一、PopupWindow的简介

java.lang.Object
↳
    android.widget.PopupWindow

PopupWindow：弹出框。在activity上需要的地方显示该控件。

二、自定义PopupWindow的使用

1、自定义PopupWindow的布局

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="match_parent"
              android:orientation="vertical">

    <TextView
        android:id="@+id/tv_take_video"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="视频"/>

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="@color/colorAccent"/>

    <View
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:background="@color/colorAccent"/>

    <TextView
        android:id="@+id/tv_cancel"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="取消"/>

    <TextView
        android:id="@+id/tv_take_picture"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:text="照片"
        />


</LinearLayout>

可以用ListView、RecyclerView，需要多写一个Item布局

2、自定义PopupWindow继承于PopupWindow

package com.example.administrator.popwindow;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.widget.PopupWindow;
import android.widget.TextView;

/**
 * creat by Ann
 * creat on ${DATA}
 * description
 */
public class ChooseFilePopupwindow extends PopupWindow implements View.OnClickListener {

    /** 上下文 */
    private Activity mActivity;
    /** 根布局 */
    private View mRootView;
    private TextView mTvTakePicture;
    private TextView mTvTakeVideo;
    private TextView mTvCancel;

    private ChooseFilePopViewClickListener mChooseFilePopViewClickListener;

    public ChooseFilePopupwindow(Activity activity) {
        this.mActivity = activity;
        initConfig(ViewGroup.LayoutParams.MATCH_PARENT,ViewGroup.LayoutParams.WRAP_CONTENT);
        initView();
    }

    public ChooseFilePopupwindow(Activity activity, int width, int height) {
        this.mActivity = activity;
        initConfig(width, height);
        initView();
    }

    @SuppressLint("NewApi")
    private void initConfig(int width, int height) {
        this.setWidth(width);
        this.setHeight(height);
        this.setFocusable(true);
        this.setTouchable(true);
        this.setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
        this.setOutsideTouchable(true);
        this.setElevation(25f);
        mActivity.getWindow().addFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND);//达到背景全部变暗的效果
//        mActivity.getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_ADJUST_RESIZE |
//                WindowManager.LayoutParams.SOFT_INPUT_STATE_HIDDEN);
//        this.setAnimationStyle(R.style.BottomPopuAnim);
        this.setOnDismissListener(new OnDismissListener() {

            @Override
            public void onDismiss() {
                WindowManager.LayoutParams params = mActivity.getWindow().getAttributes();
                mActivity.getWindow().setDimAmount(0f);
                params.alpha = 1.0f;
                mActivity.getWindow().setAttributes(params);
            }
        });
    }

    private void initView() {
        mRootView = LayoutInflater.from(mActivity).inflate(R.layout.popupwindow_choose_file, null, false);
        mTvCancel = mRootView.findViewById(R.id.tv_cancel);
        mTvTakePicture = mRootView.findViewById(R.id.tv_take_picture);
        mTvTakeVideo = mRootView.findViewById(R.id.tv_take_video);
        mTvCancel.setOnClickListener(this);
        mTvTakePicture.setOnClickListener(this);
        mTvTakeVideo.setOnClickListener(this);
        setContentView(mRootView);
    }

    /**
     * 显示
     * @param parent 关联父布局
     */
    public void show(View parent) {
        WindowManager.LayoutParams params = mActivity.getWindow().getAttributes();
        params.alpha = 0.7f;
        mActivity.getWindow().setDimAmount(0.7f);
        mActivity.getWindow().setAttributes(params);
        this.showAtLocation(parent, Gravity.BOTTOM, 0, 0);
    }


    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.tv_take_picture:
                dismiss();
                if(mChooseFilePopViewClickListener != null){
                    mChooseFilePopViewClickListener.takePicture();
                }
                break;
            case R.id.tv_take_video:
                dismiss();
                if(mChooseFilePopViewClickListener != null){
                    mChooseFilePopViewClickListener.takeVideo();
                }
                break;
            case R.id.tv_cancel:
                dismiss();
                break;
        }
    }

    public void setChooseFilePopViewClickListener(ChooseFilePopViewClickListener mChooseFilePopViewClickListener) {
        this.mChooseFilePopViewClickListener = mChooseFilePopViewClickListener;
    }

    public interface ChooseFilePopViewClickListener{
        public void takePicture();
        public void takeVideo();
    }
}

3、在activity中显示PopupWindow(可以自行选择，不适用回调方法)

package com.example.administrator.popwindow;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;

public class MainActivity extends AppCompatActivity {
    Button button;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        button = findViewById(R.id.btn_pop);
        button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                ChooseFilePopupwindow popwindow = new ChooseFilePopupwindow(MainActivity.this);
                popwindow.show(button);
                popwindow.setChooseFilePopViewClickListener(new ChooseFilePopupwindow.ChooseFilePopViewClickListener() {
                    @Override
                    public void takePicture() {
                        Toast.makeText(MainActivity.this,"点击了拍照",Toast.LENGTH_LONG).show();
                    }

                    @Override
                    public void takeVideo() {
                        Toast.makeText(MainActivity.this,"点击了摄像",Toast.LENGTH_LONG).show();
                    }
                });
            }
        });
    }
}

总结：想好popupwindow样式进行布局---->自定义popupwindow继承于popupwindow，做好逻辑的处理（初始化，位置，大小，背景是否变暗，popupwindow的Item点击事件。）------>在activity中创建并显示。