Android PopUpWindow使用详解

//一：
public PopupWindow (Context context)
//二：
public PopupWindow(View contentView)
//三：
public PopupWindow(View contentView, int width, int height)
//四：
public PopupWindow(View contentView, int width, int height, boolean focusable)

//相对某个控件的位置（正左下方），无偏移
showAsDropDown(View anchor)：
//相对某个控件的位置，有偏移;xoff表示x轴的偏移
showAsDropDown(View anchor, int xoff, int yoff)：
//正中央Gravity.CENTER，下方Gravity.BOTTOM等
showAtLocation(View parent, int gravity, int x, int y)：

<?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">


    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="20sp"
        android:textColor="#000"
        android:text="我是一个PopupWindow"
        />

</LinearLayout>

  //将xml文件转成view
        View view = LayoutInflater.from(MainActivity.this).inflate(R.layout.popupwindow,null);
        //创建popupWindow 
        PopupWindow popupWindow = new PopupWindow(MainActivity.this);
        //载入布局
        popupWindow.setContentView(view);
        //设置宽高
        popupWindow.setWidth(ViewGroup.LayoutParams.WRAP_CONTENT);
        popupWindow.setHeight(ViewGroup.LayoutParams.WRAP_CONTENT);

      //设置显示位置 正左下方无偏移

        popupWindow.showAsDropDown(mTvShow);

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.PopupWindow;
import android.widget.TextView;

public class MainActivity extends AppCompatActivity {


    TextView mTvShow;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mTvShow = findViewById(R.id.tvshow);
        mTvShow.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                myPopupWindow();
            }
        });
    }




    private  void myPopupWindow(){
        //将xml文件转成view
        View view = LayoutInflater.from(MainActivity.this).inflate(R.layout.popupwindow,null);
        PopupWindow popupWindow = new PopupWindow(MainActivity.this);
        popupWindow.setContentView(view);
        popupWindow.setWidth(ViewGroup.LayoutParams.WRAP_CONTENT);
        popupWindow.setHeight(ViewGroup.LayoutParams.WRAP_CONTENT);

        //PopupWindow popupWindow = new PopupWindow(MainActivity.this,ViewGroup.LayoutParams.WRAP_CONTENT,ViewGroup.LayoutParams.WRAP_CONTENT,true);


        //进行正常页面设置




        //设置显示位置 正左下方无偏移

        popupWindow.showAsDropDown(mTvShow);

        //popupwindow 点击外围页面 不会自动消失 因此需要手动设置一个关闭
        view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                popupWindow.dismiss();
            }
        });


    }
}