最近有公司有一個需求 需要將環信的視訊聊天視窗縮小 類似微信那樣，可以放大，並且縮小後可以看到文字聊天的視窗。看了環信的程式碼 發現文字聊天和視訊聊天是兩個獨立的activity,於是想到activity如何能懸浮並且 在他下面的activity能獲得焦點，試了幾次發現不能實現。後來有想到一種辦法 ，這種辦法比較笨拙，但是真的實現了，我將視訊聊天的邏輯和圖文的邏輯寫到了一個activity裡面，視訊聊天的介面採用懸浮視窗，當在聊天介面的時候需要啟動視訊介面 便將視訊的view 新增到windowmanager中，實現懸浮 並且可以改變大小，在小視窗的模式下 還可以傳送圖文訊息。

網盤地址：http://pan.baidu.com/s/1jIcBNfg，希望可以幫到有同樣需求的人。

主要程式碼片段：

/**************************** 視訊懸浮窗********************************/
WindowManager mWindowManager;
WindowManager.LayoutParams wmParams;
public void showFloatWindow() {
    wmParams = new WindowManager.LayoutParams();
mWindowManager = (WindowManager) getSystemService(Context.WINDOW_SERVICE);
 
wmParams.type = WindowManager.LayoutParams.TYPE_SYSTEM_ALERT;
wmParams.format = PixelFormat.RGBA_8888;
wmParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE;
wmParams.gravity = Gravity.LEFT | Gravity.TOP;
wmParams.x = 0;
wmParams.y = 0;
wmParams.width = ScreenUtil.getScreenWidth(ChatActivity.this
 
);
wmParams.height = ScreenUtil.getScreenHeight(ChatActivity.this) - ScreenUtil.getNavigationBottomHeight(ChatActivity.this);
viewRootView.setParams(wmParams);
viewRootView.setOnClickListener(new View.OnClickListener() {
        @Override
public void onClick(View v) {
            if(isChangefreeState){
                changeFloatSize();
isChangefreeState = false;
}
        }
    });
mWindowManager.addView(viewRootView, wmParams);
isAddWindowManager = true;
}

public void changeFloatSize() {
    if (!isChangefreeState) {
        wmParams.x = ScreenUtil.getScreenWidth(ChatActivity.this);
wmParams.y = 0;
wmParams.width = ScreenUtil.getScreenWidth(ChatActivity.this) / 3;
wmParams.height = ScreenUtil.getScreenHeight(ChatActivity.this) / 3;
mWindowManager.updateViewLayout(viewRootView, wmParams);
callStateTextView.setVisibility(View.INVISIBLE);
chronometer.setVisibility(View.INVISIBLE);
nickTextView.setVisibility(View.INVISIBLE);
switchCameraBtn.setVisibility(View.INVISIBLE);
voiceContronlLayout.setVisibility(View.INVISIBLE);
hangupBtn.setVisibility(View.INVISIBLE);
changeBtn.setVisibility(View.INVISIBLE);
} else {
        wmParams.x = 0;
wmParams.y = 0;
wmParams.width = ScreenUtil.getScreenWidth(ChatActivity.this);
wmParams.height = ScreenUtil.getScreenHeight(ChatActivity.this) - ScreenUtil.getNavigationBottomHeight(ChatActivity.this);
mWindowManager.updateViewLayout(viewRootView, wmParams);
callStateTextView.setVisibility(View.VISIBLE);
chronometer.setVisibility(View.VISIBLE);
nickTextView.setVisibility(View.VISIBLE);
switchCameraBtn.setVisibility(View.VISIBLE);
voiceContronlLayout.setVisibility(View.VISIBLE);
hangupBtn.setVisibility(View.VISIBLE);
changeBtn.setVisibility(View.VISIBLE);
}

}

public void removeFloatWindow() {
        if (viewRootView != null && isAddWindowManager) {
            mWindowManager = (WindowManager) getSystemService(Context.WINDOW_SERVICE);
mWindowManager.removeView(viewRootView);
isAddWindowManager = false;
}

}