Android视频播放器屏幕左侧边随手指上下滑动亮度调节功能的原理实现

本文给大家分享Android视频播放器屏幕左侧边随手指上下滑动亮度调节功能的原理实现，具体代码如下所示：

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>

以上所述是小编给大家介绍的Android视频播放器屏幕左侧边随手指上下滑动亮度调节功能的原理实现网站的支持！

来源：http://blog.csdn.net/qq_32521313/article/details/56832974