Android的对话框有两种:PopupWindow和AlertDialog。它们的不同点在于:
- AlertDialog的位置固定,而PopupWindow的位置可以随意
- AlertDialog是非阻塞线程的,而PopupWindow是阻塞线程的
PopupWindow的位置按照有无偏移分,可以分为偏移和无偏移两种;按照参照物的不同,可以分为相对于某个控件(Anchor锚)和相对于父控件。具体如下
- showAsDropDown(View anchor):相对某个控件的位置(正左下方),无偏移
- showAsDropDown(View anchor, int xoff, int yoff):相对某个控件的位置,有偏移
- showAtLocation(View parent, int gravity, int x, int y):相对于父控件的位置(例如正中央Gravity.CENTER,下方Gravity.BOTTOM等),可以设置偏移或无偏移
下面通过一个Demo讲解(解释看注释):
main.xml
- <?xml version="1.0" encoding="utf-8"?>
- <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
- android:layout_width="fill_parent"
- android:layout_height="fill_parent"
- android:orientation="vertical" >
-
- <TextView
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:text="@string/hello" />
-
- <Button
- android:id="@+id/button01"
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:text="以自己为Anchor,不偏移" />
-
- <Button
- android:id="@+id/button02"
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:text="以自己为Anchor,有偏移" />
-
- <Button
- android:id="@+id/button03"
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:text="以屏幕中心为参照,不偏移(正中间)" />
-
- <Button
- android:id="@+id/button04"
- android:layout_width="fill_parent"
- android:layout_height="wrap_content"
- android:text="以屏幕下方为参照,下方中间" />
-
- </LinearLayout>
popup_window.xml
- <?xml version="1.0" encoding="utf-8"?>
- <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:background="#00FF00"
- android:orientation="vertical" >
-
- <TextView
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:text="选择状态:"
- android:textColor="@android:color/white"
- android:textSize="20px" />
-
- <RadioGroup
- android:id="@+id/radioGroup"
- android:layout_width="wrap_content"
- android:layout_height="wrap_content"
- android:orientation="vertical" >
-
- <RadioButton android:text="在线" />
-
- <RadioButton android:text="离线" />
-
- <RadioButton android:text="隐身" />
- </RadioGroup>
-
- </LinearLayout>
PopupWindowDemoActivity.java
- package com.tianjf;
-
- import android.app.Activity;
- import android.os.Bundle;
- import android.view.Gravity;
- import android.view.LayoutInflater;
- import android.view.View;
- import android.view.View.OnClickListener;
- import android.widget.Button;
- import android.widget.PopupWindow;
- import android.widget.RadioGroup;
- import android.widget.RadioGroup.OnCheckedChangeListener;
-
- public class PopupWindowDemoActivity extends Activity implements OnClickListener,
- OnCheckedChangeListener {
-
- private Button mbutton01;
- private Button mbutton02;
- private Button mbutton03;
- private Button mbutton04;
- private PopupWindow mPopupWindow;
-
- private int mScreenWidth;
-
- private int mScreenHeight;
-
- private int mPopupWindowWidth;
-
- private int mPopupWindowHeight;
-
- @Override
- public void onCreate(Bundle savedInstanceState) {
- super.onCreate(savedInstanceState);
- setContentView(R.layout.main);
-
- mbutton01 = (Button) findViewById(R.id.button01);
- mbutton02 = (Button) findViewById(R.id.button02);
- mbutton03 = (Button) findViewById(R.id.button03);
- mbutton04 = (Button) findViewById(R.id.button04);
-
- mbutton01.setOnClickListener(this);
- mbutton02.setOnClickListener(this);
- mbutton03.setOnClickListener(this);
- mbutton04.setOnClickListener(this);
- }
-
- @Override
- public void onClick(View v) {
- switch (v.getId()) {
-
- case R.id.button01:
- getPopupWindowInstance();
- mPopupWindow.showAsDropDown(v);
- break;
-
-
- case R.id.button02:
- getPopupWindowInstance();
- mPopupWindow.showAsDropDown(v, 50, 50);
- break;
-
-
- case R.id.button03:
- getPopupWindowInstance();
- mPopupWindow.showAtLocation(v, Gravity.CENTER, 0, 0);
- break;
-
-
- case R.id.button04:
- getPopupWindowInstance();
- mPopupWindow.showAtLocation(v, Gravity.BOTTOM, 0, 50);
- break;
-
- default:
- break;
- }
- }
-
- @Override
- public void onCheckedChanged(RadioGroup group, int checkedId) {
- mPopupWindow.dismiss();
- }
-
-
- private void getPopupWindowInstance() {
- if (null != mPopupWindow) {
- mPopupWindow.dismiss();
- return;
- } else {
- initPopuptWindow();
- }
- }
-
-
- private void initPopuptWindow() {
- LayoutInflater layoutInflater = LayoutInflater.from(this);
- View popupWindow = layoutInflater.inflate(R.layout.popup_window, null);
- RadioGroup radioGroup = (RadioGroup) popupWindow.findViewById(R.id.radioGroup);
- radioGroup.setOnCheckedChangeListener(this);
-
-
-
-
-
- mPopupWindow = new PopupWindow(popupWindow, 100, 130);
-
-
- mScreenWidth = getWindowManager().getDefaultDisplay().getWidth();
- mScreenWidth = getWindowManager().getDefaultDisplay().getHeight();
- mPopupWindowWidth = mPopupWindow.getWidth();
- mPopupWindowHeight = mPopupWindow.getHeight();
- }
- }