Android视频播放器屏幕左侧边随手指上下滑动亮度调节变暗变亮原理实现

Android视频播放器屏幕左侧边随手指上下滑动亮度调节变暗变亮原理实现

Java代码：

package zhangphil.app;

import android.app.Activity;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.WindowManager;
import android.widget.TextView;

public class MainActivity extends Activity {
private float startY = 0;//手指按下时的Y坐标
private float startX = 0;//手指按下时的Y坐标

private TextView brightnessTextView;
private View mVideoView;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mVideoView = LayoutInflater.from(this).inflate(R.layout.activity_main, null);
setContentView(mVideoView);
brightnessTextView = (TextView) mVideoView.findViewById(R.id.text);
}

/*
* 设置屏幕亮度
* 0 最暗
* 1 最亮
*/
public void setBrightness(float brightness) {
WindowManager.LayoutParams lp = getWindow().getAttributes();
lp.screenBrightness = lp.screenBrightness + brightness / 255.0f;
if (lp.screenBrightness > 1) {
lp.screenBrightness = 1;
} else if (lp.screenBrightness < 0.1) {
lp.screenBrightness = (float) 0.1;
}
getWindow().setAttributes(lp);

float sb = lp.screenBrightness;
brightnessTextView.setText((int) Math.ceil(sb * 100) + "%");
}

@Override
public boolean onTouchEvent(MotionEvent event) {
int screenWidth = mVideoView.getWidth();

switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
startX = event.getX();
startY = event.getY();
break;

case MotionEvent.ACTION_MOVE:
float endY = event.getY();
float distanceY = startY - endY;
if (startX > screenWidth / 2) {
//右边
//在这里处理音量
} else {
//屏幕左半部分上滑，亮度变大，下滑，亮度变小

final double FLING_MIN_DISTANCE = 0.5;
final double FLING_MIN_VELOCITY = 0.5;
if (distanceY > FLING_MIN_DISTANCE && Math.abs(distanceY) > FLING_MIN_VELOCITY) {
setBrightness(10);
}
if (distanceY < FLING_MIN_DISTANCE && Math.abs(distanceY) > FLING_MIN_VELOCITY) {
setBrightness(-10);
}
}
break;
}

return super.onTouchEvent(event);
}
}

activity_main.xml布局文件：
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@mipmap/ic_launcher">

<TextView
android:id="@+id/text"
android:layout_width="150dp"
android:layout_height="50dp"
android:layout_gravity="center"
android:background="@android:color/holo_orange_light"
android:gravity="center"
android:textColor="@android:color/white" />
</FrameLayout>