这是我第一次在csdn上写文章，因为自己还是个实习生，总感觉实力不够，写不出好文章。做android实习生已经5个多月了，记录一下平时用到的知识。这个指南针view是我在csdn看到原形，感觉很好玩的。然后我自己就动手写这个。效果如下：

下面是自定义view代码:

package com.example.viewlearn;

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.graphics.Paint.Style;

import android.graphics.Typeface;

import android.util.AttributeSet;

import android.view.View;

class CompassView extends View {

private Paint mCirclePaint;//外圆画笔

private Paint mTextPaint;//方位画笔

private Paint mLinepaint;//刻度画笔

private float mDegree = 0f;//指针度

private int mTextHight;//字高

private Paint mDegreePain;//指针度画笔

private Paint mSmallCirclePaint;//内圆画笔

private Paint mSmallerCirclePaint;//最小内圆画笔

private Paint mPointerPaint;//指针画笔

private Paint mBorderPaint;//外圆边框画笔

public CompassView(Context context) {

super(context);

initView();

}

public CompassView(Context context, AttributeSet attrs) {

super(context, attrs);

initView();

}

public CompassView(Context context, AttributeSet attrs, int defStyle) {

super(context, attrs, defStyle);

initView();

}

public float getmDegree() {

return mDegree;

}

public void setmDegree(float mDegree) {

this.mDegree = mDegree;

invalidate();

}

@Override

protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {

int width = measure(widthMeasureSpec);

int height = measure(heightMeasureSpec);

int d = Math.min(width, height);

setMeasuredDimension(d, d);

}

protected int measure(int measureSpec){

int size = 0;

int measureMode = MeasureSpec.getMode(measureSpec);

if(measureMode == MeasureSpec.UNSPECIFIED){

size = 250;

}else{

size = MeasureSpec.getSize(measureSpec);

}

return size;

}

protected void initView(){

mBorderPaint = new Paint(Paint.ANTI_ALIAS_FLAG);

mBorderPaint.setColor(Color.WHITE);

mCirclePaint = new Paint(Paint.ANTI_ALIAS_FLAG);

mCirclePaint.setColor(getResources().getColor(R.color.shape1_color));

mCirclePaint.setAntiAlias(true);

mCirclePaint.setStrokeWidth(2f);

mCirclePaint.setStyle(Style.STROKE);

mTextPaint = new Paint(Paint.ANTI_ALIAS_FLAG);

mTextPaint.setColor(getResources().getColor(R.color.location_color));

mTextPaint.setTextSize(35f);

mTextPaint.setTypeface(Typeface.DEFAULT_BOLD);

mLinepaint = new Paint(Paint.ANTI_ALIAS_FLAG);

mLinepaint.setColor(getResources().getColor(R.color.line_color));

mDegreePain = new Paint(Paint.ANTI_ALIAS_FLAG);

mDegreePain.setColor(getResources().getColor(R.color.degress_color));

mDegreePain.setTextSize(16f);

mSmallCirclePaint = new Paint(Paint.ANTI_ALIAS_FLAG);

mSmallCirclePaint.setColor(getResources().getColor(R.color.small_circle_bg));

mSmallerCirclePaint = new Paint(Paint.ANTI_ALIAS_FLAG);

mSmallerCirclePaint.setColor(Color.WHITE);

mPointerPaint = new Paint(Paint.ANTI_ALIAS_FLAG);

mPointerPaint.setColor(getResources().getColor(R.color.pointer_color));

mPointerPaint.setStrokeWidth(2f);

mTextHight = (int) mLinepaint.measureText("NN");

