[源码]-指南针

为什么80%的码农都做不了架构师？>>>   

本人用的是的soso地图,以前版本(1.7)发现默认是有指南针的,但是升级成最新事,在界面发现有一个指针的东西,但是用过之后,发现它指的方向也不是正北(注意,指南针一般指针所指方向为正北),而且在转动方向的时候,这个指针还一会指东一会儿指西,由时准备自已写一个功能简单的指南针(只指示正北功能)

写成后的界面如下

package com.nt.compass;

import android.content.Context;
import android.graphics.*;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.view.View;

public class ActivityMain extends GraphicsActivity {

	private SensorManager mSensorManager;
	private Sensor mSensor;
	private SampleView mView;
	private float[] mValues;

	private final SensorEventListener mListener = new SensorEventListener() {
		public void onSensorChanged(SensorEvent event) {
			mValues = event.values;
			if (mView != null) {
				mView.invalidate();
			}
		}

		public void onAccuracyChanged(Sensor sensor, int accuracy) {
		}
	};

	@SuppressWarnings("deprecation")
	@Override
	protected void onCreate(Bundle icicle) {
		super.onCreate(icicle);
		mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
		mSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_ORIENTATION);
		mView = new SampleView(this);
		setContentView(mView);
	}

	@Override
	protected void onResume() {
		super.onResume();

		mSensorManager.registerListener(mListener, mSensor,
				SensorManager.SENSOR_DELAY_GAME);
	}

	@Override
	protected void onStop() {
		mSensorManager.unregisterListener(mListener);
		super.onStop();
	}

	private class SampleView extends View {
		private Paint mPaint = new Paint();
		private Path mPath = new Path();

		public SampleView(Context context) {
			super(context);

			mPath.moveTo(0, -50);
			mPath.lineTo(-20, 60);
			mPath.lineTo(0, 50);
			mPath.lineTo(20, 60);
			mPath.close();
		}

		@Override
		protected void onDraw(Canvas canvas) {
			Paint paint = mPaint;

			canvas.drawColor(Color.WHITE);

			paint.setAntiAlias(true);
			paint.setColor(Color.BLACK);
			paint.setStyle(Paint.Style.FILL);

			int w = canvas.getWidth();
			int h = canvas.getHeight();
			int cx = w / 2;
			int cy = h / 2;

			canvas.translate(cx, cy);
			if (mValues != null) {
				canvas.rotate(-mValues[0]);
			}
			canvas.drawPath(mPath, mPaint);
		}

		@Override
		protected void onAttachedToWindow() {
			super.onAttachedToWindow();
		}

		@Override
		protected void onDetachedFromWindow() {
			super.onDetachedFromWindow();
		}
	}
}

package com.nt.compass;

import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;

class GraphicsActivity extends Activity {
    private static final boolean TEST_PICTURE = false;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
    }

    @Override
    public void setContentView(View view) {
        if (TEST_PICTURE) {
            ViewGroup vg = new PictureLayout(this);
            vg.addView(view);
            view = vg;
        }

        super.setContentView(view);
    }
}

package com.nt.compass;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Picture;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.view.ViewParent;

public class PictureLayout extends ViewGroup {
	private final Picture mPicture = new Picture();

	public PictureLayout(Context context) {
		super(context);
	}

	public PictureLayout(Context context, AttributeSet attrs) {
		super(context, attrs);
	}

	@Override
	public void addView(View child) {
		if (getChildCount() > 1) {
			throw new IllegalStateException(
					"PictureLayout can host only one direct child");
		}

		super.addView(child);
	}

	@Override
	public void addView(View child, int index) {
		if (getChildCount() > 1) {
			throw new IllegalStateException(
					"PictureLayout can host only one direct child");
		}

		super.addView(child, index);
	}

	@Override
	public void addView(View child, LayoutParams params) {
		if (getChildCount() > 1) {
			throw new IllegalStateException(
					"PictureLayout can host only one direct child");
		}

		super.addView(child, params);
	}

	@Override
	public void addView(View child, int index, LayoutParams params) {
		if (getChildCount() > 1) {
			throw new IllegalStateException(
					"PictureLayout can host only one direct child");
		}

		super.addView(child, index, params);
	}

	@Override
	protected LayoutParams generateDefaultLayoutParams() {
		return new LayoutParams(LayoutParams.MATCH_PARENT,
				LayoutParams.MATCH_PARENT);
	}

	@Override
	protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
		final int count = getChildCount();

		int maxHeight = 0;
		int maxWidth = 0;

		for (int i = 0; i < count; i++) {
			final View child = getChildAt(i);
			if (child.getVisibility() != GONE) {
				measureChild(child, widthMeasureSpec, heightMeasureSpec);
			}
		}

		maxWidth += getPaddingLeft() + getPaddingRight();
		maxHeight += getPaddingTop() + getPaddingBottom();

		Drawable drawable = getBackground();
		if (drawable != null) {
			maxHeight = Math.max(maxHeight, drawable.getMinimumHeight());
			maxWidth = Math.max(maxWidth, drawable.getMinimumWidth());
		}

		setMeasuredDimension(resolveSize(maxWidth, widthMeasureSpec),
				resolveSize(maxHeight, heightMeasureSpec));
	}

	private void drawPict(Canvas canvas, int x, int y, int w, int h, float sx,
			float sy) {
		canvas.save();
		canvas.translate(x, y);
		canvas.clipRect(0, 0, w, h);
		canvas.scale(0.5f, 0.5f);
		canvas.scale(sx, sy, w, h);
		canvas.drawPicture(mPicture);
		canvas.restore();
	}

	@Override
	protected void dispatchDraw(Canvas canvas) {
		super.dispatchDraw(mPicture.beginRecording(getWidth(), getHeight()));
		mPicture.endRecording();

		int x = getWidth() / 2;
		int y = getHeight() / 2;

		drawPict(canvas, 0, 0, x, y, 1, 1);
		drawPict(canvas, x, 0, x, y, -1, 1);
		drawPict(canvas, 0, y, x, y, 1, -1);
		drawPict(canvas, x, y, x, y, -1, -1);

	}

	@Override
	public ViewParent invalidateChildInParent(int[] location, Rect dirty) {
		location[0] = getLeft();
		location[1] = getTop();
		dirty.set(0, 0, getWidth(), getHeight());
		return getParent();
	}

	@Override
	protected void onLayout(boolean changed, int l, int t, int r, int b) {
		final int count = super.getChildCount();

		for (int i = 0; i < count; i++) {
			final View child = getChildAt(i);
			if (child.getVisibility() != GONE) {
				final int childLeft = getPaddingLeft();
				final int childTop = getPaddingTop();
				child.layout(childLeft, childTop,
						childLeft + child.getMeasuredWidth(),
						childTop + child.getMeasuredHeight());

			}
		}
	}
}

此软件可以不需要布局文件,布局全部采用代码生成,使用到了手机相应的传感器

注意,此指南针指针所指方向为正北,界面比较简单,没有做任何美化,有需要的可以查看附件
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指南针apk下载

指南针源码

转载于:https://my.oschina.net/chenzz/blog/119593