服務獲取和基本參數設置

       // 獲取應用的Context
        mContext = context.getApplicationContext();
        // 獲取WindowManager
        mWindowManager = (WindowManager) mContext
                .getSystemService(Context.WINDOW_SERVICE);
　　   //參數設置：
        final WindowManager.LayoutParams params = new WindowManager.LayoutParams();
        // 類型
        params.type = WindowManager.LayoutParams.TYPE_SYSTEM_ALERT;
        // WindowManager.LayoutParams.TYPE_SYSTEM_ALERT
        // 設置flag
        int flags = WindowManager.LayoutParams.FLAG_ALT_FOCUSABLE_IM;
        // | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;
        // 如果設置了WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE，彈出的View收不到Back鍵的事件
        params.flags = flags;
        // 不設置這個彈出框的透明遮罩顯示為黑色
        params.format = PixelFormat.TRANSLUCENT;
        // FLAG_NOT_TOUCH_MODAL不阻塞事件傳遞到後面的窗口
        // 設置 FLAG_NOT_FOCUSABLE 懸浮窗口較小時，後面的應用圖標由不可長按變為可長按
        // 不設置這個flag的話，home頁的劃屏會有問題
        params.width = LayoutParams.MATCH_PARENT;
        params.height = LayoutParams.MATCH_PARENT;
        params.gravity = Gravity.CENTER;

具體實現

package com.robert.floatingwindow;
import android.content.Context;
import android.graphics.PixelFormat;
import android.graphics.Rect;
import android.view.Gravity;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnKeyListener;
import android.view.View.OnTouchListener;
import android.view.WindowManager;
import android.view.View.OnClickListener;
import android.view.WindowManager.LayoutParams;
import android.widget.Button;
/**
* 彈窗輔助類
*
* @ClassName WindowUtils
*
*
*/
public class WindowUtils {
    private static final String LOG_TAG = "WindowUtils";
    private static View mView = null;
    private static WindowManager mWindowManager = null;
    private static Context mContext = null;
    public static Boolean isShown = false;
    /**
     * 顯示彈出框
     *
     * @param context
     * @param view
     */
    public static void showPopupWindow(final Context context) {
        if (isShown) {
            LogUtil.i(LOG_TAG, "return cause already shown");
            return;
        }
        isShown = true;
        LogUtil.i(LOG_TAG, "showPopupWindow");
        // 獲取應用的Context
        mContext = context.getApplicationContext();
        // 獲取WindowManager
        mWindowManager = (WindowManager) mContext
                .getSystemService(Context.WINDOW_SERVICE);
        mView = setUpView(context);
        final WindowManager.LayoutParams params = new WindowManager.LayoutParams();
        // 類型
        params.type = WindowManager.LayoutParams.TYPE_SYSTEM_ALERT;
        // WindowManager.LayoutParams.TYPE_SYSTEM_ALERT
        // 設置flag
        int flags = WindowManager.LayoutParams.FLAG_ALT_FOCUSABLE_IM;
        // | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;
        // 如果設置了WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE，彈出的View收不到Back鍵的事件
        params.flags = flags;
        // 不設置這個彈出框的透明遮罩顯示為黑色
        params.format = PixelFormat.TRANSLUCENT;
        // FLAG_NOT_TOUCH_MODAL不阻塞事件傳遞到後面的窗口
        // 設置 FLAG_NOT_FOCUSABLE 懸浮窗口較小時，後面的應用圖標由不可長按變為可長按
        // 不設置這個flag的話，home頁的劃屏會有問題
        params.width = LayoutParams.MATCH_PARENT;
        params.height = LayoutParams.MATCH_PARENT;
        params.gravity = Gravity.CENTER;
        mWindowManager.addView(mView, params);
        LogUtil.i(LOG_TAG, "add view");
    }
    /**
     * 隱藏彈出框
     */
    public static void hidePopupWindow() {
        LogUtil.i(LOG_TAG, "hide " + isShown + ", " + mView);
        if (isShown && null != mView) {
            LogUtil.i(LOG_TAG, "hidePopupWindow");
            mWindowManager.removeView(mView);
            isShown = false;
        }
    }
    private static View setUpView(final Context context) {
        LogUtil.i(LOG_TAG, "setUp view");
        View view = LayoutInflater.from(context).inflate(R.layout.popupwindow,
                null);
        Button positiveBtn = (Button) view.findViewById(R.id.positiveBtn);
        positiveBtn.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                LogUtil.i(LOG_TAG, "ok on click");
                // 打開安裝包
                // 隱藏彈窗
                WindowUtils.hidePopupWindow();
            }
        });
        Button negativeBtn = (Button) view.findViewById(R.id.negativeBtn);
        negativeBtn.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                LogUtil.i(LOG_TAG, "cancel on click");
                WindowUtils.hidePopupWindow();
            }
        });
        // 點擊窗口外部區域可消除
        // 這點的實現主要將懸浮窗設置為全屏大小，外層有個透明背景，中間一部分視為內容區域
        // 所以點擊內容區域外部視為點擊懸浮窗外部
        final View popupWindowView = view.findViewById(R.id.popup_window);// 非透明的內容區域
        view.setOnTouchListener(new OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                LogUtil.i(LOG_TAG, "onTouch");
                int x = (int) event.getX();
                int y = (int) event.getY();
                Rect rect = new Rect();
                popupWindowView.getGlobalVisibleRect(rect);
                if (!rect.contains(x, y)) {
                    WindowUtils.hidePopupWindow();
                }
                LogUtil.i(LOG_TAG, "onTouch : " + x + ", " + y + ", rect: "
                        + rect);
                return false;
            }
        });
        // 點擊back鍵可消除
        view.setOnKeyListener(new OnKeyListener() {
            @Override
            public boolean onKey(View v, int keyCode, KeyEvent event) {
                switch (keyCode) {
                case KeyEvent.KEYCODE_BACK:
                    WindowUtils.hidePopupWindow();
                    return true;
                default:
                    return false;
                }
            }
        });
        return view;
    }
}