Android使用重力传感器实现随重力旋转的图标-技术圈

相机拍摄都有横屏拍摄和竖屏拍摄，横竖屏切换，图标也会跟着重力方向旋转，于是也做了一个相机旋转效果。

啥也不说了，先上效果图，gif大小限制，只截取了一小段：

在Android平台中，传感器框架通常是使用一个标准的三维坐标系去表示一个值的。以方向传感器为例，确定一个方向当然也需要一个三维坐标，三个方向值就是一个长度为3的float数组。‍

旋转工具类：

根据重力传感器的监听，获取X、Y方向上分量计算数值角度。

为了不实时旋转，定义4个方向范围，对应角度分别为0，90，

180，270度，遍历view作属性动画。

import android.animation.ObjectAnimator;import android.app.Activity;import android.content.Context;import android.hardware.Sensor;import android.hardware.SensorEvent;import android.hardware.SensorEventListener;import android.hardware.SensorManager;import android.view.View;import java.util.ArrayList;
public class RotateSensorUtil implements SensorEventListener{    private Context context;    private SensorManager sensorManager;    //默认旋转角度code，分别为 0,1/2,3,4/-1    private int curRotateCode = 0;    //记录当前的角度，每次旋转从此处开始    private int curAngle = 0;    //需要操作旋转的集合    private ArrayList<View> views = new ArrayList<>();
    public RotateSensorUtil(Context context, ArrayList<View> views){
        this.context = context;        this.views = views;        sensorManager = (SensorManager) context.getSystemService(Context.SENSOR_SERVICE);        //通过传感器管理器获取重力加速度传感器        sensorManager.registerListener(this,sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER),SensorManager.SENSOR_DELAY_NORMAL);    }
    @Override    public void onSensorChanged(SensorEvent event) {        if(event.sensor.getType() != Sensor.TYPE_ACCELEROMETER){            return;        }
        float[] values = event.values;        float ax = values[0];        float ay = values[1];

        double g = Math.sqrt(ax * ax + ay * ay);        double cos = ay / g;        if (cos > 1) {            cos = 1;        } else if (cos < -1) {            cos = -1;        }        double rad = Math.acos(cos);        if (ax < 0) {            rad = 2 * Math.PI - rad;        }
        int uiRot = ((Activity)context).getWindowManager().getDefaultDisplay().getRotation();        double uiRad = Math.PI / 2 * uiRot;        rad -= uiRad;
        checkBundray((int) rad);    }
    @Override    public void onAccuracyChanged(Sensor sensor, int accuracy) {
    }
    /**     * 旋转检测     * @param rotateCode     */    private void checkBundray(int rotateCode){        if(rotateCode == 2) rotateCode = 1;        if(rotateCode == -1) rotateCode = 4;        int angle = 0;
        switch (rotateCode){            case 0:                angle = 0;                break;            case 1:                angle = 90;                break;            case 3:                angle = 180;                break;            case 4:                angle = 270;                break;        }
        if(rotateCode == curRotateCode){
        }else{            valueRotateAnim(angle);            curAngle = angle;            curRotateCode = rotateCode;        }    }
    private void valueRotateAnim(int angle){        //特别处理从270-0度的反向旋转        if(curAngle == 270){            angle = 360;        }        for(int i=0;i<views.size();i++){            startRotateAnim(views.get(i),300,curAngle,angle);        }    }
    public void unregisterSensor(){        sensorManager.unregisterListener(this);    }
    public void startRotateAnim(View view,long time,int fromAngle,float toAngle){        ObjectAnimator animRotate = ObjectAnimator.ofFloat(view,"rotation",fromAngle,toAngle);        animRotate.setDuration(time);        animRotate.start();    }
}

MainActivity调用，传递所有要旋转图标，并调用相机。

import android.graphics.SurfaceTexture;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.view.TextureView;import android.view.View;import android.view.WindowManager;import android.widget.ImageView;import java.util.ArrayList;import butterknife.Bind;import butterknife.ButterKnife;
public class MainActivity extends AppCompatActivity implements TextureView.SurfaceTextureListener {    @Bind(R.id.textureview)    TextureView textureview;    @Bind(R.id.iv_close)    ImageView ivClose;    @Bind(R.id.more)    ImageView more;    @Bind(R.id.iv_switch)    ImageView ivSwitch;    @Bind(R.id.iv_pic)    ImageView ivPic;    @Bind(R.id.iv_beauty)    ImageView ivBeauty;    @Bind(R.id.iv_face)    ImageView ivFace;    @Bind(R.id.iv_filter)    ImageView ivFilter;    private TextureView textureView;    private OpenCamera openCamera;    private RotateSensorUtil sensorUtil;    private ArrayList<View> rotateViews = new ArrayList<>();
    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);        setContentView(R.layout.activity_main);        ButterKnife.bind(this);
        openCamera();        addViews();        startAnim();    }
    private void startAnim() {        sensorUtil = new RotateSensorUtil(this,rotateViews);    }
    private void addViews(){        rotateViews.add(ivClose);        rotateViews.add(more);        rotateViews.add(ivSwitch);        rotateViews.add(ivPic);        rotateViews.add(ivBeauty);        rotateViews.add(ivFace);        rotateViews.add(ivFilter);    }
    private void openCamera(){        textureView = (TextureView) findViewById(R.id.textureview);        openCamera = new OpenCamera(getApplicationContext(), textureView);
        openCamera.startCameraThread();
        if (!textureView.isAvailable()) {            textureView.setSurfaceTextureListener(this);        } else {            openCamera.startPreview();        }    }
    @Override    protected void onDestroy() {        super.onDestroy();
        sensorUtil.unregisterSensor();    }
    @Override    public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {        openCamera.setupCamera(width, height);  //设置相机参数,回调的是textureview的宽高        openCamera.openCamera();    }
    @Override    public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {
    }
    @Override    public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {        return false;    }
    @Override    public void onSurfaceTextureUpdated(SurfaceTexture surface) {
    }}

源码地址：

https://github.com/18380438200/GravitySensor

到这里就结束啦。