Android realizes drop down display of entry effect

In this article, we share the specific code of Android drop-down display items for your reference. The specific contents are as follows

Layout file

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:background="#000000"
tools:context="com.example.a2_.MainActivity">

<EditText
  android:id="@+id/et_input"
  android:layout_width="match_parent"
  android:layout_height="wrap_content"
  android:textColor="#fff"
  android:text=" Please enter content " />

<ImageButton
  android:padding="6dp"
  android:background="@null"
  android:layout_alignRight="@id/et_input"
  android:id="@+id/ib"
  android:src="@mipmap/down_arrow"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content" />
</RelativeLayout>

Entry layout file

<?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="wrap_content"
android:padding="5dp"
android:descendantFocusability="blocksDescendants"
android:orientation="horizontal">

<ImageView

  android:src="@mipmap/user"
  android:id="@+id/iv_user"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content" />

<TextView
  android:layout_weight="1"
  android:id="@+id/tv_data"
  android:text="100"
  android:textColor="#000000"
  android:gravity="center_horizontal"
  android:layout_width="0dp"
  android:layout_height="wrap_content" />

<ImageButton
  android:background="@null"
  android:src="@mipmap/delete"
  android:id="@+id/iv_delete"
  android:layout_width="wrap_content"
  android:layout_height="wrap_content" />

</LinearLayout>

Core code

package com.example.a2_;

import android.graphics.drawable.ColorDrawable;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.EditText;
import android.widget.ImageButton;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.PopupWindow;
import android.widget.TextView;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {

private EditText et_input;
private PopupWindow popupWindow;
private ListView lv_list;
private ArrayList<String> data;
private MyAdapter myAdapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);

  // Initialize control 
  et_input = (EditText) findViewById(R.id.et_input);
  ImageButton ib = (ImageButton) findViewById(R.id.ib);

  // Initialize a data source 
  initData();
  // Create 1 A listView
  lv_list = new ListView(this);
  // To listview Setting Background 
  lv_list.setBackgroundResource(R.mipmap.listview_background);
  // To listview Setting adapter 
  myAdapter = new MyAdapter();
  lv_list.setAdapter(myAdapter);
  // To listview Set entry click events 
  lv_list.setOnItemClickListener(new AdapterView.OnItemClickListener() {
    @Override
    public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
      // When clicked to 1 When the number of entries is , The content of this entry is displayed in the input box 
      et_input.setText(data.get(position));
      popupWindow.dismiss();
    }
  });

  // Set click events for buttons 
  ib.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
      // When the drop-down button is clicked , Show list options 
      showPopup();
    }
  });

}

// Initialization data 
private void initData() {
  // Create 1 Set of , Used to store data 
  data = new ArrayList<>();
  // Pass for Loop to create data 
  for (int i = 1;i<20;i++){
    data.add(100+i+"");
  }
}

// Show drop-down list entries 
private void showPopup() {
  // Create PopupWindow Object 
  popupWindow = new PopupWindow(lv_list,et_input.getWidth(),500,true);
  // In order to make list items hidden by clicking on areas other than list items, , Set for list entries 1 Background 
  popupWindow.setBackgroundDrawable(new ColorDrawable());
  // Make list entries appear   And specify under which list entry to display 
  popupWindow.showAsDropDown(et_input);
}

// Create 1 Adapters 
class MyAdapter extends BaseAdapter{

  @Override
  public int getCount() {
    return data.size();
  }

  @Override
  public String getItem(int position) {
    return data.get(position);
  }

  @Override
  public long getItemId(int position) {
    return position;
  }

  @Override
  public View getView(final int position, View convertView, ViewGroup parent) {
    // Judge convertView Whether it is empty or not 
    if (convertView==null){
      convertView = View.inflate(MainActivity.this,R.layout.lv_item,null);

    }
    // Find the control 
    TextView tv_data = (TextView) convertView.findViewById(R.id.tv_data);
    ImageView iv_delete = (ImageView) convertView.findViewById(R.id.iv_delete);

    // Set click events 
    iv_delete.setOnClickListener(new View.OnClickListener() {
      @Override
      public void onClick(View v) {
        // Delete the data in the collection 
        data.remove(position);
        // Refresh page 
        myAdapter.notifyDataSetChanged();
      }
    });
    // Get data 
    String data = getItem(position);
    // Setting data 
    tv_data.setText(data);
    return convertView;
  }
}

}