Android开发实验三

@author 赖昌平

AndroidUI组件

一、实验环境:

Android Studio + Android 5.0

二、实验内容

1.Android ListView的用法

代码

MainActivity.java

package com.lab.labs;import androidx.appcompat.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.AdapterView;import android.widget.ListView;import android.widget.SimpleAdapter;import android.widget.Toast;import java.util.ArrayList;import java.util.HashMap;import java.util.List;import java.util.Map;public class MainActivity extends AppCompatActivity {private String[] names = new String[]{\"Lion\",\"Tiger\",\"Monkey\",\"Dog\",\"Cat\",\"Elephant\"};private int[] imgIds = new int[]{R.drawable.lion,R.drawable.tiger,R.drawable.monkey,R.drawable.dog,R.drawable.cat,R.drawable.elephant};@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);List<Map<String,Object>> lists = new ArrayList<>();for (int i = 0;i < names.length;i++){Map<String,Object> list = new HashMap<>();list.put(\"images\",imgIds[i]);list.put(\"names\",names[i]);lists.add(list);}ListView listView = findViewById(R.id.list_view01);SimpleAdapter simpleAdapter = new SimpleAdapter(MainActivity.this,lists, R.layout.simple_adapter,new String[] {\"names\",\"images\"},new int[] {R.id.names,R.id.images});listView.setAdapter(simpleAdapter);listView.setOnItemClickListener(new AdapterView.OnItemClickListener(){@Overridepublic void onItemClick(AdapterView<?> parent, View view, int position, long id) {Toast toast = Toast.makeText(MainActivity.this,names[position],Toast.LENGTH_SHORT);toast.show();}});}}

simple_adapter.xml:

<?xml version=\"1.0\" encoding=\"utf-8\"?><androidx.constraintlayout.widget.ConstraintLayout xmlns:android=\"http://schemas.android.com/apk/res/android\"xmlns:app=\"http://schemas.android.com/apk/res-auto\"android:layout_width=\"match_parent\"android:layout_height=\"match_parent\"android:orientation=\"vertical\"><TextViewandroid:id=\"@+id/names\"android:layout_width=\"match_parent\"android:layout_height=\"match_parent\"android:textSize=\"50dp\"/><ImageViewandroid:id=\"@+id/images\"android:layout_width=\"70dp\"android:layout_height=\"70dp\"app:layout_constraintLeft_toRightOf=\"@id/names\"app:layout_constraintRight_toRightOf=\"parent\"app:layout_constraintTop_toTopOf=\"parent\"app:layout_constraintHorizontal_bias=\"1.0\"/></androidx.constraintlayout.widget.ConstraintLayout>

activity_main.xml

<?xml version=\"1.0\" encoding=\"utf-8\"?><androidx.constraintlayout.widget.ConstraintLayout xmlns:android=\"http://schemas.android.com/apk/res/android\"xmlns:tools=\"http://schemas.android.com/tools\"android:layout_width=\"match_parent\"android:layout_height=\"match_parent\"tools:context=\".MainActivity\"android:orientation=\"vertical\"><ListViewandroid:id=\"@+id/list_view01\"android:layout_height=\"wrap_content\"android:layout_width=\"match_parent\"tools:ignore=\"MissingConstraints\" /></androidx.constraintlayout.widget.ConstraintLayout>

效果图

2.创建自定义布局的AlertDialog

代码

Main2Activity.java

package com.lab.labs;import android.app.Dialog;import android.content.Context;import android.graphics.Point;import android.os.Bundle;import android.view.Display;import android.view.WindowManager;import androidx.annotation.NonNull;import androidx.appcompat.app.AppCompatActivity;public class Main2Activity extends AppCompatActivity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);AlertDialog alertDialog = new AlertDialog(Main2Activity.this);alertDialog.show();}}class AlertDialog extends Dialog {public AlertDialog(@NonNull Context context) {super(context);}@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main2);WindowManager windowManager = getWindow().getWindowManager();Display display = windowManager.getDefaultDisplay();WindowManager.LayoutParams p = getWindow().getAttributes();Point size = new Point();display.getSize(size);p.width = size.x;getWindow().setAttributes(p);}}

