详解Android如何实现可任意拖动的悬浮窗功能

import android.content.Context;
import android.content.Intent;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.util.TypedValue;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.WindowManager;
import android.widget.LinearLayout;
import com.xinrui.recordscreen.R;
import java.lang.reflect.Field;
/**
 *
 */
public class RecordScreenView extends LinearLayout implements View.OnClickListener{
  private WindowManager mWindowManager;
  private WindowManager.LayoutParams mLayoutParams;
  private long mLastDownTime;
  private float mLastDownX;
  private float mLastDownY;
  private boolean mIsLongTouch;
  private boolean mIsTouching;
  private float mTouchSlop;
  private final static long LONG_CLICK_LIMIT = 20;
  private final static int TIME_COUNT = 0;
  private int mStatusBarHeight;
  private int mCurrentMode,time=0;
  private final static int MODE_NONE = 0x000;
  private final static int MODE_MOVE = 0x001;
  private int mOffsetToParent;
  private int mOffsetToParentY;
  private Context mContext;
  public RecordScreenView(Context context) {
    super(context);
    this.mContext=context;
    mWindowManager = (WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE);
    initView();
  }
  private void initView() {
    View view = inflate(getContext(), R.layout.layout_ball, this)；
    mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();
    mCurrentMode = MODE_NONE;
    recordtime(0);
    mStatusBarHeight = getStatusBarHeight();
    mOffsetToParent = dip2px(25);
    mOffsetToParentY = mStatusBarHeight + mOffsetToParent;
    view.setOnTouchListener(new OnTouchListener() {
      @Override
      public boolean onTouch(View v, final MotionEvent event) {
        switch (event.getAction()) {
          case MotionEvent.ACTION_DOWN:
            mIsTouching = true;
            mLastDownTime = System.currentTimeMillis();
            mLastDownX = event.getX();
            mLastDownY = event.getY();
            postDelayed(new Runnable() {
              @Override
              public void run() {
                if (isLongTouch()) {
                  mIsLongTouch = true;
                }
              }
            }, LONG_CLICK_LIMIT);
            break;
          case MotionEvent.ACTION_MOVE:
            if (!mIsLongTouch && isTouchSlop(event)) {
              return true;
            }
            if (mIsLongTouch && (mCurrentMode == MODE_NONE || mCurrentMode == MODE_MOVE)) {
              mLayoutParams.x = (int) (event.getRawX() - mOffsetToParent);
              mLayoutParams.y = (int) (event.getRawY() - mOffsetToParentY);
              mWindowManager.updateViewLayout(RecordScreenView.this, mLayoutParams);//不断刷新悬浮窗的位置
              mCurrentMode = MODE_MOVE;
            }
            break;
          case MotionEvent.ACTION_CANCEL:
          case MotionEvent.ACTION_UP:
            mIsTouching = false;
            if (mIsLongTouch) {
              mIsLongTouch = false;
            }
            mCurrentMode = MODE_NONE;
            break;
        }
        return true;
      }
    });
  }
  private boolean isLongTouch() {
    long time = System.currentTimeMillis();
    if (mIsTouching && mCurrentMode == MODE_NONE && (time - mLastDownTime >= LONG_CLICK_LIMIT)) {
      return true;
    }
    return false;
  }
  /**
   * 判断是否是轻微滑动
   *
   * @param event
   * @return
   */
  private boolean isTouchSlop(MotionEvent event) {
    float x = event.getX();
    float y = event.getY();
    if (Math.abs(x - mLastDownX) < mTouchSlop && Math.abs(y - mLastDownY) < mTouchSlop) {
      return true;
    }
    return false;
  }
  public void setLayoutParams(WindowManager.LayoutParams params) {
    mLayoutParams = params;
  }
  /**
   * 获取通知栏高度
   *
   * @return
   */
  private int getStatusBarHeight() {
    int statusBarHeight = 0;
    try {
      Class<?> c = Class.forName("com.android.internal.R$dimen");
      Object o = c.newInstance();
      Field field = c.getField("status_bar_height");
      int x = (Integer) field.get(o);
      statusBarHeight = getResources().getDimensionPixelSize(x);
    } catch (Exception e) {
      e.printStackTrace();
    }
    return statusBarHeight;
  }
  public int dip2px(float dip) {
    return (int) TypedValue.applyDimension(
        TypedValue.COMPLEX_UNIT_DIP, dip, getContext().getResources().getDisplayMetrics()
    );
  }
}

import android.content.Context;
import android.graphics.PixelFormat;
import android.view.Gravity;
import android.view.WindowManager;
import android.view.WindowManager.LayoutParams;

/**
 * Created by wangxiandeng on 2016/11/25.
 */

public class FloatWindowManager {
  private static RecordScreenView mBallView;

  private static WindowManager mWindowManager;


  public static void addBallView(Context context) {
    if (mBallView == null) {
      WindowManager windowManager = getWindowManager(context);
      int screenWidth = windowManager.getDefaultDisplay().getWidth();
      int screenHeight = windowManager.getDefaultDisplay().getHeight();
      mBallView = new RecordScreenView(context);
      LayoutParams params = new LayoutParams();
      params.x = screenWidth/2;
      params.y = screenHeight/2+150;
      params.width = LayoutParams.WRAP_CONTENT;
      params.height = LayoutParams.WRAP_CONTENT;
      params.gravity = Gravity.LEFT | Gravity.TOP;
      params.type = LayoutParams.TYPE_APPLICATION_OVERLAY;
      params.format = PixelFormat.RGBA_8888;
      params.flags = LayoutParams.FLAG_NOT_TOUCH_MODAL
          | LayoutParams.FLAG_NOT_FOCUSABLE;
      mBallView.setLayoutParams(params);
      windowManager.addView(mBallView, params);
    }
  }

  public static void removeBallView(Context context) {
    if (mBallView != null) {
      WindowManager windowManager = getWindowManager(context);
      windowManager.removeView(mBallView);
      mBallView = null;
    }
  }

  private static WindowManager getWindowManager(Context context) {
    if (mWindowManager == null) {
      mWindowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
    }
    return mWindowManager;
  }
}

import android.app.Activity;
import android.content.Intent;
import android.os.Build;
import android.os.Bundle;
import android.provider.Settings;
import android.util.Log;
import android.widget.Toast;

import com.xinrui.recordscreen.view.FloatWindowManager;

public class MainActivity extends Activity {

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (Build.VERSION.SDK_INT >= 23) {
    //设置中请求开启悬浮窗权限
      if (!Settings.canDrawOverlays(this)) {
        Intent intent = new Intent(Settings.ACTION_MANAGE_OVERLAY_PERMISSION);
        intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        startActivity(intent);
        Toast.makeText(this, MainActivity.this.getResources().getString(R.string.open_float), Toast.LENGTH_SHORT).show();
      }else{
        initView();
      }
    }
  }

  private void initView() {
    FloatWindowManager.addBallView(MainActivity.this);
    finish();
  }
}

<?xml version="1.0" encoding="utf-8"?>

  
  
  
  //悬浮窗权限