1.返回键实现对话框弹出是否退出应用程序
package com.example.myapplication; import android.app.AlertDialog; import androidx.appcompat.app.AppCompatActivity; import android.content.DialogInterface; import android.os.Bundle; public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } @Override public void onBackPressed() { AlertDialog.Builder builder=new AlertDialog.Builder(this) .setTitle("普通对话框") .setMessage("是否退出至主菜单") // .setIcon(R.drawable.ic_launcher_background) .setPositiveButton("确定", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); MainActivity.this.finish(); } }) .setNegativeButton("取消", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int which) { dialog.dismiss(); } }); AlertDialog dialog=builder.create(); dialog.show(); }
2.实现以下场景：从一个activity中点击一个按钮后，弹出一个单选按钮对话框，上面有“男”“女”两个选项，选定后，TOAST弹出 你选择了男，或你选择了女（参考书上改字体）
package com.example.myapplication; import androidx.appcompat.app.AlertDialog; import androidx.appcompat.app.AppCompatActivity; import android.content.DialogInterface; import android.os.Bundle; import android.view.View; import android.widget.Toast; public class MainActivity extends AppCompatActivity implements View.OnClickListener { int x = 0; private String Arr[] = {"你选择了男","你选择了女"}; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); findViewById(R.id.bt).setOnClickListener(this); } @Override public void onClick(View v){ AlertDialog dialog; AlertDialog.Builder builder = new AlertDialog.Builder(this); builder.setTitle("性别"); builder.setSingleChoiceItems(new String[]{"男", "女"}, 0, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int i) { x = i; // Toast.makeText(MainActivity.this,Arr[i], Toast.LENGTH_SHORT).show(); } }); builder.setPositiveButton("确定", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int i) { // final String items[]={"男","女"}; Toast.makeText(MainActivity.this,Arr[x], Toast.LENGTH_SHORT).show(); dialog.dismiss(); } }); builder.setNegativeButton("取消", new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialog, int i) { dialog.dismiss(); } }); dialog = builder.create(); dialog.show(); }
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <!-- <TextView--> <!-- android:layout_width="wrap_content"--> <!-- android:layout_height="wrap_content"--> <!-- android:text="Hello World!"--> <!-- app:layout_constraintBottom_toBottomOf="parent"--> <!-- app:layout_constraintLeft_toLeftOf="parent"--> <!-- app:layout_constraintRight_toRightOf="parent"--> <!-- app:layout_constraintTop_toTopOf="parent" />--> <Button android:id="@+id/bt" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="请选择你的性别" android:layout_marginTop="20dp" android:layout_gravity="center"/> </LinearLayout>
3.布局(详见:Android第五周上机word文档)
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" android:background="#82CAEB"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="1.TextView显示文本信息" android:layout_gravity="center" android:layout_marginTop="20dp" android:textColor="#9C27B0"/> <Button android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_marginTop="10dp" android:layout_marginLeft="10dp" android:layout_marginRight="10dp" android:text="2.按钮" android:textColor="#9C27B0" android:background="#ffffff"/> <EditText android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="3.编辑框：请输入信息" android:textColorHint="#9C27B0" android:layout_margin="10dp"/> <RadioGroup android:layout_width="wrap_content" android:layout_height="wrap_content" android:orientation="horizontal"> <RadioButton android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="25dp" android:textColor="#9C27B0" android:text="4.男" android:layout_marginLeft="10dp"/> <RadioButton android:layout_width="wrap_content" android:layout_height="wrap_content" android:textSize="25dp" android:textColor="#9C27B0" android:text="女" android:layout_marginLeft="10dp"/> </RadioGroup> <CheckBox android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="电脑" android:textSize="20sp" android:textColor="#9C27B0" android:layout_margin="10dp"/> <CheckBox android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="手机" android:textSize="20sp" android:textColor="#9C27B0" android:layout_marginLeft="10dp"/> </LinearLayout>
4.教材p76页 图3—17购物商城界面
package com.example.myapplication; import androidx.appcompat.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.ImageView; import android.widget.ListView; import android.widget.TextView; public class MainActivity extends AppCompatActivity { private ListView mListView; private String [] titles={"桌子","苹果","蛋糕","线衣","猕猴桃","围巾"}; private String [] prices={"1800元","10元/kg","300元","350元","10元/kg","280元"}; private int [] icons={R.drawable.table,R.drawable.apple,R.drawable.cake,R.drawable.wireclothes,R.drawable.kiwifruit,R.drawable.scarf}; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mListView = (ListView) findViewById(R.id.lv); MyBaseAdapter myAdapter = new MyBaseAdapter(); mListView.setAdapter(myAdapter); } class MyBaseAdapter extends BaseAdapter{ @Override public int getCount() { return titles.length; } @Override public Object getItem(int position) { return titles[position]; } @Override public long getItemId(int position) { return position; } @Override public View getView(int i, View view, ViewGroup viewGroup) { View view1= View.inflate(MainActivity.this,R.layout.list_item,null); TextView title = (TextView)view1.findViewById(R.id.title); TextView price = (TextView)view1.findViewById(R.id.price); ImageView iv = (ImageView)view1.findViewById(R.id.iv); title.setText(titles[i]); price.setText(prices[i]); iv.setBackgroundResource(icons[i]); return view1; } } }
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity" android:orientation="vertical"> <TextView android:id="@+id/tv" android:layout_width="match_parent" android:layout_height="50dp" android:text="购物商城" android:textColor="#E8E3E9" android:background="#3F51B5" android:textSize="20sp" android:gravity="center"/> <ListView android:id="@+id/lv" android:layout_width="match_parent" android:layout_height="wrap_content"/> </LinearLayout>
本文章为转载内容，我们尊重原作者对文章享有的著作权。如有内容错误或侵权问题，欢迎原作者联系我们进行内容更正或删除文章。
