Android仿小米指南针功能

<?xml version="1.0" encoding="utf-8"?><resources>    <color name="colorPrimary">#3F51B5</color>    <color name="colorPrimaryDark">#303F9F</color>    <color name="colorAccent">#FF4081</color>    <color name="black">#000</color>    <color name="darkRed">#702216</color>    <color name="lightGray">#323232</color>    <color name="deepGray">#8B8B8B</color>    <color name="white">#fff</color>    <color name="red">#f00</color>    <color name="ocbg">#237EAD</color></resources>

    /**     * 指南针外部可简单分为两部分     * 1、用Path实现小三角形     * 2、两个圆弧     */    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)    private void drawCompassOutSide() {        mCanvas.save();        //小三角形的高度        int mTriangleHeight=40;        //定义Path画小三角形        mOutsideTriangle.moveTo(width/2,mTextHeight-mTriangleHeight);        //小三角形的边长        float mTriangleSide = 46.18f;        //画出小三角形        mOutsideTriangle.lineTo(width/2-mTriangleSide/2,mTextHeight);        mOutsideTriangle.lineTo(width/2+mTriangleSide/2,mTextHeight);        mOutsideTriangle.close();        mCanvas.drawPath(mOutsideTriangle,mOutSideCircumPaint);
        //画圆弧        mDarkRedPaint.setStrokeWidth((float) 5);        mLightGrayPaint.setStrokeWidth((float)5);        mDeepGrayPaint.setStrokeWidth((float)3);        mLightGrayPaint.setStyle(Paint.Style.STROKE);        mCanvas.drawArc(width/2-mOutSideRadius,mTextHeight,width/2+mOutSideRadius,mTextHeight+mOutSideRadius*2,-80,120,false,mLightGrayPaint);        mCanvas.drawArc(width/2-mOutSideRadius,mTextHeight,width/2+mOutSideRadius,mTextHeight+mOutSideRadius*2,40,20,false,mDeepGrayPaint);        mCanvas.drawArc(width/2-mOutSideRadius,mTextHeight,width/2+mOutSideRadius,mTextHeight+mOutSideRadius*2,-100,-20,false,mLightGrayPaint);        mCanvas.drawArc(width/2-mOutSideRadius,mTextHeight,width/2+mOutSideRadius,mTextHeight+mOutSideRadius*2,-120,-120,false,mDarkRedPaint);        mCanvas.restore();    }

    /**     * 指南针外接圆，和外部圆换道理差不多     */    @RequiresApi(api = Build.VERSION_CODES.LOLLIPOP)    private void drawCompassCircum() {        mCanvas.save();        //外接圆小三角形的高度        int mTriangleHeight=(mOutSideRadius-mCircumRadius)/2;
        mCanvas.rotate(-val,width/2,mOutSideRadius+mTextHeight);        mCircumTriangle.moveTo(width/2,mTriangleHeight+mTextHeight);        //内接三角形的边长,简单数学运算        float mTriangleSide = (float) ((mTriangleHeight/(Math.sqrt(3)))*2);        mCircumTriangle.lineTo(width/2-mTriangleSide/2,mTextHeight+mTriangleHeight*2);        mCircumTriangle.lineTo(width/2+mTriangleSide/2,mTextHeight+mTriangleHeight*2);        mCircumTriangle.close();        mCanvas.drawPath(mCircumTriangle,mCircumPaint);        mCanvas.drawArc(width/2-mCircumRadius,mTextHeight+mOutSideRadius-mCircumRadius,                width/2+mCircumRadius,mTextHeight+mOutSideRadius+mCircumRadius,-85,350,false,mDeepGrayPaint);        mAnglePaint.setStrokeWidth(5f);        if (val<=180){            valCompare = val;            mCanvas.drawArc(width/2-mCircumRadius,mTextHeight+mOutSideRadius-mCircumRadius,                    width/2+mCircumRadius,mTextHeight+mOutSideRadius+mCircumRadius,-85,valCompare,false,mAnglePaint);        }else{            valCompare = 360-val;            mCanvas.drawArc(width/2-mCircumRadius,mTextHeight+mOutSideRadius-mCircumRadius,                    width/2+mCircumRadius,mTextHeight+mOutSideRadius+mCircumRadius,-95,-valCompare,false,mAnglePaint);        }
        mCanvas.restore();    }

 private void drawInnerCricle() {
        mInnerShader = new RadialGradient(width/2,mOutSideRadius+mTextHeight,mCircumRadius-40, Color.parseColor("#323232"),                Color.parseColor("#000000"),Shader.TileMode.CLAMP);        mInnerPaint.setShader(mInnerShader);        mCanvas.drawCircle(width/2,mOutSideRadius+mTextHeight,mCircumRadius-40,mInnerPaint);    }

  private void drawCompassDegreeScale() {        mCanvas.save();        //获取N文字的宽度        mNorthPaint.getTextBounds("N",0,1,mPositionRect);        int mPositionTextWidth = mPositionRect.width();        int mPositionTextHeight = mPositionRect.height();        //获取W文字宽度,因为W比较宽 所以要单独获取        mNorthPaint.getTextBounds("W",0,1,mPositionRect);        int mWPositionTextWidth = mPositionRect.width();        int mWPositionTextHeight = mPositionRect.height();        //获取小刻度，两位数的宽度        mSamllDegreePaint.getTextBounds("30",0,1,mSencondRect);        int mSencondTextWidth = mSencondRect.width();        int mSencondTextHeight = mSencondRect.height();        //获取小刻度，3位数的宽度        mSamllDegreePaint.getTextBounds("30",0,1,mThirdRect);        int mThirdTextWidth = mThirdRect.width();        int mThirdTextHeight = mThirdRect.height();
        mCanvas.rotate(-val,width/2,mOutSideRadius+mTextHeight);

