android:angle="90",Android手机 G-sensor 倾斜度引出的开发问题

srclinuxandroidframeworksbasepolicysrccomandroidinternalpolicyImplWindowOrientationListener.java

private static final int MAX_TILT = 75; //手机的倾斜度阈值，改大则手机倾斜度(相对于水平面)很小屏幕就会旋转，改大手机倾斜度需要很大，屏幕才会旋转。

函数public void onSensorChanged(SensorEvent event) {

// Calculate the tilt angle.

// This is the angle between the up vector and the x-y plane (the plane of

// the screen) in a range of [-90, 90] degrees.

// -90 degrees: screen horizontal and facing the ground (overhead)

// 0 degrees: screen vertical

// 90 degrees: screen horizontal and facing the sky (on table)

final int tiltAngle = (int) Math.round(

Math.asin(z / magnitude) * RADIANS_TO_DEGREES);//计算手机倾斜的角度。

// If the tilt angle is too close to horizontal then we cannot determine

// the orientation angle of the screen.

if (Math.abs(tiltAngle) > MAX_TILT) { //如果采集到的手机倾斜角度大于android系统设定的默认值MAX_TILT 就不会上报

if (LOG) {

Slog.v(TAG, "Ignoring sensor data, tilt angle too high: "

+ "tiltAngle=" + tiltAngle);

}

clearPredictedRotationLocked();

}

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