Android实现音乐播放器锁屏页

<activity  
  android:name=".LockActivity" 
  android:excludeFromRecents="true"  
  android:exported="false"  
  android:launchMode="singleInstance"  
  android:noHistory="true"  
  android:screenOrientation="portrait"  
  android:taskAffinity="com.ztk.lock"  
  android:theme="@style/LockScreenTheme"/>

<style name="LockScreenTheme" parent="AppTheme">
    <item name="android:windowIsTranslucent">true</item>
    <item name="android:windowBackground">@android:color/transparent</item>
    <item name="android:colorBackgroundCacheHint">@null</item>
    <item name="android:backgroundDimEnabled">false</item>
    <item name="android:windowAnimationStyle">@null</item>
    <item name="android:windowContentOverlay">@null</item>
 </style> 

@Override
protected void onCreate(Bundle savedInstanceState) {  
   super.onCreate(savedInstanceState);  
     getWindow().addFlags(WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD | WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED);
   fullScreen(this);  
   setContentView(R.layout.activity_lock);
}

public static void fullScreen(Activity activity) {  
  if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {    
      if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {      
      //5.x开始需要把颜色设置透明，否则导航栏会呈现系统默认的浅灰色      
      Window window = activity.getWindow();      
      View decorView = window.getDecorView();      
      //两个 flag 要结合使用，表示让应用的主体内容占用系统状态栏的空间      
      int option = View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN          
             | View.SYSTEM_UI_FLAG_LAYOUT_STABLE;      
      decorView.setSystemUiVisibility(option);      
      window.addFlags(WindowManager.LayoutParams.FLAG_DRAWS_SYSTEM_BAR_BACKGROUNDS);      
      window.setStatusBarColor(Color.TRANSPARENT);    
  } else {      
    Window window = activity.getWindow();      
    WindowManager.LayoutParams attributes = window.getAttributes();      
    int flagTranslucentStatus = WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS;      
    attributes.flags |= flagTranslucentStatus;      
    window.setAttributes(attributes);    
  }  
 }
}

@Override
public void onBackPressed() {}

@Override
public boolean onTouchEvent(MotionEvent event) {  
  switch (event.getActionMasked()) {    
    case MotionEvent.ACTION_DOWN:      
      downX = tempX = (int) event.getRawX();      
      downY = (int) event.getRawY();      
      break;    
    case MotionEvent.ACTION_MOVE:      
      int moveX = (int) event.getRawX();      
      int deltaX = tempX - moveX;      
      tempX = moveX;      
      if (Math.abs(moveX - downX) > mTouchSlop 
        && Math.abs((int) event.getRawY() - downY) < mTouchSlop) {
        isSliding = true;      
      }      
      if (moveX - downX >= 0 && isSliding) {        
        mParentView.scrollBy(deltaX, 0);      
      }      
      break;    
    case MotionEvent.ACTION_UP:      i
      sSliding = false;      
      if (mParentView.getScrollX() <= -viewWidth / 4) {        
      isFinish = true;        
      scrollRight();      
      } else {        
         scrollOrigin();        
         isFinish = false;      
       }      
      break;    
    default:      
    break;  
  }  
  return true;
}

public class HintTextView extends AppCompatTextView {  
  private Paint paint;    
  private int mWidth;  
  private LinearGradient gradient;  
  private Matrix matrix;  
  /**   
   * 渐变的速度   
   */  
  private int deltaX; 
 
  public HintTextView(Context context) {    
    super(context, null);  
  } 
 
  public HintTextView(Context context, AttributeSet attrs) {    
    super(context, attrs);  
  }  
 
  {    
  paint = getPaint();  
  } 
 
  @Override  
  protected void onSizeChanged(int w, int h, int oldw, int oldh) {    
    super.onSizeChanged(w, h, oldw, oldh);    
    if(mWidth == 0 ){      
      mWidth = getMeasuredWidth();      
      //颜色渐变器      
      gradient = new LinearGradient(0, 0, mWidth, 0, new int[]{Color.GRAY, Color.WHITE, Color.GRAY}, 
      new float[]{0.3f,0.5f,1.0f}, 
      Shader.TileMode.CLAMP);      
      paint.setShader(gradient);      
      matrix = new Matrix();    
      }  
  }
 
  @Override  
  protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);    
    if(matrix !=null){      
      deltaX += mWidth / 8;      
      if(deltaX > 2 * mWidth){        
        deltaX = -mWidth;      
       }    
    }    
    //通过矩阵的平移实现    
    matrix.setTranslate(deltaX, 0);    
    gradient.setLocalMatrix(matrix);    
    postInvalidateDelayed(100);  
  }
}

<service  
  android:name=".service.PlayService"  
  android:process=":main" />

ScreenBroadcastReceiver screenBroadcastReceiver;
@Nullable
@Override
public IBinder onBind(Intent intent) {  
  return null;
}
@Override
public void onCreate() {  
  super.onCreate();  
  screenBroadcastReceiver = new ScreenBroadcastReceiver();  
  final IntentFilter filter = new IntentFilter();  
  filter.addAction(Intent.ACTION_SCREEN_OFF);  
  registerReceiver(screenBroadcastReceiver, filter);
}
 
public class ScreenBroadcastReceiver extends BroadcastReceiver {  
  @Override  
  public void onReceive(Context context, Intent intent) {    
    handleCommandIntent(intent);  
    }
  }
 
private void handleCommandIntent(Intent intent) {  
  final String action = intent.getAction();  
  if (Intent.ACTION_SCREEN_OFF.equals(action) ){    
    Intent lockScreen = new Intent(this, LockActivity.class);    
    lockScreen.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);    
    startActivity(lockScreen);  
    }
  }
  @Override
  public void onDestroy() {  
    super.onDestroy();  
    unregisterReceiver(screenBroadcastReceiver);
 }