activity_main2.xml

<?xml version=\"1.0\" encoding=\"utf-8\"?><androidx.constraintlayout.widget.ConstraintLayout xmlns:android=\"http://schemas.android.com/apk/res/android\"android:layout_width=\"match_parent\"android:layout_height=\"match_parent\"xmlns:app=\"http://schemas.android.com/apk/res-auto\"><TextViewandroid:id=\"@+id/title\"android:layout_width=\"match_parent\"android:layout_height=\"wrap_content\"android:text=\"ANDROID APP\"android:textSize=\"40dp\"android:gravity=\"center\"android:padding=\"10dp\"android:textColor=\"@android:color/white\"android:background=\"@android:color/holo_orange_light\"app:layout_constraintTop_toTopOf=\"parent\"/><EditTextandroid:id=\"@+id/userName\"android:layout_width=\"match_parent\"android:layout_height=\"wrap_content\"android:hint=\" Username\"app:layout_constraintTop_toBottomOf=\"@id/title\"android:textSize=\"25dp\"/><EditTextandroid:id=\"@+id/password\"android:layout_width=\"match_parent\"android:layout_height=\"wrap_content\"android:hint=\" Password\"android:textSize=\"25dp\"android:inputType=\"textPassword\"app:layout_constraintTop_toBottomOf=\"@id/userName\" /><Buttonandroid:id=\"@+id/cancel_button\"android:layout_width=\"0dp\"android:layout_height=\"wrap_content\"android:text=\"取消\"android:textColor=\"#333333\"android:textSize=\"25dp\"android:background=\"@android:color/white\"app:layout_constraintLeft_toLeftOf=\"parent\"app:layout_constraintRight_toLeftOf=\"@id/confirm_button\"app:layout_constraintTop_toBottomOf=\"@id/password\" /><Buttonandroid:id=\"@+id/confirm_button\"android:layout_width=\"0dp\"android:layout_height=\"wrap_content\"android:text=\"登录\"android:textColor=\"#333333\"android:textSize=\"25dp\"android:background=\"@android:color/white\"app:layout_constraintTop_toBottomOf=\"@id/password\"app:layout_constraintLeft_toRightOf=\"@id/cancel_button\"app:layout_constraintRight_toRightOf=\"parent\"/></androidx.constraintlayout.widget.ConstraintLayout>

效果图

3.使用XML定义菜单

代码

Main3Activity.java

package com.lab.labs;import androidx.appcompat.app.AppCompatActivity;import android.graphics.Color;import android.os.Bundle;import android.view.Menu;import android.view.MenuInflater;import android.view.MenuItem;import android.widget.TextView;import android.widget.Toast;public class Main3Activity extends AppCompatActivity {private TextView test;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main3);test = findViewById(R.id.test);registerForContextMenu(test);}@Overridepublic boolean onCreateOptionsMenu(Menu menu) {MenuInflater menuinflater = getMenuInflater();menuinflater.inflate(R.menu.menu, menu);return true;}@Overridepublic boolean onOptionsItemSelected(MenuItem item) {switch (item.getItemId()) {case R.id.menu_size_1:test.setTextSize(11);return true;case R.id.menu_size_2:test.setTextSize(16);return true;case R.id.menu_size_3:test.setTextSize(21);return true;case R.id.menu_common:Toast.makeText(Main3Activity.this,\"这是普通菜单项\",Toast.LENGTH_SHORT).show();return true;case R.id.menu_color_red:test.setTextColor(Color.RED);return true;case R.id.menu_color_yellow:test.setTextColor(Color.YELLOW);return true;default:return super.onOptionsItemSelected(item);}}}

activity_main3.xml(主页面)

<?xml version=\"1.0\" encoding=\"utf-8\"?><androidx.constraintlayout.widget.ConstraintLayout xmlns:android=\"http://schemas.android.com/apk/res/android\"xmlns:tools=\"http://schemas.android.com/tools\"android:layout_width=\"match_parent\"android:layout_height=\"match_parent\"tools:context=\".Main3Activity\"><TextViewandroid:id=\"@+id/test\"android:layout_width=\"0dp\"android:layout_height=\"wrap_content\"android:text=\"用于测试的内容\"android:textSize=\"16dp\"tools:ignore=\"MissingConstraints\" /></androidx.constraintlayout.widget.ConstraintLayout>

menu.xml

<?xml version=\"1.0\" encoding=\"utf-8\"?><menu xmlns:android=\"http://schemas.android.com/apk/res/android\"><itemandroid:id=\"@+id/menu_size\"android:title=\"字体大小\"><menu xmlns:android=\"http://schemas.android.com/apk/res/android\"><itemandroid:id=\"@+id/menu_size_1\"android:title=\"小\" /><itemandroid:id=\"@+id/menu_size_2\"android:title=\"中\" /><itemandroid:id=\"@+id/menu_size_3\"android:title=\"大\" /></menu></item><itemandroid:id=\"@+id/menu_common\"android:title=\"普通菜单项\" /><itemandroid:id=\"@+id/menu_color\"android:title=\"字体颜色\"><menu xmlns:android=\"http://schemas.android.com/apk/res/android\"><itemandroid:id=\"@+id/menu_color_red\"android:title=\"红色\" /><itemandroid:id=\"@+id/menu_color_yellow\"android:title=\"黄色\" /></menu></item></menu>