lang.Math.*;
public class MainActivity extends AppCompatActivity {
    DrawableView drawableView;
    LinearLayout row(boolean isRow1) {
        LinearLayout layout=new LinearLayout(this);
        layout.setOrientation(LinearLayout.HORIZONTAL);
        LinearLayout.LayoutParams layoutParams=new LinearLayout.LayoutParams(w,d);
        int m=(int)round(w*margin);
        layoutParams.setMargins(m,m,m,m);
        for(int i=0;i<n;i++)
            layout.addView(drawableView=new DrawableView(this,i,isRow1),layoutParams);
        return layout;
    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
        DisplayMetrics metrics=new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getMetrics(metrics);
        w=d=(int)round(metrics.densityDpi);
        LinearLayout row1=row(true);
        LinearLayout row2=row(false);
        LinearLayout layout=new LinearLayout(this);
        layout.setOrientation(LinearLayout.VERTICAL);
        layout.addView(row1);
        layout.addView(row2);
        LinearLayout l=new LinearLayout(this);
        setContentView(layout);
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        return true;
    }
    public class DrawableView extends View {
        public DrawableView(Context context,int column,boolean isRow1) {
            super(context);
            setBackgroundColor(Color.TRANSPARENT);
            this.column=column;
            text=""+(char)('0'+column);
            int r=(int)round(w*radius);
            d0=new ShapeDrawable(new RoundRectShape(new float[]{r,r,r,r,r,r,r,r},null,null));
            d0.getPaint().setColor(0xff000000);
            d0.setBounds(0,0,w,d);
            d1=new ShapeDrawable(new RoundRectShape(new float[]{r,r,r,r,r,r,r,r},null,null));
            d1.getPaint().setColor(on[column]);
            d1.setBounds(edge,edge,w-edge,d-edge);
            d2=new ShapeDrawable(new RoundRectShape(new float[]{r,r,r,r,r,r,r,r},null,null));
            int b=(int)round(w*border);
            d2.setBounds(b/2,b/2,w-b/2,d-b/2);
            d2.getPaint().setColor(isRow1?on[column]:off[column]);
        }
        protected void onDraw(Canvas canvas) {
            d0.draw(canvas);
            d1.draw(canvas);
            d2.draw(canvas);
            Paint paint = new Paint();
            //paint.setColor(Color.WHITE);
            paint.setStyle(Paint.Style.FILL);
            //canvas.drawPaint(paint);
            paint.setColor(Color.CYAN);
            paint.setTextSize(w*95/100);
            Rect r=new Rect();
            paint.getTextBounds(text,0,1,r); // were switched
            canvas.drawRect(r,paint);  // were switched
            int x=(w-r.width())/2,y=(d-r.height())/2;
            paint.setColor(Color.BLACK);
            canvas.drawText(text,x,d-y,paint);
        }
        final int column;
        final String text;
        ShapeDrawable d0, d1, d2;
    }
    final int n=5, edge=1;
    double margin=.10, radius=.05, border=.15;
    int w, d;
    final int[] on=new int[]{0xffff0000,0xffffff00,0xff00ff00,0xff0000ff,0xffff8000};
    final int[] off=new int[]{0xff800000,0xff808000,0xff008000,0xff000080,0xff804000};
}

此版本尝试对可绘制对象进行子类化并使用按钮。但是按钮的绘图似乎干扰了绘制我的可绘制形状。看起来边界被忽略了。

package acme.drawables;
import android.content.*;
import android.content.pm.*;
import android.graphics.*;
import android.graphics.drawable.*;
import android.graphics.drawable.shapes.*;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.*;
import android.view.Menu;
import android.view.View;
import android.widget.*;