        //画刻度线        for (int i = 0; i < 240; i++) {
            if (i==0||i==60||i==120||i==180){                mCanvas.drawLine(getWidth() / 2, mTextHeight+mOutSideRadius-mCircumRadius+10,                        getWidth() / 2,  mTextHeight+mOutSideRadius-mCircumRadius+30, mDeepGrayPaint);            }else{                mCanvas.drawLine(getWidth() / 2, mTextHeight+mOutSideRadius-mCircumRadius+10,                        getWidth() / 2,  mTextHeight+mOutSideRadius-mCircumRadius+30, mLightGrayPaint);            }            if (i==0){                mCanvas.drawText("N", this.width /2-mPositionTextWidth/2,mTextHeight+mOutSideRadius-mCircumRadius+40+mPositionTextHeight,mNorthPaint);            }else if (i==60){                mCanvas.drawText("E", this.width /2-mPositionTextWidth/2,mTextHeight+mOutSideRadius-mCircumRadius+40+mPositionTextHeight,mOthersPaint);            }else if (i==120){                mCanvas.drawText("S", this.width /2-mPositionTextWidth/2,mTextHeight+mOutSideRadius-mCircumRadius+40+mPositionTextHeight,mOthersPaint);            }else if (i==180){                mCanvas.drawText("W", this.width /2-mWPositionTextWidth/2,mTextHeight+mOutSideRadius-mCircumRadius+40+mWPositionTextHeight,mOthersPaint);            }else if (i==20){                mCanvas.drawText("30", this.width /2-mSencondTextWidth/2,mTextHeight+mOutSideRadius-mCircumRadius+40+mSencondTextHeight,mSamllDegreePaint);            }else if (i==40){                mCanvas.drawText("60", this.width /2-mSencondTextWidth/2,mTextHeight+mOutSideRadius-mCircumRadius+40+mSencondTextHeight,mSamllDegreePaint);            }else if (i==80){                mCanvas.drawText("120", this.width /2-mThirdTextWidth/2,mTextHeight+mOutSideRadius-mCircumRadius+40+mThirdTextHeight,mSamllDegreePaint);            }else if (i==100){                mCanvas.drawText("150", this.width /2-mThirdTextWidth/2,mTextHeight+mOutSideRadius-mCircumRadius+40+mThirdTextHeight,mSamllDegreePaint);            }else if (i==140){                mCanvas.drawText("210", this.width /2-mThirdTextWidth/2,mTextHeight+mOutSideRadius-mCircumRadius+40+mThirdTextHeight,mSamllDegreePaint);            }else if (i==160){                mCanvas.drawText("240", this.width /2-mThirdTextWidth/2,mTextHeight+mOutSideRadius-mCircumRadius+40+mThirdTextHeight,mSamllDegreePaint);            }else if (i==200){                mCanvas.drawText("300", this.width /2-mThirdTextWidth/2,mTextHeight+mOutSideRadius-mCircumRadius+40+mThirdTextHeight,mSamllDegreePaint);            }else if (i==220){                mCanvas.drawText("330", this.width /2-mThirdTextWidth/2,mTextHeight+mOutSideRadius-mCircumRadius+40+mThirdTextHeight,mSamllDegreePaint);            }            mCanvas.rotate(1.5f, mCenterX, mOutSideRadius+mTextHeight);        }        mCanvas.restore();    }

 <com.example.customviewdemo.Mi        android:id="@+id/miui"        android:layout_width="match_parent"        android:layout_height="match_parent"        android:background="@color/black" />

public class MainActivity extends AppCompatActivity {    private SensorManager sensorManager;    private SensorEventListener sensorEventListener;    private Mi miui;    private float val;
    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);
        miui = findViewById(R.id.miui);        //传感器        sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);        //传感器监听        sensorEventListener = new SensorEventListener() {            @Override            public void onSensorChanged(SensorEvent event) {                val = event.values[0];                miui.setVal(val);            }
            @Override            public void onAccuracyChanged(Sensor sensor, int accuracy) {            }        };
        //注册传感器服务        sensorManager.registerListener(sensorEventListener, sensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION),                SensorManager.SENSOR_DELAY_GAME);    }
    @Override    protected void onDestroy() {        super.onDestroy();        //取消注册传感器服务        sensorManager.unregisterListener(sensorEventListener);    }}