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public PopupWindow (Context context)
public PopupWindow(View contentView)
public PopupWindow(int width, int height)
public PopupWindow(View contentView, int width, int height)
public PopupWindow(View contentView, int width, int height, boolean focusable)showAsDropDown(View anchor)：相對某個控件的位置（正左下方），無偏移
showAsDropDown(View anchor, int xoff, int yoff)：相對某個控件的位置，有偏移
showAtLocation(View parent, int gravity, int x, int y)：相對于父控件的位置（例如正中央Gravity.CENTER，下方Gravity.BOTTOM等），可以設置偏移或無偏移具體如下所示
//創建對象
PopupWindow popupWindow = new PopupWindow(this);
View inflate = LayoutInflater.from(this).inflate(R.layout.view_pop_custom, null);
//設置view布局
popupWindow.setContentView(inflate);
popupWindow.setWidth(LinearLayout.LayoutParams.WRAP_CONTENT);
popupWindow.setHeight(LinearLayout.LayoutParams.WRAP_CONTENT);
//設置動畫的方法
popupWindow.setAnimationStyle(R.style.BottomDialog);
//設置PopUpWindow的焦點，設置為true之后，PopupWindow內容區域，才可以響應點擊事件
popupWindow.setTouchable(true);
//設置背景透明
popupWindow.setBackgroundDrawable(new ColorDrawable(0x00000000));
//點擊空白處的時候讓PopupWindow消失
popupWindow.setOutsideTouchable(true);
// true時，點擊返回鍵先消失 PopupWindow
// 但是設置為true時setOutsideTouchable，setTouchable方法就失效了（點擊外部不消失，內容區域也不響應事件）
// false時PopupWindow不處理返回鍵，默認是false
popupWindow.setFocusable(false);
//設置dismiss事件
popupWindow.setOnDismissListener(new PopupWindow.OnDismissListener() {
@Override
public void onDismiss() {
}
});
boolean showing = popupWindow.isShowing();
if (!showing){
//show，并且可以設置位置
popupWindow.showAsDropDown(mTv1);
}先看問題代碼，下面這個不會出現彈窗，思考：為什么？
PopupWindow popupWindow = new PopupWindow(this);
View inflate = LayoutInflater.from(this).inflate(R.layout.view_pop_custom, null);
popupWindow.setContentView(inflate);
popupWindow.setAnimationStyle(R.style.BottomDialog);
popupWindow.showAsDropDown(mTv1);首先先來看看源碼
可以看出，先判斷是否show，如果沒有showing的話，則進行contentView賦值，如果mWindowManager為null，則取獲取mWindowManager，這個很重要。最后便是根據SDK版本而不是在構造函數中設置附加InDecor的默認設置，因為構造函數中可能沒有上下文對象。我們只想在這里設置默認，如果應用程序尚未設置附加InDecor。
public void setContentView(View contentView) {
//判斷是否show，如果已經show，則返回
if (isShowing()) {
return;
}
//賦值
mContentView = contentView;
if (mContext == null && mContentView != null) {
mContext = mContentView.getContext();
}
if (mWindowManager == null && mContentView != null) {
mWindowManager = (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);
}
//在這里根據SDK版本而不是在構造函數中設置附加InDecor的默認設置，因為構造函數中可能沒有上下文對象。我們只想在這里設置默認，如果應用程序尚未設置附加InDecor。
if (mContext != null && !mAttachedInDecorSet) {
setAttachedInDecor(mContext.getApplicationInfo().targetSdkVersion
>= Build.VERSION_CODES.LOLLIPOP_MR1);
}}
public void setAttachedInDecor(boolean enabled) {
mAttachedInDecor = enabled;
mAttachedInDecorSet = true;
}先來看一下showAsDropDown(View anchor)部分代碼
public void showAsDropDown(View anchor) {
showAsDropDown(anchor, 0, 0);
}//主要看這個方法
//注意啦：關于更多內容，可以參考我的博客大匯總：https://github.com/yangchong211/YCBlogs
public void showAsDropDown(View anchor, int xoff, int yoff, int gravity) {
if (isShowing() || mContentView == null) {
return;
}
TransitionManager.endTransitions(mDecorView);
//下面單獨講
//https://github.com/yangchong211/YCBlogs
