第五、六周作业

1.返回键实现对话框弹出是否退出应用程序

 1 package com.example.myapplication5and6;
 2 
 3 import androidx.appcompat.app.AlertDialog;
 4 import androidx.appcompat.app.AppCompatActivity;
 5 
 6 import android.content.DialogInterface;
 7 import android.os.Bundle;
 8 
 9 public class MainActivity extends AppCompatActivity {
10 
11     @Override
12     protected void onCreate(Bundle savedInstanceState) {
13         super.onCreate(savedInstanceState);
14         setContentView(R.layout.activity_main);
15     }
16     public void onBackPressed(){
17         final AlertDialog dialog;
18         AlertDialog.Builder builder=new AlertDialog.Builder(this)
19                 .setTitle("普通对话框")
20                 .setIcon(R.mipmap.ic_launcher)
21                 .setMessage("是否退出应用：")
22                 .setPositiveButton("确定", new DialogInterface.OnClickListener() {
23                     @Override
24                     public void onClick(DialogInterface dialog, int i) {
25                         dialog.dismiss();
26                         MainActivity.this.finish();
27                     }
28                 })
29                 .setNegativeButton("取消", new DialogInterface.OnClickListener() {
30                     @Override
31                     public void onClick(DialogInterface dialog, int i) {
32                         dialog.dismiss();
33                     }
34                 });
35         dialog=builder.create();
36         dialog.show();
37     }
38 }

 

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）

activity_main.xml

 1 <?xml version="1.0" encoding="utf-8"?>
 2 
 3 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 4     android:layout_width="match_parent"
 5     android:layout_height="match_parent"
 6     android:orientation="vertical">
 7     <Button
 8         android:id="@+id/btn"
 9         android:layout_width="wrap_content"
10         android:layout_height="wrap_content"
11         android:text="请选择您的性别"
12         android:onClick="onClick"
13         android:layout_gravity="center"/>
14 
15 </LinearLayout>

 

 1 package com.example.myapplication5and62;
 2 
 3 import androidx.appcompat.app.AlertDialog;
 4 import androidx.appcompat.app.AppCompatActivity;
 5 
 6 import android.content.DialogInterface;
 7 import android.os.Bundle;
 8 import android.view.View;
 9 import android.widget.Button;
10 import android.widget.Toast;
11 
12 public class MainActivity extends AppCompatActivity {
13     private Button button;
14 
15     @Override
16     protected void onCreate(Bundle savedInstanceState) {
17         super.onCreate(savedInstanceState);
18         setContentView(R.layout.activity_main);
19 
20     }
21     public void onClick(View v) {
22         AlertDialog dialog;
23         AlertDialog.Builder builder=new AlertDialog.Builder(this);
24                 builder.setTitle("请选择您的性别");
25                 builder.setIcon(R.mipmap.ic_launcher);
26                 final String[] sexs = new String[]{"男","女"};
27                 builder.setSingleChoiceItems(sexs, -1, new DialogInterface.OnClickListener() {
28                     @Override
29                     public void onClick(DialogInterface dialog, int i) {
30                         Toast.makeText(MainActivity.this, "您选择了: " + sexs[i], Toast.LENGTH_SHORT).show();
31                         dialog.dismiss();
32                     }
33                 });
34 
35         dialog=builder.create();
36         dialog.show();
37 
38 
39 
40     }
41 }

 

 

3.布局(详见:Android第五周上机word文档)

 

 1  <?xml version="1.0" encoding="utf-8"?>
 2 
 3 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 4     android:layout_height="match_parent"
 5     android:layout_width="match_parent"
 6     android:background="#000000"
 7     android:orientation="vertical">
 8     <TextView
 9         android:layout_width="wrap_content"
10         android:layout_height="wrap_content"
11         android:text="1.TextView显示文本信息"
12         android:textColor="#FD0101"
13         android:textSize="25dp"
14         android:layout_gravity="center"
15         android:layout_marginTop="20dp"
16         android:textStyle="italic"/>
17     <Button
18         android:layout_width="350dp"
19         android:layout_height="wrap_content"
20         android:text="2.按钮"
21         android:textColor="#FD0101"
22         android:layout_gravity="center"/>
23     <EditText
24         android:layout_width="350dp"
25         android:layout_height="wrap_content"
26         android:text="3.编辑框：请输入信息"
27         android:textColor="#FD0101"
28         android:layout_gravity="center"/>
29     <LinearLayout
30         android:layout_width="wrap_content"
31         android:layout_height="wrap_content">
32         <RadioButton
33             android:layout_width="wrap_content"
34             android:layout_height="wrap_content"
35             android:text="4.男"
36             android:textColor="#FD0101"
37             android:layout_marginLeft="25dp"/>
38         <RadioButton
39             android:layout_width="wrap_content"
40             android:layout_height="wrap_content"
41             android:text="5.女"
42             android:textColor="#FD0101" />
43     </LinearLayout>
44     <CheckBox
45         android:layout_width="wrap_content"
46         android:layout_height="wrap_content"
47         android:text="电脑"
48         android:textColor="#FD0101"
49         android:layout_marginLeft="25dp"/>
50     <CheckBox
51         android:layout_width="wrap_content"
52         android:layout_height="wrap_content"
53         android:text="手机"
54         android:textColor="#FD0101"
55         android:layout_marginLeft="25dp"/>

 

 

4.教材p76页 图3—17购物商城界面