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

 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_VELOCITY) { setBrightness(-10); } } break; } return super.onTouchEvent(event); } }