attachToAnchor(anchor, xoff, yoff, gravity);
mIsShowing = true;
mIsDropdown = true;
//通過createPopupLayoutParams方法創建和初始化LayoutParams
final WindowManager.LayoutParams p = createPopupLayoutParams(anchor.getWindowToken());
preparePopup(p);
final boolean aboveAnchor = findDropDownPosition(anchor, p, xoff, yoff,
p.width, p.height, gravity);
updateAboveAnchor(aboveAnchor);
p.accessibilityIdOfAnchor = (anchor != null) ? anchor.getAccessibilityViewId() : -1;
invokePopup(p);}
接著來看看attachToAnchor(anchor, xoff, yoff, gravity)源碼
關于四種引用的深入介紹可以參考我的這邊文章：01.四種引用比較與源碼分析
private void attachToAnchor(View anchor, int xoff, int yoff, int gravity) {
detachFromAnchor();
final ViewTreeObserver vto = anchor.getViewTreeObserver();
if (vto != null) {
vto.addOnScrollChangedListener(mOnScrollChangedListener);
}
final View anchorRoot = anchor.getRootView();
anchorRoot.addOnAttachStateChangeListener(mOnAnchorRootDetachedListener);
mAnchor = new WeakReference<>(anchor);
mAnchorRoot = new WeakReference<>(anchorRoot);
mIsAnchorRootAttached = anchorRoot.isAttachedToWindow();
mAnchorXoff = xoff;
mAnchorYoff = yoff;
mAnchoredGravity = gravity;
}
接著看看dismissImmediate(View decorView, ViewGroup contentHolder, View contentView)源碼
第三步，講mDecorView，mBackgroundView置為null
private void dismissImmediate(View decorView, ViewGroup contentHolder, View contentView) {
// If this method gets called and the decor view doesn't have a parent,
// then it was either never added or was already removed. That should
// never happen, but it's worth checking to avoid potential crashes.
if (decorView.getParent() != null) {
mWindowManager.removeViewImmediate(decorView);
}
if (contentHolder != null) {
contentHolder.removeView(contentView);
}
// This needs to stay until after all transitions have ended since we
// need the reference to cancel transitions in preparePopup().
mDecorView = null;
mBackgroundView = null;
mIsTransitioningToDismiss = false;
}通過createDecorView(View contentView)方法可以知道，是PopupDecorView直接new出來的布局對象decorView，外面包裹了一層PopupDecorView，這里的PopupDecorView也是我們自定義的FrameLayout的子類，然后看一下里面的代碼：
private class PopupDecorView extends FrameLayout {
private TransitionListenerAdapter mPendingExitListener;
public PopupDecorView(Context context) {
super(context);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
final int x = (int) event.getX();
final int y = (int) event.getY();
if ((event.getAction() == MotionEvent.ACTION_DOWN)
&& ((x < 0) || (x >= getWidth()) || (y < 0) || (y >= getHeight()))) {
dismiss();
return true;
} else if (event.getAction() == MotionEvent.ACTION_OUTSIDE) {
dismiss();
return true;
} else {
return super.onTouchEvent(event);
}
}
}new CustomPopupWindow.PopupWindowBuilder(this)
//.setView(R.layout.pop_layout)
.setView(contentView)
.setFocusable(true)
//彈出popWindow時，背景是否變暗
.enableBackgroundDark(true)
//控制亮度
.setBgDarkAlpha(0.7f)
.setOutsideTouchable(true)
.setAnimationStyle(R.style.popWindowStyle)
.setOnDissmissListener(new PopupWindow.OnDismissListener() {
@Override
public void onDismiss() {
//對話框銷毀時
}
})
.create()
.showAsDropDown(tv6,0,10);免責聲明：本站發布的內容（圖片、視頻和文字）以原創、轉載和分享為主，文章觀點不代表本網站立場，如果涉及侵權請聯系站長郵箱：is@yisu.com進行舉報，并提供相關證據，一經查實，將立刻刪除涉嫌侵權內容。