import static java.lang.Math.*;
public class MainActivity extends AppCompatActivity {
    LinearLayout row(boolean isRow1) {
        LinearLayout layout=new LinearLayout(this);
        layout.setOrientation(LinearLayout.HORIZONTAL);
        LinearLayout.LayoutParams layoutParams=new LinearLayout.LayoutParams(w,d);
        int m=(int)round(w*margin);
        layoutParams.setMargins(m,m,m,m);
        if(true)
            for(int i=0;i<n;i++) { // subclass drawable
                Button b=new Button(this);
                b.setText(""+(char)('0'+i));
                b.setBackground(new MyDrawable(i,i/n%2==0));
                layout.addView(b,layoutParams);
            }
        else
            for(int i=0;i<n;i++) // use drawable view with canvas draw text
                layout.addView(drawableView=new DrawableView(i,isRow1),layoutParams);
        return layout;
    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
        DisplayMetrics metrics=new DisplayMetrics();
        getWindowManager().getDefaultDisplay().getMetrics(metrics);
        w=d=(int)round(metrics.densityDpi);
        LinearLayout row1=row(true);
        LinearLayout row2=row(false);
        LinearLayout layout=new LinearLayout(this);
        layout.setOrientation(LinearLayout.VERTICAL);
        layout.addView(row1);
        layout.addView(row2);
        LinearLayout l=new LinearLayout(this);
        setContentView(layout);
    }
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        return true;
    }
    public class MyDrawable extends Drawable {
        public MyDrawable(int column,boolean isRow1) {
            drawableView=new DrawableView(column,isRow1);
        }
        public void setAlpha(int alpha) {
            System.out.println("ignoring set alpha to: "+alpha);
        }
        public void setColorFilter(ColorFilter colorFilter) {
            System.out.println("ignoring set color filter to: "+colorFilter);
        }
        public int getOpacity() {
            return PixelFormat.OPAQUE;
        }
        public void draw(Canvas canvas) {
            System.out.println(this+" is drawing.");
            drawableView.d0.draw(canvas);
            System.out.println("d0 bounds: "+drawableView.d0.getBounds());
            drawableView.d1.draw(canvas);
            System.out.println("d1 bounds: "+drawableView.d1.getBounds());
            drawableView.d2.draw(canvas);
            System.out.println("d2 bounds: "+drawableView.d2.getBounds());
        }
        final DrawableView drawableView; // cheat by delegating
    }
    public class DrawableView extends View {
        public DrawableView(int column,boolean isRow1) {
            super(MainActivity.this);
            setBackgroundColor(Color.TRANSPARENT);
            this.column=column;
            text=""+(char)('0'+column);
            int r=(int)round(w*radius);
            d0=new ShapeDrawable(new RoundRectShape(new float[]{r,r,r,r,r,r,r,r},null,null));
            d0.getPaint().setColor(0xff000000);
            d0.setBounds(0,0,w,d);
            d1=new ShapeDrawable(new RoundRectShape(new float[]{r,r,r,r,r,r,r,r},null,null));
            d1.getPaint().setColor(on[column]);
            d1.setBounds(edge,edge,w-edge,d-edge);
            d2=new ShapeDrawable(new RoundRectShape(new float[]{r,r,r,r,r,r,r,r},null,null));
            int b=(int)round(w*border);
            d2.setBounds(b/2,b/2,w-b/2,d-b/2);
            d2.getPaint().setColor(isRow1?on[column]:off[column]);
        }
        protected void onDraw(Canvas canvas) {
            d0.draw(canvas);
            d1.draw(canvas);
            d2.draw(canvas);
            Paint paint=new Paint();
            //paint.setColor(Color.WHITE);
            paint.setStyle(Paint.Style.FILL);
            //canvas.drawPaint(paint);
            paint.setColor(Color.CYAN);
            paint.setTextSize(w*95/100);
            Rect r=new Rect();
            canvas.drawRect(r,paint);
            paint.getTextBounds(text,0,1,r);
            int x=(w-r.width())/2, y=(d-r.height())/2;
            paint.setColor(Color.BLACK);
            canvas.drawText(text,x,d-y,paint);
        }
        final int column;
        final String text;
        ShapeDrawable d0, d1, d2;
    }
    DrawableView drawableView;
    final int n=5, edge=1;
    double margin=.10, radius=.05, border=.15;
    int w, d;
    final int[] on=new int[]{0xffff0000,0xffffff00,0xff00ff00,0xff0000ff,0xffff8000};
    final int[] off=new int[]{0xff800000,0xff808000,0xff008000,0xff000080,0xff804000};
}