Android开发-Sensor传感器-AndroidStudio(二)小方

转载请注明出处：http://blog.csdn.net/iwanghang/article/details/53418690

我正在参加CSDN 2016博客之星评选，希望得到您的宝贵一票~
http://blog.csdn.net/vote/candidate.html?username=iwanghang
请为我投票，谢谢 ~~
如果没有CSDN账号 直接使用微信/QQ/微博登陆 就能投票了~~

用传感器做一个小方块自由移动，以屏幕为边界~

既然是以屏幕为边界，那么左上角肯定是坐标0,0，右下角如何获取呢
就要用到Displaymetrics 取得手机屏幕大小的关键类，

我用一段代码我具体表示一下如何获取屏幕大小，请看：

public static String getDisplayMetrics(Context cx) {
String str = "";
DisplayMetrics dm = new DisplayMetrics();
//取得DisplayMetrics对象方法一
//dm = cx.getApplicationContext().getResources().getDisplayMetrics();
//取得DisplayMetrics对象方法二
((Activity)cx).getWindowManager().getDefaultDisplay().getMetrics(dm);
int screenWidth = dm.widthPixels;
int screenHeight = dm.heightPixels;
float density = dm.density;
float xdpi = dm.xdpi;
float ydpi = dm.ydpi;

str += "The absolute width:" + String.valueOf(screenWidth) + "pixels\n";
str += "The absolute heightin:" + String.valueOf(screenHeight) + "pixels\n";
str += "The logical density of the display.:" + String.valueOf(density)
+ "\n";
str += "X dimension :" + String.valueOf(xdpi) + "pixels per inch\n";
str += "Y dimension :" + String.valueOf(ydpi) + "pixels per inch\n";

return str;
}

其实，很多时候，我们做屏幕适配的时候，获取屏幕大小会比较有用~
之前打算写一篇屏幕适配的博文，但是想了想，可以说的内容太少了~
做为一个Android的新手，屏幕适配会用，但是实际上经手过的需要屏幕适配的项目还没有
所以迟迟没写，等有了相关经验一定写一下屏幕适配~

注意这个Demo没有计算状态栏和标题栏的高度，所以要去掉/隐藏状态栏和标题栏
我这边用真机测试，所以用别人手机拍了一个MP4，又用GifCam抓取变成GIF，但是大小为8M上传不了
我的同事用PS，帮我转换了一下颜色深度和大小，才勉强变成2M以内，我同事的博客http://blog.csdn.net/sundayaaron

项目源码下载(免积分)：http://download.csdn.net/detail/iwanghang/9698771

我们看一下动态GIF图和代码



MainActivity.java:

package com.iwanghang.sensordemo2;

import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.view.WindowManager;

public class MainActivity extends AppCompatActivity {

private RectView rv;

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

//隐藏标题栏
getSupportActionBar().hide();
//取消状态栏
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);

// 获取屏幕宽高
DisplayMetrics dm = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(dm);
rv = new RectView(this,dm.widthPixels,dm.heightPixels);
setContentView(rv);
SensorManager sm = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
Sensor type_gravity = sm.getDefaultSensor(Sensor.TYPE_GRAVITY);// 重力传感器
sm.registerListener(new SensorEventListener() {
@Override
public void onSensorChanged(SensorEvent sensorEvent) {
float x = sensorEvent.values[0];
float y = sensorEvent.values[1];
System.out.println("x = " + x + " + " + y);
rv.rect.setLeft(Math.round(x)*10);
rv.rect.setTop(Math.round(y)*10);
rv.invalidate(); // 重绘
}
@Override
public void onAccuracyChanged(Sensor sensor, int i) {

}
},type_gravity,SensorManager.SENSOR_DELAY_NORMAL);

}
}

Rect.java:

package com.iwanghang.sensordemo2;

/**
* 小方块 对象
*/
public class Rect {

float left = 100, top = 100, right = 100, bottom = 100;
private int width,height;

public Rect(int width, int height) {
this.width = width;
this.height = height;
left = width/2-right/2;
top = height/2-bottom/2;
}

public float getLeft() {
return left;
}

public void setLeft(float left) {
this.left -= left;
if (this.left<=0){
this.left = 0;
}else if(this.left>=width-this.right){
this.left = width-this.right;
}
}

public float getTop() {
return top;
}

public void setTop(float top) {
this.top += top;
if (this.top<=0){
this.top = 0;
}else if(this.top>=height-this.bottom){
this.top = height-this.bottom;
}
}

public float getRight() {
return right;
}

public void setRight(float right) {
this.right = right;
}

public float getBottom() {
return bottom;
}

public void setBottom(float bottom) {
this.bottom = bottom;
}
}

RectView.java:

package com.iwanghang.sensordemo2;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.view.View;

/**
* 小方块 视图
*/
public class RectView extends View{

Rect rect;
private int widh,height;
Paint paint;

public RectView(Context context, int width, int height) {
super(context);
this.widh = width;
this.height = height;
paint = new Paint(); // 实例化画笔
paint.setColor(Color.GREEN);
rect = new Rect(width,height);
}

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawRect(rect.getLeft(),rect.getTop(),rect.getLeft()+rect.getRight(),rect.getTop()+rect.getBottom(),paint);
}
}

avtivity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="com.iwanghang.sensordemo2.MainActivity">

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Hello World!" />
</RelativeLayout>

转载请注明出处：http://blog.csdn.net/iwanghang/article/details/53418690

欢迎移动开发爱好者交流
沈阳或周边城市公司有意开发Android，请与我联系
联系方式



微信：iwanghang
QQ：413711276
邮箱：iwanghang@qq.com