}

@Override

protected void onDraw(Canvas canvas) {

super.onDraw(canvas);

int px = getMeasuredWidth()/2;

int py = getMeasuredHeight()/2;

int radius = Math.min(px, py);

int smallRadius = (int)(radius * 0.5);

int smallerRadius =(int)(radius * 0.2);

canvas.drawCircle(px, py, radius,mBorderPaint);//外圆边框

canvas.drawCircle(px, py, radius,mCirclePaint);//外圆

canvas.drawCircle(px, py, smallRadius,mSmallCirclePaint);//小圆

canvas.drawCircle(px, py, smallerRadius,mSmallerCirclePaint);//最小圆

canvas.drawText(String.valueOf((int)mDegree)+"°", px-mTextHight*2, py+mTextHight, mTextPaint);//指针度数

canvas.save();

canvas.rotate(-mDegree, px, py);

for(int i = 0;i<24;i++){

int linePy = py-radius+(radius/20);

int textPy = linePy + mTextHight+10;

canvas.drawLine(px, py - radius, px, linePy, mLinepaint);//短刻度

canvas.save();

if (i % 6 == 0) {

String location = null;

switch (i) {

case 0:

location = "N";

canvas.drawLine(px, py-smallRadius, px, textPy+20, mPointerPaint);//指针

canvas.drawLine(px, py-mTextHight, px, py-smallerRadius, mPointerPaint);//指针

break;

case 6:

location = "W";

break;

case 12:

location = "S";

break;

case 18:

location = "E";

break;

}

canvas.drawLine(px, py - radius, px, linePy*2, mLinepaint);//长刻度

canvas.drawText(location, px-mTextHight/2-6, textPy+15, mTextPaint);//方位

}else if(i%3 == 0){

canvas.drawText(String.valueOf(i*15), px-mTextHight, textPy, mDegreePain);//刻度文字

}

canvas.restore();

canvas.rotate(-15, px, py);

}

canvas.restore();

}

}

因为只是demo，我偷懒没有自定义方位的enum。

下面是Activity代码：

package com.example.viewlearn;

import android.hardware.Sensor;

import android.hardware.SensorEvent;

import android.hardware.SensorEventListener;

import android.hardware.SensorManager;

import android.os.Bundle;

import android.os.Handler;

import android.os.Message;

import android.util.Log;

import android.widget.TextView;

import android.annotation.SuppressLint;

import android.app.Activity;

import android.content.Context;

public class MainActivity extends Activity {

private CompassView mCompassView;

private SensorManager mSensorManager;

private TextView mPositionView;

private SensorListener mListener = new SensorListener();

@SuppressLint("HandlerLeak")

private Handler mHandler = new Handler(){

public void handleMessage(Message msg) {

Position position = (Position) msg.obj;

mCompassView.setmDegree(position.getDegree());

mPositionView.setText(position.getPositionStr());

}

};

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

mSensorManager = (SensorManager) this.getSystemService(Context.SENSOR_SERVICE);

mCompassView = (CompassView) this.findViewById(R.id.view_compass);

mPositionView = (TextView) this.findViewById(R.id.position);

}

@Override

protected void onResume() {

Sensor sensor = mSensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION);

mSensorManager.registerListener(mListener,sensor,SensorManager.SENSOR_DELAY_GAME);

super.onResume();

}

@Override

protected void onPause() {

mSensorManager.unregisterListener(mListener);

super.onPause();

}

public class SensorListener implements SensorEventListener{

@Override

public void onAccuracyChanged(Sensor sensor, int accuracy) {

}

@Override

public void onSensorChanged(SensorEvent event) {

float degree = event.values[0];

String positionstr = null;

if (22.5 >= degree || degree >= 337.5) {

positionstr = "N";

} else if (22.5 < degree && degree <= 67.5) {

positionstr = "NE";

} else if (67.5 < degree && degree <= 112.5) {

positionstr = "E";

} else if (112.5 < degree && degree <= 157.5) {

positionstr = "SE";

} else if (157.5 < degree && degree <= 202.5) {

positionstr = "S";

} else if (202.5 < degree && degree <= 247.5) {

positionstr = "SW";

} else if (247.5 < degree && degree <= 292.5) {

positionstr = "W";

}else if(292.5

positionstr = "NW";

}

Message msg = mHandler.obtainMessage();

msg.obj = new Position(degree, positionstr);

msg.sendToTarget();

}

}

}