Android之自定义Button控件

1、首先我们创一个Java类，自己命名，然后在里面进行相关的设计

public class MyButton extends View {  
  
    public MyButton(Context context) {  
        super(context);  
    }  
  
    public MyButton(Context context, @Nullable AttributeSet attrs) {  
        super(context, attrs);  
    }  
  
    public MyButton(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {  
        super(context, attrs, defStyleAttr);  
    }  
  
    public MyButton(Context context, @Nullable AttributeSet attrs, int defStyleAttr, int defStyleRes) {  
        super(context, attrs, defStyleAttr, defStyleRes);  
    }  
  
    @Override  
    protected void onDraw(Canvas canvas) {  
        super.onDraw(canvas);  
        //设置背景颜色  
        canvas.drawColor(Color.GRAY);  
        //实例化路径  
        Path path=new Path();  
        path.moveTo(100,100);  
        path.lineTo(100,400);  
        path.lineTo(400,400);  
        path.lineTo(100,100);  
  
  
  
        //实例化一个画笔  
        Paint paint=new Paint();  
        paint.setColor(Color.RED);  
  
        //设置空心  
        paint.setStyle(Paint.Style.STROKE);  
        //设置画笔的粗细  
        paint.setStrokeWidth(12);  
  
        //画路径  
        canvas.drawPath(path,paint);  
  
        //设置画笔的粗细  
        paint.setStrokeWidth(3);  
        paint.setColor(Color.BLACK);  
        //设置字体的大小  
        paint.setTextSize(50);  
        //画文字  
        canvas.drawText("按钮",150,350,paint);  
  
    }  

2、设置画布的宽和高

只用重写onMeasure这个方法，然后设置它的宽高就可以控制这个控件了

 @Override  
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {  
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);  
        //设置画布的宽和高  
        setMeasuredDimension(450,450);  
    }  

3、然后在xml文件使用我们自己写的Button

<?xml version="1.0" encoding="utf-8"?>  
<LinearLayout  
    xmlns:android="http://schemas.android.com/apk/res/android"  
    xmlns:app="http://schemas.android.com/apk/res-auto"  
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"  
    android:layout_height="match_parent"  
    tools:context="com.zking.laci.android16_diyui.MainActivity"  
    android:orientation="vertical"  
    >  
  
    <com.zking.laci.android16_diyui.MyButton  
        android:layout_width="match_parent"  
        android:layout_height="match_parent"  
        android:id="@+id/mybtn_main"  
        android:layout_gravity="center_horizontal"  
        />  
  
</LinearLayout>  

3、最后在相对应的Activity中来设置监听检验

public class MainActivity extends AppCompatActivity {  
  
    private MyButton myButton;  
  
    @Override  
    protected void onCreate(Bundle savedInstanceState) {  
        super.onCreate(savedInstanceState);  
        setContentView(R.layout.activity_main);  
        //获得该ID的控件  
        myButton = (MyButton) findViewById(R.id.mybtn_main);  
        //给该控件设置监听  
        myButton.setOnClickListener(new View.OnClickListener() {  
            @Override  
            public void onClick(View v) {  
                Toast.makeText(MainActivity.this, "点击了", Toast.LENGTH_SHORT).show();  
            }  
        });  
    }  
}