自定义View之继承View

逃离我推掉我的手 2022-06-12 14:21 276阅读 0赞

![效果图，点击按钮增加圆圈][SouthEast]

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自定义View源代码

package com.example.administrator.youku_animi.MyView;
    
    
    import android.content.Context;
    import android.graphics.Canvas;
    import android.graphics.Color;
    import android.graphics.Paint;
    import android.graphics.RectF;
    import android.util.AttributeSet;
    import android.view.View;
    import android.view.WindowManager;
    
    /** * Created by Administrator on 2017/7/24 0024. */
    
    public class NewView extends View { 
    
        int mWindowWidth;
        //中心点
        int mCircleXY ;
        float mSweepAngle = 25f;
        float mRadius;
        RectF mArcRectF;
        Paint mCirclePaint, mArcPaint, mTextPaint;
        String mShowText; 
        int mShowTextSize;
        public NewView(Context context, AttributeSet attrs)
        {
            super(context, attrs);
            WindowManager wm = (WindowManager) getContext()
                    .getSystemService(Context.WINDOW_SERVICE);
    
            mWindowWidth = wm.getDefaultDisplay().getWidth();
    
            mCircleXY = mWindowWidth / 2;
            mRadius = (float) (mWindowWidth*0.5/2) ;
            mShowText = "It 's OK";
            mShowTextSize = mShowText.length();
            mArcRectF = new RectF(
                    (float)(mWindowWidth*0.2),
                    (float)(mWindowWidth*0.2),
                    (float)(mWindowWidth*0.8),
                    (float)(mWindowWidth*0.8)
            );
    
            mCirclePaint = new Paint();
            //给画笔设置颜色
            mCirclePaint.setColor(getResources().getColor(android.R.color.holo_blue_bright));
            mCirclePaint.setStyle(Paint.Style.FILL);
            mCirclePaint.setStrokeWidth(4);
    
            mArcPaint= new Paint();
            mArcPaint.setColor(getResources().getColor(android.R.color.holo_red_dark));
            mArcPaint.setStyle(Paint.Style.STROKE);
            mArcPaint.setStrokeWidth(20);
    
            mTextPaint = new Paint();
            mTextPaint.setColor(getResources().getColor(android.R.color.secondary_text_light));
            mTextPaint.setStyle(Paint.Style.STROKE);
            //设置画笔粗细
            mTextPaint.setStrokeWidth(1);
            //设置文字居中
            mTextPaint.setTextAlign(Paint.Align.CENTER);
            //设置抗锯齿
            mTextPaint.setAntiAlias(true);
            //设置文字大小
            mTextPaint.setTextSize(100);
        }
    
        @Override
        protected void onDraw(Canvas canvas)
        {
            //绘制圆
            canvas.drawCircle(mCircleXY, mCircleXY, mRadius, mCirclePaint);
            //绘制弧线
            canvas.drawArc(mArcRectF, 270, mSweepAngle, false, mArcPaint);
            //绘制文字
            canvas.drawText(mShowText, 0, mShowTextSize,
                    mCircleXY, mCircleXY + (mShowTextSize / 4), mTextPaint);
    // canvas.save();
            super.onDraw(canvas);
    // canvas.restore();
        }
    
        //改变外圆的角度
        public void setmSweepValue(float sweepValue)
        {
            if (sweepValue != 0)
            {
                mSweepAngle += 5;
            }
            else
            {
                mSweepAngle = 25;
            }
            this.invalidate();
        }
    }

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xml布局文件

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:newview="http://schemas.android.com/apk/res-auto" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent">
        <com.example.administrator.youku_animi.MyView.NewView android:id="@+id/newview_test" android:layout_width="match_parent" android:layout_height="500dp" />
        <Button android:id="@+id/btn" android:text="click" android:layout_width="match_parent" android:layout_height="wrap_content" />
    
    </LinearLayout>

Activity..

package com.example.administrator.youku_animi;
    
    import android.app.Activity;
    import android.os.Bundle;
    import android.view.View;
    import android.widget.Button;
    
    import com.example.administrator.youku_animi.MyView.NewView;
    
    /** * Created by Administrator on 2017/7/24 0024. */
    
    public class NewViewTest extends Activity { 
        NewView newView;
        Button button;
        @Override
        protected void onCreate(Bundle savedInstanceState)
        {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.new_view_test);
            newView = (NewView) findViewById(R.id.newview_test);
    
            button = (Button) findViewById(R.id.btn);
            button.setOnClickListener(new View.OnClickListener()
            {
                @Override
                public void onClick(View view)
                {
                    newView.setmSweepValue(1);
                }
            });
        }
    }

[SouthEast]: /images/20220612/9ad8e93f91d74db698667df8dbf6475e.png